Author name code: ireland
ADS astronomy entries on 2022-09-14
author:"Ireland, Jack" NOT =author:"Ireland, J.G."
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Title: Information architecture at the Solar Data Analysis Center
Authors: Ireland, Jack
Bibcode: 2022cosp...44.3486I
Altcode:
Understanding the physics of the Sun and solar phenomena is of central
importance to understanding space weather. This dovetails with the
mission of the Solar Data Analysis Center (SDAC), which is to support
the scientific study of the Sun. As the solar physics community embraces
new computational capabilities, new analysis tools and new workflows,
the nature of the information architecture support from the SDAC is
changing in response, consistent with its mission. In this presentation
I will discuss some recent new initiatives that support and follow where
the solar and broader heliophysics community is leading. This includes
testbed data analysis environments in commercial cloud providers,
experiments in using CPU/GPU computing clusters for data analysis,
support for improved data products, data citation, and data search
and download. I will also briefly introduce the Heliophysics Digital
Resource Library (HDRL), an umbrella organization that is co-ordinating
information architecture development efforts between the SDAC, the
Space Physics Data Facility, and the Heliophysics Data and Modeling
Consortium, and works in tandem with the Community Coordinated Modeling
Center.
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Stansby, David; Shih, Albert Y.; Hughitt,
V. Keith; Ryan, Daniel F.; Liedtke, Simon; Pérez-Suárez, David;
Vishnunarayan K, I.; Hayes, Laura; Chakraborty, Pritish; Inglis,
Andrew; Pattnaik, Punyaslok; Sipőcz, Brigitta; Sharma, Rishabh;
Leonard, Andrew; Hewett, Russell; Barnes, Will; Hamilton, Alex; Manhas,
Abhijeet; Panda, Asish; Earnshaw, Matt; Choudhary, Nitin; Kumar, Ankit;
Singh, Raahul; Chanda, Prateek; Akramul Haque, Md; Kirk, Michael S;
Mueller, Michael; Konge, Sudarshan; Srivastava, Rajul; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Maloney, Shane;
Charlton, Michael; Mishra, Sashank; Paul, Jeffrey Aaron; MacBride,
Conor; Chorley, Nicky; Himanshu; Chouhan, Aryan; Modi, Sanskar;
Sharma, Yash; Mason, James Paul; Naman9639; Zivadinovic, Lazar; Bobra,
Monica G.; Campos Rozo, Jose Ivan; Manley, Larry; Ivashkiv, Kateryna;
Chatterjee, Agneet; Von Forstner, Johan Freiherr; Bazán, Juanjo;
Akira Stern, Kris; Evans, John; Jain, Sarthak; Malocha, Michael;
Ghosh, Sourav; Stańczak, Dominik; SophieLemos; Ranjan Singh, Rajiv;
De Visscher, Ruben; Verma, Shresth; Airmansmith97; Buddhika, Dumindu;
Sharma, Swapnil; Pathak, Himanshu; Rideout, Jai Ram; Agrawal, Ankit;
Alam, Arib; Bates, Matt; Park, Jongyeob; Shukla, Devansh; Mishra,
Pankaj; Dubey, Sanjeev; Taylor, Garrison; Dacie, Sally; Jacob; Goel,
Dhruv; Sharma, Deepankar; Inchaurrandieta, Mateo; Cetusic, Goran;
Reiter, Guntbert; Zahniy, Serge; Sidhu, Sudeep; Bray, Erik M.;
Meszaros, Tomas; Eigenbrot, Arthur; Surve, Rutuja; Parkhi, Utkarsh;
Robitaille, Thomas; Pandey, Abhishek; Price-Whelan, Adrian; J, Amogh;
Chicrala, André; Ankit; Guennou, Chloé; D'Avella, Daniel; Williams,
Daniel; Verma, Dipanshu; Ballew, Jordan; Murphy, Nick; Lodha, Priyank;
Bose, Abhigyan; Augspurger, Tom; Krishan, Yash; Honey; Neerajkulk;
Altunian, Noah; Ranjan, Kritika; Bhope, Adwait; Molina, Carlos;
Gomillion, Reid; Kothari, Yash; Streicher, Ole; Wiedemann, Bernhard
M.; Mampaey, Benjamin; Nomiya, Yukie; Mridulpandey; Habib, Ishtyaq;
Letts, Joseph; Agarwal, Samriddhi; Singh Gaba, Amarjit; Hill, Andrew;
Keşkek, Duygu; Kumar, Gulshan; Verstringe, Freek; Mackenzie Dover,
Fionnlagh; Tollerud, Erik; Arias, Emmanuel; Srikanth, Shashank; Jain,
Shubham; Stone, Brandon; Kustov, Arseniy; Smith, Arfon; Sinha, Anubhav;
Kannojia, Swapnil; Mehrotra, Ambar; Yadav, Tannmay; Paul, Tathagata;
Wilkinson, Tessa D.; Caswell, Thomas A; Braccia, Thomas; Pereira, Tiago
M. D.; Gates, Tim; Yasintoda; Kien Dang, Trung; Wilson, Alasdair;
Bankar, Varun; Bahuleyan, Abijith; B, Abijith; Platipo; Stevens,
Abigail L.; Gyenge, Norbert G; Schoentgen, Mickaël; Shahdadpuri,
Nakul; Dedhia, Megh; Mendero, Matthew; Cheung, Mark; Agrawal, Yudhik;
Mangaonkar, Manas; Lyes, MOULOUDI Mohamed; Resakra; Ghosh, Koustav;
Hiware, Kaustubh; Chaudhari, Kaustubh; Reddy Mekala, Rajasekhar;
Krishna, Kalpesh; Buitrago-Casas, Juan Camilo; Das, Ratul; Mishra,
Rishabh; Sharma, Rohan; Wimbish, Jaylen; Calixto, James; Babuschkin,
Igor; Mathur, Harsh; Murray, Sophie A.; Nakul-Shahdadpuri
Bibcode: 2022zndo....591887M
Altcode: 2021zndo....591887M
The community-developed, free and open-source solar data analysis
environment for Python.
Title: heliopython/heliopy: HelioPy 1.0.0
Authors: Stansby, David; Rai, Yatharth; Argall, Matthew; JeffreyBroll;
Haythornthwaite, Richard; Teunissen, Jannis; Shaw, Siddhant; Xypnox;
Saha, Ritwik; Ireland, Jack; Lim, P. L.; Badman, Samuel; Mishra,
Sashank; Badger, The Gitter; DupuisIRT; Tlml
Bibcode: 2022zndo...1009079S
Altcode: 2019zndo...1009079S
HelioPy is now end-of-life.
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Stansby, David; Shih, Albert Y.; Hughitt,
V. Keith; Ryan, Daniel F.; Liedtke, Simon; Pérez-Suárez, David;
Vishnunarayan K, I.; Hayes, Laura; Chakraborty, Pritish; Inglis,
Andrew; Pattnaik, Punyaslok; Sipőcz, Brigitta; Sharma, Rishabh;
Leonard, Andrew; Hewett, Russell; Hamilton, Alex; Manhas, Abhijeet;
Panda, Asish; Earnshaw, Matt; Barnes, Will; Choudhary, Nitin; Kumar,
Ankit; Singh, Raahul; Chanda, Prateek; Akramul Haque, Md; Kirk, Michael
S; Konge, Sudarshan; Mueller, Michael; Srivastava, Rajul; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Maloney, Shane;
Charlton, Michael; Mishra, Sashank; Chorley, Nicky; Himanshu; Chouhan,
Aryan; Modi, Sanskar; Mason, James Paul; Sharma, Yash; Naman9639;
Zivadinovic, Lazar; Campos Rozo, Jose Ivan; Bobra, Monica G.; Manley,
Larry; Paul, Jeffrey Aaron; Ivashkiv, Kateryna; Chatterjee, Agneet;
Akira Stern, Kris; Von Forstner, Johan Freiherr; Bazán, Juanjo; Jain,
Sarthak; Evans, John; Ghosh, Sourav; Malocha, Michael; Stańczak,
Dominik; SophieLemos; Verma, Shresth; De Visscher, Ruben; Ranjan Singh,
Rajiv; Airmansmith97; Buddhika, Dumindu; Pathak, Himanshu; Alam, Arib;
Agrawal, Ankit; Sharma, Swapnil; Rideout, Jai Ram; Bates, Matt; Park,
Jongyeob; Mishra, Pankaj; Goel, Dhruv; Sharma, Deepankar; Taylor,
Garrison; Cetusic, Goran; Reiter, Guntbert; Jacob; Inchaurrandieta,
Mateo; Dacie, Sally; Dubey, Sanjeev; Parkhi, Utkarsh; Sidhu, Sudeep;
Surve, Rutuja; Eigenbrot, Arthur; Meszaros, Tomas; Bray, Erik M.;
Zahniy, Serge; Guennou, Chloé; Bose, Abhigyan; Ankit; Chicrala,
André; J, Amogh; D'Avella, Daniel; Ballew, Jordan; Price-Whelan,
Adrian; Robitaille, Thomas; Augspurger, Tom; Murphy, Nick; Lodha,
Priyank; Krishan, Yash; Pandey, Abhishek; Honey; Verma, Dipanshu;
Neerajkulk; Williams, Daniel; Wiedemann, Bernhard M.; Kothari, Yash;
Mridulpandey; Habib, Ishtyaq; Molina, Carlos; Mampaey, Benjamin;
Streicher, Ole; Nomiya, Yukie; Gomillion, Reid; Letts, Joseph; Bhope,
Adwait; Hill, Andrew; Keşkek, Duygu; Ranjan, Kritika; Pereira,
Tiago M. D.; Kien Dang, Trung; Bankar, Varun; Bahuleyan, Abijith; B,
Abijith; Stevens, Abigail L.; Agrawal, Yudhik; Nakul-Shahdadpuri;
Ghosh, Koustav; Hiware, Kaustubh; Yasintoda; Krishna, Kalpesh;
Lyes, MOULOUDI Mohamed; Mangaonkar, Manas; Cheung, Mark; Platipo;
Buitrago-Casas, Juan Camilo; Mendero, Matthew; Dedhia, Megh; Wimbish,
Jaylen; Calixto, James; Babuschkin, Igor; Schoentgen, Mickaël; Mathur,
Harsh; Kumar, Gulshan; Verstringe, Freek; Mackenzie Dover, Fionnlagh;
Tollerud, Erik; Gyenge, Norbert G; Arias, Emmanuel; Reddy Mekala,
Rajasekhar; MacBride, Conor; Das, Ratul; Mishra, Rishabh; Stone,
Brandon; Resakra; Agarwal, Samriddhi; Chaudhari, Kaustubh; Kustov,
Arseniy; Smith, Arfon; Srikanth, Shashank; Jain, Shubham; Mehrotra,
Ambar; Singh Gaba, Amarjit; Kannojia, Swapnil; Yadav, Tannmay; Paul,
Tathagata; Wilkinson, Tessa D.; Caswell, Thomas A; Murray, Sophie A.
Bibcode: 2021zndo...5751998M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: Facilitating Heliophysics Data Discovery with Cloud
Collaboration: Development for the HSO Connect Program
Authors: Alshatnawi, Amr; Thompson, Barbara; Ireland, Jack; Roberts,
D. Aaron; Damas, M. Chantale
Bibcode: 2021AGUFMSA15B1930A
Altcode:
The HSO (Heliophysics System Observatory) Connect programs goal is to
link the Heliophysics community together, and establish a connection for
collaboration and data sharing. It is often difficult for researchers to
share data and also find new resources, which leads many of them to use
a specific data set or resource for most of their research. Since there
are numerous data sources, developing an environment for data sharing
is very beneficial as it will allow scientists to reach different data
more easily and efficiently. The focus of this project was to develop
and test different cloud collaboration environments. To achieve this
the NASA Amazon Web Services cloud was used by the HelioAnalytics
team for collaboration on code development. This cloud allowed the
development of the Heliophysics JupyterHub, which was used to create
Jupyter notebooks that researched multiple instances of data and model
products from different missions. JupyterHub also allows users to
configure their environment, so they can access and request different
data. In order to share these notebooks and data, a GitHub site was
created for the HSO Connect project. The objective of the GitHub site
is to facilitate data resources and code sharing. This site will also
contain different data models, tools, and services that will support
the goal of the program. Developing and using these different cloud
collaboration tools will provide a more efficient and simple way to
access and share data, it will also improve code development as it will
allow participants to share along with work on each others code. The
outcome achieved from using these cloud collaboration tools will help
connect observations from HSO missions with other observations from
different Science Mission Directorate missions.
Title: Report on a Workshop to Understand Heliophysics Research
Infrastructure
Authors: Thomas, Brian; Candey, Robert; Fung, Shing; Ireland, Jack;
Jian, Lan; Kirk, Michael; Kuznetsova, Maria; McGranaghan, Ryan;
Roberts, D. Aaron; Thompson, Barbara
Bibcode: 2021AGUFMSH44C..01T
Altcode:
We report observations and findings from a three-day virtual workshop
on heliophysics research infrastructure. The workshop, held on May
17-19, 2021, was organized by the NASA Goddard Space Flight Center
to examine the current NASA heliophysics research infrastructure
and determine which elements were most utilized, what gaps exist in
these elements between current utility and desired capability and,
from a user standpoint, what a future state for the infrastructure
might look like. Approximately 40 subject matter experts (SMEs)
with backgrounds in heliophysics research, computer science and
research infrastructure were gathered to consider these topics. Key
gaps identified include enhancements to science data products,
improved support for collaboration and open science, and a need for
more sophisticated information discovery. We will discuss these gaps
and how they connect to the participants imagined future state which
emphasizes a faster ability to get to the good stuff by improved
service delivery and infrastructure support.
Title: Evaluating pointing strategies for future solar flare missions
Authors: Inglis, Andrew; Ireland, Jack; Shih, Albert; Christe, Steven
Bibcode: 2021AGUFMSH25E2118I
Altcode:
Solar flares are events of intense scientific interest. Missions whose
science objectives depend on observing solar flares must often make
difficult decisions on where to target their observations if they do
not observe the full solar disk. Therefore, we simulate and analyze
the performance of different observation strategies using historical
flare and active region data from 2011 to 2014. We test a number of
different target selection strategies based on active region complexity
and recent flare activity, each of which is examined under a range of
operational assumptions. The mission responsiveness to new information
is investigated as a key factor determining flare observation
performance, while the instrument field-of-view is also explored. We
study various metrics such as the number of flares observed, the size of
flares observed, and operational considerations such as the number of
mission re-points that are required, and the distribution of pointing
locations on the Sun. Overall, a future low-earth orbit flare mission
is anticipated to observe between 35 - 47% of large flares that occur,
while a mission with an uninterrupted view of the Sun could observe
between 48 - 62% of large flares. Target selection methods based
on recent flare activity showed the best overall performance, but
required more repointings than other methods. It is also shown that
target selection methods based on active region complexities show a
significant pointing bias towards the western solar hemisphere. These
results provide valuable performance estimates for a future mission
focused on solar flares, and inform the requirements that would ensure
mission success.
Title: Adding RESTful web services to the Virtual Solar Observatory:
How to write Data Providers in Python
Authors: Mansky, Edmund; Oien, Niles; Davey, Alisdair; Spencer,
Jennifer; Ireland, Jack
Bibcode: 2021AGUFMSH55A1819M
Altcode:
The Virtual Solar Observatory (VSO) is expanding the methods by which
it can query and support new data providers. In particular we describe
how we are are adding support for RESTful web services to the VSO
codebase. The ability to query Data Providers as RESTful web services
generalizes the VSO so both SOAP and REST data transfer mechanisms are
supported. We detail the requirements needed to add queries to remote
RESTful services from a multi-threaded Perl application. Examples of
RESTful Data Providers written in Python, using Flask, for GONG, Parker
Solar Probe WISPR and Solar Orbiter EUI data are illustrated. The next
major observatory that will be added to VSO is the Daniel K. Inouye
Solar Telescope (DKIST). We discuss the steps needed to integrate the
new DKIST Data Provider, written in Python. We also describe support
in the VSO for TAP queries to ESA data sources. We examine how we are
automatically validating our RESTful services, in both Perl and Python
and describe how we are creating unit tests in Python and load testing
using Locust to improve the quality of the VSO services. In summary,
all the steps needed to create new RESTful Data Providers in Python
are presented.
Title: New initiatives from the Solar Data Analysis Center
Authors: Ireland, Jack; Amezcua, Arthur; Davey, Alisdair; Inglis,
Andrew; Mansky, Edmund; Martens, Petrus; Oien, Niles; Spencer,
Jennifer; Yashiro, Seiji
Bibcode: 2021AGUFMSH55A1823I
Altcode:
We describe new initiatives undertaken by the Solar Data Analysis Center
(SDAC) to better support the solar physics community. The role of the
SDAC is to support the scientific analysis of solar physics data. The
SDAC has begun a new effort to catalog solar physics data resources from
around the web. The purpose of this effort is to more fully understand
the breadth of solar physics data that are available, to provide a
place where users from solar physics and other disciplines can search
a curated catalog of data resources, and to inform the development of
new SDAC capabilities that are aligned with NASA's Heliophysics Digital
Resource Library initiative. Resources that are in scope include solar
physics data from NASA (and non-NASA) supported missions and instruments
(both current and historical), rocket and balloon experiments, cubesats
and smallsats, and ground based instruments and facilities (for example,
eclipse observations). Also in scope are online resources that describe
solar features and events (for example, the HEK and the CDAW list
of CMEs), and solar physics related data products which are not the
primary data products of NASA solar physics missions/instruments:
for example, the Helioviewer JPEG2000 image files and machine learning
ready datasets fall in to this category. Another new initiative under
development is the regular testing of the command-line Virtual Solar
Observatory (VSO) clients. We are developing a VSO testing capability
that performs automated data searches using the same SunPy, Solarsoft
and VSO code that the solar physics community uses on a daily basis. The
purpose of this testing capability is to capture important diagnostic
information of the data search and download functionality of the VSO,
SunPy and Solarsoft. This information will be used to improve the VSO,
SunPy and Solarsoft. Finally, we describe some recent updates to the
capabilities of the VSO, including newly available datasets.
Title: Evaluating Pointing Strategies for Future Solar Flare Missions
Authors: Inglis, Andrew R.; Ireland, Jack; Shih, Albert Y.; Christe,
Steven D.
Bibcode: 2021SoPh..296..153I
Altcode: 2021arXiv211013208I
Solar flares are events of intense scientific interest. Although
certain solar conditions are known to be associated with flare
activity, the exact location and timing of an individual flare on
the Sun cannot as yet be predicted with certainty. Missions whose
science objectives depend on observing solar flares must often make
difficult decisions on where to target their observations if they do
not observe the full solar disk. Yet, there is little analysis in the
literature that might guide these mission operations to maximize their
opportunities to observe flares. In this study, we analyze and simulate
the performance of different observation strategies using historical
flare and active region data from 2011 to 2014. We test a number of
different target selection strategies based on active region complexity
and recent flare activity, each of which is examined under a range of
operational assumptions. In each case, we investigate various metrics
such as the number of flares observed, the size of flares observed,
and operational considerations such as the number of instrument
repoints required. Overall, target selection methods based on recent
flare activity showed the best overall performance but required more
repointings than other methods. The mission responsiveness to new
information is identified as another strong factor determining flare
observation performance. It is also shown that target selection methods
based on active region complexities show a significant pointing bias
toward the western solar hemisphere. As expected, the number of flares
observed grows quickly with field-of-view size until the approximate
size of an active region is reached, but further improvements beyond
the active region size are much more incremental. These results provide
valuable performance estimates for a future mission focused on solar
flares and inform the requirements that would ensure mission success.
Title: heliopython/heliopy: HelioPy 0.15.4
Authors: Stansby, David; Rai, Yatharth; Argall, Matthew; JeffreyBroll;
Haythornthwaite, Richard; Teunissen, Jannis; Shaw, Siddhant; Aditya;
Saha, Ritwik; Ireland, Jack; Lim, P. L.; Badman, Samuel; Mishra,
Sashank; Badger, The Gitter; DupuisIRT; Tlml
Bibcode: 2021zndo...5090511S
Altcode:
Python for heliospheric and planetary physics
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Stansby, David; Shih, Albert Y.; Hughitt,
V. Keith; Ryan, Daniel F.; Liedtke, Simon; Pérez-Suárez, David;
Vishnunarayan K, I.; Hayes, Laura; Chakraborty, Pritish; Inglis,
Andrew; Pattnaik, Punyaslok; Sipőcz, Brigitta; Sharma, Rishabh;
Leonard, Andrew; Hewett, Russell; Hamilton, Alex; Manhas, Abhijeet;
Panda, Asish; Earnshaw, Matt; Barnes, Will; Choudhary, Nitin; Kumar,
Ankit; Singh, Raahul; Chanda, Prateek; Akramul Haque, Md; Kirk, Michael
S; Konge, Sudarshan; Mueller, Michael; Srivastava, Rajul; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Maloney, Shane;
Charlton, Michael; Mishra, Sashank; Chorley, Nicky; Himanshu; Chouhan,
Aryan; Modi, Sanskar; Mason, James Paul; Sharma, Yash; Naman9639;
Zivadinovic, Lazar; Campos Rozo, Jose Ivan; Bobra, Monica G.; Manley,
Larry; Paul, Jeffrey Aaron; Ivashkiv, Kateryna; Chatterjee, Agneet;
Akira Stern, Kris; Von Forstner, Johan Freiherr; Bazán, Juanjo; Jain,
Sarthak; Evans, John; Ghosh, Sourav; Malocha, Michael; Stańczak,
Dominik; SophieLemos; Verma, Shresth; De Visscher, Ruben; Ranjan Singh,
Rajiv; Airmansmith97; Buddhika, Dumindu; Pathak, Himanshu; Alam, Arib;
Agrawal, Ankit; Sharma, Swapnil; Rideout, Jai Ram; Bates, Matt; Park,
Jongyeob; Mishra, Pankaj; Goel, Dhruv; Sharma, Deepankar; Taylor,
Garrison; Cetusic, Goran; Reiter, Guntbert; Jacob; Inchaurrandieta,
Mateo; Dacie, Sally; Dubey, Sanjeev; Parkhi, Utkarsh; Sidhu, Sudeep;
Surve, Rutuja; Eigenbrot, Arthur; Meszaros, Tomas; Bray, Erik M.;
Zahniy, Serge; Guennou, Chloé; Bose, Abhigyan; Ankit; Chicrala,
André; J, Amogh; D'Avella, Daniel; Ballew, Jordan; Price-Whelan,
Adrian; Robitaille, Thomas; Augspurger, Tom; Murphy, Nick; Lodha,
Priyank; Krishan, Yash; Pandey, Abhishek; Honey; Verma, Dipanshu;
Neerajkulk; Williams, Daniel; Wiedemann, Bernhard M.; Kothari, Yash;
Mridulpandey; Habib, Ishtyaq; Molina, Carlos; Mampaey, Benjamin;
Streicher, Ole; Nomiya, Yukie; Gomillion, Reid; Letts, Joseph; Bhope,
Adwait; Hill, Andrew; Keşkek, Duygu; Ranjan, Kritika; Pereira,
Tiago M. D.; Kien Dang, Trung; Bankar, Varun; Bahuleyan, Abijith; B,
Abijith; Stevens, Abigail L.; Agrawal, Yudhik; Nakul-Shahdadpuri;
Ghosh, Koustav; Hiware, Kaustubh; Yasintoda; Krishna, Kalpesh;
Lyes, MOULOUDI Mohamed; Mangaonkar, Manas; Cheung, Mark; Platipo;
Buitrago-Casas, Juan Camilo; Mendero, Matthew; Dedhia, Megh; Wimbish,
Jaylen; Calixto, James; Babuschkin, Igor; Schoentgen, Mickaël; Mathur,
Harsh; Kumar, Gulshan; Verstringe, Freek; Mackenzie Dover, Fionnlagh;
Tollerud, Erik; Gyenge, Norbert G; Arias, Emmanuel; Reddy Mekala,
Rajasekhar; MacBride, Conor; Das, Ratul; Mishra, Rishabh; Stone,
Brandon; Resakra; Agarwal, Samriddhi; Chaudhari, Kaustubh; Kustov,
Arseniy; Smith, Arfon; Srikanth, Shashank; Jain, Shubham; Mehrotra,
Ambar; Singh Gaba, Amarjit; Kannojia, Swapnil; Yadav, Tannmay; Paul,
Tathagata; Wilkinson, Tessa D.; Caswell, Thomas A; Murray, Sophie A.
Bibcode: 2021zndo...5068086M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: Updates To The Virtual Solar Observatory
Authors: Ireland, J.; Amezcua, A.; Davey, A.; Hourcle, J.; Mansky,
E.; Martens, P.; Oien, N.; Spencer, J.
Bibcode: 2021AAS...23821302I
Altcode:
The Virtual Solar Observatory (VSO) is a community-driven tool that
allows users to seamlessly search for data from multiple, geographically
distributed solar data providers. In this presentation we will describe
the latest updates to the VSO, including newly available data sets,
and the adoption and use of REST (REpresentational State Transfer)
and TAP (Table Access Protocol) methods that expand the reach of the
VSO. We will also describe the VSO's support for data providers written
in Python, and the VSO's interaction with the SunPy Project to bring
access to solar data via a SunPy VSO client. Finally, we will briefly
outline how the VSO will contribute to NASA's Heliophysics Digital
Resource Library.
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Stansby, David; Shih, Albert Y.; Hughitt,
V. Keith; Ryan, Daniel F.; Liedtke, Simon; Pérez-Suárez, David;
Vishnunarayan K, I.; Hayes, Laura; Chakraborty, Pritish; Inglis,
Andrew; Pattnaik, Punyaslok; Sipőcz, Brigitta; Sharma, Rishabh;
Leonard, Andrew; Hewett, Russell; Hamilton, Alex; Manhas, Abhijeet;
Panda, Asish; Earnshaw, Matt; Barnes, Will; Choudhary, Nitin; Kumar,
Ankit; Singh, Raahul; Chanda, Prateek; Akramul Haque, Md; Kirk, Michael
S; Konge, Sudarshan; Mueller, Michael; Srivastava, Rajul; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Maloney, Shane;
Charlton, Michael; Mishra, Sashank; Chorley, Nicky; Himanshu; Chouhan,
Aryan; Modi, Sanskar; Mason, James Paul; Sharma, Yash; Naman9639;
Zivadinovic, Lazar; Campos Rozo, Jose Ivan; Bobra, Monica G.; Manley,
Larry; Paul, Jeffrey Aaron; Ivashkiv, Kateryna; Chatterjee, Agneet;
Akira Stern, Kris; Von Forstner, Johan Freiherr; Bazán, Juanjo; Jain,
Sarthak; Evans, John; Ghosh, Sourav; Malocha, Michael; Stańczak,
Dominik; SophieLemos; Verma, Shresth; De Visscher, Ruben; Ranjan Singh,
Rajiv; Airmansmith97; Buddhika, Dumindu; Pathak, Himanshu; Alam, Arib;
Agrawal, Ankit; Sharma, Swapnil; Rideout, Jai Ram; Bates, Matt; Park,
Jongyeob; Mishra, Pankaj; Goel, Dhruv; Sharma, Deepankar; Taylor,
Garrison; Cetusic, Goran; Reiter, Guntbert; Jacob; Inchaurrandieta,
Mateo; Dacie, Sally; Dubey, Sanjeev; Parkhi, Utkarsh; Sidhu, Sudeep;
Surve, Rutuja; Eigenbrot, Arthur; Meszaros, Tomas; Bray, Erik M.;
Zahniy, Serge; Guennou, Chloé; Bose, Abhigyan; Ankit; Chicrala,
André; J, Amogh; D'Avella, Daniel; Ballew, Jordan; Price-Whelan,
Adrian; Robitaille, Thomas; Augspurger, Tom; Murphy, Nick; Lodha,
Priyank; Krishan, Yash; Pandey, Abhishek; Honey; Verma, Dipanshu;
Neerajkulk; Williams, Daniel; Wiedemann, Bernhard M.; Kothari, Yash;
Mridulpandey; Habib, Ishtyaq; Molina, Carlos; Mampaey, Benjamin;
Streicher, Ole; Nomiya, Yukie; Gomillion, Reid; Letts, Joseph; Bhope,
Adwait; Hill, Andrew; Keşkek, Duygu; Ranjan, Kritika; Pereira,
Tiago M. D.; Kien Dang, Trung; Bankar, Varun; Bahuleyan, Abijith; B,
Abijith; Stevens, Abigail L.; Agrawal, Yudhik; Nakul-Shahdadpuri;
Ghosh, Koustav; Hiware, Kaustubh; Yasintoda; Krishna, Kalpesh;
Lyes, MOULOUDI Mohamed; Mangaonkar, Manas; Cheung, Mark; Platipo;
Buitrago-Casas, Juan Camilo; Mendero, Matthew; Dedhia, Megh; Wimbish,
Jaylen; Calixto, James; Babuschkin, Igor; Schoentgen, Mickaël; Mathur,
Harsh; Kumar, Gulshan; Verstringe, Freek; Mackenzie Dover, Fionnlagh;
Tollerud, Erik; Gyenge, Norbert G; Arias, Emmanuel; Reddy Mekala,
Rajasekhar; MacBride, Conor; Das, Ratul; Mishra, Rishabh; Stone,
Brandon; Resakra; Agarwal, Samriddhi; Chaudhari, Kaustubh; Kustov,
Arseniy; Smith, Arfon; Srikanth, Shashank; Jain, Shubham; Mehrotra,
Ambar; Singh Gaba, Amarjit; Kannojia, Swapnil; Yadav, Tannmay; Paul,
Tathagata; Wilkinson, Tessa D.; Caswell, Thomas A; Murray, Sophie A.
Bibcode: 2021zndo...4762113M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: heliopython/heliopy: HelioPy 0.15.3
Authors: Stansby, David; Rai, Yatharth; Argall, Matthew; JeffreyBroll;
Haythornthwaite, Richard; Erwin, Nathaniel; Teunissen, Jannis; Shaw,
Siddhant; Aditya; Saha, Ritwik; Ireland, Jack; Lim, P. L.; Badman,
Samuel; Mishra, Sashank; Badger, The Gitter; DupuisIRT; Tlml
Bibcode: 2021zndo...4643882S
Altcode:
Python for heliospheric and planetary physics
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Shih, Albert Y.; Stansby, David; Hughitt,
V. Keith; Ryan, Daniel F.; Liedtke, Simon; Pérez-Suárez, David;
Vishnunarayan K, I.; Hayes, Laura; Chakraborty, Pritish; Inglis,
Andrew; Pattnaik, Punyaslok; Sipőcz, Brigitta; Sharma, Rishabh;
Leonard, Andrew; Hewett, Russell; Hamilton, Alex; Manhas, Abhijeet;
Panda, Asish; Earnshaw, Matt; Barnes, Will; Choudhary, Nitin; Kumar,
Ankit; Singh, Raahul; Chanda, Prateek; Akramul Haque, Md; Kirk, Michael
S; Mueller, Michael; Konge, Sudarshan; Srivastava, Rajul; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Charlton, Michael;
Mishra, Sashank; Maloney, Shane; Chorley, Nicky; Himanshu; Chouhan,
Aryan; Mason, James Paul; Modi, Sanskar; Sharma, Yash; Zivadinovic,
Lazar; Naman9639; Campos Rozo, Jose Ivan; Manley, Larry; Bobra,
Monica G.; Chatterjee, Agneet; Ivashkiv, Kateryna; Von Forstner,
Johan Freiherr; Bazán, Juanjo; Akira Stern, Kris; Evans, John; Jain,
Sarthak; Malocha, Michael; Ghosh, Sourav; Airmansmith97; Stańczak,
Dominik; Ranjan Singh, Rajiv; De Visscher, Ruben; Verma, Shresth;
SophieLemos; Agrawal, Ankit; Alam, Arib; Buddhika, Dumindu; Pathak,
Himanshu; Rideout, Jai Ram; Sharma, Swapnil; Park, Jongyeob; Bates,
Matt; Mishra, Pankaj; Sharma, Deepankar; Goel, Dhruv; Taylor, Garrison;
Cetusic, Goran; Reiter, Guntbert; Jacob; Inchaurrandieta, Mateo;
Dacie, Sally; Dubey, Sanjeev; Eigenbrot, Arthur; Bray, Erik M.; Paul,
Jeffrey Aaron; Surve, Rutuja; Zahniy, Serge; Sidhu, Sudeep; Meszaros,
Tomas; Parkhi, Utkarsh; Bose, Abhigyan; Pandey, Abhishek; Price-Whelan,
Adrian; J, Amogh; Chicrala, André; Ankit; Guennou, Chloé; D'Avella,
Daniel; Williams, Daniel; Verma, Dipanshu; Ballew, Jordan; Murphy,
Nick; Lodha, Priyank; Robitaille, Thomas; Augspurger, Tom; Krishan,
Yash; Honey; Neerajkulk; Hill, Andrew; Mampaey, Benjamin; Wiedemann,
Bernhard M.; Molina, Carlos; Keşkek, Duygu; Habib, Ishtyaq; Letts,
Joseph; Streicher, Ole; Gomillion, Reid; Kothari, Yash; Mridulpandey;
Stevens, Abigail L.; B, Abijith; Bahuleyan, Abijith; Mehrotra, Ambar;
Smith, Arfon; Kustov, Arseniy; Stone, Brandon; MacBride, Conor; Arias,
Emmanuel; Tollerud, Erik; Mackenzie Dover, Fionnlagh; Verstringe,
Freek; Kumar, Gulshan; Mathur, Harsh; Babuschkin, Igor; Calixto,
James; Wimbish, Jaylen; Buitrago-Casas, Juan Camilo; Krishna, Kalpesh;
Hiware, Kaustubh; Ghosh, Koustav; Ranjan, Kritika; Mangaonkar, Manas;
Cheung, Mark; Mendero, Matthew; Schoentgen, Mickaël; Gyenge, Norbert
G; Reddy Mekala, Rajasekhar; Mishra, Rishabh; Srikanth, Shashank;
Jain, Shubham; Kannojia, Swapnil; Yadav, Tannmay; Paul, Tathagata;
Wilkinson, Tessa D.; Caswell, Thomas A; Pereira, Tiago M. D.; Kien
Dang, Trung; Agrawal, Yudhik; Nakul-Shahdadpuri; Platipo; Resakra;
Yasintoda; Murray, Sophie A.
Bibcode: 2021zndo...4641821M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Shih, Albert Y.; Stansby, David; Hughitt,
V. Keith; Ryan, Daniel F.; Liedtke, Simon; Pérez-Suárez, David; I.,
Vishnunarayan K; Hayes, Laura; Chakraborty, Pritish; Inglis, Andrew;
Pattnaik, Punyaslok; Sipőcz, Brigitta; Sharma, Rishabh; Leonard,
Andrew; Hewett, Russell; Hamilton, Alex; Manhas, Abhijeet; Panda,
Asish; Earnshaw, Matt; Barnes, Will; Choudhary, Nitin; Kumar, Ankit;
Singh, Raahul; Chanda, Prateek; Akramul Haque, Md; Kirk, Michael S;
Mueller, Michael; Konge, Sudarshan; Srivastava, Rajul; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Charlton, Michael;
Mishra, Sashank; Maloney, Shane; Chorley, Nicky; Himanshu; Chouhan,
Aryan; Mason, James Paul; Modi, Sanskar; Sharma, Yash; Zivadinovic,
Lazar; Naman9639; Campos Rozo, Jose Ivan; Manley, Larry; Bobra,
Monica G.; Chatterjee, Agneet; Ivashkiv, Kateryna; von Forstner,
Johan Freiherr; Bazán, Juanjo; Akira Stern, Kris; Evans, John; Jain,
Sarthak; Malocha, Michael; Ghosh, Sourav; Airmansmith97; Stańczak,
Dominik; Ranjan Singh, Rajiv; De Visscher, Ruben; Verma, Shresth;
SophieLemos; Agrawal, Ankit; Alam, Arib; Buddhika, Dumindu; Pathak,
Himanshu; Rideout, Jai Ram; Sharma, Swapnil; Park, Jongyeob; Bates,
Matt; Mishra, Pankaj; Sharma, Deepankar; Goel, Dhruv; Taylor, Garrison;
Cetusic, Goran; Reiter, Guntbert; Jacob; Inchaurrandieta, Mateo;
Dacie, Sally; Dubey, Sanjeev; Eigenbrot, Arthur; Bray, Erik M.; Paul,
Jeffrey Aaron; Surve, Rutuja; Zahniy, Serge; Sidhu, Sudeep; Meszaros,
Tomas; Parkhi, Utkarsh; Bose, Abhigyan; Pandey, Abhishek; Price-Whelan,
Adrian; J, Amogh; Chicrala, André; Ankit; Guennou, Chloé; D'Avella,
Daniel; Williams, Daniel; Verma, Dipanshu; Ballew, Jordan; Murphy,
Nick; Lodha, Priyank; Robitaille, Thomas; Augspurger, Tom; Krishan,
Yash; honey; neerajkulk; Hill, Andrew; Mampaey, Benjamin; Wiedemann,
Bernhard M.; Molina, Carlos; Keşkek, Duygu; Habib, Ishtyaq; Letts,
Joseph; Streicher, Ole; Gomillion, Reid; Kothari, Yash; mridulpandey;
Stevens, Abigail L.; B, Abijith; Bahuleyan, Abijith; Mehrotra, Ambar;
Smith, Arfon; Kustov, Arseniy; Stone, Brandon; MacBride, Conor; Arias,
Emmanuel; Tollerud, Erik; Mackenzie Dover, Fionnlagh; Verstringe,
Freek; Kumar, Gulshan; Mathur, Harsh; Babuschkin, Igor; Calixto,
James; Wimbish, Jaylen; Buitrago-Casas, Juan Camilo; Krishna, Kalpesh;
Hiware, Kaustubh; Ghosh, Koustav; Ranjan, Kritika; Mangaonkar, Manas;
Cheung, Mark; Mendero, Matthew; Schoentgen, Mickaël; Gyenge, Norbert
G; Reddy Mekala, Rajasekhar; Mishra, Rishabh; Srikanth, Shashank;
Jain, Shubham; Kannojia, Swapnil; Yadav, Tannmay; Paul, Tathagata;
Wilkinson, Tessa D.; Caswell, Thomas A; Pereira, Tiago M. D.; Kien
Dang, Trung; Agrawal, Yudhik; nakul-shahdadpuri; platipo; resakra;
yasintoda; Murray, Sophie A.
Bibcode: 2021zndo...4580466M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Shih, Albert Y.; Stansby, David; Hughitt,
V. Keith; Ryan, Daniel F.; Liedtke, Simon; Pérez-Suárez, David;
Vishnunarayan K, I.; Hayes, Laura; Chakraborty, Pritish; Inglis,
Andrew; Pattnaik, Punyaslok; Sipőcz, Brigitta; Sharma, Rishabh;
Leonard, Andrew; Hewett, Russell; Hamilton, Alex; Manhas, Abhijeet;
Panda, Asish; Earnshaw, Matt; Barnes, Will; Choudhary, Nitin; Kumar,
Ankit; Singh, Raahul; Chanda, Prateek; Akramul Haque, Md; Kirk, Michael
S; Mueller, Michael; Konge, Sudarshan; Srivastava, Rajul; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Charlton, Michael;
Mishra, Sashank; Maloney, Shane; Chorley, Nicky; Himanshu; Chouhan,
Aryan; Mason, James Paul; Modi, Sanskar; Sharma, Yash; Zivadinovic,
Lazar; Naman9639; Campos Rozo, Jose Ivan; Manley, Larry; Bobra,
Monica G.; Chatterjee, Agneet; Ivashkiv, Kateryna; Von Forstner,
Johan Freiherr; Bazán, Juanjo; Akira Stern, Kris; Evans, John; Jain,
Sarthak; Malocha, Michael; Ghosh, Sourav; Airmansmith97; Stańczak,
Dominik; Ranjan Singh, Rajiv; De Visscher, Ruben; Verma, Shresth;
SophieLemos; Agrawal, Ankit; Alam, Arib; Buddhika, Dumindu; Pathak,
Himanshu; Rideout, Jai Ram; Sharma, Swapnil; Park, Jongyeob; Bates,
Matt; Mishra, Pankaj; Sharma, Deepankar; Goel, Dhruv; Taylor, Garrison;
Cetusic, Goran; Reiter, Guntbert; Jacob; Inchaurrandieta, Mateo;
Dacie, Sally; Dubey, Sanjeev; Eigenbrot, Arthur; Bray, Erik M.; Paul,
Jeffrey Aaron; Surve, Rutuja; Zahniy, Serge; Sidhu, Sudeep; Meszaros,
Tomas; Parkhi, Utkarsh; Bose, Abhigyan; Pandey, Abhishek; Price-Whelan,
Adrian; J, Amogh; Chicrala, André; Ankit; Guennou, Chloé; D'Avella,
Daniel; Williams, Daniel; Verma, Dipanshu; Ballew, Jordan; Murphy,
Nick; Lodha, Priyank; Robitaille, Thomas; Augspurger, Tom; Krishan,
Yash; Honey; Neerajkulk; Hill, Andrew; Mampaey, Benjamin; Wiedemann,
Bernhard M.; Molina, Carlos; Keşkek, Duygu; Habib, Ishtyaq; Letts,
Joseph; Streicher, Ole; Gomillion, Reid; Kothari, Yash; Mridulpandey;
Stevens, Abigail L.; B, Abijith; Bahuleyan, Abijith; Mehrotra, Ambar;
Smith, Arfon; Kustov, Arseniy; Stone, Brandon; MacBride, Conor; Arias,
Emmanuel; Tollerud, Erik; Mackenzie Dover, Fionnlagh; Verstringe,
Freek; Kumar, Gulshan; Mathur, Harsh; Babuschkin, Igor; Calixto,
James; Wimbish, Jaylen; Buitrago-Casas, Juan Camilo; Krishna, Kalpesh;
Hiware, Kaustubh; Ghosh, Koustav; Ranjan, Kritika; Mangaonkar, Manas;
Cheung, Mark; Mendero, Matthew; Schoentgen, Mickaël; Gyenge, Norbert
G; Reddy Mekala, Rajasekhar; Mishra, Rishabh; Srikanth, Shashank;
Jain, Shubham; Kannojia, Swapnil; Yadav, Tannmay; Paul, Tathagata;
Wilkinson, Tessa D.; Caswell, Thomas A; Pereira, Tiago M. D.; Kien
Dang, Trung; Agrawal, Yudhik; Nakul-Shahdadpuri; Platipo; Resakra;
Yasintoda; Murray, Sophie A.
Bibcode: 2021zndo...4555172M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Hughitt, V. Keith; Shih, Albert Y.; Ryan,
Daniel F.; Liedtke, Simon; Stansby, David; Pérez-Suárez, David;
Vishnunarayan K, I.; Chakraborty, Pritish; Inglis, Andrew; Pattnaik,
Punyaslok; Sipőcz, Brigitta; Hayes, Laura; Sharma, Rishabh; Leonard,
Andrew; Hewett, Russell; Hamilton, Alex; Panda, Asish; Earnshaw,
Matt; Choudhary, Nitin; Kumar, Ankit; Singh, Raahul; Barnes, Will;
Chanda, Prateek; Akramul Haque, Md; Kirk, Michael S; Konge, Sudarshan;
Mueller, Michael; Srivastava, Rajul; Manhas, Abhijeet; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Charlton, Michael;
Maloney, Shane; Mishra, Sashank; Chorley, Nicky; Himanshu; Modi,
Sanskar; Mason, James Paul; Sharma, Yash; Naman9639; Bobra, Monica G.;
Campos Rozo, Jose Ivan; Manley, Larry; Chatterjee, Agneet; Bazán,
Juanjo; Jain, Sarthak; Evans, John; Ghosh, Sourav; Malocha, Michael;
De Visscher, Ruben; Ranjan Singh, Rajiv; Stańczak, Dominik; Verma,
Shresth; Airmansmith97; Agrawal, Ankit; Buddhika, Dumindu; Pathak,
Himanshu; Sharma, Swapnil; Alam, Arib; Bates, Matt; Park, Jongyeob;
Mishra, Pankaj; Rideout, Jai Ram; Sharma, Deepankar; Dubey, Sanjeev;
Inchaurrandieta, Mateo; Reiter, Guntbert; Goel, Dhruv; Dacie, Sally;
Jacob; Cetusic, Goran; Taylor, Garrison; Meszaros, Tomas; Bray,
Erik M.; Eigenbrot, Arthur; Zahniy, Serge; Zivadinovic, Lazar;
Parkhi, Utkarsh; Robitaille, Thomas; J, Amogh; Chicrala, André;
Ankit; Guennou, Chloé; D'Avella, Daniel; Williams, Daniel; Ballew,
Jordan; Murphy, Nick; Lodha, Priyank; Surve, Rutuja; Bose, Abhigyan;
Augspurger, Tom; Krishan, Yash; Neerajkulk; Habib, Ishtyaq; Letts,
Joseph; Kothari, Yash; Keşkek, Duygu; Honey; Molina, Carlos;
Streicher, Ole; Gomillion, Reid; Wiedemann, Bernhard M.; Mampaey,
Benjamin; Hill, Andrew; Akira Stern, Kris; Mittal, Gulshan; Verstringe,
Freek; Mackenzie Dover, Fionnlagh; Arias, Emmanuel; Stone, Brandon;
Kannojia, Swapnil; Kustov, Arseniy; Yadav, Tannmay; Wilkinson, Tessa
D.; Pereira, Tiago M. D.; Mridulpandey; Smith, Arfon; Kien Dang, Trung;
Mehrotra, Ambar; Price-Whelan, Adrian; B, Abijith; Yasintoda; Stevens,
Abigail L.; Agrawal, Yudhik; Gyenge, Norbert; Schoentgen, Mickaël;
Abijith-Bahuleyan; Mendero, Matthew; Mangaonkar, Manas; Cheung, Mark;
Reddy Mekala, Rajasekhar; Hiware, Kaustubh; Mishra, Rishabh; Krishna,
Kalpesh; Buitrago-Casas, Juan Camilo; Shashank, S; Wimbish, Jaylen;
Calixto, James; Babuschkin, Igor; Mathur, Harsh; Srikanth, Shashank;
Jamescalixto; Kumar, Gulshan; Gyenge, Norbert G; Murray, Sophie A.
Bibcode: 2021zndo...4421322M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: How SDAC/VSO/Helioviewer can be used by the international
community within the framework of the IHDEA
Authors: Ireland, Jack
Bibcode: 2021cosp...43E2388I
Altcode:
The heliophysics community has developed facilities that support
scientific investigations around the world; the Solar Data Analysis
Center (SDAC), the Virtual Solar Observatory (VSO) and the Helioviewer
Project (HVP). The SDAC stores and makes available solar physics data
from multiple NASA missions and other instruments. The VSO provides
clients and services that give its users a homogeneous data search and
download interface to multiple geographically distributed heterogeneous
solar data archives. The HVP provides solar data visualization clients
and services. These facilities have become key components in the
international infrastructure of heliophysics. However, the availability
of large and complex observational datasets, ever increasing modeling
capability, and new data analysis tools, presents new scientific
opportunities that challenge this existing infrastructure. In this
talk the current roles and capabilities of the SDAC, VSO and HVP in the
international heliophysics data environment will be outlined briefly. I
will also describe how the SDAC, VSO and HVP could evolve in response
to the changing needs of the worldwide scientific community. The role
of the International Heliophysics Data Environment Alliance (IHDEA),
particularly in its capacity as a standards and recommendations body,
will also be discussed in relation to potential extensions to the SDAC,
VSO and HVP. Finally, I will also discuss the role that the scientific
community can play in guiding how the existing data infrastructure
can be adapted to serve their needs.
Title: Power spectrum power-law indices as a diagnostic of coronal
heating
Authors: Ireland, Jack; Bradshaw, Stephen; Kirk, Michael; Viall,
Nicholeen
Bibcode: 2021cosp...43E1805I
Altcode:
We investigate the coronal heating of active regions using time-series
analysis and hydrodynamic modeling. Viall & Klimchuk 2011, 2012,
2014, 2017 have shown that the timing of active region coronal emission
brightenings in multiple channels of Solar Dynamics Observatory
Atmospheric Imaging Assembly (SDO/AIA) approximates that derived
from simulations of a nanoflare-heated corona. Using Numerical
HYDrodynamic RADiative Emission Model for the Solar Atmosphere
(HYDRAD)-based simulations of AIA emission for an AR, Bradshaw &
Viall 2016 have shown that the timing of coronal emission brightenings
is dependent on the properties of the nanoflare energy distribution
and occurrence rate. Relatedly, Ireland et al. 2015 show that average
power spectra $P(f)$ (where $f$ is frequency) of time series of AIA
171Å and 193Å AR images are dominated by power laws, $P(f)\approx
f^{-z}$, $z>0$. This may be explainable by assuming a distribution
of exponentially decaying events of emission along the line-of-sight
which can also result in power-law power spectra. We present analyses
that test the hypothesis that a distribution of nanoflare events
causes both the emission power-law power spectrum in AIA time-series
as well as the observed brightening time-lags. Firstly, we show that
the power-law indices of Fourier power spectra of the same simulated
data described in Bradshaw & Viall 2016 depends on the frequency
of nanoflares used. Secondly, using the observational AIA time-series
data analyzed by Viall & Klimchuk (2013), we obtain and discuss the
correlations of the cross-channel time-lags with the power-law indices
of Fourier power spectra in each AIA channel. Finally, we discuss the
ability of power-law indices and time-lags together to constrain the
underlying nanoflare frequency distribution.
Title: A Survey of Computational Tools in Solar Physics
Authors: Bobra, M.; Mumford, S.; Hewett, R. J.; Christe, S.; Reardon,
K.; Savage, S. L.; Ireland, J.; Mendes Domingos Pereira, T.; Chen,
B.; Pérez-Suárez, D.
Bibcode: 2020AGUFMSH0100001B
Altcode:
The SunPy project is happy to announce the results of the solar physics
community survey! For six months last year, between February
and July 2019, the SunPy Project asked members of the solar physics
community to fill out a 13-question survey about computational software
and hardware. A total of 364 community members, across 35 countries,
took our survey. We found that 99±0.5% of respondents use
software in their research and 66% use the Python scientific software
stack. Students are twice as likely as faculty, staff scientists, and
researchers to use Python. In this respect, the astrophysics and solar
physics communities differ widely: 78% of solar physics faculty, staff
scientists, and researchers in our sample uses IDL, compared with 44%
of astrophysics faculty and scientists sampled by Momcheva and Tollerud
(2015). We also found that most respondents (63±4%) have not taken
any computer science courses at an undergraduate or graduate level. We
found that a small fraction of respondents use the commercial cloud (5%)
or a regional or national cluster (14%) for their research. Finally,
we found that 73±4% of respondents cite scientific software in their
research, although only 42±3% do so routinely. Our survey results
are published in the journal Solar Physics and available via open
access at the following URL: https://doi.org/10.1007/s11207-020-01622-2.
Title: Investigating power law power spectra as a diagnostic of
nanoflare coronal heating in active regions
Authors: Ireland, J.; Bradshaw, S. J.; Viall, N. M.; Kirk, M. S.
Bibcode: 2020AGUFMSH0370006I
Altcode:
Power spectra of time series of synthetic AIA emission derived
from simulations of coronal heating in a realistic active region
geometry are analyzed. The synthetic AIA emissions are the same as
those described in Bradshaw & Viall 2016 ApJ, 821, 63. In those
simulations, low, intermediate and high frequency nanoflare occurrence
rates are postulated and the consequent synthetic AIA observations are
calculated. Bradshaw & Viall (2016) calculate the time lags between
hotter and cooler synthetic AIA channels derived via cross-correlation
of time series, and show that these timelags are broadly similar to
those derived from observational data. Power spectra of time series
of synthetic AIA emission are fit by a model P(f) = Af-n +
C, where f is frequency, n>0, A>C>0. For all six synthetic
AIA channels, it is shown that the fit power law index n depends
on AIA channel, spatial location, and the frequency of nanoflare
energy deposition. This suggests that power spectra of time series
of observational AIA data contain information on the frequency of
nanoflare energy deposition. We discuss the use of power law power
spectra as a possible diagnostic of nanoflare heating in observational
data. We demonstrated that the analysis of power spectra may provide
further constraints on the distribution of heating frequencies in
active regions, complementary to existing constraints derived from
other observables such as emission measure slopes and time lags.
Title: Updates on the Fundamentals of Impulsive Energy Release in
the Corona Explorer (FIERCE) mission concept
Authors: Shih, A. Y.; Glesener, L.; Krucker, S.; Guidoni, S. E.;
Christe, S.; Reeves, K.; Gburek, S.; Caspi, A.; Alaoui, M.; Allred,
J. C.; Battaglia, M.; Baumgartner, W.; Dennis, B. R.; Drake, J. F.;
Goetz, K.; Golub, L.; Hannah, I. G.; Hayes, L.; Holman, G.; Inglis,
A.; Ireland, J.; Kerr, G. S.; Klimchuk, J. A.; McKenzie, D. E.; Moore,
C. S.; Musset, S.; Reep, J. W.; Ryan, D.; Saint-Hilaire, P.; Savage,
S. L.; Schwartz, R.; Seaton, D. B.; Steslicki, M.; Woods, T. N.
Bibcode: 2020AGUFMSH0480012S
Altcode:
The Fundamentals of Impulsive Energy Release in the Corona Explorer
( FIERCE ) Medium-Class Explorer (MIDEX) mission concept addresses
the following science questions: What are the physical origins
of space-weather events? How are particles accelerated at the
Sun? How is impulsively released energy transported throughout
the solar atmosphere? How is the solar corona heated? FIERCE
achieves its science objectives through co-optimized X-ray and extreme
ultraviolet (EUV) observations by the following instruments: FOXSI,
a focusing hard X-ray spectroscopic imager that is able to capture the
full range of emission in flares and CMEs (e.g., faint coronal sources
near bright chromospheric sources) THADIS, a high-resolution,
fast-cadence EUV imager that will not saturate for even intense flares
to follow dynamic changes in the configuration of plasma structures
STC, a soft X-ray spectrometer that provides detailed thermal and
elemental composition diagnostics If selected, FIERCE will launch
in 2025, near the peak of the next solar cycle, which is also well timed
with perihelia of Parker Solar Probe and Solar Orbiter . We describe the
status and latest updates of the mission concept since it was proposed
to NASA last year. We also highlight the anticipated science return
from co-observations with other observatories/instruments such as the
Expanded Owens Valley Solar Array (EOVSA) or the STIX instrument on
Solar Orbiter .
Title: 3D Visualisation of Solar Data with JHelioviewer
Authors: Mueller, D.; Nicula, B.; Verstringe, F.; Bourgoignie, B.;
Csillaghy, A.; Laube, S.; Berghmans, D.; Ireland, J.; Fleck, B.
Bibcode: 2020AGUFMSH0360001M
Altcode:
The Solar Orbiter and Parker Solar Probe missions focus on exploring
the linkage between the Sun and the heliosphere. These new missions
are collecting unique data that will allow us to study the coupling
between macroscopic physical processes to those on kinetic scales, the
generation of solar energetic particles and their propagation into the
heliosphere and the origin and acceleration of solar wind plasma. The scientific community now has access to large volumes of complex
remote-sensing and in-situ observations from different vantage points,
complemented by petabytes of simulation data. Answering overarching
science questions like "How do solar transients drive heliospheric
variability and space weather?" will only be possible if the science
community has the necessary tools at hand to visualize these data
and assimilate them into sophisticated models. A key piece
needed to bridge the gap between observables, derived quantities like
magnetic field extrapolations and model output is a tool to routinely
and intuitively visualise large heterogeneous, multidimensional,
time-dependent data sets. The open-source JHelioviewer software,
which is part of the ESA/NASA Helioviewer Project, is addressing this
need. This contribution highlights recent extensions of JHelioviewer's
functionality, in particular those of interest for Solar Orbiter.
Title: SunPy 2.0: the community-developed open-source solar data
analysis environment for Python
Authors: Murray, S. A.; Barnes, W.; Bobra, M.; Christe, S.; Freij,
N.; Hayes, L.; Ireland, J.; Mumford, S.; Pérez-Suárez, D.; Ryan,
D.; Shih, A. Y.; Chanda, P.; Hewett, R.; Hughitt, V. K.; Hill, A.;
Hiware, K.; Inglis, A.; Kirk, M. S.; Konge, S.; Mason, J. P.; Maloney,
S.; Panda, A.; Park, J.; M D Pereira, T.; Reardon, K.; Savage, S. L.;
Sipocz, B.; Stansby, D.; Jain, Y.; Taylor, G.; Yadav, T.; Kien, H. T.;
Chen, B.; Glogowski, K.
Bibcode: 2020AGUFMSH0100006M
Altcode:
The SunPy project facilitates and promotes the use and development
of several community-led, free, and open-source data analysis
software packages for solar physics based on the scientific
Python environment. The project achieves this goal by developing
and maintaining the SunPy core package and supporting an ecosystem
of affiliated packages. The SunPy community is pleased to announce
the release of version 2.0! Some highlights for this release include
updates to the Fido data search and retrieval tool, various fixes to the
sunpy.map sub package, and integration of differential rotation into
the sunpy.coordinates framework. Also new in SunPy 2.0 is the aiapy
package for analyzing data from SDO/AIA, which replaces aiaprep. Learn
more about how to install and use the publicly available code at sunpy.org , as well as information about
how to get involved with the community!
Title: HSO Connect: Creating User-driven Infrastructure for Space
Science
Authors: Kirk, M. S.; Fung, S. F.; Ireland, J.; Jian, L.; Kuznetsova,
M. M.; MacNeice, P. J.; DiBraccio, G. A.; McGranaghan, R. M.; Roberts,
D. A.; Thomas, B. A.; Thompson, B. J.; Weigand, C.; Zheng, Y.
Bibcode: 2020AGUFMSH0180008K
Altcode:
The NASA Heliophysics System Observatory (HSO Connect) project is an
initiative to gain the most utility from data available for space
physics. The HSO Connect community comprises GSFC/NASA, NCAR's
Whole Heliosphere and Planetary Interactions (WHPI) program and
the Parker Solar Probe (PSP) project team at APL (Applied Physics
Lab). The purpose of HSO Connect is to unify the community and
provide observations coordinated around the PSP mission and other high
profile Heliophysics projects requiring unique integration. We share
the HSO Connect approach to curating and providing resources critical
to discovery, including observational data, related data products,
and basic tools to analyze the observations as well as providing the
same access to models and simulations which explain the data. To
support an interoperable and reusable data system to last beyond the
HSO Connect lifetime, we have worked with the community of end users to
identify, from their perspective, the most impactful "questions" which
they want HSO Connect to answer for them (for example, "Where the data
associated with phenomenon "X" might be stored and accessible?"). We
have utilized this feedback to prioritize how to better combine existing
capabilities and to identify which infrastructure capabilities need
to be augmented or created. We will show how we have utilized the
community feedback to determine both impact and ease of implementation,
used this information to derive critical requirements for HSO Connect
and used this information to align existing capabilities and create
missing infrastructure within resourcing limits.
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Hughitt, V. Keith; Shih, Albert Y.; Ryan,
Daniel F.; Liedtke, Simon; Stansby, David; Pérez-Suárez, David;
Vishnunarayan K, I.; Chakraborty, Pritish; Inglis, Andrew; Pattnaik,
Punyaslok; Sipőcz, Brigitta; Hayes, Laura; Sharma, Rishabh; Leonard,
Andrew; Hewett, Russell; Hamilton, Alex; Panda, Asish; Earnshaw,
Matt; Choudhary, Nitin; Kumar, Ankit; Singh, Raahul; Barnes, Will;
Chanda, Prateek; Akramul Haque, Md; Kirk, Michael S; Konge, Sudarshan;
Mueller, Michael; Srivastava, Rajul; Manhas, Abhijeet; Jain, Yash;
Bennett, Samuel; Baruah, Ankit; Arbolante, Quinn; Charlton, Michael;
Maloney, Shane; Mishra, Sashank; Chorley, Nicky; Himanshu; Modi,
Sanskar; Mason, James Paul; Sharma, Yash; Naman9639; Bobra, Monica G.;
Campos Rozo, Jose Ivan; Manley, Larry; Chatterjee, Agneet; Bazán,
Juanjo; Jain, Sarthak; Evans, John; Ghosh, Sourav; Malocha, Michael;
De Visscher, Ruben; Ranjan Singh, Rajiv; Stańczak, Dominik; Verma,
Shresth; Airmansmith97; Agrawal, Ankit; Buddhika, Dumindu; Pathak,
Himanshu; Sharma, Swapnil; Alam, Arib; Bates, Matt; Park, Jongyeob;
Mishra, Pankaj; Rideout, Jai Ram; Sharma, Deepankar; Dubey, Sanjeev;
Inchaurrandieta, Mateo; Reiter, Guntbert; Goel, Dhruv; Dacie, Sally;
Jacob; Cetusic, Goran; Taylor, Garrison; Meszaros, Tomas; Bray,
Erik M.; Eigenbrot, Arthur; Zahniy, Serge; Zivadinovic, Lazar;
Parkhi, Utkarsh; Robitaille, Thomas; J, Amogh; Chicrala, André;
Ankit; Guennou, Chloé; D'Avella, Daniel; Williams, Daniel; Ballew,
Jordan; Murphy, Nick; Lodha, Priyank; Surve, Rutuja; Bose, Abhigyan;
Augspurger, Tom; Krishan, Yash; Neerajkulk; Habib, Ishtyaq; Letts,
Joseph; Kothari, Yash; Keşkek, Duygu; Honey; Molina, Carlos;
Streicher, Ole; Gomillion, Reid; Wiedemann, Bernhard M.; Mampaey,
Benjamin; Hill, Andrew; Akira Stern, Kris; Mittal, Gulshan; Verstringe,
Freek; Mackenzie Dover, Fionnlagh; Arias, Emmanuel; Stone, Brandon;
Kannojia, Swapnil; Kustov, Arseniy; Yadav, Tannmay; Wilkinson, Tessa
D.; Pereira, Tiago M. D.; Mridulpandey; Smith, Arfon; Kien Dang, Trung;
Mehrotra, Ambar; Price-Whelan, Adrian; B, Abijith; Yasintoda; Stevens,
Abigail L.; Agrawal, Yudhik; Gyenge, Norbert; Schoentgen, Mickaël;
Abijith-Bahuleyan; Mendero, Matthew; Mangaonkar, Manas; Cheung, Mark;
Reddy Mekala, Rajasekhar; Hiware, Kaustubh; Mishra, Rishabh; Krishna,
Kalpesh; Buitrago-Casas, Juan Camilo; Shashank, S; Wimbish, Jaylen;
Calixto, James; Babuschkin, Igor; Mathur, Harsh; Srikanth, Shashank;
Jamescalixto; Kumar, Gulshan; Gyenge, Norbert G; Murray, Sophie A.
Bibcode: 2020zndo...3940415M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: Machine Learning in Heliophysics and Space Weather Forecasting:
A White Paper of Findings and Recommendations
Authors: Nita, Gelu; Georgoulis, Manolis; Kitiashvili, Irina; Sadykov,
Viacheslav; Camporeale, Enrico; Kosovichev, Alexander; Wang, Haimin;
Oria, Vincent; Wang, Jason; Angryk, Rafal; Aydin, Berkay; Ahmadzadeh,
Azim; Bai, Xiaoli; Bastian, Timothy; Filali Boubrahimi, Soukaina; Chen,
Bin; Davey, Alisdair; Fereira, Sheldon; Fleishman, Gregory; Gary, Dale;
Gerrard, Andrew; Hellbourg, Gregory; Herbert, Katherine; Ireland,
Jack; Illarionov, Egor; Kuroda, Natsuha; Li, Qin; Liu, Chang; Liu,
Yuexin; Kim, Hyomin; Kempton, Dustin; Ma, Ruizhe; Martens, Petrus;
McGranaghan, Ryan; Semones, Edward; Stefan, John; Stejko, Andrey;
Collado-Vega, Yaireska; Wang, Meiqi; Xu, Yan; Yu, Sijie
Bibcode: 2020arXiv200612224N
Altcode:
The authors of this white paper met on 16-17 January 2020 at the New
Jersey Institute of Technology, Newark, NJ, for a 2-day workshop that
brought together a group of heliophysicists, data providers, expert
modelers, and computer/data scientists. Their objective was to discuss
critical developments and prospects of the application of machine and/or
deep learning techniques for data analysis, modeling and forecasting
in Heliophysics, and to shape a strategy for further developments in
the field. The workshop combined a set of plenary sessions featuring
invited introductory talks interleaved with a set of open discussion
sessions. The outcome of the discussion is encapsulated in this white
paper that also features a top-level list of recommendations agreed
by participants.
Title: heliopython/heliopy: HelioPy 0.11.1
Authors: Stansby, David; Rai, Yatharth; Argall, Matthew; JeffreyBroll;
Haythornthwaite, Richard; Erwin, Nathaniel; Shaw, Siddhant; Aditya;
Saha, Ritwik; Mishra, Sashank; Badger, The Gitter; Badman, Samuel;
Lim, P. L.; Ireland, Jack
Bibcode: 2020zndo...3834844S
Altcode:
Python for heliospheric and planetary physics
Title: SunPy
Authors: Mumford, Stuart J.; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Hughitt, V. Keith; Shih, Albert Y.; Ryan, Daniel
F.; Liedtke, Simon; Pérez-Suárez, David; Chakraborty, Pritish;
Vishnunarayan K, I.; Inglis, Andrew; Pattnaik, Punyaslok; Sipőcz,
Brigitta; Sharma, Rishabh; Leonard, Andrew; Stansby, David; Hewett,
Russell; Hamilton, Alex; Hayes, Laura; Panda, Asish; Earnshaw, Matt;
Choudhary, Nitin; Kumar, Ankit; Chanda, Prateek; Akramul Haque, Md;
Kirk, Michael S; Mueller, Michael; Konge, Sudarshan; Srivastava, Rajul;
Jain, Yash; Bennett, Samuel; Baruah, Ankit; Barnes, Will; Charlton,
Michael; Maloney, Shane; Chorley, Nicky; Himanshu; Modi, Sanskar;
Mason, James Paul; Naman9639; Campos Rozo, Jose Ivan; Manley, Larry;
Chatterjee, Agneet; Evans, John; Malocha, Michael; Bobra, Monica G.;
Ghosh, Sourav; Airmansmith97; Stańczak, Dominik; De Visscher, Ruben;
Verma, Shresth; Agrawal, Ankit; Buddhika, Dumindu; Sharma, Swapnil;
Park, Jongyeob; Bates, Matt; Goel, Dhruv; Taylor, Garrison; Cetusic,
Goran; Jacob; Inchaurrandieta, Mateo; Dacie, Sally; Dubey, Sanjeev;
Sharma, Deepankar; Bray, Erik M.; Rideout, Jai Ram; Zahniy, Serge;
Meszaros, Tomas; Bose, Abhigyan; Chicrala, André; Ankit; Guennou,
Chloé; D'Avella, Daniel; Williams, Daniel; Ballew, Jordan; Murphy,
Nick; Lodha, Priyank; Robitaille, Thomas; Krishan, Yash; Hill, Andrew;
Eigenbrot, Arthur; Mampaey, Benjamin; Wiedemann, Bernhard M.; Molina,
Carlos; Keşkek, Duygu; Habib, Ishtyaq; Letts, Joseph; Bazán,
Juanjo; Arbolante, Quinn; Gomillion, Reid; Kothari, Yash; Sharma,
Yash; Stevens, Abigail L.; Price-Whelan, Adrian; Mehrotra, Ambar;
Kustov, Arseniy; Stone, Brandon; Kien Dang, Trung; Arias, Emmanuel;
Mackenzie Dover, Fionnlagh; Verstringe, Freek; Kumar, Gulshan;
Mathur, Harsh; Babuschkin, Igor; Wimbish, Jaylen; Buitrago-Casas,
Juan Camilo; Krishna, Kalpesh; Hiware, Kaustubh; Mangaonkar, Manas;
Mendero, Matthew; Schoentgen, Mickaël; Gyenge, Norbert G; Streicher,
Ole; Reddy Mekala, Rajasekhar; Mishra, Rishabh; Srikanth, Shashank;
Jain, Sarthak; Yadav, Tannmay; Wilkinson, Tessa D.; Pereira, Tiago
M. D.; Agrawal, Yudhik; Jamescalixto; Yasintoda; Murray, Sophie A.
Bibcode: 2020zndo...3779284M
Altcode:
The community-developed, free and open-source solar data analysis
environment for Python.
Title: heliopython/heliopy: HelioPy 0.10.1
Authors: Stansby, David; Rai, Yatharth; Argall, Matthew; Broll,
Jeffrey; Erwin, Nathaniel; Shaw, Siddhant; Aditya; Saha, Ritwik;
Mishra, Sashank; Lim, P. L.; Ireland, Jack
Bibcode: 2020zndo...3739114S
Altcode:
Python for heliospheric and planetary physics
Title: A Survey of Computational Tools in Solar Physics
Authors: Bobra, Monica G.; Mumford, Stuart J.; Hewett, Russell J.;
Christe, Steven D.; Reardon, Kevin; Savage, Sabrina; Ireland, Jack;
Pereira, Tiago M. D.; Chen, Bin; Pérez-Suárez, David
Bibcode: 2020SoPh..295...57B
Altcode: 2020arXiv200314186B
The SunPy Project developed a 13-question survey to understand the
software and hardware usage of the solar-physics community. Of the
solar-physics community, 364 members across 35 countries responded
to our survey. We found that 99 ±0.5 % of respondents use software
in their research and 66% use the Python scientific-software
stack. Students are twice as likely as faculty, staff scientists,
and researchers to use Python rather than Interactive Data Language
(IDL). In this respect, the astrophysics and solar-physics communities
differ widely: 78% of solar-physics faculty, staff scientists, and
researchers in our sample uses IDL, compared with 44% of astrophysics
faculty and scientists sampled by Momcheva and Tollerud (2015). 63
±4 % of respondents have not taken any computer-science courses at an
undergraduate or graduate level. We also found that most respondents use
consumer hardware to run software for solar-physics research. Although
82% of respondents work with data from space-based or ground-based
missions, some of which (e.g. the Solar Dynamics Observatory and Daniel
K. Inouye Solar Telescope) produce terabytes of data a day, 14% use
a regional or national cluster, 5% use a commercial cloud provider,
and 29% use exclusively a laptop or desktop. Finally, we found that
73 ±4 % of respondents cite scientific software in their research,
although only 42 ±3 % do so routinely.
Title: heliopython/heliopy: HelioPy 0.10.0
Authors: Stansby, David; Rai, Yatharth; Argall, Matthew; JeffreyBroll;
Erwin, Nathaniel; Shaw, Siddhant; Aditya; Saha, Ritwik; Mishra,
Sashank; Badger, The Gitter; Lim, P. L.; Ireland, Jack
Bibcode: 2020zndo...3676651S
Altcode:
Python for heliospheric and planetary physics
Title: SunPy: A Python package for Solar Physics
Authors: Mumford, Stuart; Freij, Nabil; Christe, Steven; Ireland,
Jack; Mayer, Florian; Hughitt, V.; Shih, Albert; Ryan, Daniel; Liedtke,
Simon; Pérez-Suárez, David; Chakraborty, Pritish; K, Vishnunarayan;
Inglis, Andrew; Pattnaik, Punyaslok; Sipőcz, Brigitta; Sharma,
Rishabh; Leonard, Andrew; Stansby, David; Hewett, Russell; Hamilton,
Alex; Hayes, Laura; Panda, Asish; Earnshaw, Matt; Choudhary, Nitin;
Kumar, Ankit; Chanda, Prateek; Haque, Md; Kirk, Michael; Mueller,
Michael; Konge, Sudarshan; Srivastava, Rajul; Jain, Yash; Bennett,
Samuel; Baruah, Ankit; Barnes, Will; Charlton, Michael; Maloney,
Shane; Chorley, Nicky; Himanshu; Modi, Sanskar; Mason, James; Naman;
Campos Rozo, Jose Ivan; Manley, Larry; Chatterjee, Agneet; Evans,
John; Malocha, Michael; Bobra, Monica; Ghosh, Sourav; Airmansmith;
Stańczak, Dominik; De Visscher, Ruben; Verma, Shresth; Agrawal, Ankit;
Buddhika, Dumindu; Sharma, Swapnil; Park, Jongyeob; Bates, Matt; Goel,
Dhruv; Taylor, Garrison; Cetusic, Goran; Jacob; Inchaurrandieta, Mateo;
Dacie, Sally; Dubey, Sanjeev; Sharma, Deepankar; Bray, Erik; Rideout,
Jai; Zahniy, Serge; Meszaros, Tomas; Bose, Abhigyan; Chicrala, André;
Ankit; Guennou, Chloé; D'Avella, Daniel; Williams, Daniel; Ballew,
Jordan; Murphy, Nick; Lodha, Priyank; Robitaille, Thomas; Krishan,
Yash; Hill, Andrew; Eigenbrot, Arthur; Mampaey, Benjamin; Wiedemann,
Bernhard; Molina, Carlos; Keşkek, Duygu; Habib, Ishtyaq; Letts,
Joseph; Bazán, Juanjo; Arbolante, Quinn; Gomillion, Reid; Kothari,
Yash; Sharma, Yash; Stevens, Abigail; Price-Whelan, Adrian; Mehrotra,
Ambar; Kustov, Arseniy; Stone, Brandon; Dang, Trung; Arias, Emmanuel;
Dover, Fionnlagh; Verstringe, Freek; Kumar, Gulshan; Mathur, Harsh;
Babuschkin, Igor; Wimbish, Jaylen; Buitrago-Casas, Juan; Krishna,
Kalpesh; Hiware, Kaustubh; Mangaonkar, Manas; Mendero, Matthew;
Schoentgen, Mickaël; Gyenge, Norbert; Streicher, Ole; Mekala,
Rajasekhar; Mishra, Rishabh; Srikanth, Shashank; Jain, Sarthak;
Yadav, Tannmay; Wilkinson, Tessa; Pereira, Tiago; Agrawal, Yudhik;
Jamescalixto; Yasintoda; Murray, Sophie
Bibcode: 2020JOSS....5.1832M
Altcode:
No abstract at ADS
Title: The SunPy Project: Open Source Development and Status of the
Version 1.0 Core Package
Authors: SunPy Community; Barnes, Will T.; Bobra, Monica G.; Christe,
Steven D.; Freij, Nabil; Hayes, Laura A.; Ireland, Jack; Mumford,
Stuart; Perez-Suarez, David; Ryan, Daniel F.; Shih, Albert Y.; Chanda,
Prateek; Glogowski, Kolja; Hewett, Russell; Hughitt, V. Keith; Hill,
Andrew; Hiware, Kaustubh; Inglis, Andrew; Kirk, Michael S. F.; Konge,
Sudarshan; Mason, James Paul; Maloney, Shane Anthony; Murray, Sophie
A.; Panda, Asish; Park, Jongyeob; Pereira, Tiago M. D.; Reardon,
Kevin; Savage, Sabrina; Sipőcz, Brigitta M.; Stansby, David; Jain,
Yash; Taylor, Garrison; Yadav, Tannmay; Rajul; Dang, Trung Kien
Bibcode: 2020ApJ...890...68S
Altcode: 2020ApJ...890...68A
The goal of the SunPy project is to facilitate and promote the
use and development of community-led, free, and open source data
analysis software for solar physics based on the scientific Python
environment. The project achieves this goal by developing and
maintaining the sunpy core package and supporting an ecosystem of
affiliated packages. This paper describes the first official stable
release (version 1.0) of the core package, as well as the project
organization and infrastructure. This paper concludes with a discussion
of the future of the SunPy project.
Title: Combined Next-Generation X-ray and EUV Observations with the
FIERCE Mission Concept
Authors: Shih, A. Y.; Glesener, L.; Christe, S.; Reeves, K.; Gburek,
S.; Alaoui, M.; Allred, J. C.; Baumgartner, W.; Caspi, A.; Dennis,
B. R.; Drake, J. F.; Goetz, K.; Golub, L.; Guidoni, S. E.; Inglis,
A.; Hannah, I. G.; Holman, G.; Hayes, L.; Ireland, J.; Kerr, G. S.;
Klimchuk, J. A.; Krucker, S.; McKenzie, D. E.; Moore, C. S.; Musset,
S.; Reep, J. W.; Ryan, D.; Saint-Hilaire, P.; Savage, S. L.; Seaton,
D. B.; Steslicki, M.; Woods, T. N.
Bibcode: 2019AGUFMSH33A..08S
Altcode:
While there have been significant advances in our understanding
of impulsive energy release at the Sun through the combination
of RHESSI X-ray observations and SDO/AIA EUV observations, there
is a clear science need for significantly improved X-ray and EUV
observations. These new observations must capture the full range
of emission in flares and CMEs (e.g., faint coronal sources near
bright chromospheric sources), connect the intricate evolution of
energy release with dynamic changes in the configuration of plasma
structures, and identify the signatures of impulsive energy release in
even the quiescent Sun. The Fundamentals of Impulsive Energy Release
in the Corona Explorer ( FIERCE ) MIDEX mission concept makes these
observations by combining the two instruments previously proposed on the
FOXSI SMEX mission concept - a focusing hard X-ray spectroscopic imager
and a soft X-ray spectrometer - with a high-resolution EUV imager that
will not saturate for even intense flares. All instruments observe at
high cadence to capture the initiation of solar transient events and
the fine time structure within events. FIERCE would launch in mid-2025,
near the peak of the next solar cycle, which is also well timed with
perihelions of Parker Solar Probe and Solar Orbiter.
Title: FIERCE Science: Expected Results From a High-Energy
Medium-Class Explorer
Authors: Glesener, L.; Shih, A. Y.; Christe, S.; Reeves, K.; Gburek,
S.; Alaoui, M.; Allred, J. C.; Baumgartner, W.; Caspi, A.; Dennis,
B. R.; Drake, J. F.; Golub, L.; Goetz, K.; Guidoni, S. E.; Hannah,
I. G.; Hayes, L.; Holman, G.; Inglis, A.; Ireland, J.; Kerr, G. S.;
Klimchuk, J. A.; Krucker, S.; McKenzie, D. E.; Moore, C. S.; Musset,
S.; Reep, J. W.; Ryan, D.; Saint-Hilaire, P.; Savage, S. L.; Seaton,
D. B.; Steslicki, M.; Woods, T. N.
Bibcode: 2019AGUFMSH31C3313G
Altcode:
A variety of individual X-ray and EUV instruments have probed
high-energy aspects of the Sun over the decades, each contributing
pieces to the puzzles of the energization, heating, and acceleration of
solar plasma and particles. But fundamental difficulties in sensitivity
and dynamic range impart big challenges in probing the details of
particle acceleration sites, understanding how eruptions and flares are
initiated, and tracking the intricacies of energy transfer as flares
evolve. The Fundamentals of Impulsive Energy Release in the Corona
Explorer ( FIERCE ) mission will make substantial leaps forward in
these scientific ventures by combining a variety of instruments into
one platform, each optimized to have high sensitivity and dynamic
range. FIERCE is a proposed NASA Heliophysics Medium-Class Explorer
that will investigate high-energy solar phenomena across a variety
of spectral and spatial dimensions. It combines hard X-ray imaging
spectroscopy (via focusing, for the first time for a solar-dedicated
spacecraft), spatially integrated soft X-ray spectroscopy, and fast,
high-resolution extreme ultraviolet imaging at coronal and flare
temperatures. FIERCE uses this array of instruments to make important
contributions toward probing the genesis of space weather events,
the acceleration of particles, the transport of flare energy, and the
heating of the corona. Here, we present some of the expected science
outcomes for the FIERCE observatory, concentrating on the ways in which
FIERCE can probe confined and eruptive events, particle acceleration
everywhere it may occur on the Sun, and the connections of solar
high-energy phenomena to the heliosphere.
Title: SunPy v1.0, the community-developed, free and open-source
solar data analysis environment for Python.
Authors: Christe, S.; Barnes, W. T.; Bobra, M.; Freij, N.; Hayes,
L.; Ireland, J.; Mumford, S.; Pérez-Suárez, D.; Ryan, D.; Shih,
A. Y.; Chanda, P.; Glogowski, S.; Hewett, R.; Hughitt, V. K.; Hill,
A.; Hiware, K.; Inglis, A.; Kirk, M. S.; Konge, S.; Mason, J. P.;
Maloney, S.; Park, J.; Pereira, T. J.; Reardon, K.; Savage, S. L.;
Yadav, T.; Taylor, G.; Stansby, D.; Jain, Y.; Sipocz, B.; Rajulapati,
C. R.; Panda, A.
Bibcode: 2019AGUFMSH41C3309C
Altcode:
The SunPy project facilitates and promotes the use and development
of several community-led, free, and open source data analysis
software packages for solar physics based on the scientific Python
environment. The project achieves this goal by developing and
maintaining the sunpy core package and supporting an ecosystem of
affiliated packages. The SunPy project is pleased to announce the 1.0
release of the sunpy package. This new release is the first stable
release of the packages and includes several important new features
such as improved data downloading capabilities, a large enhancement in
coordinate and coordinate transformations capabilities, new map utility
functions, and a new logging functionality amongst others. This talk
will present how the sunpy package can be used for solar data analysis
and discuss the roadmap for package.
Title: AWARE: An Algorithm for the Automated Characterization of
EUV Waves in the Solar Atmosphere
Authors: Ireland, Jack; Inglis, Andrew R.; Shih, Albert Y.; Christe,
Steven; Mumford, Stuart; Hayes, Laura A.; Thompson, Barbara J.;
Hughitt, V. Keith
Bibcode: 2019SoPh..294..158I
Altcode: 2018arXiv180407325I
Extreme ultraviolet (EUV) waves are large-scale propagating
disturbances observed in the solar corona, frequently associated with
coronal mass ejections and flares. They appear as faint, extended
structures propagating from a source region across the structured
solar corona. Since their discovery, over 200 papers discussing their
properties, causes, and physical nature have been published. However,
despite this their fundamental properties and the physics of their
interactions with other solar phenomena are still not understood. To
further the understanding of EUV waves, we have constructed the
Automated Wave Analysis and Reduction (AWARE) algorithm for the
measurement of EUV waves. AWARE is implemented in two stages. In the
first stage, we use a new type of running difference image, the running
difference persistence image, which enables the efficient isolation of
propagating, bright wavefronts as they travel across the corona. In the
second stage, AWARE detects the presence of a wavefront, and measures
the distance, velocity, and acceleration of that wavefront across the
Sun. The fit of propagation models to the wave progress isolated in
the first stage is achieved using the Random Sample Consensus (RANSAC)
algorithm. AWARE is tested against simulations of EUV wave propagation,
and is applied to measure EUV waves in observational data from the
Atmospheric Imaging Assembly (AIA). We also comment on unavoidable
systematic errors that bias the estimation of wavefront velocity and
acceleration. In addition, the full AWARE software suite comes with a
package that creates simulations of waves propagating across the disk
from arbitrary starting points.
Title: heliopython/heliopy: HelioPy 0.8.1
Authors: Stansby, David; Rai, Yatharth; JeffreyBroll; Erwin, Nathaniel;
Shaw, Siddhant; Gogia, Arpit; Aditya; Saha, Ritwik; Mishra, Sashank;
Badger, The Gitter; Ireland, Jack
Bibcode: 2019zndo...3368264S
Altcode:
Python for heliospheric and planetary physics
Title: heliopython/heliopy: HelioPy 0.8.0
Authors: Stansby, David; Rai, Yatharth; Broll, Jeffrey; Shaw, Siddhant;
Gogia, Arpit; Aditya; Saha, Ritwik; Mishra, Sashank; Ireland, Jack
Bibcode: 2019zndo...3256541S
Altcode:
Python for heliospheric and planetary physics
Title: The Focusing Optics X-ray Solar Imager (FOXSI)
Authors: Christe, Steven; Shih, Albert Y.; Krucker, Sam; Glesener,
Lindsay; Saint-Hilaire, Pascal; Caspi, Amir; Gburek, Szymon;
Steslicki, Marek; Allred, Joel C.; Battaglia, Marina; Baumgartner,
Wayne H.; Drake, James; Goetz, Keith; Grefenstette, Brian; Hannah,
Iain; Holman, Gordon D.; Inglis, Andrew; Ireland, Jack; Klimchuk,
James A.; Ishikawa, Shin-Nosuke; Kontar, Eduard; Massone, Anna-maria;
Piana, Michele; Ramsey, Brian; Schwartz, Richard A.; Woods, Thomas N.;
Chen, Bin; Gary, Dale E.; Hudson, Hugh S.; Kowalski, Adam; Warmuth,
Alexander; White, Stephen M.; Veronig, Astrid; Vilmer, Nicole
Bibcode: 2019AAS...23422501C
Altcode:
The Focusing Optics X-ray Solar Imager (FOXSI), a SMEX mission concept
in Phase A, is the first-ever solar-dedicated, direct-imaging, hard
X-ray telescope. FOXSI provides a revolutionary new approach to
viewing explosive magnetic-energy release on the Sun by detecting
signatures of accelerated electrons and hot plasma directly in
and near the energy-release sites of solar eruptive events (e.g.,
solar flares). FOXSI's primary science objective is to understand the
mystery of how impulsive energy release leads to solar eruptions, the
primary drivers of space weather at Earth, and how those eruptions are
energized and evolve. FOXSI addresses three important science questions:
(1) How are particles accelerated at the Sun? (2) How do solar plasmas
get heated to high temperatures? (3) How does magnetic energy released
on the Sun lead to flares and eruptions? These fundamental physics
questions are key to our understanding of phenomena throughout
the Universe from planetary magnetospheres to black hole accretion
disks. FOXSI measures the energy distributions and spatial structure of
accelerated electrons throughout solar eruptive events for the first
time by directly focusing hard X-rays from the Sun. This naturally
enables high imaging dynamic range, while previous instruments have
typically been blinded by bright emission. FOXSI provides 20-100 times
more sensitivity as well as 20 times faster imaging spectroscopy
than previously available, probing physically relevant timescales
(<1 second) never before accessible. FOXSI's launch in July 2022
is aligned with the peak of the 11-year solar cycle, enabling FOXSI
to observe the many large solar eruptions that are expected to take
place throughout its two-year mission.
Title: AWARE: An algorithm for the automated characterization of
EUV waves in the solar atmosphere
Authors: Ireland, Jack; Inglis, Andrew; Shih, Albert Y.; Christe,
Steven; Mumford, Stuart; Hayes, Laura A.; Thompson, Barbara J.;
Hughitt, V. Keith
Bibcode: 2019AAS...23410707I
Altcode:
Extreme ultraviolet (EUV) waves are large-scale propagating
disturbances observed in the solar corona, frequently associated with
coronal mass ejections and flares. They appear as faint, extended
structures propagating from a source region across the structured solar
corona. Since their discovery, over two hundred papers discussing their
properties, causes and physical nature have been published. However,
despite this their fundamental properties and the physics of their
interactions with other solar phenomena are still not understood. To
further the understanding of EUV waves, we have constructed the
Automated Wave Analysis and REduction (AWARE) algorithm for the
measurement of EUV waves. AWARE is implemented in two stages. In the
first stage, we use a new type of running difference image, the running
difference persistence image, which enables the efficient isolation
of propagating, brightening wavefronts as they propagate across the
corona. In the second stage, AWARE detects the presence of a wavefront,
and measures the distance, velocity and acceleration of that wavefront
across the Sun. The fit of propagation models to the wave progress
isolated in the first stage is achieved using the Random Sample and
Consensus (RANSAC) algorithm. AWARE is tested against simulations of EUV
wave propagation, and is applied to measure EUV waves in observational
data from the Atmospheric Imaging Assembly (AIA). We also comment on
unavoidable systematic errors that bias the estimation of wavefront
velocity and acceleration. In addition, the full AWARE software suite
comes with a package that creates simulations of waves propagating
across the disk from arbitrary starting points.
Title: Persistent Quasi-periodic Pulsations during a Large X-class
Solar Flare
Authors: Hayes, Laura A.; Gallagher, Peter T.; Dennis, Brian R.;
Ireland, Jack; Inglis, Andrew; Morosan, Diana E.
Bibcode: 2019ApJ...875...33H
Altcode: 2019arXiv190301328H
Solar flares often display pulsating and oscillatory signatures in the
emission, known as quasi-periodic pulsations (QPP). QPP are typically
identified during the impulsive phase of flares, yet in some cases,
their presence is detected late into the decay phase. Here, we report
extensive fine structure QPP that are detected throughout the large X8.2
flare from 2017 September 10. Following the analysis of the thermal
pulsations observed in the Geostationary Operational Environmental
Satellite/X-ray sensor and the 131 Å channel of Solar Dynamics
Observatory/Atmospheric Imaging Assembly, we find a pulsation period of
∼65 s during the impulsive phase followed by lower amplitude QPP with
a period of ∼150 s in the decay phase, up to three hours after the
peak of the flare. We find that during the time of the impulsive QPP,
the soft X-ray source observed with the Reuven Ramaty High Energy Solar
Spectroscopic Imager rapidly rises at a velocity of approximately 17 km
s-1 following the plasmoid/coronal mass ejection eruption. We
interpret these QPP in terms of a manifestation of the reconnection
dynamics in the eruptive event. During the long-duration decay phase
lasting several hours, extended downward contractions of collapsing
loops/plasmoids that reach the top of the flare arcade are observed
in EUV. We note that the existence of persistent QPP into the decay
phase of this flare are most likely related to these features. The
QPP during this phase are discussed in terms of magnetohydrodynamic
wave modes triggered in the post-flaring loops.
Title: MAVENSDC/cdflib: CDFLib 0.3.9
Authors: SDC, MAVEN; Stansby, David; Hirsch, Michael, Ph. D.; Harter,
Bryan; Ireland, Jack
Bibcode: 2019zndo...2543499S
Altcode:
A python module for reading NASA's Common Data Format (cdf) files
Title: Detection of Three-minute Oscillations in Full-disk Lyman-alpha
Emission during a Solar Flare
Authors: Milligan, Ryan O.; Fleck, Bernhard; Ireland, Jack; Fletcher,
Lyndsay; Dennis, Brian R.
Bibcode: 2018csc..confE..36M
Altcode:
In a recent study of spatially-integrated Lyman-alpha line emission
(Lya, 1216A) from GOES/EUVS, we detected the presence of acoustic
3-minute oscillations during an X-class solar flare. Similar
periodicities were also found - in phase - in Lyman continuum data from
SDO/EVE, and the 1600A and 1700A channels on SDO/AIA. The implication
is that the chromosphere responds dynamically at its acoustic cutoff
frequency to an impulsive injection of energy. Since the 3-minute
period was not detected at hard X-ray energies in RHESSI data we can
state that this 3-minute oscillation does not depend on the rate of
energisation of non-thermal electrons. This finding suggests that
chromospheric mechanical energy should be included in the flare
energy budget, and that fluctuations in Lya emission may influence
the composition and dynamics of planetary atmospheres during periods
of high activity. Knowledge of the behaviour of this emission during
flares could be important when interpreting future science results
from the EUI instrument on Solar Orbiter which will obtain high cadence
images in Lya.
Title: Power spectrum power-law indices as a diagnostic of coronal
heating
Authors: Ireland, Jack; Viall, Nicholeen; Bradshaw, Stephen; Kirk,
Michael
Bibcode: 2018csc..confE.119I
Altcode:
We investigate the coronal heating of active regions by bringing
together novel data analysis techniques with hydrodynamic modeling in
a new and unique way. Viall & Klimchuk 2011, 2012, 2014, 2017 have
shown that the timing of active region coronal emission brightenings
in multiple channels of Solar Dynamics Observatory Atmospheric
Imaging Assembly (SDO/AIA) follows that expected from simulations
of a nanoflare-heated corona. Using Numerical HYDrodynamic RADiative
Emission Model for the Solar Atmosphere (HYDRAD)-based simulations of
AIA emission for an AR, Bradshaw & Viall 2016 have shown that the
timing of coronal emission brightenings is dependent on the properties
of the nanoflare energy distribution and occurrence rate. Relatedly,
Ireland et al. 2015 show that average power spectra P(f) (where f is
frequency) of time series of AIA 171Å and 193Å AR images are dominated
by power laws, P(f) f^{-z}, z>0. Ireland et al. 2015 show that a
distribution of exponentially decaying events of emission E along the
line-of-sight, where N(E) E^{-m} and the size of the emission depends
on its duration T such that E T^{k} creates a power law power spectrum
P(f) f^{-k(2-m)}. We present analyses that test the hypothesis that
a distribution of nanoflare events causes both the emission power-law
power spectrum in AIA time-series as well as the observed brightening
time-lags. Firstly, we show that the power-law indices of Fourier power
spectra of the same simulated data described in Bradshaw & Viall
2016 depends on the frequency of nanoflares used. Secondly, using the
same observational AIA time-series data analyzed by Viall & Klimchuk
(2012), we obtain correlations of the cross-channel time-lags with the
power-law indices of Fourier power spectra in each AIA channel. Finally,
the ability of power-law indices and time-lags together to constrain
the underlying nanoflare frequency distribution is discussed.
Title: New developments and applications of Helioviewer Project
services
Authors: Vorobyev, Kirill; Ireland, Jack; Connolly, Rachel
Bibcode: 2018csc..confE.120V
Altcode:
The Helioviewer Project enables heliospheric data visualization,
supporting data from multiple missions and instruments. It enables the
visualization of petabytes of solar data from SDO and other missions,
and provides tools to create downloadable media, track solar events,
and access the science data behind the images. We discuss the latest
changes to Helioviewer Project services, in particular the web client
helioviewer.org, the provision of images from the Mauna Loa Solar
Observatory, and support for the labeling of celestial bodies and the
orbits of the Parker Solar Probe and the Solar Orbiter. We discuss
the use of the Helioviewer Project API to develop a helioviewer.org
user interface aligned with US middle and high school instructional
use, available at student.helioviewer.org, created specifically for
students. This client offers many of the same features of the fully
fledged helioviewer.org, but is streamlined to lower the barrier
to entry. This new client provides the means to access targeted
observation layers which serve to highlight a subset of the available
observations and events that are aligned with educational standards,
making it easier to dive-in and begin the process of discovery. The new
client student.helioviewer.org and associated educational resources,
has been developed in conjunction with WGBH's Bringing the Universe to
America's Classroom Project and distributed on PBS LearningMedia. We
discuss the usage of this client in comparison to helioviewer.org and
describe how student.helioviewer.org can drive a back-end redesign of
Helioviewer Project services to take full advantage of cloud computing
architectures.
Title: AWARE: An algorithm for the automated characterization of
EUV waves in the solar atmosphere
Authors: Ireland, Jack; Inglis, Andrew; Shih, Albert; Christe, Steven;
Mumford, Stuart; Hayes, Laura; Thompson, Barbara; Hughitt, Keith
Bibcode: 2018csc..confE..21I
Altcode:
Extreme ultraviolet (EUV) waves are large-scale propagating
disturbances observed in the solar corona, frequently associated with
coronal mass ejections and flares. They appear as faint, extended
structures propagating from a source region across the structured solar
corona. Since their discovery, over two hundred papers discussing their
properties, causes and physical nature have been published. However,
despite this their fundamental properties and the physics of their
interactions with other solar phenomena are still not understood. To
further the understanding of EUV waves, we have constructed the
Automated Wave Analysis and REduction (AWARE) algorithm for the
measurement of EUV waves. AWARE is implemented in two stages. In the
first stage, we use a new type of running difference image, the running
difference persistence image, which enables the efficient isolation
of propagating, brightening wavefronts as they propagate across the
corona. In the second stage, AWARE detects the presence of a wavefront,
and measures the distance, velocity and acceleration of that wavefront
across the Sun. The fit of propagation models to the wave progress
isolated in the first stage is achieved using the Random Sample and
Consensus (RANSAC) algorithm. AWARE is tested against simulations of EUV
wave propagation, and is applied to measure EUV waves in observational
data from the Atmospheric Imaging Assembly (AIA). We also comment on
unavoidable systematic errors that bias the estimation of wavefront
velocity and acceleration. In addition, the full AWARE software suite
comes with a package that creates simulations of waves propagating
across the disk from arbitrary starting points.
Title: Roadmap for Reliable Ensemble Forecasting of the Sun-Earth
System
Authors: Nita, Gelu; Angryk, Rafal; Aydin, Berkay; Banda, Juan;
Bastian, Tim; Berger, Tom; Bindi, Veronica; Boucheron, Laura; Cao,
Wenda; Christian, Eric; de Nolfo, Georgia; DeLuca, Edward; DeRosa,
Marc; Downs, Cooper; Fleishman, Gregory; Fuentes, Olac; Gary, Dale;
Hill, Frank; Hoeksema, Todd; Hu, Qiang; Ilie, Raluca; Ireland,
Jack; Kamalabadi, Farzad; Korreck, Kelly; Kosovichev, Alexander;
Lin, Jessica; Lugaz, Noe; Mannucci, Anthony; Mansour, Nagi; Martens,
Petrus; Mays, Leila; McAteer, James; McIntosh, Scott W.; Oria, Vincent;
Pan, David; Panesi, Marco; Pesnell, W. Dean; Pevtsov, Alexei; Pillet,
Valentin; Rachmeler, Laurel; Ridley, Aaron; Scherliess, Ludger; Toth,
Gabor; Velli, Marco; White, Stephen; Zhang, Jie; Zou, Shasha
Bibcode: 2018arXiv181008728N
Altcode:
The authors of this report met on 28-30 March 2018 at the New Jersey
Institute of Technology, Newark, New Jersey, for a 3-day workshop
that brought together a group of data providers, expert modelers, and
computer and data scientists, in the solar discipline. Their objective
was to identify challenges in the path towards building an effective
framework to achieve transformative advances in the understanding
and forecasting of the Sun-Earth system from the upper convection
zone of the Sun to the Earth's magnetosphere. The workshop aimed to
develop a research roadmap that targets the scientific challenge
of coupling observations and modeling with emerging data-science
research to extract knowledge from the large volumes of data (observed
and simulated) while stimulating computer science with new research
applications. The desire among the attendees was to promote future
trans-disciplinary collaborations and identify areas of convergence
across disciplines. The workshop combined a set of plenary sessions
featuring invited introductory talks and workshop progress reports,
interleaved with a set of breakout sessions focused on specific topics
of interest. Each breakout group generated short documents, listing
the challenges identified during their discussions in addition to
possible ways of attacking them collectively. These documents were
combined into this report-wherein a list of prioritized activities
have been collated, shared and endorsed.
Title: Tracing the Origins of the Solar Wind by Tracking Flows and
Disturbances in Coronagraph Data
Authors: Thompson, Barbara J.; Attie, Raphael; DeForest, Craig E.;
Gibson, Sarah E.; Hess Webber, Shea A.; Ireland, Jack; Kirk, Michael
S. F.; Kwon, Ryun Young; McGranaghan, Ryan; Viall, Nicholeen M.
Bibcode: 2018shin.confE..47T
Altcode:
The challenge of identifying transient motions in solar imagery has
been addressed in a number of ways. A variety of methods have been
developed to detect and characterize the motion and extent of coronal
mass ejections, for example. We discuss the adaptation of CME and
solar transient detection methods to trace smaller-scale perturbations
consistent with solar wind motions in the inner heliosphere (out to 10
RSun). We evaluate several methods, and compare the speed and structure
results to model predictions. In particular, we discuss how high-cadence
heliospheric imagery can be used to track small scale solar density
variations throughout the solar wind, serving as a proxy for in situ
velocity detection, but with global and continuous coverage.
Title: Tracking Flows and Disturbances in Coronagraph Data
Authors: Thompson, Barbara J.; Attie, Raphael; DeForest, Craig E.;
Gibson, Sarah E.; Hess Webber, Shea A.; Inglis, Anfew R.; Ireland,
Jack; Kirk, Michael S.; Kwon, RyunYoung; Viall, Nicholeen M.
Bibcode: 2018tess.conf30922T
Altcode:
The challenge of identifying transient motions in solar imagery has
been addressed in a number of ways. A variety of methods have been
developed to detect and characterize the motion and extent of coronal
mass ejections, for example. We discuss the adaptation of CME and
solar transient detection methods to trace smaller-scale perturbations
consistent with solar wind motions in the inner heliosphere (over 10
RSun). We evaluate several methods, and compare the speed and structure
results to model predictions. In particular, we discuss how high-cadence
heliospheric imagery can be used to track small scale solar density
variations throughout the solar wind, serving as a proxy for in situ
velocity detection, but with global and continuous coverage.
Title: The Focusing Optics X-ray Solar Imager (FOXSI)
Authors: Christe, Steven; Shih, Albert Y.; Krucker, Sam; Glesener,
Lindsay; Saint-Hilaire, Pascal; Caspi, Amir; Allred, Joel C.; Chen,
Bin; Battaglia, Marina; Drake, James Frederick; Gary, Dale E.; Goetz,
Keith; Gburek, Szymon; Grefenstette, Brian; Hannah, Iain G.; Holman,
Gordon; Hudson, Hugh S.; Inglis, Andrew R.; Ireland, Jack; Ishikawa,
Shin-nosuke; Klimchuk, James A.; Kontar, Eduard; Kowalski, Adam F.;
Massone, Anna Maria; Piana, Michele; Ramsey, Brian; Schwartz, Richard;
Steslicki, Marek; Ryan, Daniel; Warmuth, Alexander; Veronig, Astrid;
Vilmer, Nicole; White, Stephen M.; Woods, Thomas N.
Bibcode: 2018tess.conf40444C
Altcode:
We present FOXSI (Focusing Optics X-ray Solar Imager), a Small Explorer
(SMEX) Heliophysics mission that is currently undergoing a Phase A
concept study. FOXSI will provide a revolutionary new perspective on
energy release and particle acceleration on the Sun. FOXSI's primary
instrument, the Direct Spectroscopic Imager (DSI), is a direct imaging
X-ray spectrometer with higher dynamic range and better than 10x the
sensitivity of previous instruments. Flown on a 3-axis-stabilized
spacecraft in low-Earth orbit, DSI uses high-angular-resolution
grazing-incidence focusing optics combined with state-of-the-art
pixelated solid-state detectors to provide direct imaging of solar hard
X-rays for the first time. DSI is composed of a pair of X-ray telescopes
with a 14-meter focal length enabled by a deployable boom. DSI has a
field of view of 9 arcminutes and an angular resolution of better than 8
arcsec FWHM; it will cover the energy range from 3 up to 50-70 keV with
a spectral resolution of better than 1 keV. DSI will measure each photon
individually and will be able to create useful images at a sub-second
temporal resolution. FOXSI will also measure soft x-ray emission down
to 0.8 keV with a 0.25 keV resolution with its secondary instrument,
the Spectrometer for Temperature and Composition (STC) provided by
the Polish Academy of Sciences. Making use of an attenuator-wheel and
high-rate-capable detectors, FOXSI will be able to observe the largest
flares without saturation while still maintaining the sensitivity to
detect X-ray emission from weak flares, escaping electrons, and hot
active regions. This presentation will cover the data products and
software that can be expected from FOXSI and how they could be used
by the community.
Title: SunPy: Python for Solar Physics
Authors: Ireland, Jack
Bibcode: 2018tess.conf40442I
Altcode:
SunPy is a community-developed open-source software library for
solar physics. It is written in Python, a free, cross-platform,
general-purpose, high-level programming language which is being
increasingly adopted throughout the scientific community. SunPy aims to
provide the software for obtaining and analyzing solar and heliospheric
data. This poster introduces a new major release, SunPy version 0.8. The
first major new feature introduced is Fido, the new primary interface to
download data. It provides a consistent and powerful search interface
to all major data providers including the VSO and the JSOC, as well as
individual data sources such as GOES XRS time series. It is also easy
to add new data sources as they become available, i.e. DKIST. The
second major new feature is the SunPy coordinate framework. This
provides a powerful way of representing coordinates, allowing simple
and intuitive conversion between coordinate systems and viewpoints of
different instruments (i.e., Solar Orbiter and the Parker Solar Probe),
including transformation to astrophysical frames like ICRS. Other new
features including new timeseries capabilities with better support
for concatenation and metadata, updated documentation and example
gallery. SunPy is distributed through pip and conda and all of its
code is publicly available (sunpy.org).
Title: On the Performance of Multi-Instrument Solar Flare Observations
During Solar Cycle 24
Authors: Milligan, Ryan O.; Ireland, Jack
Bibcode: 2018tess.conf40802M
Altcode:
Our current fleet of space-based solar observatories offer us a wealth
of opportunities to study solar flares over a range of wavelengths,
and the greatest advances in our understanding of flare physics often
come from coordinated observations between different instruments. While
many current missions/instruments have their own individual flare
lists, there has been little or no effort into cataloging which flares
have been observed by various combinations of instruments. In this
study we present an evaluation of how well the solar community has
performed in jointly observing solar flares - either intentionally or
serendipitously - during a 6.5 year period spanning the peak of Solar
Cycle 24. We consider all flares greater than GOES class C1, that
may have been observed by RHESSI, SDO/EVE (MEGS-A and -B), EIS, SOT,
and XRT on Hinode, and IRIS. Out of the 6953 flares that we consider,
40 were jointly observed by either 6 or all 7 instruments. Using each
instrument's individual rate of success in observing flares, we show
that the number of flares co-observed by 3 or more instruments is higher
than the number expected under the assumption that the instruments
operated independently of one another. Our study illustrates that these
missions often acted in cooperation, or at least had aligned goals. The
difficulty in scheduling coordinated observations for solar-flare
research is discussed with respect to instruments projected to begin
operations during Solar Cycle 25, such as the Daniel K. Inouye Solar
Telescope, Solar Orbiter, and Parker Solar Probe.
Title: Understanding the usage of the Helioviewer Project clients
and services
Authors: Ireland, Jack; Zahniy, Serge; Mueller, Daniel; Nicula, Bogdan;
Verstringe, Freek; Bourgoignie, Bram; Buchlin, Eric; Alingery, Pablo
Bibcode: 2018tess.conf30286I
Altcode:
The Helioviewer Project enables visual exploration of the Sun
and the inner heliosphere for everyone, everywhere via intuitive
interfaces and novel technology. The project mainly develops two
clients, helioviewer.org and JHelioviewer, and the server-side
capabilities accessed via those clients. Images from many different
ground and space-based sources are currently available from multiple
servers. Solar and heliospheric feature and event information,
magnetic field extrapolations and important time-series can also be
browsed and visualized using Helioviewer Project clients. Users of the
Helioviewer Project have made over two million movies and many millions
of screenshots since detailed (and anonymous) logging of Helioviewer
Project usage was implemented in February 2011. These usage logs are
analyzed to give a detailed breakdown on user interaction with solar
and heliospheric data via Helioviewer Project clients and services. We
present summary statistics on how our users are using our clients
and services, which data they are interested in, and how they choose
to interact with different data sources. At the poster presentation
we will also be soliciting ideas from the community to improve our
clients and services.
Title: VizieR Online Data Catalog: Quasi-periodic pulsations in
solar flares (Inglis+, 2016)
Authors: Inglis, A. R.; Ireland, J.; Dennis, B. R.; Hayes, L.;
Gallagher, P.
Bibcode: 2018yCat..18330284I
Altcode:
We have used data from the Geostationary Operational Environmental
Satellite (GOES) instrument series, and from Fermi/Gamma-ray Burst
Monitor (GBM). For this reason, we choose the interval 2011 February 1
- 2015 December 31, as it not only coincides with the availability of
GOES-15 satellite data, but also includes regular solar observations
by GBM. GOES satellites are equipped with solar X-ray detectors
that record the incident flux in the 0.5-4Å and 1-8Å wavelength
ranges. Solar X-ray data from the most recent satellite, GOES-15,
has been available since 2010 at a nominal 2s cadence. To access the
GOES catalog, we use the Heliophysics Event Knowledgebase (HEK). Fermi/GBM operates in the 8keV-40MeV range and regularly observes
emission from solar flares, with a solar duty cycle of ~60%, similar
to the solar-dedicated Reuven Ramaty High Energy Solar Spectroscopic
Imager (RHESSI). To accumulate the database of Fermi/GBM events,
we use the GBM trigger catalog produced by the instrument team,
selecting all events marked as flares. (2 data files).
Title: On the Performance of Multi-Instrument Solar Flare Observations
During Solar Cycle 24
Authors: Milligan, Ryan O.; Ireland, Jack
Bibcode: 2018SoPh..293...18M
Altcode: 2017arXiv170304412M
The current fleet of space-based solar observatories offers us
a wealth of opportunities to study solar flares over a range of
wavelengths. Significant advances in our understanding of flare
physics often come from coordinated observations between multiple
instruments. Consequently, considerable efforts have been, and continue
to be, made to coordinate observations among instruments (e.g. through
the Max Millennium Program of Solar Flare Research). However, there
has been no study to date that quantifies how many flares have been
observed by combinations of various instruments. Here we describe a
technique that retrospectively searches archival databases for flares
jointly observed by the Ramaty High Energy Solar Spectroscopic Imager
(RHESSI), Solar Dynamics Observatory (SDO)/EUV Variability Experiment
(EVE - Multiple EUV Grating Spectrograph (MEGS)-A and -B, Hinode/(EUV
Imaging Spectrometer, Solar Optical Telescope, and X-Ray Telescope),
and Interface Region Imaging Spectrograph (IRIS). Out of the 6953
flares of GOES magnitude C1 or greater that we consider over the 6.5
years after the launch of SDO, 40 have been observed by 6 or more
instruments simultaneously. Using each instrument's individual rate
of success in observing flares, we show that the numbers of flares
co-observed by 3 or more instruments are higher than the number expected
under the assumption that the instruments operated independently of
one another. In particular, the number of flares observed by larger
numbers of instruments is much higher than expected. Our study
illustrates that these missions often acted in cooperation, or at
least had aligned goals. We also provide details on an interactive
widget (Solar Flare Finder), now available in SSWIDL, which allows
a user to search for flaring events that have been observed by a
chosen set of instruments. This provides access to a broader range of
events in order to answer specific science questions. The difficulty
in scheduling coordinated observations for solar-flare research is
discussed with respect to instruments projected to begin operations
during Solar Cycle 25, such as the Daniel K. Inouye Solar Telescope,
Solar Orbiter, and Parker Solar Probe.
Title: Studying the Kinematic Behavior of Coronal Mass Ejections
and Other Solar Phenomena using the Time-Convolution Mapping Method
Authors: Hess Webber, Shea A.; Thompson, Barbara J.; Kwon, Ryun Young;
Ireland, Jack
Bibcode: 2018AAS...23131504H
Altcode:
An improved understanding of the kinematic properties of CMEs and
CME-associated phenomena has several impacts: 1) a less ambiguous
method of mapping propagating structures into their inner coronal
manifestations, 2) a clearer view of the relationship between the
“main” CME and CME-associated brightenings, and 3) an improved
identification of the heliospheric sources of shocks, Type II
bursts, and SEPs. We present the results of a mapping technique that
facilitates the separation of CMEs and CME-associated brightenings
(such as shocks) from background corona. The Time Convolution Mapping
Method (TCMM) segments coronagraph data to identify the time history
of coronal evolution, the advantage being that the spatiotemporal
evolution profiles allow users to separate features with different
propagation characteristics. For example, separating “main”
CME mass from CME-associated brightenings or shocks is a well-known
obstacle, which the TCMM aids in differentiating. A TCMM CME map is
made by first recording the maximum value each individual pixel in
the image reaches during the traversal of the CME. Then the maximum
value is convolved with an index to indicate the time that the pixel
reached that value. The TCMM user is then able to identify continuous
“kinematic profiles,” indicating related kinematic behavior, and
also identify breaks in the profiles that indicate a discontinuity in
kinematic history (i.e. different structures or different propagation
characteristics). The maps obtained from multiple spacecraft viewpoints
(i.e., STEREO and SOHO) can then be fit with advanced structural models
to obtain the 3D properties of the evolving phenomena. We will also
comment on the TCMM's further applicability toward the tracking of
prominences, coronal hole boundaries and coronal cavities.
Title: Detection of 3-Minute Oscillations in Full-Disk Lyman-alpha
Emission During A Solar Flare
Authors: Milligan, R. O.; Ireland, J.; Fleck, B.; Hudson, H. S.;
Fletcher, L.; Dennis, B. R.
Bibcode: 2017AGUFMSH41A2739M
Altcode:
We report the detection of chromospheric 3-minute oscillations in
disk-integrated EUV irradiance observations during a solar flare. A
wavelet analysis of detrended Lyman-alpha (from GOES/EUVS) and
Lyman continuum (from SDO/EVE) emission from the 2011 February 15
X-class flare revealed a 3-minute period present during the flare's
main phase. The formation temperature of this emission locates this
radiation to the flare's chromospheric footpoints, and similar behaviour
is found in the SDO/AIA 1600A and 1700A channels, which are dominated
by chromospheric continuum. The implication is that the chromosphere
responds dynamically at its acoustic cutoff frequency to an impulsive
injection of energy. Since the 3-minute period was not found at hard
X-ray energies (50-100 keV) in RHESSI data we can state that this
3-minute oscillation does not depend on the rate of energization of, or
energy deposition by, non-thermal electrons. However, a second period of
120 s found in both hard X-ray and chromospheric emission is consistent
with episodic electron energization on 2-minute timescales. Our
finding on the 3-minute oscillation suggests that chromospheric
mechanical energy should be included in the flare energy budget, and
the fluctuations in the Lyman-alpha line may influence the composition
and dynamics of planetary atmospheres during periods of high activity.
Title: The Focusing Optics X-ray Solar Imager (FOXSI) SMEX Mission
Authors: Christe, S.; Shih, A. Y.; Krucker, S.; Glesener, L.;
Saint-Hilaire, P.; Caspi, A.; Allred, J. C.; Battaglia, M.; Chen, B.;
Drake, J. F.; Gary, D. E.; Goetz, K.; Gburek, S.; Grefenstette, B.;
Hannah, I. G.; Holman, G.; Hudson, H. S.; Inglis, A. R.; Ireland,
J.; Ishikawa, S. N.; Klimchuk, J. A.; Kontar, E.; Kowalski, A. F.;
Massone, A. M.; Piana, M.; Ramsey, B.; Schwartz, R.; Steslicki, M.;
Turin, P.; Ryan, D.; Warmuth, A.; Veronig, A.; Vilmer, N.; White,
S. M.; Woods, T. N.
Bibcode: 2017AGUFMSH44A..07C
Altcode:
We present FOXSI (Focusing Optics X-ray Solar Imager), a Small Explorer
(SMEX) Heliophysics mission that is currently undergoing a Phase A
concept study. FOXSI will provide a revolutionary new perspective
on energy release and particle acceleration on the Sun. FOXSI is
a direct imaging X-ray spectrometer with higher dynamic range and
better than 10x the sensitivity of previous instruments. Flown
on a 3-axis-stabilized spacecraft in low-Earth orbit, FOXSI uses
high-angular-resolution grazing-incidence focusing optics combined
with state-of-the-art pixelated solid-state detectors to provide direct
imaging of solar hard X-rays for the first time. FOXSI is composed of
a pair of x-ray telescopes with a 14-meter focal length enabled by a
deployable boom. Making use of a filter-wheel and high-rate-capable
solid-state detectors, FOXSI will be able to observe the largest flares
without saturation while still maintaining the sensitivity to detect
x-ray emission from weak flares, escaping electrons, and hot active
regions. This mission concept is made possible by past experience with
similar instruments on two FOXSI sounding rocket flights, in 2012 and
2014, and on the HEROES balloon flight in 2013. FOXSI's hard X-ray
imager has a field of view of 9 arcminutes and an angular resolution
of better than 8 arcsec; it will cover the energy range from 3 up to
50-70 keV with a spectral resolution of better than 1 keV; and it will
have sub-second temporal resolution.
Title: Quasi-Periodic Pulsations in the Earth's Ionosphere
Synchronized with Solar Flare Emission
Authors: Hayes, L.; Gallagher, P.; McCauley, J.; Dennis, B. R.;
Ireland, J.; Inglis, A. R.
Bibcode: 2017AGUFMSH51C2514H
Altcode:
Solar flare activity is a powerful factor affecting the geophysical
processes in the Earth's ionosphere. In particular, X-ray photons with
wavelength < 10 A can penetrate down to the D-region ( 60-90 km in
altitude) resulting in a dramatic increase of ionization in this lowest
lying region of the Earth's ionosphere. This manifests as a substantial
enhancement of electron density height profile at these altitudes to
extents large enough to change the propagation conditions for Very
Low Frequency (VLF 3-30 kHz) radio waves that travel in the waveguide
formed by the Earth and the lower ionosphere. Recently, it has become
clear that flares exhibit quasi-periodic pulsations with periods of
seconds to minutes at EUV, X-ray and gamma-ray wavelengths. To date,
it has not been known if the Earth's ionosphere is sensitive to these
dynamic solar pulsations. Here, we report ionospheric pulsations with
periods of 20 minutes that are synchronized with a set of pulsating
flare loops using VLF observations of the ionospheric D-layer together
with X-ray and EUV observations of a solar flare from the NOAA/GOES
and NASA/SDO satellites. Modeling of the ionosphere show that the
D-region electron density varies by up to an order of magnitude over
the timescale of the pulsations. Our results show that the Earth's
ionosphere is more sensitive to small-scale changes in solar activity
than previously thought.
Title: Anticipated Results from the FOXSI SMEX Mission
Authors: Shih, A. Y.; Christe, S.; Krucker, S.; Glesener, L.;
Saint-Hilaire, P.; Caspi, A.; Allred, J. C.; Battaglia, M.; Chen, B.;
Drake, J. F.; Gary, D. E.; Gburek, S.; Goetz, K.; Grefenstette, B.;
Gubarev, M.; Hannah, I. G.; Holman, G.; Hudson, H. S.; Inglis, A. R.;
Ireland, J.; Ishikawa, S. N.; Klimchuk, J. A.; Kontar, E.; Kowalski,
A. F.; Massone, A. M.; Piana, M.; Ramsey, B.; Ryan, D.; Schwartz,
R.; Steslicki, M.; Turin, P.; Veronig, A.; Vilmer, N.; Warmuth, A.;
White, S. M.; Woods, T. N.
Bibcode: 2017AGUFMSH43C..03S
Altcode:
While there have been significant advances in our understanding
of impulsive energy release at the Sun since the advent of RHESSI
observations, there is a clear need for new X-ray observations that
can capture the full range of emission in flares (e.g., faint coronal
sources near bright chromospheric sources), follow the intricate
evolution of energy release and changes in morphology, and search
for the signatures of impulsive energy release in even the quiescent
Sun. The FOXSI Small Explorer (SMEX) mission, currently undergoing a
Phase A concept study, combines state-of-the-art grazing-incidence
focusing optics with pixelated solid-state detectors to provide
direct imaging of hard X-rays for the first time on a solar
observatory. FOXSI's X-ray observations will provide quantitative
information on (1) the non-thermal populations of accelerated electrons
and (2) the thermal plasma distributions at the high temperatures
inaccessible through other wavelengths. FOXSI's major science questions
include: Where are electrons accelerated and on what time scales? Where
do escaping flare-accelerated electrons originate? What is the energy
input of accelerated electrons into the chromosphere and corona? How
much do flare-like processes heat the corona above active regions? Here
we present examples with simulated observations to show how FOXSI's
capabilities will address and resolve these and other questions.
Title: Understanding the usage of the Helioviewer Project clients
and services
Authors: Ireland, J.; Zahniy, S.; Mueller, D.; Nicula, B.; Verstringe,
F.; Bourgoignie, B.; Buchlin, E.; Alingery, P.
Bibcode: 2017AGUFMSH51C2507I
Altcode:
The Helioviewer Project enables visual exploration of the Sun
and the inner heliosphere for everyone, everywhere via intuitive
interfaces and novel technology. The project mainly develops two
clients, helioviewer.org and JHelioviewer, and the server-side
capabilities accessed via those clients. Images from many different
ground and space-based sources are currently available from multiple
servers. Solar and heliospheric feature and event information,
magnetic field extrapolations and important time-series can also be
browsed and visualized using Helioviewer Project clients. Users of the
Helioviewer Project have made over two million movies and many millions
of screenshots since detailed (and anonymous) logging of Helioviewer
Project usage was implemented in February 2011. These usage logs are
analyzed to give a detailed breakdown on user interaction with solar
and heliospheric data via Helioviewer Project clients and services. We
present summary statistics on how our users are using our clients
and services, which data they are interested in, and how they choose
to interact with different data sources. At the poster presentation
we will also be soliciting ideas from the community to improve our
clients and services.
Title: 3D Visualization of Solar Data: Preparing for Solar Orbiter
and Parker Solar Probe
Authors: Mueller, D.; Nicula, B.; Felix, S.; Verstringe, F.;
Bourgoignie, B.; Csillaghy, A.; Berghmans, D.; Jiggens, P.; Ireland,
J.; Fleck, B.
Bibcode: 2017AGUFMSH23D2686M
Altcode:
Solar Orbiter and Parker Solar Probe will focus on exploring the
linkage between the Sun and the heliosphere. These new missions will
collect unique data that will allow us to study, e.g., the coupling
between macroscopic physical processes to those on kinetic scales,
the generation of solar energetic particles and their propagation
into the heliosphere and the origin and acceleration of solar wind
plasma. Combined with the several petabytes of data from NASA's Solar
Dynamics Observatory, the scientific community will soon have access
to multidimensional remote-sensing and complex in-situ observations
from different vantage points, complemented by petabytes of simulation
data. Answering overarching science questions like "How do solar
transients drive heliospheric variability and space weather?" will
only be possible if the community has the necessary tools at hand. In
this contribution, we will present recent progress in visualizing the
Sun and its magnetic field in 3D using the open-source JHelioviewer
framework, which is part of the ESA/NASA Helioviewer Project.
Title: SunPy: Python for Solar Physics
Authors: Bobra, M.; Inglis, A. R.; Mumford, S.; Christe, S.; Freij,
N.; Hewett, R.; Ireland, J.; Martinez Oliveros, J. C.; Reardon, K.;
Savage, S. L.; Shih, A. Y.; Pérez-Suárez, D.
Bibcode: 2017AGUFMSH51C2508B
Altcode:
SunPy is a community-developed open-source software library for
solar physics. It is written in Python, a free, cross-platform,
general-purpose, high-level programming language which is being
increasingly adopted throughout the scientific community. SunPy aims to
provide the software for obtaining and analyzing solar and heliospheric
data. This poster introduces a new major release, SunPy version 0.8. The
first major new feature introduced is Fido, the new primary interface to
download data. It provides a consistent and powerful search interface
to all major data providers including the VSO and the JSOC, as well as
individual data sources such as GOES XRS time series. It is also easy
to add new data sources as they become available, i.e. DKIST. The
second major new feature is the SunPy coordinate framework. This
provides a powerful way of representing coordinates, allowing simple
and intuitive conversion between coordinate systems and viewpoints of
different instruments (i.e., Solar Orbiter and the Parker Solar Probe),
including transformation to astrophysical frames like ICRS. Other new
features including new timeseries capabilities with better support
for concatenation and metadata, updated documentation and example
gallery. SunPy is distributed through pip and conda and all of its
code is publicly available (sunpy.org).
Title: Detection of Three-minute Oscillations in Full-disk Lyα
Emission during a Solar Flare
Authors: Milligan, Ryan O.; Fleck, Bernhard; Ireland, Jack; Fletcher,
Lyndsay; Dennis, Brian R.
Bibcode: 2017ApJ...848L...8M
Altcode: 2017arXiv170909037M
In this Letter we report the detection of chromospheric 3-minute
oscillations in disk-integrated EUV irradiance observations during a
solar flare. A wavelet analysis of detrended Lyα (from GOES/EUVS) and
Lyman continuum (from Solar Dynamics Observatory (SDO)/EVE) emission
from the 2011 February 15 X-class flare (SOL2011-02-15T01:56) revealed
a ∼3 minute period present during the flare’s main phase. The
formation temperature of this emission locates this radiation at the
flare’s chromospheric footpoints, and similar behavior is found
in the SDO/Atmospheric Imaging Assembly 1600 and 1700 Å channels,
which are dominated by chromospheric continuum. The implication is
that the chromosphere responds dynamically at its acoustic cutoff
frequency to an impulsive injection of energy. Since the 3-minute
period was not found at hard X-ray (HXR) energies (50-100 keV) in
Reuven Ramaty High Energy Solar Spectroscopic Imager data we can
state that this 3-minute oscillation does not depend on the rate of
energization of non-thermal electrons. However, a second period of 120
s found in both HXR and chromospheric lightcurves is consistent with
episodic electron energization on 2-minute timescales. Our finding on
the 3-minute oscillation suggests that chromospheric mechanical energy
should be included in the flare energy budget, and the fluctuations in
the Lyα line may influence the composition and dynamics of planetary
atmospheres during periods of high activity.
Title: Pulsations in the Earth's Lower Ionosphere Synchronized With
Solar Flare Emission
Authors: Hayes, Laura A.; Gallagher, Peter T.; McCauley, Joseph;
Dennis, Brian R.; Ireland, Jack; Inglis, Andrew
Bibcode: 2017JGRA..122.9841H
Altcode: 2017arXiv171001725H
Solar flare emission at X-ray and extreme ultraviolet (EUV) energies
can cause substantial enhancements in the electron density in the
Earth's lower ionosphere. It has now become clear that flares exhibit
quasi-periodic pulsations with timescales of minutes at X-ray energies,
but to date, it has not been known if the ionosphere is sensitive to
this variability. Here using a combination of very low frequency (24
kHz) measurement together with space-based X-ray and EUV observations,
we report pulsations of the ionospheric D region, which are synchronized
with a set of pulsating flare loops. Modeling of the ionosphere show
that the D region electron density varies by up to an order of magnitude
over the timescale of the pulsations (∼ 20 min). Our results reveal
that the Earth's ionosphere is more sensitive to small-scale changes
in solar soft X-ray flux than previously thought and implies that
planetary ionospheres are closely coupled to small-scale changes in
solar/stellar activity.
Title: JHelioviewer. Time-dependent 3D visualisation of solar and
heliospheric data
Authors: Müller, D.; Nicula, B.; Felix, S.; Verstringe, F.;
Bourgoignie, B.; Csillaghy, A.; Berghmans, D.; Jiggens, P.;
García-Ortiz, J. P.; Ireland, J.; Zahniy, S.; Fleck, B.
Bibcode: 2017A&A...606A..10M
Altcode: 2017arXiv170507628M
Context. Solar observatories are providing the world-wide community
with a wealth of data, covering wide time ranges (e.g. Solar and
Heliospheric Observatory, SOHO), multiple viewpoints (Solar TErrestrial
RElations Observatory, STEREO), and returning large amounts of data
(Solar Dynamics Observatory, SDO). In particular, the large volume of
SDO data presents challenges; the data are available only from a few
repositories, and full-disk, full-cadence data for reasonable durations
of scientific interest are difficult to download, due to their size
and the download rates available to most users. From a scientist's
perspective this poses three problems: accessing, browsing, and finding
interesting data as efficiently as possible.
Aims: To address
these challenges, we have developed JHelioviewer, a visualisation
tool for solar data based on the JPEG 2000 compression standard
and part of the open source ESA/NASA Helioviewer Project. Since the
first release of JHelioviewer in 2009, the scientific functionality
of the software has been extended significantly, and the objective
of this paper is to highlight these improvements.
Methods:
The JPEG 2000 standard offers useful new features that facilitate the
dissemination and analysis of high-resolution image data and offers
a solution to the challenge of efficiently browsing petabyte-scale
image archives. The JHelioviewer software is open source, platform
independent, and extendable via a plug-in architecture.
Results: With JHelioviewer, users can visualise the Sun for any time
period between September 1991 and today; they can perform basic image
processing in real time, track features on the Sun, and interactively
overlay magnetic field extrapolations. The software integrates solar
event data and a timeline display. Once an interesting event has
been identified, science quality data can be accessed for in-depth
analysis. As a first step towards supporting science planning of the
upcoming Solar Orbiter mission, JHelioviewer offers a virtual camera
model that enables users to set the vantage point to the location of
a spacecraft or celestial body at any given time.
Title: Improving Our Understanding of the 3D Coronal Evolution of
CME Propagation
Authors: Hess Webber, Shea A.; Thompson, Barbara J.; Ireland, Jack;
Kwon, Ryun Young
Bibcode: 2017SPD....4820603H
Altcode:
An improved understanding of the kinematic properties of CMEs and
CME-associated phenomena has several impacts: 1) a less ambiguous
method of mapping propagating structures into their inner coronal
manifestations, 2) a clearer view of the relationship between the
“main” CME and CME-associated brightenings, and 3) an improved
identification of the heliospheric sources of shocks, Type II
bursts, and SEPs. We present the results of a mapping technique that
facilitates the separation of CMEs and CME-associated brightenings
(such as shocks) from background corona. The Time Convolution Mapping
Method (TCMM) segments coronagraph data to identify the time history
of coronal evolution, the advantage being that the spatiotemporal
evolution profiles allow users to separate features with different
propagation characteristics. For example, separating “main”
CME mass from CME-associated brightenings or shocks is a well-known
obstacle, which the TCMM aids in differentiating. A TCMM CME map is
made by first recording the maximum value each individual pixel in
the image reaches during the traversal of the CME. Then the maximum
value is convolved with an index to indicate the time that the pixel
reached that value. The TCMM user is then able to identify continuous
“kinematic profiles,” indicating related kinematic behavior, and
also identify breaks in the profiles that indicate a discontinuity in
kinematic history (i.e. different structures or different propagation
characteristics). The maps obtained from multiple spacecraft viewpoints
(i.e., STEREO and SOHO) can then be fit with advanced structural models
to obtain the 3D properties of the evolving phenomena.
Title: SunPy 0.8 - Python for Solar Physics
Authors: Inglis, Andrew; Bobra, Monica; Christe, Steven; Hewett,
Russell; Ireland, Jack; Mumford, Stuart; Martinez Oliveros, Juan
Carlos; Perez-Suarez, David; Reardon, Kevin P.; Savage, Sabrina;
Shih, Albert Y.; Ryan, Daniel; Sipocz, Brigitta; Freij, Nabil
Bibcode: 2017SPD....4811506I
Altcode:
SunPy is a community-developed open-source software library for
solar physics. It is written in Python, a free, cross-platform,
general-purpose, high-level programming language which is being
increasingly adopted throughout the scientific community. Python is
one of the top ten most often used programming languages, as such
it provides a wide array of software packages, such as numerical
computation (NumPy, SciPy), machine learning (scikit-learn), signal
processing (scikit-image, statsmodels) to visualization and plotting
(matplotlib, mayavi). SunPy aims to provide the software for obtaining
and analyzing solar and heliospheric data. This poster introduces
a new major release of SunPy (0.8). This release includes two major
new functionalities, as well as a number of bug fixes. It is based on
1120 contributions from 34 unique contributors. Fido is the new primary
interface to download data. It provides a consistent and powerful search
interface to all major data sources provides including VSO, JSOC, as
well as individual data sources such as GOES XRS time series and and is
fully pluggable to add new data sources, i.e. DKIST. In anticipation of
Solar Orbiter and the Parker Solar Probe, SunPy now provides a powerful
way of representing coordinates, allowing conversion between coordinate
systems and viewpoints of different instruments, including preliminary
reprojection capabilities. Other new features including new timeseries
capabilities with better support for concatenation and metadata, updated
documentation and example gallery. SunPy is distributed through pip
and conda and all of its code is publicly available (sunpy.org).
Title: Searching for evidence of quasi-periodic pulsations in solar
flares using the AFINO code
Authors: Inglis, Andrew; Ireland, Jack; Dennis, Brian R.; Hayes,
Laura Ann; Gallagher, Peter T.
Bibcode: 2017SPD....4840005I
Altcode:
The AFINO (Automated Flare Inference of Oscillations) code is a new
tool to allow analysis of temporal solar data in search of oscillatory
signatures. Using AFINO, we carry out a large-scale search for evidence
of signals consistent with quasi-periodic pulsations (QPP) in solar
flares, focusing on the 1-300 s timescale. We analyze 675 M- and X-class
flares observed by GOES in 1-8 Å soft X-rays between 2011 February
1 and 2015 December 31. Additionally, over the same era we analyze
Fermi/GBM 15-25 keV X-ray data for each of these flares associated
with a GBM solar flare trigger, a total of 261 events. Using a model
comparison method and the Bayesian Information Criterion statistic,
we determine whether there is evidence for a substantial enhancement
in the Fourier power spectrum that may be consistent with a QPP-like
signature.Quasi-steady periodic signatures appear more prevalently in
thermal soft X-ray data than in the counterpart hard X-ray emission:
according to AFINO ~30% of GOES flares but only ~8% of the same
flares observed by GBM show strong signatures consistent with
classical interpretations of QPP, which include MHD wave processes
and oscillatory reconnection events. For both datasets, preferred
characteristic timescales of ~5-30 s were found in the QPP-like events,
with no clear dependence on flare magnitude. Individual events in the
sample also show similar characteristic timescales in both GBM and GOES
data sets, indicating that the same phenomenon is sometimes observed
simultaneously in soft and hard X-rays. We discuss the implications
of these survey results, and future developments of the analysis
method. AFINO continues to run daily on new flares observed by GOES,
and the full AFINO catalogue is made available online.
Title: Thermal Time Evolution of Non-Flaring Active Regions Determined
by SDO/AIA
Authors: Wright, Paul James; Hannah, Iain; Viall, Nicholeen; MacKinnon,
Alexander; Ireland, Jack; Bradshaw, Stephen
Bibcode: 2017SPD....4840203W
Altcode:
We present the pixel-level time evolution of DEM maps from SDO/AIA
data using two different methods (Hannah et al. 2012; Cheung et
al. 2015). These sets of Differential Emission Measure (DEM) maps
allow us to determine the slopes of the DEM throughout non-flaring
structures, and investigate how this changes with time, a crucial
parameter in terms of how these flux tubes are being heated. We
present this analysis on both real and synthetic data allowing us to
understand how robustly we can recover the thermal time evolution. As
this analysis also produces the time series in different temperature
bands we can further investigate the underlying heating mechanisms by
applying a variety of techniques to probe the frequency and nature of
the heating, such as time-lag analysis (Viall & Klimchuck 2012;
2016), power spectrum analysis (Ireland et al. 2015), and Local
Intermittency Measure (Dinkelaker & MacKinnon 2013a,b).
Title: Probing the Smallest Solar Scales Available in AIA
Authors: Kirk, Michael S.; Ireland, Jack; Young, C. Alex
Bibcode: 2017SPD....4820706K
Altcode:
The solar imaging axiom, “the closer we look, the more we see,”
is as true now in the era of routine sub-arcsecond imaging as it has
ever been. To make the most of these images and observe features at
the instrumental limits of spatial and temporal resolution, we must
first effectively assess and remove image noise. Noise is present in
any measurement due to both instrumental and random effects. At the
pixel scale, the noise component of the image can become significant
and impede feature recognition and segmentation. A Poisson-Gaussian
model of noise is well suited in the digital imaging environment due
to the statistical distributions of photons and the characteristics
of the CCD. We create a practical estimate of noise in the AIA images
across the detector CCD using a variety of statistical techniques. We
find that at the smallest scales, spatial and temporal signals are
linked. This means that it is impossible to estimate and remove the
noise at the smallest spatial scales without considering the temporal
changes between images.
Title: The 2012 November 20 impulsive SEP event: likely sources and
their properties
Authors: Ireland, Jack; de Nolfo, Georgia; Fleishman, Gregory; Ryan,
James; Gary, Dale
Bibcode: 2017shin.confE..84I
Altcode:
Helium-3 (3He) enriched impulsive events are one of the most common
phenomena associated with eruptive events on the Sun. In most cases,
impulsive ions are associated with increases in electron intensity,
though not always. We examine an unusual event in which 3He ions were
abundant but there was no detectable accompanying electron signature. We
derive injections times from 3He ions observed with ACE/ULEIS and
LEMPT/WIND that are consistent with jets emanating from either of
two active regions on the Sun. Both active regions exhibit jetting
features but only one has type III radio emission associated with it. We
evaluate the potential for ion and electron acceleration and escape}
within these two regions using the Nonlinear Force-Free Field (NLFFF)
extrapolation of the underlying magnetic field and discuss scenarios
of ion acceleration with suppressed electron acceleration.
Title: Detection and Interpretation of Long-lived X-Ray Quasi-periodic
Pulsations in the X-class Solar Flare on 2013 May 14
Authors: Dennis, Brian R.; Tolbert, Anne K.; Inglis, Andrew; Ireland,
Jack; Wang, Tongjiang; Holman, Gordon D.; Hayes, Laura A.; Gallagher,
Peter T.
Bibcode: 2017ApJ...836...84D
Altcode: 2017arXiv170603689D
Quasi-periodic pulsations (QPP) seen in the time derivative of the
GOES soft X-ray light curves are analyzed for the X3.2 event on 2013
May 14. The pulsations are apparent for a total of at least two hours
from the impulsive phase to well into the decay phase, with a total
of 163 distinct pulses evident to the naked eye. A wavelet analysis
shows that the characteristic timescale of these pulsations increases
systematically from ∼25 s at 01:10 UT, the time of the GOES peak,
to ∼100 s at 02:00 UT. A second “ridge” in the wavelet power
spectrum, most likely associated with flaring emission from a different
active region, shows an increase from ∼40 s at 01:40 UT to ∼100 s
at 03:10 UT. We assume that the QPP that produced the first ridge result
from vertical kink-mode oscillations of the newly formed loops following
magnetic reconnection in the coronal current sheet. This allows us to
estimate the magnetic field strength as a function of altitude given the
density, loop length, and QPP timescale as functions of time determined
from the GOES light curves and Ramaty High Energy Solar Spectroscopic
Imager (RHESSI) images. The calculated magnetic field strength of the
newly formed loops ranges from ∼500 G at an altitude of 24 Mm to a low
value of ∼10 G at 60 Mm, in general agreement with the expected values
at these altitudes. Fast sausage-mode oscillations are also discussed
and cannot be ruled out as an alternate mechanism for producing the QPP.
Title: Exploring impulsive solar magnetic energy release and particle
acceleration with focused hard X-ray imaging spectroscopy
Authors: Christe, Steven; Krucker, Samuel; Glesener, Lindsay; Shih,
Albert; Saint-Hilaire, Pascal; Caspi, Amir; Allred, Joel; Battaglia,
Marina; Chen, Bin; Drake, James; Dennis, Brian; Gary, Dale; Gburek,
Szymon; Goetz, Keith; Grefenstette, Brian; Gubarev, Mikhail; Hannah,
Iain; Holman, Gordon; Hudson, Hugh; Inglis, Andrew; Ireland, Jack;
Ishikawa, Shinosuke; Klimchuk, James; Kontar, Eduard; Kowalski, Adam;
Longcope, Dana; Massone, Anna-Maria; Musset, Sophie; Piana, Michele;
Ramsey, Brian; Ryan, Daniel; Schwartz, Richard; Stęślicki, Marek;
Turin, Paul; Warmuth, Alexander; Wilson-Hodge, Colleen; White, Stephen;
Veronig, Astrid; Vilmer, Nicole; Woods, Tom
Bibcode: 2017arXiv170100792C
Altcode:
How impulsive magnetic energy release leads to solar eruptions and how
those eruptions are energized and evolve are vital unsolved problems
in Heliophysics. The standard model for solar eruptions summarizes
our current understanding of these events. Magnetic energy in the
corona is released through drastic restructuring of the magnetic
field via reconnection. Electrons and ions are then accelerated by
poorly understood processes. Theories include contracting loops,
merging magnetic islands, stochastic acceleration, and turbulence at
shocks, among others. Although this basic model is well established,
the fundamental physics is poorly understood. HXR observations
using grazing-incidence focusing optics can now probe all of the key
regions of the standard model. These include two above-the-looptop
(ALT) sources which bookend the reconnection region and are likely
the sites of particle acceleration and direct heating. The science
achievable by a direct HXR imaging instrument can be summarized by the
following science questions and objectives which are some of the most
outstanding issues in solar physics (1) How are particles accelerated
at the Sun? (1a) Where are electrons accelerated and on what time
scales? (1b) What fraction of electrons is accelerated out of the
ambient medium? (2) How does magnetic energy release on the Sun lead
to flares and eruptions? A Focusing Optics X-ray Solar Imager (FOXSI)
instrument, which can be built now using proven technology and at modest
cost, would enable revolutionary advancements in our understanding of
impulsive magnetic energy release and particle acceleration, a process
which is known to occur at the Sun but also throughout the Universe.
Title: New features of the Helioviewer Project
Authors: Ireland, J.; Zahniy, S.; Nicula, B.; Mueller, D.; Felix,
S.; Verstringe, F.; Bourgoignie, B.
Bibcode: 2016AGUFMSH11A2212I
Altcode:
This year saw the release of major new upgrades to the capabilities
of helioviewer.org and JHelioviewer. The helioviewer.org interface
was completely re-designed, and now provides image and feature/event
time-lines and data download capabilities. JHelioviewer introduced
interactive time-series, the ability to query different servers for
different data, and image reprojection. We introduce the new features
of these software releases and give use cases. We will summarize our
latest usage statistics, and discuss what's coming up next for the
Helioviewer Project. We will also be soliciting bug reports, requests
for new features and comments on the effectiveness of helioviewer.org
and JHelioviewer. What would you like to see next from the Helioviewer
Project?
Title: A Large-Scale Search for Evidence of Quasi-Periodic Pulsations
in Solar Flare X-ray Emission
Authors: Inglis, A. R.; Ireland, J.; Dennis, B. R.; Hayes, L.;
Gallagher, P.
Bibcode: 2016AGUFMSH21E2563I
Altcode:
The nature of quasi-periodic pulsations in solar flares is poorly
constrained, and critically the general prevalence of such signals
in solar flares is unknown. We present the results of a large-scale,
statistically robust search for evidence of signals consistent with
quasi-periodic pulsations in solar flares, focusing on the 1 - 300s
timescale. We analyse 675 M- and X-class flares observed by GOES in 1-8A
soft X-rays between 2011 February 1 and 2015 December 31. Additionally,
we analyse 209 events in the same time interval observed by Fermi/GBM
in 15-25 keV X-rays. We use a novel model comparison approach, testing
three models applied to the Fourier power spectra of each flare. From
this we determine whether there is evidence for a substantial
enhancement in the Fourier domain that may be consistent with a QPP
signature. Our findings are that 30% of GOES events and 16% of Fermi/GBM
events show signatures consistent with classical interpretations of
QPP. The remaining events are adequately described by single power-law
or broken power-law Fourier power spectra. For both instruments,
a preferred characteristic timescale of 5-30 s was found, with no
dependence on flare magnitude in GOES, and weak dependence in GBM. We
also show that, for events where a detection occurred in both Fermi/GBM
and GOES datasets, similar characteristic timescales were found with
both instruments. We discuss the implications of these results for
our understanding of solar flares and possible QPP mechanisms.
Title: The Focusing Optics X-ray Solar Imager (FOXSI) SMEX Mission
Authors: Christe, S.; Shih, A. Y.; Krucker, S.; Glesener, L.;
Saint-Hilaire, P.; Caspi, A.; Allred, J. C.; Battaglia, M.; Chen,
B.; Drake, J. F.; Gary, D. E.; Goetz, K.; Grefenstette, B.; Hannah,
I. G.; Holman, G.; Hudson, H. S.; Inglis, A. R.; Ireland, J.; Ishikawa,
S. N.; Klimchuk, J. A.; Kontar, E.; Kowalski, A. F.; Massone, A. M.;
Piana, M.; Ramsey, B.; Gubarev, M.; Schwartz, R. A.; Steslicki, M.;
Ryan, D.; Turin, P.; Warmuth, A.; White, S. M.; Veronig, A.; Vilmer,
N.; Dennis, B. R.
Bibcode: 2016AGUFMSH13A2281C
Altcode:
We present FOXSI (Focusing Optics X-ray Solar Imager), a recently
proposed Small Explorer (SMEX) mission that will provide a revolutionary
new perspective on energy release and particle acceleration on the
Sun. FOXSI is a direct imaging X-ray spectrometer with higher dynamic
range and better than 10x the sensitivity of previous instruments. Flown
on a 3-axis stabilized spacecraft in low-Earth orbit, FOXSI uses
high-angular-resolution grazing-incidence focusing optics combined
with state-of-the-art pixelated solid-state detectors to provide direct
imaging of solar hard X-rays for the first time. FOXSI is composed of
two individual x-ray telescopes with a 14-meter focal length enabled by
a deployable boom. Making use of a filter-wheel and high-rate-capable
solid-state detectors, FOXSI will be able to observe the largest flares
without saturation while still maintaining the sensitivity to detect
x-ray emission from weak flares, escaping electrons, and hot active
regions. This SMEX mission is made possible by past experience with
similar instruments on two sounding rocket flights, in 2012 and 2014,
and on the HEROES balloon flight in 2013. FOXSI will image the Sun
with a field of view of 9 arcminutes and an angular resolution of
better than 8 arcsec; it will cover the energy range from 3 to 100
keV with a spectral resolution of better than 1 keV; and it will have
sub-second temporal resolution.
Title: Dynamic Mapping of Coronal Activity
Authors: Thompson, B. J.; Uritsky, V. M.; Ireland, J.; Young, C. A.;
Kirk, M. S.
Bibcode: 2016AGUFMSH11A2224T
Altcode:
There is a great deal of variation in how CMEs are manifested in
EUV and coronagraph images. Complicating the issue is the range
of CME-associated phenomena: shocks, waves, prominences, flares,
dimmings, to name a few. None of these phenomena are a necessary
or sufficient condition for a CME. However, each can provide clues
as to CME origin, topology, and kinematics. New analysis strategies
have been devised specifically to extract key properties of CMEs and
CME-associated phenomena, with results that are converging towards
a more consistent model of solar eruptive menagerie. We will discuss
techniques such as Persistence Mapping and Time Convolution mapping,
and how they are used to extract the dynamics of eruptive phenomena.
Title: A Large-scale Search for Evidence of Quasi-periodic Pulsations
in Solar Flares
Authors: Inglis, A. R.; Ireland, J.; Dennis, B. R.; Hayes, L.;
Gallagher, P.
Bibcode: 2016ApJ...833..284I
Altcode: 2016arXiv161007454I
The nature of quasi-periodic pulsations (QPP) in solar flares is
poorly constrained, and critically the general prevalence of such
signals in solar flares is unknown. Therefore, we perform a large-scale
search for evidence of signals consistent with QPP in solar flares,
focusing on the 1-300 s timescale. We analyze 675 M- and X-class flares
observed by the Geostationary Operational Environmental Satellite (GOES)
series in 1-8 Å soft X-rays between 2011 February 1 and 2015 December
31. Additionally, over the same era we analyze Fermi/Gamma-ray Burst
Monitor (GBM) 15-25 keV X-ray data for each of these flares associated
with a Fermi/GBM solar flare trigger, a total of 261 events. Using
a model comparison method, we determine whether there is evidence
for a substantial enhancement in the Fourier power spectrum that may
be consistent with a QPP signature, based on three tested models;
a power-law plus a constant, a broken power-law plus constant, and a
power-law-plus-constant with an additional QPP signature component. From
this, we determine that ∼30% of GOES events and ∼8% of Fermi/GBM
events show strong signatures consistent with classical interpretations
of QPP. For the remaining events either two or more tested models
cannot be strongly distinguished from each other, or the events are
well-described by single power-law or broken power-law Fourier power
spectra. For both instruments, a preferred characteristic timescale of
∼5-30 s was found in the QPP-like events, with no dependence on flare
magnitude in either GOES or GBM data. We also show that individual
events in the sample show similar characteristic timescales in both
GBM and GOES data sets. We discuss the implications of these results
for our understanding of solar flares and possible QPP mechanisms.
Title: Thermal Time Evolution of Non-Flaring Active Regions Determined
by SDO/AIA
Authors: Wright; Paul J.; Hannah, Iain G.; Viall, Nicholee M.; Ireland,
Jack; Bradshaw, Stephen J.
Bibcode: 2016usc..confE..34W
Altcode:
Hydrodynamical models of unresolved flux tubes are able to reproduce
observed coronal loops under the condition that each strand is
impulsively heated and subsequently cools. It is the frequency
of this heating and cooling that determines the temperature
distribution within a loop, and is recoverable by determination
of the low-temperature slope of the differential emission measure
(DEM). Alternatively, the cross-correlation of pixel-level SDO/AIA
light curves (time-lag analysis; Viall & Klimchuck, 2012; 2013;
2015; 2016) is becoming an increasingly popular analysis technique
in order to investigate coronal heating. While the observed time-lag
between two AIA channels can be indicative of heating or cooling, the
inherent multi-thermal nature of the AIA responses can mask the true
dynamical situation of the underlying plasma. We therefore recover
the thermal time evolution at the pixel-level by producing DEM maps
(Hannah et al, 2012; Cheung et al, 2015). We present this analysis
on both real and synthetic AIA maps of non-flaring active regions,
the latter approach allowing us to understand how robustly we can
recover the true thermal time evolution. However a single DEM alone
does not provide information about how the plasma is heating/cooling
or how the different components are related. We therefore investigate
the time evolution using a variety of complementary techniques such
as time-lag analysis, power spectrum analysis (Ireland et al, 2015),
as well as studying the temporal evolution of the DEM slope.
Title: AWARE - The Automated EUV Wave Analysis and REduction algorithm
Authors: Ireland, J.; Inglis; A. R.; Shih, A. Y.; Christe, S.; Mumford,
S.; Hayes, L. A.; Thompson, B. J.
Bibcode: 2016usc..confE..59I
Altcode:
Extreme ultraviolet (EUV) waves are large-scale propagating disturbances
observed in the solar corona, frequently associated with coronal
mass ejections and flares. Since their discovery over two hundred
papers discussing their properties, causes and physics have been
published. However, their fundamental nature and the physics of their
interactions with other solar phenomena are still not understood. To
further the understanding of EUV waves, and their relation to other
solar phenomena, we have constructed the Automated Wave Analysis and
REduction (AWARE) algorithm for the detection of EUV waves over the full
Sun. The AWARE algorithm is based on a novel image processing approach
to isolating the bright wavefront of the EUV as it propagates across
the corona. AWARE detects the presence of a wavefront, and measures
the distance, velocity and acceleration of that wavefront across the
Sun. Results from AWARE are compared to results from other algorithms
for some well known EUV wave events. Suggestions are also give for
further refinements to the basic algorithm presented here.
Title: What would you like to see next from the Helioviewer Project?
Authors: Ireland, Jack; Zahniy, S.
Bibcode: 2016usc..confE..17I
Altcode:
This year saw the release of major new upgrades to the capabilities
of helioviewer.org and JHelioviewer. We review the new features of
this software and report our latest usage statistics. We will also be
soliciting bug reports, requests for new features and comments on the
effectiveness of helioviewer.org and JHelioviewer. What would you like
to see next from the Helioviewer Project?
Title: Estimating and Separating Noise from AIA Images
Authors: Kirk, Michael S.; Ireland, Jack; Young, C. Alex; Pesnell,
W. Dean
Bibcode: 2016usc..confE..26K
Altcode:
All digital images are corrupted by noise and SDO AIA is no
different. In most solar imaging, we have the luxury of high photon
counts and low background contamination, which when combined with
carful calibration, minimize much of the impact noise has on the
measurement. Outside high-intensity regions, such as in coronal holes,
the noise component can become significant and complicate feature
recognition and segmentation. We create a practical estimate of noise
in the high-resolution AIA images across the detector CCD in all seven
EUV wavelengths. A mixture of Poisson and Gaussian noise is well suited
in the digital imaging environment due to the statistical distributions
of photons and the characteristics of the CCD. Using state-of-the-art
noise estimation techniques, the publicly available solar images, and
coronal loop simulations; we construct a maximum-a-posteriori assessment
of the error in these images. The estimation and mitigation of noise
not only provides a clearer view of large-scale solar structure in
the solar corona, but also provides physical constraints on fleeting
EUV features observed with AIA.
Title: Inferring Magnetic Fields and Electron Densities from Coronal
Seismology
Authors: McAteer, R. T. J.; Ireland, J.
Bibcode: 2016usc..confE..54M
Altcode:
The solar corona oscillates at many different spatial sizes and
temporal size scales. However, much remains unknown about many of
these oscillations: they are intermittent for unknown reasons; appear
on some coronal features and not on others; and may, or may not,
be magnetohydrodynamic (MHD) wave modes. Using a series of automated
oscillation detection routines, we extract space-time-density maps from
a quagmire of oscillating loops. From these data products, we extract
coronal magnetic fields and densities in order to to differentiate
between potential excitation mechanisms and between potential damping
mechanisms. The spread of periods, amplitudes, and damping times,
allow us to map the spatial distribution of these parameters. Initial
periods of P 300-500s, result in inferred coronal magnetic field of B
20G-50G. The decrease in the oscillation period of the loop position
corresponds to a drop in number density inside each coronal loop,
as predicted by MHD. As the the period drops below a threshold of P
300s, our MHD model cannot explain the sudden observed decrease in
both period and density and so a secondary dissipation mechanism must
occur at this point in time and space.
Title: Quasi-Periodic Pulsations in Hydrogen Emission During Solar
Flares
Authors: Milligan, Ryan; Ireland, Jack; Inglis, Andrew
Bibcode: 2016usc..confE..31M
Altcode:
There have been increasing reports of quasi-periodic pulsations (QPPs)
during solar flares in the literature recently. These recurrent
variations in intensity have been detected over a wide range of
wavelengths, most prevalently in X-rays and radio waves. The nature
of these pulsations is still in dispute but they are widely agreed
to be evidence for either a form of periodic driver of nonthermal
electrons (such as magnetic reconnection) or magnetohydrodynamic
oscillations. Flare observations of QPPs at EUV wavelengths have
been scarce in recent years, and those in the literature are often
derived from broadband measurements leaving some ambiguity as to
whether the periodic behavior was occurring in the line(s) or the
continuum. Here we present evidence for synchronous QPPs in the Lyman
continuum (from SDO/EVE) and the Lyman-alpha line (from GOES/EUVS)
during the well-studied 15 February 2011 X-class flare. The data were
detrended using a Savitzky-Golay filter to reveal a periodicity of 2-3
minutes during the impulsive phase. Similar values were found in the
SDO/AIA 1600A and 1700A channels despite being saturated, although no
such evidence was found in the higher order Lyman lines (Lyman-beta,
Lyman-gamma, Lyman-delta, etc). The formation temperature of the
Lyman series of hydrogen suggests this emission is coming from the
chromospheric footpoints, implying a quasi-periodic heating response
due to a bursty energy release mechanism in the corona.
Title: Quasi-periodic Pulsations during the Impulsive and Decay
phases of an X-class Flare
Authors: Hayes, L. A.; Gallagher, P. T.; Dennis, B. R.; Ireland, J.;
Inglis, A. R.; Ryan, D. F.
Bibcode: 2016ApJ...827L..30H
Altcode: 2016arXiv160706957H
Quasi-periodic pulsations (QPPs) are often observed in X-ray emission
from solar flares. To date, it is unclear what their physical origins
are. Here, we present a multi-instrument investigation of the nature
of QPP during the impulsive and decay phases of the X1.0 flare of 2013
October 28. We focus on the character of the fine structure pulsations
evident in the soft X-ray (SXR) time derivatives and compare this
variability with structure across multiple wavelengths including hard
X-ray and microwave emission. We find that during the impulsive phase
of the flare, high correlations between pulsations in the thermal and
non-thermal emissions are seen. A characteristic timescale of ∼20 s is
observed in all channels and a second timescale of ∼55 s is observed
in the non-thermal emissions. SXR pulsations are seen to persist into
the decay phase of this flare, up to 20 minutes after the non-thermal
emission has ceased. We find that these decay phase thermal pulsations
have very small amplitude and show an increase in characteristic
timescale from ∼40 s up to ∼70 s. We interpret the bursty nature
of the co-existing multi-wavelength QPPs during the impulsive phase
in terms of episodic particle acceleration and plasma heating. The
persistent thermal decay phase QPPs are most likely connected with
compressive magnetohydrodynamic processes in the post-flare loops such
as the fast sausage mode or the vertical kink mode.
Title: Science Objectives of the FOXSI Small Explorer Mission Concept
Authors: Shih, Albert Y.; Christe, Steven; Alaoui, Meriem; Allred,
Joel C.; Antiochos, Spiro K.; Battaglia, Marina; Buitrago-Casas,
Juan Camilo; Caspi, Amir; Dennis, Brian R.; Drake, James; Fleishman,
Gregory D.; Gary, Dale E.; Glesener, Lindsay; Grefenstette, Brian;
Hannah, Iain; Holman, Gordon D.; Hudson, Hugh S.; Inglis, Andrew R.;
Ireland, Jack; Ishikawa, Shin-Nosuke; Jeffrey, Natasha; Klimchuk, James
A.; Kontar, Eduard; Krucker, Sam; Longcope, Dana; Musset, Sophie; Nita,
Gelu M.; Ramsey, Brian; Ryan, Daniel; Saint-Hilaire, Pascal; Schwartz,
Richard A.; Vilmer, Nicole; White, Stephen M.; Wilson-Hodge, Colleen
Bibcode: 2016SPD....47.0814S
Altcode:
Impulsive particle acceleration and plasma heating at the Sun, from the
largest solar eruptive events to the smallest flares, are related to
fundamental processes throughout the Universe. While there have been
significant advances in our understanding of impulsive energy release
since the advent of RHESSI observations, there is a clear need for
new X-ray observations that can capture the full range of emission
in flares (e.g., faint coronal sources near bright chromospheric
sources), follow the intricate evolution of energy release and changes
in morphology, and search for the signatures of impulsive energy
release in even the quiescent Sun. The FOXSI Small Explorer (SMEX)
mission concept combines state-of-the-art grazing-incidence focusing
optics with pixelated solid-state detectors to provide direct imaging
of hard X-rays for the first time on a solar observatory. We present
the science objectives of FOXSI and how its capabilities will address
and resolve open questions regarding impulsive energy release at the
Sun. These questions include: What are the time scales of the processes
that accelerate electrons? How do flare-accelerated electrons escape
into the heliosphere? What is the energy input of accelerated electrons
into the chromosphere, and how is super-heated coronal plasma produced?
Title: Quasi-Periodic Pulsations (QPP) in a Long-Duration Flare
Authors: Dennis, Brian R.; Tolbert, Anne K.; Inglis, Andrew R.;
Ireland, Jack; Wang, Tongjiang; Holman, Gordon D.; Hayes, Laura Ann;
Gallagher, Peter T.
Bibcode: 2016SPD....47.0605D
Altcode:
We have detected 163 distinct peaks in the time derivative of the
GOES light curve of the X-class flare on 2013 May 14. QPP were
detected for the first two hours of this 8-hour event. The thermal
X-ray source revealed in RHESSI 6 - 12 keV images eventually rose
to an altitude of over 60 km at a rate of 1.6 km/s. The mean QPP
time scale increased from ~10 s during the impulsive phase to ~100
s some two hours later. Interpreting the QPP as being produced by
vertical kink mode oscillations has allowed estimates to be made of
the coronal magnetic field strength as a function of altitude. This
uses the measured QPP time scales with the length and densities of
the oscillating loops determined from the emission measure and source
volume given by the RHESSI imaging spectroscopy observations. Applying
this analysis to other events will further test the idea that vertical
kink-mode oscillations are the source of QPP during both the impulsive
and decay phases. If this origin is established, then QPP can be used as
a diagnostic of the conditions in the corona close to the energy release
site. In particular, it should be possible to obtain estimates of the
Alfven speed, density, beta value, and magnetic field strength in the
region of the soft X-ray emitting plasma. During the impulsive phase,
other processes, presumably connected to the energy release process
itself, can dominate to produce the more chaotic impulsive nature of
the emission light curve.
Title: First large-scale statistical search for evidence of pulsations
in solar flares
Authors: Inglis, Andrew; Ireland, Jack; Dennis, Brian R.; Hayes,
Laura Ann
Bibcode: 2016SPD....47.0639I
Altcode:
The nature of quasi-periodic pulsations in solar flares remains poorly
constrained, and the general prevalence of such signals in solar
flares is unknown, due to the lack of large-scale studies. Therefore,
we perform the first large-scale, statistically robust search for
evidence of signals consistent with quasi-periodic pulsations in
solar flares, focusing on the 1 - 300 s timescale. We analyse 684
M- and X-class flares observed by GOES in soft X-rays between 2011
February 1 and 2015 December 31. Additionally, we analyse 210 events
in the same time interval observed by Fermi/GBM in hard X-rays. Using
a model comparison method, we determine whether there is evidence for
a substantial enhancement in the Fourier power spectrum that may be
consistent with a QPP signature. From this, we determine the fraction
of GOES events and Fermi/GBM events showing signatures consistent with
classical descriptions of QPP. A further subset of events, particularly
in GOES data, show evidence for very broad enhancements in Fourier
power. These latter events may be consistent with signatures where
the characteristic timescale is substantially evolving over time, or
where complex signal behaviour is present. We also show that, for events
where a detection occurred in both Fermi/GBM and GOES datasets, similar
characteristic timescales were found with both instruments. We discuss
the implications of these results for our understanding of solar flares.
Title: 25 Years of Self-organized Criticality: Numerical Detection
Methods
Authors: McAteer, R. T. James; Aschwanden, Markus J.; Dimitropoulou,
Michaila; Georgoulis, Manolis K.; Pruessner, Gunnar; Morales, Laura;
Ireland, Jack; Abramenko, Valentyna
Bibcode: 2016SSRv..198..217M
Altcode: 2015SSRv..tmp...31M; 2015arXiv150608142M
The detection and characterization of self-organized criticality
(SOC), in both real and simulated data, has undergone many
significant revisions over the past 25 years. The explosive
advances in the many numerical methods available for detecting,
discriminating, and ultimately testing, SOC have played a critical
role in developing our understanding of how systems experience and
exhibit SOC. In this article, methods of detecting SOC are reviewed;
from correlations to complexity to critical quantities. A description
of the basic autocorrelation method leads into a detailed analysis
of application-oriented methods developed in the last 25 years. In
the second half of this manuscript space-based, time-based and
spatial-temporal methods are reviewed and the prevalence of power
laws in nature is described, with an emphasis on event detection and
characterization. The search for numerical methods to clearly and
unambiguously detect SOC in data often leads us outside the comfort
zone of our own disciplines—the answers to these questions are often
obtained by studying the advances made in other fields of study. In
addition, numerical detection methods often provide the optimum link
between simulations and experiments in scientific research. We seek
to explore this boundary where the rubber meets the road, to review
this expanding field of research of numerical detection of SOC systems
over the past 25 years, and to iterate forwards so as to provide some
foresight and guidance into developing breakthroughs in this subject
over the next quarter of a century.
Title: Deriving Kinematic Properties of Non-Radial, Asymmetric and
Deflecting CMEs: Methods and Implications
Authors: Thompson, B. J.; Liewer, P. C.; Mays, M. L.; Richardson,
I. G.; Kwon, R.; Ofman, L.; Makela, P. A.; Ireland, J.; Hess, P.;
Waldron, Z.
Bibcode: 2015AGUFMSH33B2467T
Altcode:
An improved understanding of the kinematic properties of CMEs and
CME-associated phenomena has several impacts: 1) a less ambiguous
method of mapping propagating structures into their inner coronal
manifestations, 2) a clearer view of the relationship between the
"main" CME and CME-associated brightenings, and 3) an improved
identification of the heliospheric sources of shocks, Type II bursts,
and SEPs. However, there are several challenges in characterizing
the kinematic properties of CMEs. Most rapidly-evolving eruptions are
accompanied by changes in the surrounding corona. The larger the impact
on the surrounding corona, the more difficult it is to separate the
"main" CME from the CME-associated brightenings. Complicating the
issue is the range of observed propagation properties: super-radial
expansion, asymmetric expansion, non-radial propagation, and alterations
in the direction of propagation. These properties can be a function
of both the internal magnetic structure of the CME and the structure
of the corona through which the CME is propagating. While the relative
contribution of internal/external factors can be difficult to assess,
it is of fundamental importance because it not only reveals the nature
of CMEs but also CME-associated phenomena such as EUV waves, Type
II radio bursts, shocks, and SEPs. Most halo CMEs are a combination
of both the "main" CME and the CME-associated brightenings, but
new diagnostic methods such as time convolution mapping can help
separate the CME mass from the impacted corona. Additionally, while
most CME-fitting methods assume symmetry about the radial direction,
adaptive methods allow us to study highly asymmetric CME expansion
and take into account the fundamentally different natures of the CME
and the shocked/deflected corona. Several methods will be examined,
and each has their respective strengths and weaknesses; for example,
the difference between the direction of a highly non-radial CME and a
sun-centered model's orientation can exceed 45 degrees, which impacts
our ability to correctly assess changes in propagation direction and
the causes of these changes. We examine the assumptions inherent in
these methods and how they may produce artifacts that can influence
conclusions about CME kinematics.
Title: Capabilities of a FOXSI Small Explorer
Authors: Inglis, A. R.; Christe, S.; Glesener, L.; Krucker, S.; Dennis,
B. R.; Shih, A.; Wilson-Hodge, C.; Gubarev, M.; Hudson, H. S.; Kontar,
E.; Buitrago Casas, J. C.; Drake, J. F.; Caspi, A.; Holman, G.; Allred,
J. C.; Ryan, D.; Alaoui, M.; White, S. M.; Saint-Hilaire, P.; Klimchuk,
J. A.; Hannah, I. G.; Antiochos, S. K.; Grefenstette, B.; Ramsey,
B.; Jeffrey, N. L. S.; Reep, J. W.; Schwartz, R. A.; Ireland, J.
Bibcode: 2015AGUFMSH43B2456I
Altcode:
We present the FOXSI (Focusing Optics X-ray Solar Imager) small explorer
(SMEX) concept, a mission dedicated to studying particle acceleration
and energy release on the Sun. FOXSI is designed as a 3-axis stabilized
spacecraft in low-Earth orbit making use of state-of-the-art grazing
incidence focusing optics, allowing for direct imaging of solar
X-rays. The current design being studied features three telescope
modules deployed in a low-inclination low-earth orbit (LEO). With a 15
meter focal length enabled by a deployable boom, FOXSI will observe
the Sun in the 3-50 keV energe range. The FOXSI imaging concept has
already been tested on two sounding rocket flights, in 2012 and 2014
and on the HEROES balloon payload flight in 2013. FOXSI will image
the Sun with an angular resolution of 5'', a spectral resolution of
0.5 keV, and sub-second temporal resolution using CdTe detectors. In
this presentation we investigate the science objectives and targets
which can be accessed from this mission. Because of the defining
characteristic of FOXSI is true imaging spectroscopy with high dynamic
range and sensitivity, a brand-new perspective on energy release on the
Sun is possible. Some of the science targets discussed here include;
flare particle acceleration processes, electron beams, return currents,
sources of solar energetic particles (SEPs), as well as understanding
X-ray emission from active region structures and the quiescent corona.
Title: Spatial variation of AIA coronal Fourier power spectra
Authors: Ireland, J.; Mcateer, R. T. J.
Bibcode: 2015AGUFMSH54B..01I
Altcode:
We describe a study of the spatial distribution of the properties
of the Fourier power spectrum of time-series of AIA 171Å and 193Å
data. The area studied includes examples of physically different
components of the corona, such as coronal moss, a sunspot, quiet Sun
and fan loop footpoints. We show that a large fraction of the power
spectra are well modeled by a power spectrum that behaves like a power
law f-n (n>0)at lower frequencies f, dropping to a constant value
at higher frequencies. We also show that there are areas where the
power spectra are better described by the above power spectrum model,
plus a narrow band oscillatory feature, centered in the 3-5 minute
oscillation range. These narrow-band spectral features are thought
to be due to the propagation of oscillations from lower down in solar
atmosphere to hotter. This allows us to produce maps of large areas of
the corona showing where the propagation from one waveband to another
does and does not occur. This is an important step in understanding
wave propagation in different layers in the corona. We also show the
171Å and 193Å power spectrum power law indices are correlated, with
171Å power law indices in the range n = 1.8 to 2.8, and 193Å power
law indices n = 2 to 3.5 approximately. Maps of the power law index
show that different ranges of values of the power law indices occur
in spatially contiguous parts of the corona, indicating that local
spatial structure may play a role in defining the power law index
value. Taken with our previous result from Ireland et al. (2015) that
physically different parts of the corona have different mean values of
the power law index, this new result strongly suggests that the same
mechanism producing the observed power law power spectrum is operating
everywhere across the corona. We discuss the nanoflare hypothesis as
a possible explanation of these observations.
Title: Coronal Seismology: Inferring Magnetic Fields and Exploring
Damping Mechanisms
Authors: McAteer, R. T. James; Ireland, Jack
Bibcode: 2015IAUGA..2257620M
Altcode:
Recent observations in extreme ultra-violet wavelengths have shown
that the solar corona oscillates at many different spatial sizes and
temporal size scales. However, much remains unknown about many of these
oscillations; they are intermittent for unknown reasons, appear on some
coronal features and not on other, similar, neighboring features, and
may (or may not) be magnetohydrodynamic (MHD) wave modes. Definitive
causes of the structure and origins of these oscillations are still
largely lacking. Here, we use automated oscillation detection routines
to study a large sample of oscillations, inferring physical mechanisms
as to how and why the corona varies.First, we measure the oscillation
content of different physical regions on the Sun in SDO AIA data, using
two different automated oscillation detection algorithms. This shows a
power-law distribution in oscillatory frequency, disagreeing with strong
historical assumptions about the nature of coronal heating and coronal
seismology. We show how such disagreements can be reconciled by using
a power-law background for oscillatory signals.Second we use coronal
seismology to provide a means to infer coronal plasma parameters and
to differentiate between potential damping mechanisms. Recent sets of
kink-mode observations (usually 5-8 loops) have come insights into how
the coronal is structured and how it evolves. We present a complex
set of flare-induced, off-limb, coronal kink-mode oscillations of
almost 100 loops. These display a spread of periods, amplitudes, and
damping times, allowing us to probe the spatial distribution of these
parameters for the first time. Both Fourier and Wavelet routines are
used to automatically extract and characterize these oscillations. An
initial period of P~500s, results in an inferred coronal magnetic field
of B~20G. The decrease in the oscillation period of the loop position
corresponds to a drop in number density inside the coronal loop, as
predicted by MHD. As the the period drops below a threshold of P~300s,
our MHD model cannot explain the sudden decrease in both period and
density. A secondary dissipation mechanism must occur at this point
in time and space.
Title: The Helioviewer Project: Solar and Heliospheric Data
Visualization
Authors: Stys, Jeffrey E.; Ireland, Jack; Müller, Daniel
Bibcode: 2015TESS....140304S
Altcode:
Helioviewer.org enables the simultaneous exploration of multiple
heterogeneous solar and heliospheric data sets. The latest iteration
of this open-source web application brings significant visual and
functional enhancements to the user interface. Long overdue from a
usability perspective, these changes also pave the way for significant
new capabilities planned for the future. Emphasis is placed on the
solar imagery, which is now always displayed full-screen. Controls
for selecting image layers, feature and event annotations, and
observation date and time are presented in a light-weight overlay
with individually collapsible sub-sections. Secondary functions such
as movie and screenshot generation, link and image sharing, news and
community videos are now intuitively grouped and kept out of the way
until needed. Tight integration with external services such as the
Virtual Solar Observatory and SDO Cut-out Service allows scientists to
issue precisely defined requests to download science data sets via the
web, SolarSoft/IDL, and SunPy/Python after definining and previewing
them visually. Finally, documentation of the Helioviewer Public API has
been enhanced and expanded, making it simpler to integrate Helioviewer
data into scientific workflows.
Title: Coronal Fourier Power Spectra: Implications for Coronal
Seismology and Coronal Heating
Authors: Ireland, Jack; McAteer, James; Inglis, Andrew
Bibcode: 2015TESS....121304I
Altcode:
The dynamics of regions of the solar corona are investigated using
Atmospheric Imaging Assembly 171 Å and 193 Å data. The coronal
emission from the quiet Sun, coronal loop footprints, coronal moss,
and from above a sunspot is studied. It is shown that the mean Fourier
power spectra in these regions can be described by a power law at lower
frequencies that tails to a flat spectrum at higher frequencies, plus
a Gaussian-shaped contribution that varies depending on the region
studied. This Fourier spectral shape is in contrast to the commonly
held assumption that coronal time series are well described by the sum
of a long timescale background trend plus Gaussian-distributed noise,
with some specific locations also showing an oscillatory signal. The
implications of the observed spectral shape on the fields of coronal
seismology and the automated detection of oscillations in the corona
are discussed. The power-law contribution to the shape of the Fourier
power spectrum is interpreted as being due to the summation of a
distribution of exponentially decaying emission events along the line
of sight. This is consistent with the idea that the solar atmosphere
is heated everywhere by small energy deposition events.
Title: SunPy: Solar Physics in Python
Authors: Ryan, Daniel; Christe, Steven; Mumford, Stuart; Perez Suarez,
David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew; Liedtke, Simon;
Hewett, Russel
Bibcode: 2015TESS....140307R
Altcode:
SunPy is a community-developed open-source software library for
solar physics. It is written in Python, a free, cross-platform,
general-purpose, high-level programming language which is being
increasingly adopted throughout the scientific community as
well as further afield. This has resulted in a wide array of
software packages useful for scientific computing, from numerical
computation (NumPy, SciPy, etc.), to machine learning (scifitlearn),
to visualization and plotting (matplotlib). SunPy aims to provide
required specialised software for analysing solar and heliospheric
datasets in Python. The current version is 0.5 with 0.6 expected
to be released later this year. SunPy provides solar data access
through integration with the Virtual Solar Observatory (VSO),
the Heliophysics Event Knowledgebase (HEK), and the HELiophysics
Integrated Observatory (HELIO) webservices. It supports common data
types from major solar missions such as images (SDO/AIA, STEREO,
PROBA2/SWAP etc.), time series (GOES/XRS, SDO/EVE, PROBA2/LYRA),
and radio spectra (e-Callisto, STEREO/WAVES). SunPy’s code base is
publicly available through github.com and can be contributed to by
anyone. In this poster we demonstrate SunPy’s functionality and
future goals of the project. We also encourage interested users to
become involved in further developing SunPy.
Title: Automated Wave Analysis and Reduction in EUV (AWARE): a tool
for the detection and characterization of EUV waves.
Authors: Inglis, Andrew; Ireland, Jack; Christe, Steven; Shih, Albert;
Hayes, Laura
Bibcode: 2015TESS....140313I
Altcode:
Extreme ultraviolet (EUV) waves are large-scale and faint propagating
disturbances observed in the solar corona, frequently associated
with coronal mass ejections and flares. Since their discovery over two
hundred papers discussing their properties, causes and physics have been
published. However, their fundamental nature and the physics of their
interactions with other solar phenomena are still not understood. To
further the understanding of EUV waves, and their relation to other
solar phenomena, we are developing AWARE - the Automated Wave Analysis
and REduction algorithm for the detection of EUV waves over the full
Sun. AWARE is a Python-based, open-source algorithm that utilizes the
SunPy data analysis package and general purpose signal processing
libraries. The core detection algorithm is based on a novel image
processing approach to isolating the bright wavefront of the EUV
as it propagates across the confounding background emission of the
complex structured solar corona. The location, speed and acceleration
of the wavefront as a function of direction from the source events are
calculated. We describe the core image processing steps of the AWARE
algorithm, and demonstrate its application to observational data from
SDO/AIA and STEREO/EUVI.
Title: The Radiated Energy Budget Of Chromospheric Plasma In A Major
Solar Flare Deduced From Multi-Wavelength Observations
Authors: Milligan, Ryan; Kerr, Graham Stewart; Dennis, Brian; Hudson,
Hugh; Fletcher, Lyndsay; Allred, Joel; Chamberlin, Phillip; Ireland,
Jack; Mathioudakis, Mihalis; Keenan, Francis
Bibcode: 2015TESS....130209M
Altcode:
The response of the lower solar atmosphere is an important diagnostic
tool for understanding energy transport during solar flares. The 15
February 2011 X-class flare was fortuitously observed by a host of
space-based instruments that sampled the chromospheric response over
a range of lines and continua at <20s cadence. These include the
free-bound EUV continua of H I (Lyman), He I, and He II, plus the
emission lines of He II at 304Å and H I (Lyα) at 1216Å by SDO/EVE,
the UV continua at 1600Å and 1700Å by SDO/AIA, and the white light
continuum at 4504Å, 5550Å, and 6684Å, along with the Ca II H line
at 3968Å using Hinode/SOT. RHESSI also observed the entire event at
energies up to ~100keV, making it possible to determine the properties
of the nonthermal electrons deemed to be responsible for driving the
enhanced chromospheric emission under the assumption of thick-target
collisions. Integrating over the duration of the impulsive phase,
the total energy contained in the nonthermal electrons was found to be
>2×1031 erg. By comparison, the summed energy detected by
instruments onboard SDO and Hinode amounted to ~3×1030 erg;
about 15% of the total nonthermal energy. The Lyα line was found to
dominate the measured radiative losses in contrast to the predictions
of numerical simulations. Parameters of both the driving electron
distribution and the resulting chromospheric response are presented
in detail to encourage the numerical modeling of flare heating for
this event to determine the depth of the solar atmosphere at which
these line and continuum processes originate, and the mechanism(s)
responsible for their generation.
Title: Solar and heliospheric signatures of an unusual jet event on
20 November 2012
Authors: Ireland, Jack; de Nolfo, Georgia; Ryan, James Michael
Bibcode: 2015TESS....131007I
Altcode:
We describe the solar and heliospheric signatures of an unusual jet
event seen on the Sun on 20 November 2012. The jet itself is formed very
suddenly in a piece of apparently quiet Sun distant from large opposite
polarity sources such as active regions. The jet event is associated
with a low energy (6-12 keV) flare observed by RHESSI. Higher hard
x-ray energies are not observed, indicating only low energy electrons
were produced. Several hours later, a dispersive helium-3 rich event is
seen in ACE/ULEIS data, which is not associated with electron-SEPs or
a Type III radio burst. High resolution ACE/ULEIS ion data suggest an
onset time close to the time of the jet. We discuss the heliospheric
connectivity of this event using data from STEREO, ACE, WIND and
estimates of the open magnetic flux arising from the solar surface
around the jet. Although this event is studied in detail, we have found
five other similar events in the data, and we discuss these briefly.
Title: How can we interpret and understand pulsations in solar flare
emission? A Bayesian model comparison approach.
Authors: Inglis, Andrew; Ireland, Jack; Dominique, Marie
Bibcode: 2015TESS....140605I
Altcode:
Recent work has shown that power-law-like Fourier power spectra
are an intrinsic property of solar and stellar flare signals,
similarly to other astrophysical objects such as gamma-ray bursts and
magnetars. It is therefore critical to account for this in order to
understand the nature and significance of short-timescale fluctuations
in flares.We present the results of a Bayesian model comparison
method for investigating flare time series, fully considering these
Fourier power-law properties. Using data from the PROBA2/Large Yield
Radiometer, Fermi/Gamma-ray Burst Monitor, Nobeyama Radioheliograph,
and Yohkoh/HXT instruments, we study a selection of flares from the
literature identified as 'quasi-periodic puslation (QPP)' events. While
emphasising that the observed fluctuations are real and of solar origin,
we find that, for all but one event tested, an explicit oscillation is
not required to explain the observations. Instead, the observed flare
signals are adequately described as a manifestation of a power law in
the Fourier power spectrum. This evaluation of the QPP phenomenon is
markedly different from much of the prior literature.We conclude that
the prevalence of oscillatory signatures in solar and stellar flares
may be less than previously believed. Furthermore, studying the slope of
the observed Fourier power spectrum as a function of energy may provide
us with a diagnostic window into the fundamental nature of solar flares.
Title: Coronal Fourier Power Spectra: Implications for Coronal
Seismology and Coronal Heating
Authors: Ireland, J.; McAteer, R. T. J.; Inglis, A. R.
Bibcode: 2015ApJ...798....1I
Altcode: 2014arXiv1410.2171I
The dynamics of regions of the solar corona are investigated using
Atmospheric Imaging Assembly 171 Å and 193 Å data. The coronal
emission from the quiet Sun, coronal loop footprints, coronal moss,
and from above a sunspot is studied. It is shown that the mean Fourier
power spectra in these regions can be described by a power law at lower
frequencies that tails to a flat spectrum at higher frequencies, plus
a Gaussian-shaped contribution that varies depending on the region
studied. This Fourier spectral shape is in contrast to the commonly
held assumption that coronal time series are well described by the sum
of a long timescale background trend plus Gaussian-distributed noise,
with some specific locations also showing an oscillatory signal. The
implications of the observed spectral shape on the fields of coronal
seismology and the automated detection of oscillations in the corona
are discussed. The power-law contribution to the shape of the Fourier
power spectrum is interpreted as being due to the summation of a
distribution of exponentially decaying emission events along the line
of sight. This is consistent with the idea that the solar atmosphere
is heated everywhere by small energy deposition events.
Title: Quasi-periodic Pulsations in Solar and Stellar Flares:
Re-evaluating their Nature in the Context of Power-law Flare Fourier
Spectra
Authors: Inglis, A. R.; Ireland, J.; Dominique, M.
Bibcode: 2015ApJ...798..108I
Altcode: 2014arXiv1410.8162I
The nature of quasi-periodic pulsations (QPPs) in solar and stellar
flares remains debated. Recent work has shown that power-law-like
Fourier power spectra are an intrinsic property of solar and
stellar flare signals, a property that many previous studies of this
phenomenon have not accounted for. Hence a re-evaluation of the existing
interpretations and assumptions regarding QPPs is needed. We adopt a
Bayesian method for investigating this phenomenon, fully considering
the Fourier power-law properties of flare signals. Using data from the
PROBA2/Large Yield Radiometer, Fermi/Gamma-ray Burst Monitor, Nobeyama
Radioheliograph, and Yohkoh/HXT instruments, we study a selection of
flares from the literature identified as QPP events. Additionally,
we examine optical data from a recent stellar flare that appears
to exhibit oscillatory properties. We find that, for all but one
event tested, an explicit oscillation is not required to explain the
observations. Instead, the flare signals are adequately described as
a manifestation of a power law in the Fourier power spectrum. However,
for the flare of 1998 May 8, strong evidence for an explicit oscillation
with P ≈ 14-16 s is found in the 17 GHz radio data and the 13-23
keV Yohkoh/HXT data. We conclude that, most likely, many previously
analyzed events in the literature may be similarly described by power
laws in the flare Fourier power spectrum, without invoking a narrowband,
oscillatory component. Hence the prevalence of oscillatory signatures
in solar and stellar flares may be less than previously believed. The
physical mechanism behind the appearance of the observed power laws
is discussed.
Title: SunPy—Python for solar physics
Authors: SunPy Community, The; Mumford, Stuart J.; Christe, Steven;
Pérez-Suárez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew
R.; Liedtke, Simon; Hewett, Russell J.; Mayer, Florian; Hughitt,
Keith; Freij, Nabil; Meszaros, Tomas; Bennett, Samuel M.; Malocha,
Michael; Evans, John; Agrawal, Ankit; Leonard, Andrew J.; Robitaille,
Thomas P.; Mampaey, Benjamin; Iván Campos-Rozo, Jose; Kirk, Michael S.
Bibcode: 2015CS&D....8a4009S
Altcode: 2015arXiv150502563S
This paper presents SunPy (version 0.5), a community-developed
Python package for solar physics. Python, a free, cross-platform,
general-purpose, high-level programming language, has seen widespread
adoption among the scientific community, resulting in the availability
of a large number of software packages, from numerical computation
(NumPy, SciPy) and machine learning (scikit-learn) to visualization
and plotting (matplotlib). SunPy is a data-analysis environment
specializing in providing the software necessary to analyse solar
and heliospheric data in Python. SunPy is open-source software (BSD
licence) and has an open and transparent development workflow that
anyone can contribute to. SunPy provides access to solar data through
integration with the Virtual Solar Observatory (VSO), the Heliophysics
Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory
(HELIO) webservices. It currently supports image data from major solar
missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from
missions such as GOES, SDO/EVE, and PROBA2/LYRA, and radio spectra from
e-Callisto and STEREO/SWAVES. We describe SunPy´s functionality,
provide examples of solar data analysis in SunPy, and show how
Python-based solar data-analysis can leverage the many existing tools
already available in Python. We discuss the future goals of the project
and encourage interested users to become involved in the planning and
development of SunPy.
Title: Automated Wave Analysis and Reduction in EUV (AWARE): a tool
for the detection and characterization of EUV waves.
Authors: Inglis, A. R.; Ireland, J.; Shih, A.; Christe, S.; Hayes, L.
Bibcode: 2014AGUFMSH21A4090I
Altcode:
Extreme ultraviolet (EUV) waves are large-scale and faint propagating
disturbances observed in the solar corona, frequently associated
with coronal mass ejections and flares. Since their discovery over two
hundred papers discussing their properties, causes and physics have been
published. However, their fundamental nature and the physics of their
interactions with other solar phenomena are still not understood. To
further the understanding of EUV waves, and their relation to other
solar phenomena, we are developing AWARE - the Automated Wave Analysis
and REduction algorithm for the detection of EUV waves over the full
Sun. AWARE is a Python-based, open-source algorithm that utilizes the
SunPy data analysis package and general purpose signal processing
libraries. The core detection algorithm is based on a novel image
processing approach to isolating the bright wavefront of the EUV
as it propagates across the confounding background emission of the
complex structured solar corona. The location, speed and acceleration
of the wavefront as a function of direction from the source events are
calculated. We describe the core image processing steps of the AWARE
algorithm, and demonstrate its application to observational data from
SDO/AIA and STEREO/EUVI.
Title: Coronal Fourier power spectra: implications for coronal
heating and coronal seismology
Authors: Ireland, J.; Mcateer, R. T. J.; Inglis, A. R.
Bibcode: 2014AGUFMSH13C4128I
Altcode:
The dynamics of regions of the solar corona are investigated using
AIA 171 and 193 Angstrom data. It is shown that the mean Fourier
power spectra of emission from active region cores, above sunspots, in
loop footpoints and in the quiet Sun, follow an approximate power-law
behaviour. We show that power-law power-spectra can be formed by summing
a distribution of exponentially decaying emission events along the line
of sight, consistent with the idea that the corona is heated everywhere
by small energy deposition events. We also examine changes in Fourier
power spectrum as a function of coronal loop height to look for evidence
of a preferred location to coronal heating. The observed power-law
power spectra also have implications for coronal seismology, as all
existing observational studies do not take into account the power-law
power spectrum of the coronal emission and its attendant statistical
properties. We show that random fluctuations in the emission can be
mis-identified as oscillatory signal, and give suggestions on how to
detect oscillatory motions above a background power-law power spectrum.
Title: The Radiated Energy Budget of Chromospheric Plasma in a Major
Solar Flare Deduced from Multi-wavelength Observations
Authors: Milligan, Ryan O.; Kerr, Graham S.; Dennis, Brian R.; Hudson,
Hugh S.; Fletcher, Lyndsay; Allred, Joel C.; Chamberlin, Phillip C.;
Ireland, Jack; Mathioudakis, Mihalis; Keenan, Francis P.
Bibcode: 2014ApJ...793...70M
Altcode: 2014arXiv1406.7657M
This paper presents measurements of the energy radiated by the lower
solar atmosphere, at optical, UV, and EUV wavelengths, during an
X-class solar flare (SOL2011-02-15T01:56) in response to an injection
of energy assumed to be in the form of nonthermal electrons. Hard
X-ray observations from RHESSI were used to track the evolution of
the parameters of the nonthermal electron distribution to reveal the
total power contained in flare accelerated electrons. By integrating
over the duration of the impulsive phase, the total energy contained
in the nonthermal electrons was found to be >2 × 1031
erg. The response of the lower solar atmosphere was measured in
the free-bound EUV continua of H I (Lyman), He I, and He II, plus
the emission lines of He II at 304 Å and H I (Lyα) at 1216 Å by
SDO/EVE, the UV continua at 1600 Å and 1700 Å by SDO/AIA, and the
white light continuum at 4504 Å, 5550 Å, and 6684 Å, along with the
Ca II H line at 3968 Å using Hinode/SOT. The summed energy detected
by these instruments amounted to ~3 × 1030 erg about 15%
of the total nonthermal energy. The Lyα line was found to dominate
the measured radiative losses. Parameters of both the driving electron
distribution and the resulting chromospheric response are presented
in detail to encourage the numerical modeling of flare heating for
this event, to determine the depth of the solar atmosphere at which
these line and continuum processes originate, and the mechanism(s)
responsible for their generation.
Title: Helioviewer.org: Enhanced Solar & Heliospheric Data
Visualization
Authors: Stys, Jeffrey E.; Ireland, Jack; Hughitt, V. Keith; Mueller,
Daniel
Bibcode: 2014AAS...22421844S
Altcode:
Helioviewer.org enables the simultaneous exploration of multiple
heterogeneous solar data sets. In the latest iteration of this
open-source web application, TRACE and Hinode XRT join SDO, SOHO,
STEREO, PROBA2 SWAP, and Yohkoh SXT as supported data sets, with
significant additions to the availability of data from STEREO. Version
2 of Helioviewer's Public API for scientists and software developers
provides powerful new ways to interact with solar data, complete
with extensive documentation and usage examples. A new data coverage
visualization demystifies the availability of each data set. The
addition of a science data download tool provides a simple way to import
FITS files directly into an IDL or Python analysis environment. Finally,
a prototype timeline feature explores new ways of browsing image data
sets in our viewport as well as interacting with time series data.
Title: Power Spectra in AIA 171 and 193 and Their Implications for
Coronal Seismology
Authors: Ireland, Jack; Mcateer, Robert TJ; Inglis, Andrew
Bibcode: 2014AAS...22432321I
Altcode:
We examine Fourier power spectra of time-series of AIA 171 and
193 waveband data. We show that these power spectra exhibit a
red-noise like power-law behaviour on time-scales of interest to
coronal seismology. We show that assuming a white noise background
power spectrum when a red-noise power spectrum is present can lead
to the mistaken identification of narrow-band oscillatory power
when none is present. Thisimplies that a background power-law power
spectrum must be taken in to account when determining the presence
of narrow-band oscillations that may be due to MHD wave processes
in the solar corona. We also show that the red-noise power spectrum
is consistent with the expected power spectrum from large number of
exponentially decaying emission events with event size taken from a
power law distribution.
Title: Searching for narrow-band oscillations in solar flares in
the presence of frequency-dependent noise
Authors: Inglis, Andrew; Ireland, Jack
Bibcode: 2014AAS...22412308I
Altcode:
A common feature of solar flare emission is the appearance of short
timescale fluctuations, often interpreted in terms of oscillatory
signatures, and often referred to as quasi-periodic pulsations (QPPs)
or quasi-periodic oscilations (QPOs). These fluctuations are an
important diagnostic of solar plasma, as they are linked to the flare
reconnection and particle acceleration sites. However, it has recently
become clear that solar flare time series, like many astrophysical
objects, are often dominated by frequency-dependent 'red' noise, rather
than white noise. This frequency-dependent red-noise is commonly not
taken into account when analyzing flare time-series for narrow-band
oscillations. We demonstrate the application of a Bayesian method of
searching for narrow-band oscillations in flares (based on Vaughan 2010)
that fully accounts for frequency-dependent noise. We apply this method
to the recent flares of 2011 February 15 and 2011 June 7, utilizing
high-cadence EUV and X-ray data from the Proba-2/LYRA and Fermi/GBM
instruments. While emphasizing that the observed fluctuations are a
very real effect, we show that the emission from the selected events
can be well described by a frequency-dependent noise model, without
the need to invoke an explicit oscillatory mechanism. This presents
a challenge to our current understanding of flare fluctuations, and
suggests that narrow-band oscillations in flare emission may be much
less prevalent than previously believed.
Title: SunPy - Python for Solar Physics, Version 0.4
Authors: Christe, Steven; Mumford, Stuart; Perez-Suarez, David;
Ireland, Jack; Shih, Albert Y.; Inglis, Andrew; Liedtke, Simon;
Hewett, Russel
Bibcode: 2014AAS...22421839C
Altcode:
We presents version 0.4 of SunPy, a community-developed Python package
for solar physics. Python, a free, cross-platform, general-purpose,
high-level programming language, has seen widespread adoption among the
scientific community, resulting in the availability of a large number of
software packages, from numerical computation NumPy, SciPy and machine
learning (scikit-learn) to visualisation and plotting (matplotlib).SunPy
is a data-analysis environment specialising in providing the software
necessary to analyse solar and heliospheric datasets in Python. SunPy
is open-source software (BSD licence) and has an open and transparent
development workflow that anyone can contribute to. SunPy provides
access to solar data through integration with the Virtual Solar
Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the
HELiophysics Integrated Observatory (HELIO) webservices. It currently
supports image data from major solar missions (e.g., SDO, SOHO, STEREO,
and IRIS), time-series data from missions such as GOES, SDO/EVE, and
PROBA2/LYRA, and radio spectra from e-Callisto and STEREO/SWAVES. We
describe SunPy's functionality, provide examples of solar data analysis
in SunPy, and show how Python-based solar data-analysis can leverage
the many existing tools already available in Python. We discuss the
future goals of the project and encourage interested users to become
involved in the planning and development of SunPy.
Title: Coronal Seismology: Inferring Magnetic Fields and Exploring
Damping Mechanisms
Authors: McAteer, James; Ireland, Jack; Inglis, Andrew
Bibcode: 2014AAS...22432343M
Altcode:
Coronal seismology provides a method to both infer coronal plasma
parameters and to differentiate between potential damping mechanisms. We
study a complex set of flare-induced, off-limb, coronal kink-mode
oscillations. There are over 100 loops that display a spread of
periods, amplitudes, and damping times. These are used to create a
coronal magnetic field map, where the behavior of each loop allows
for the magnetic field strength to be determined on a case-by-case
basis. We show that both Fourier and Wavelet routines can be used to
automatically extract and characterize such oscillations, and therefore
can provide such magnetic field maps in a near-realtime setting. We
study the damping lengths and times to differentiate between several
damping mechanisms. Resonant absorption and phase mixing are both in
agreement with the damping parameters in this event, with resonant
absorption appearing the simplest explanation. We explore how such
studies can now be carried out across all available SDO EUV passbands.
Title: JHelioviewer: Visualization software for solar physics data
Authors: Mueller, Daniel; Dimitoglou, George; Caplins, Benjamin; Garcia
Ortiz, Juan Pablo; Wamsler, Benjamin; Hughitt, Keith; Alexanderian,
Alen; Ireland, Jack; Amadigwe, Desmond; Fleck, Bernhard
Bibcode: 2013ascl.soft08016M
Altcode: 2013ascl.soft08016Y
JHelioview is open source visualization software for solar physics
data. The JHelioviewer client application enables users to browse
petabyte-scale image archives; the JHelioviewer server integrates a
JPIP server, metadata catalog, and an event server. JHelioview uses
the JPEG 2000 image compression standard, which provides efficient
access to petabyte-scale image archives; JHelioviewer also allows
users to locate and manipulate specific data sets.
Title: A Community Python Library for Solar Physics (SunPy)
Authors: Christe, Steven; Shih, A. Y.; Ireland, J.; Perez-Suarez,
D.; Mumford, S.; Hughitt, V. K.; Hewett, R.; Mayer, F.; SunPy Dev Team
Bibcode: 2013SPD....44..136C
Altcode:
Python, a free, cross platform, general purpose, high-level programming
language, has seen widespread adoption among the scientific community
resulting in the availability of a large range of software, from
numerical computation (NumPy, SciPy) and machine learning to spectral
analysis and visualization (Matplotlib). SunPy is a data analysis
toolkit specializing in providing the software necessary to analyze
solar and heliospheric datasets in Python. It aims to provide a free
and open-source alternative to the IDL-based SolarSoft (SSW) solar
data analysis environment. We present the latest release of SunPy
(0.3). This release includes a major refactor of the main SunPy code
to improve ease of use for the user as well as a more consistent
interface. SunPy provides downloading capability through integration
with the Virtual Solar Observatory (VSO) and the the Heliophysics
Event Knowledgebase (HEK). It can open image fits files from major
solar missions (SDO/AIA, SOHO/EIT, SOHO/LASCO, STEREO) into WCS-aware
maps. SunPy provides advanced time-series tools for data from mission
such as GOES, SDO/EVE, and Proba2/LYRA as well as support for radio
spectra (e.g. e-Callisto). We present examples of solar data analysis
in SunPy, and show how Python-based solar data-analysis can leverage
the many existing data analysis tools already available in Python. We
discuss the future goals of the project and encourage interested users
to become involved in the planning and development of SunPy.
Title: Summary usage statistics of the Helioviewer Project
Authors: Ireland, Jack; Stys, J. E.
Bibcode: 2013SPD....44..133I
Altcode:
The Helioviewer Project enables visual exploration of the Sun and the
inner heliosphere for everyone, everywhere via intuitive interfaces
and novel technology. Images from the SDO, STEREO, SOHO, PROBA2 and
Yohkoh missions are currently available. Users of the Helioviewer
Project have made over one million movies and over two million
screenshots since detailed (and anonymous) logging of Helioviewer
Project usage was implemented in February 2011. These usage logs are
analyzed to give a detailed breakdown on user interaction with solar
and heliospheric data via Helioviewer Project clients and services. We
present summary statistics on how our users are using our clients and
services, which data they are interested in, and how they choose to
interact with different data sources.
Title: 19 January 2005 X1.3: return current or single power law beam
with a sharp low-energy cutoff?
Authors: Ireland, Jack; Holman, G. D.
Bibcode: 2013SPD....44...74I
Altcode:
We analyze RHESSI hard X-ray spectrum data from the 19 January 2005
GOES X1.3 flare to determine between two models which is a better
description of the observed spectrum. The two spectral models we
consider are the return current, and a single power law beam with a
sharp low-energy cutoff. We show that the reduced chi-squared values
arising from fitting each model to the observed spectrum are too close
to enable us to decide which model is a better description. However,
other methods are available. We demonstrate the application of
techniques from Bayesian data analysis that allow us to quantify the
relative probability of flare models, and show for the data studied,
the return current model is preferred.
Title: New Capabilities in Helioviewer Project Clients
Authors: Stys, Jeffrey E.; Ireland, J.; Müller, D.; Hughitt, V. K.
Bibcode: 2013SPD....44..149S
Altcode:
Helioviewer.org enables the simultaneous exploration of multiple
heterogeneous solar data sets. In the latest iteration of this
open-source web application, Yohkoh SXT joins SDO, SOHO, STEREO,
and PROBA2 as a supported data set. A newly enhanced user-interface
expands the utility of Helioviewer.org by adding annotations to the
imagery. Backed by data from the Heliospheric Events Knowledgebase
(HEK), Helioviewer.org can now overlay solar feature and event data
(selectively by type and detection method) through the display of
interactive marker pins, region outlines, data labels, and information
panels. The addition of a size-of-the-Earth indicator provides a
sense of the scale to solar and heliospheric features for education
and public outreach purposes.
Title: Estimating the Properties of Hard X-Ray Solar Flares by
Constraining Model Parameters
Authors: Ireland, J.; Tolbert, A. K.; Schwartz, R. A.; Holman, G. D.;
Dennis, B. R.
Bibcode: 2013ApJ...769...89I
Altcode: 2013arXiv1304.8117I
We wish to better constrain the properties of solar flares by exploring
how parameterized models of solar flares interact with uncertainty
estimation methods. We compare four different methods of calculating
uncertainty estimates in fitting parameterized models to Ramaty High
Energy Solar Spectroscopic Imager X-ray spectra, considering only
statistical sources of error. Three of the four methods are based on
estimating the scale-size of the minimum in a hypersurface formed
by the weighted sum of the squares of the differences between the
model fit and the data as a function of the fit parameters, and are
implemented as commonly practiced. The fourth method is also based
on the difference between the data and the model, but instead uses
Bayesian data analysis and Markov chain Monte Carlo (MCMC) techniques
to calculate an uncertainty estimate. Two flare spectra are modeled:
one from the Geostationary Operational Environmental Satellite X1.3
class flare of 2005 January 19, and the other from the X4.8 flare of
2002 July 23. We find that the four methods give approximately the same
uncertainty estimates for the 2005 January 19 spectral fit parameters,
but lead to very different uncertainty estimates for the 2002 July 23
spectral fit. This is because each method implements different analyses
of the hypersurface, yielding method-dependent results that can differ
greatly depending on the shape of the hypersurface. The hypersurface
arising from the 2005 January 19 analysis is consistent with a normal
distribution; therefore, the assumptions behind the three non-Bayesian
uncertainty estimation methods are satisfied and similar estimates
are found. The 2002 July 23 analysis shows that the hypersurface
is not consistent with a normal distribution, indicating that the
assumptions behind the three non-Bayesian uncertainty estimation
methods are not satisfied, leading to differing estimates of the
uncertainty. We find that the shape of the hypersurface is crucial in
understanding the output from each uncertainty estimation technique,
and that a crucial factor determining the shape of hypersurface is
the location of the low-energy cutoff relative to energies where the
thermal emission dominates. The Bayesian/MCMC approach also allows us
to provide detailed information on probable values of the low-energy
cutoff, Ec , a crucial parameter in defining the energy
content of the flare-accelerated electrons. We show that for the 2002
July 23 flare data, there is a 95% probability that Ec
lies below approximately 40 keV, and a 68% probability that it lies
in the range 7-36 keV. Further, the low-energy cutoff is more likely
to be in the range 25-35 keV than in any other 10 keV wide energy
range. The low-energy cutoff for the 2005 January 19 flare is more
tightly constrained to 107 ± 4 keV with 68% probability. Using the
Bayesian/MCMC approach, we also estimate for the first time probability
density functions for the total number of flare-accelerated electrons
and the energy they carry for each flare studied. For the 2002 July
23 event, these probability density functions are asymmetric with
long tails orders of magnitude higher than the most probable value,
caused by the poorly constrained value of the low-energy cutoff. The
most probable electron power is estimated at 1028.1
erg s-1, with a 68% credible interval estimated at
1028.1-1029.0 erg s-1, and a 95%
credible interval estimated at 1028.0-1030.2
erg s-1. For the 2005 January 19 flare spectrum, the
probability density functions for the total number of flare-accelerated
electrons and their energy are much more symmetric and narrow: the most
probable electron power is estimated at 1027.66 ± 0.01
erg s-1 (68% credible intervals). However, in this case
the uncertainty due to systematic sources of error is estimated to
dominate the uncertainty due to statistical sources of error.
Title: Preface
Authors: Ireland, J.; Young, C. A.; Leibacher, J. W.
Bibcode: 2013SoPh..283....3I
Altcode:
No abstract at ADS
Title: Bayesian model comparison of solar flare spectra
Authors: Ireland, J.; Holman, G.
Bibcode: 2012AGUFMSH43B2172I
Altcode:
The detailed understanding of solar flares requires an understanding
of the physics of accelerated electrons, since electrons carry a large
fraction of the total energy released in a flare. Hard X-ray energy
flux spectral observations of solar flares can be fit with different
parameterized models of the interaction of the flare-accelerated
electrons with the solar plasma. Each model describes different
possible physical effects that may occur in solar flares. Bayesian model
comparison provides a technique for assessing which model best describes
the data. The advantage of this technique over others is that it can
fully account for the different number and type of parameters in each
model. We demonstrate this using Ramaty High Energy Solar Spectroscopic
Imager (RHESSI) spectral data from the GOES (Geostationary Operational
Environmental Satellite) X4.8 flare of 23-July-2002. We suggest
that the observed spectrum can be reproduced using two different
parameterized models of the flare electron content. The first model
assumes that the flare-accelerated electron spectrum consisting of a
single power law with a fixed low energy cutoff assumed to be below
the range of fitted X-ray energies, interacting with a non-uniformly
ionized target. The second model assumes that the flare-accelerated
electron spectrum has a broken power law and a low energy cutoff,
which interacts with a fully ionized target plasma. The low energy
cutoff in this model is a parameter used in fitting the data. We will
introduce and use Bayesian model comparison techniques to decide which
model best explains the observed data. This work is funded by the NASA
Solar and Heliospheric Physics program.
Title: A Coral Sea Rehearsal for the Eclipse Megamovie
Authors: Hudson, H. S.; Davey, A. R.; Ireland, J.; Jones, L.; Mcintosh,
S. W.; Paglierani, R.; Pasachoff, J. M.; Peticolas, L. M.; Russell,
R. M.; Suarez Sola, F. I.; Sutherland, L.; Thompson, M. J.
Bibcode: 2012AGUFMSH11C..06H
Altcode:
The "Eclipse on the Coral Sea" - 13/14 November 2012 (GMT/Australia)
- will have happened already. Our intention is to have used this
opportunity as a trial run for the eclipse in 2017, which features
1.5 hours of totality across the whole width of the continental
US. Conceived first and foremost as an education and public outreach
activity, the plan is to engage the public in solar science and
technology by providing a way for them to include images they have taken
of the solar eclipse, into a movie representation of coronal evolution
in time. This project will assimilate as much eclipse photography as
possible from the public. The resulting movie(s) will cover all ranges
of expertise, and at the basic smartphone or hand-held digital camera
level, we expect to have obtained a huge number of images in the case
of good weather conditions. The capability of modern digital technology
to handle such a data flow is new. The basic purpose of this and the
2017 Megamovie observations is to explore this capability and its
ability to engage people from many different communities in the solar
science, astronomy, mathematics, and technology. The movie in 2017,
especially, may also have important science impact because of the
uniqueness of the corona as seen under eclipse conditions. In this
presentation we will describe our smartphone application development
(see the "Transit of Venus" app for a role model here). We will also
summarize data acquisition via both the app and more traditional web
interfaces. Although for the Coral Sea eclipse event we don't expect to
have a movie product by the time of the AGU, for the 2017 event we do
intend to assemble the heterogenous data into beautiful movies within a
short space of time after the eclipse. These movies may have relatively
low resolution but would extend to the base of the corona. We encourage
participation in the 2012 observations, noting that no total eclipse,
prior to 2017, will occur in a region with good infrastructure for
extended observations. The National Center for Atmospheric Research is
sponsored by the National Science Foundation. The Megamovie project
is supported by NSF grant AGS-1247226, and JMP's eclipse work about
the eclipses of 2012 is supported by NSF grant AGS-1047726.
Title: Automated Detection/Characterization of EUV Waves in SDO/AIA
Data
Authors: Shih, A. Y.; Ireland, J.; Christe, S.; Hughitt, V. K.; Young,
C.; Earnshaw, M. D.; Mayer, F.
Bibcode: 2012AGUFMSH11C..08S
Altcode:
Although EUV waves in the solar corona (also called coronal
bright fronts or "EIT waves") were first observed in 1996, many
questions still remain about their nature and their association
with other phenomena such as flares, CMEs, and Moreton waves. The
high-resolution, high-cadence data from the Atmospheric Imaging
Assembly (AIA) instrument on the Solar Dynamics Observatory (SDO)
allows for unprecedented analysis of the kinematics and morphology
of EUV waves. This information can be crucial for constraining and
differentiating between theoretical models. While this analysis can
be performed "by hand", the large volume of AIA data is well-suited
for automated algorithms to detect and characterize these waves. We
are developing such algorithms, which will generate a comprehensive
catalog that can be used for statistical studies, and the biases of the
algorithms can be well-studied using simulated data. We take advantage
of imaging processing methods developed in Python, a general-purpose
scientific computing language widely used used by multiple communities,
as well as the SunPy Python library. We compare the results of our
automated algorithms with other efforts that use more traditional,
human-powered methods to identify and characterize EUV waves.
Title: SunPy: Python for Solar Physics Data Analysis
Authors: Hughitt, V. Keith; Christe, S.; Ireland, J.; Shih, A.; Mayer,
F.; Earnshaw, M. D.; Young, C.; Perez-Suarez, D.; Schwartz, R.
Bibcode: 2012AAS...22052207H
Altcode:
In recent years, Python, a free cross platform general purpose
high-level programming language, has seen widespread adoption among
the scientific community resulting in the availability of wide range of
software, from numerical computation and machine learning to spectral
analysis and visualization. SunPy is a software suite specializing
in providing the tools necessary to analyze solar and heliospheric
datasets in Python. It provides a free and open-source alternative
to the IDL-based SolarSoft (SSW) solar data analysis environment. We
present the current capabilities of SunPy which include WCS-aware
map objects that allow simple overplotting of data from multiple
image FITS files; time-series objects that allow overplotting of
multiple lightcurves, and integration with online services such
as The Virtual Solar Observatory (VSO) and The Heliophysics Event
Knowledgebase (HEK). SunPy also provides functionality that is not
currently available in SSW such as advanced time series manipulation
routines and support for working with solar data stored using JPEG
2000. We present examples of solar data analysis in SunPy, and show
how Python-based solar data-analysis can leverage the many existing
data analysis tools currently available in Python. We discuss the
future goals of the project and encourage interested users to become
involved in the planning and development of SunPy.
Title: Uncertainty Estimation in Fitting Parameterized Models to
Solar Flare Hard X-ray Spectra
Authors: Ireland, Jack; Tolbert, A. K.; Holman, G. D.; Dennis, B. R.;
Schwartz, R. A.
Bibcode: 2012AAS...22020428I
Altcode:
We compare four different methods of estimating the uncertainty in fit
parameters when fitting models to Ramaty High Energy Solar Spectroscopic
Imager (RHESSI) spectral data. Two flare spectra are studied: one
from the GOES (Geostationary Operational Environmental Satellite) X1.3
class flare of 19-January-2005, and the other from the X4.8 flare of
23-July-2002. Three of our methods rely on assumptions about the shape
of the hyper-surface formed by the weighted sum of the squares of the
differences between the model fit and the data as a function of the fit
parameters, evaluated around the minimum value of the hyper-surface, to
generate uncertainty estimates. The fourth method is based on Bayesian
data analysis techniques. The four methods give approximately
equal uncertainty estimates for the 19-January-2005 model parameters,
but give very different uncertainty estimates for the 23-July-2002 model
parameters. This is because the assumptions required for the first three
methods hold approximately for the 19-January-2005 analysis, but do
not hold for the 23-July-2002 analysis. The Bayesian-based method does
not require these assumptions, and so can give reliable uncertainty
estimates regardless of the shape of the hyper-surface formed by the
model fit to the data. We show that for the 23-July-2002 spectrum,
there is a 95% probability that the low energy cutoff to the model
distribution of emitting flare electrons lies below approximately 40keV,
and a 68% probability that it lies in the estimated range 7-36 keV. The
most probable flare electron energy flux is approximately 1028.1
erg-1sec-1 with a 68% credible interval
estimated at 1028.1-29.1 erg-1sec-1,
and a 95% credible interval estimated at 1028.0-30.3
erg-1sec-1. For the 19-January-2005
spectrum, these quantities are more tightly constrained to
105±4 keV and 1027.66±0.01 erg-1sec-1
(68% uncertainties). The reasons for these disparate results are
discussed. This work is funded by the NASA Solar and Heliospheric
Physics program.
Title: Automatic Detection and Characterization of EIT Waves Observed
by AIA Data
Authors: Ireland, Jack; Christe, S.; Hughitt, V. K.; Shih, A. Y.;
Young, C. A.; Earnshaw, M. D.; Mayer, F.
Bibcode: 2012AAS...22020117I
Altcode:
EIT waves were first observed by SOHO-EIT in 1996. Many questions
still remain about their relationship to other phenomena as such as
CMEs, Moreton waves, and transverse coronal loop oscillations. This is
partly due to the limitation of past observations, such as limited time
cadence. With the new Atmospheric Imaging Assembly (AIA) onboard SDO,
we now have access to an unprecedented uninterrupted data set with
a full-Sun field of view, high dynamic range, and most importantly
a high time cadence ( 10 s). The higher cadence of AIA compared to
other instruments means that it is possible to obtain more, and
better information on the occurrence rates and properties of EIT
waves. In order to fully utilize the vast data archive of AIA,
we are developing an automated algorithm to detect EIT waves. Such
an algorithm will permit statistical analyses to be performed on
these waves providing important constraints on models. We compare
results using different image processing methods developed in Python,
a general purpose scientific computing language widely used by
multiple communities. We validate these algorithms against traditional
human-powered methods. This analysis makes use of the SunPy python
library.
Title: The Helioviewer Project: Making Petabytes of Images Available
to Everyone
Authors: Ireland, Jack; Hughitt, V. K.; Mueller, D.
Bibcode: 2012AAS...22032301I
Altcode:
The aim of the Helioviewer Project (supported by ESA and NASA) is to
design services and clients which give users everywhere the capability
to browse and visualize the behavior of the Sun and inner heliosphere
and to give access to the underlying science data. Helioviewer Project
services and clients allow users to explore archives of JPEG2000
files and easily create movies of heliospheric events at arbitrary
times, locations, time-scales and length-scales, using images
from multiple instruments, overlaid using the FITS header information
from the original science data. Images from early 1996 to the present
day are currently available. This presentation will begin with
a short summary of the JPEG2000 standard, which is used to store a
wavelet-compressed version of the original science image data and a full
copy of the FITS header. This reduces storage requirements server-side
when compared to the original science data, but also keeps important
meta-data available for use by browse clients. The JPEG2000 standard
also includes the JPEG2000 Internet Protocol (JPIP), which allows browse
clients to efficiently stream images and dynamically assembled movies
over the web by sending only the wavelet coefficients required to show
the desired portion of the movie. These features enable efficient access
to large archives of large images, such those created by the Advanced
Imaging Assembly. Current use of Helioviewer Project services and
clients will be discussed. Plans for including images from other solar
and heliospheric data-sets will also be discussed. Finally, I will
outline the future integration of Helioviewer Project visualization
capabilities with the data provision services of the Virtual Solar
Observatory (VSO) and the solar phenomena catalog services of the
Heliophysics Event Knowledgebase (HEK), to create more scientifically
useful and integrated data search, browse and acquisition tools.
Title: Helioviewer.org: Solar and Heliospheric Data Visualization
Authors: Hughitt, V. Keith; Ireland, J.; Mueller, D.
Bibcode: 2012AAS...22020707H
Altcode:
Over the past several years, Helioviewer.org has enabled thousands
of users from across the globe to explore the inner heliosphere,
providing access to over ten million images from the SOHO, SDO, and
STEREO missions. Users can explore solar image archives, create movies
on the fly, and interact with other solar and heliospheric services
like the SDO cut-out service and the Virtual Solar Observatory
(VSO). In addition to providing a powerful platform for browsing
heterogeneous sets of solar data, Helioviewer.org also seeks to be
as flexible and extensible as possible, providing access to much
its functionality via a simple Application Programming Interface
(API). The API can be used to create images and movies from data
available on Helioviewer.org, or to embed a simplified version of
Helioviewer.org into another website. Recently the Helioviewer.org API
was used for two such applications developed by outside interests: an
SDO data browser, and a Python library for solar physics data analysis
(SunPy). These applications are discussed and examples of API usage are
provided. Finally, Helioviewer.org is undergoing continual development
with new features being added monthly. Recent changes to the web
application are discussed, along with a preview of things to come.
Title: Helioviewer.org: Simple Solar and Heliospheric Data
Visualization
Authors: Hughitt, V. K.; Ireland, J.; Mueller, D.
Bibcode: 2011AGUFMED53B0790H
Altcode:
Helioviewer.org is a free and open-source web application for
exploring solar physics data in a simple and intuitive manner. Over
the past several years, Helioviewer.org has enabled thousands of users
from across the globe to explore the inner heliosphere, providing
access to over ten million images from the SOHO, SDO, and STEREO
missions. While Helioviewer.org has seen a surge in use by the public
in recent months, it is still ultimately a science tool. The newest
version of Helioviewer.org provides access to science-quality data for
all available images through the Virtual Solar Observatory (VSO). In
addition to providing a powerful platform for browsing heterogeneous
sets of solar data, Helioviewer.org also seeks to be as flexible and
extensible as possible, providing access to much of its functionality
via a simple Application Programming Interface (API). Recently,
the Helioviewer.org API was used for two such applications: a
Wordpress plugin, and a Python library for solar physics data analysis
(SunPy). These applications are discussed and examples of API usage are
provided. Finally, Helioviewer.org is undergoing continual development,
with new features being added on a regular basis. Recent updates to
Helioviewer.org are discussed, along with a preview of things to come.
Title: An automated survey of three and five minute oscillations in
active regions
Authors: Ireland, J.; Young, C.
Bibcode: 2011AGUFMSH13B1952I
Altcode:
We present the results of an survey of the automatically detected three
and five minute oscillation content of 44 active regions automatically
detected by the SDO Feature Finding Team SPoCA (Spatial Possibilistic
Clustering Algorithm; Barra et al., A&A, 2009, 505, 361). Analysis
is restricted to one hour, full cadence, cut-outs of automatically
detected active regions found in 171Å and 193Å from Atmospheric
Imaging Assembly (AIA) data on board the Solar Dynamics Observatory
(SDO). The oscillations were found using an improved version of the
automated oscillation detection algorithm of Ireland et al. 2010,
Sol. Phys. 264, 403, that also estimates the coherence and the local
phase speed of any detected oscillating region. It is shown that most
active regions only support very few oscillating regions of either
three or five minute periods. Further, very few of these oscillating
regions have a substantial coherence (greater than 0.6) and a relative
phase speed error of less than 50%, our criteria for the detection of an
identifiable and coherent wave. These results suggest that oscillating
regions in active regions are rare. Finally, a large proportion of the
regions that do oscillate with 5 minute periods do not do so coherently
and with a well-defined phase speed. These results are discussed in the
context of the recent suggestion that most five-minute oscillations are
not due to slow-mode magnetohydrodynamic waves (De Moortel et al. 2000,
A&A 355, L23) but are due to quasi-periodic flows (De Pontieu and
McIntosh, 2010, Ap. J. 722, 1013). The advantages of using automated
detection and classification methods are also briefly discussed.
Title: Automatic Detection and Characterization of EIT waves observed
by AIA Data
Authors: Christe, S.; Hughitt, V. K.; Ireland, J.; Young, C.; Shih,
A. Y.; Earnshaw, M. D.; Mayer, F.; SunPy Team
Bibcode: 2011AGUFMSH13B1958C
Altcode:
EIT waves were first observed by SOHO-EIT in 1996. Many questions
still remain about their relationship to other phenomena as such as
CMEs, Moreton waves, and transverse coronal loop oscillations. This is
likely due to the limitation of past observations (e.g. limited time
cadence). With the new Atmospheric Imaging Assembly (AIA) onboard SDO,
we now have access to an unprecedented uninterrupted data set with
a full-Sun field of view, high dynamic range, and most importantly
a high time cadence (~10 s). AIA observations have the potential to
revolutionize the study of wave phenomena in the solar corona. In order
to fully utilize the vast data archive of AIA, we are developing an
automated algorithm to detect EIT waves. Such an algorithm would permit
a standardized statistical analysis to be performed on these mysterious
waves providing important constraints on models. We present and compare
results using different numerical methods (e.g. wavelets, watershed)
developed in Python, a general purpose scientific computing language
widely used by multiple communities. We validate these algorithms
against traditional human-powered methods. This analysis makes use of
the SunPy python library.
Title: The Helioviewer Project: Solar Data Visualization and
Exploration
Authors: Hughitt, V. Keith; Ireland, J.; Müller, D.; García Ortiz,
J.; Dimitoglou, G.; Fleck, B.
Bibcode: 2011SPD....42.1517H
Altcode: 2011BAAS..43S.1517H
SDO has only been operating a little over a year, but in that short
time it has already transmitted hundreds of terabytes of data, making
it impossible for data providers to maintain a complete archive of
data online. By storing an extremely efficiently compressed subset of
the data, however, the Helioviewer project has been able to maintain a
continuous record of high-quality SDO images starting from soon after
the commissioning phase. The Helioviewer project was not designed
to deal with SDO alone, however, and continues to add support for
new types of data, the most recent of which are STEREO EUVI and
COR1/COR2 images. In addition to adding support for new types of data,
improvements have been made to both the server-side and client-side
products that are part of the project. A new open-source JPEG2000 (JPIP)
streaming server has been developed offering a vastly more flexible and
reliable backend for the Java/OpenGL application JHelioviewer. Meanwhile
the web front-end, Helioviewer.org, has also made great strides both
in improving reliability, and also in adding new features such as the
ability to create and share movies on YouTube. Helioviewer users are
creating nearly two thousand movies a day from the over six million
images that are available to them, and that number continues to grow
each day. We provide an overview of recent progress with the various
Helioviewer Project components and discuss plans for future development.
Title: Bayesian Analysis of RHESSI Flare Data: Effect of Prior
Information on Determining the Low-energy Cutoff and the Total
Electron Content
Authors: Ireland, Jack; Holman, G.; Tolbert, K.; Dennis, B. R.;
Schwatze, R. A.
Bibcode: 2011SPD....42.2228I
Altcode: 2011BAAS..43S.2228I
We use a Bayesian/Markov chain Monte Carlo (MCMC) posterior analysis to
determine credible intervals (error estimates) to the parameter values
of emission models. We model a RHESSI spectrum from the X1.9 flare of 23
July 2002 as an isothermal component plus a non-thermal bremsstrahlung
photon spectrum produced in thin-target interactions by an electron
distribution that is a double power law above a low energy cutoff. The flare-injected electron distribution models mentioned above
are subject to a low-energy cutoff. The location of this low-energy
cutoff is not known precisely since the signal-to-noise ratio of the
photons due to the non-thermal spectrum compared to the photons due
to the thermal spectrum is small at the energies where the low-energy
cutoff is thought to be. This parameter is of particular interest
since it is a key component in determining the total electron content
of flares. Bayesian data analysis allow one to include information
(priors) on the likely value of parameters. Priors force one to
explicitly quantify the expectations of the range and behavior of
parameter values in a model. Credible intervals to the model parameter
values (derived via Bayesian/Markov chain Monte Carlo (MCMC) posterior
analysis) therefore include the effect of this prior information. In
analyzing flares, priors allow one to explicitly quantify the expected
values of parameters in flare models. It is found that changing the
prior of the total integrated electron flux model parameter from a flat
prior (all values have equal probability) to a Jeffreys prior (orders
of magnitude of the parameter value have equal probability) enhances
peaks in the probability distribution of the low-energy cutoff below
25 keV. This prior-dependence suggests weak evidence for their actual
presence. We find the most probable total electron content (along with
its 68% and 95% credible interval) given the model flare spectra used.
Title: Accessing SDO Data : The Poster
Authors: Hourcle, Joseph; Addison, K.; Bogart, R.; Chamberlin, P.;
Freeland, S.; Hughitt, V. K.; Ireland, J.; Maddox, M.; Mueller, D.;
Somani, A.; Sommers, J.; Thompson, B.; solar physics data community,
The
Bibcode: 2011SPD....42.2130H
Altcode: 2011BAAS..43S.2130H
As the data from SDO are useful for a variety of purposes, including
solar physics, helioseismology, atmospheric science, space weather
forecasting, education and public outreach, a wide variety of tools
have been development to cater to the different needs of the various
groups. Systems have been developed for pipeline processing, searching,
browsing, subsetting, or simply just moving around large volumes
of data. We present a quick overview of the different systems
that can be used to access SDO data including (J)Helioviewer, the
Heliophysics Event Knowledgebase (HEK), the Virtual Solar Observatory
(VSO), the Integrated Space Weather Analysis System (iSWA), the
Data Record Management System (DRMS), and various websites. We cover
web-based applications, application programming interfaces (APIs),
and IDL command line tools. This poster serves as a supplement
to the oral presentation as a place to distribute information about
the various interfaces and to collect feedback about any unmet needs
for data access.
Title: Helioviewer: Simplifying Your Access to SDO Data
Authors: Hughitt, V. K.; Ireland, J.; Mueller, D.; Beck, J.; Lyon,
D.; Dau, A.; Dietert, H.; Nuhn, M.; Dimitoglou, G.; Fleck, B.
Bibcode: 2010AGUFMSH23C1868H
Altcode:
Over the past several years, the Helioviewer Project has evolved
from a simple web application to display images of the sun into a
suite of tools to visualize and interact with heterogeneous types of
solar data. In addition to a modular and scalable back-end server, the
Helioviewer Project now offers multiple browse clients; the original
web application has been upgraded to support high-definition movie
generation and feature and event overlays. For complex image processing
and massive data volumes, there is a stand-alone desktop application,
JHelioviewer. For a quick check of the latest images and events,
there is an iPhone application, hqTouch. The project has expanded from
the original SOHO images to include image data from SDO and event and
feature data from the HEK. We are working on adding additional image
data from other missions as well as spectral and time-series data. We
will discuss the procedure through which interested parties may process
their data for use with Helioviewer, including how to use JP2Gen to
convert FITS files into Helioviewer-compliant JPEG 2000 images, how
to setup a local instance of the Helioviewer server, and how to query
Helioviewer in your own applications using a simple web API.
Title: Automated detection of oscillatory signals in the solar
atmosphere: first results from SDO-AIA data
Authors: Ireland, J.; Young, C.; de Pontieu, B.; McIntosh, S. W.
Bibcode: 2010AGUFMSH11A1615I
Altcode:
Ireland et al. (2010) recently published a Bayesian-probability
based automated oscillation detection algorithm that finds areas
of the solar corona that support spatially contiguous oscillatory
signals. The major advantages of this algorithm are that it requires no
special knowledge of the noise characteristics or possible frequency
content of the signal, yet can calculate a probability that a time
series supports a signal in a given frequency range. This leads to
an algorithm which detects pixel areas where each pixel has a high
probability of supporting an oscillatory signal; however, the pixels
in these areas are not necessarily oscillating coherently. Earlier,
McIntosh et al. (2008) described another algorithm that first Fourier
filters time series data around a known frequency, and then calculates
the local coherence of the filtered signals in order to find areas
of the solar corona that exhibit locally strongly coherent signals
in narrow frequency ranges. The major advantages of this algorithm
are that locally coherent signals are found, and that it is simple
to calculate other parameters such as the phase speed. This leads to
an algorithm that finds groups of pixels that are coherent in narrow
frequency ranges, but that are not necessarily oscillatory in nature. In
this work we combine these two recently published automated oscillatory
signal detection algorithms and compare the new hybrid algorithm to the
progenitor algorithms. The new algorithm is applied to Advanced Imaging
Assembly (AIA) 94, 131, 171, 193, 211 and 335 Å data from the Solar
Dynamics Observatory, and we will give some first results. We also
discuss the use of this algorithm in a detection pipeline to provide
near-real time measurements of groups of coherently oscillating pixels.
Title: Automated Coronal Seismology: Curvelet Characterization of
Probability Maps of Image Data with Oscillatory Signal
Authors: Young, C.; Ireland, J.
Bibcode: 2010AGUFMSH23C1873Y
Altcode:
Automated coronal seismology will require measurements of the structure
that supports an oscillatory signal; for example, a measurement of
the loop length of a transversely oscillating loop can be used to
estimate the coronal magnetic field (Nakariakov& Ofman 2001). One
of the results from the recently published Bayesian probability
based automated oscillation detection algorithm (Ireland et al.,
2010) is a probability map. This is an image of the probability that
each pixel from a set of images contains an oscillatory signal. A
map from a significant detection contains one or more clusters
of high probability pixels dispersed amongst mostly pixels of low
probability. These low probability pixels amount to noise while the
clusters of high probability are the desired signal. A visual inspection
of the probability maps that contain significant signal reveal that
the clusters of pixels contain structure that corresponds to physical
regions in the original images i.e. oscillating loops. A necessary
step for using these oscillation probability maps is to extract and
characterize these high probability regions. A natural choice for an
appropriate representation of these structures especially given their
corresponds to real extended features such as loops is the curvelet
transform (Candes and Donoho, 1999 and Candes et al., 2005). In this
work we present a preliminary analysis of these probability maps using
curvelets to isolate and characterize regions of high probability. The
suitability of this technique for the pipeline processing of Solar
Dynamics Observatory data is also discussed.
Title: The Many Ways to Access SDO Data
Authors: Thompson, B. J.; Hourcle, J. A.; Addison, K.; Bogart, R. S.;
Chamberlin, P. C.; Dietert, H.; Freeland, S. L.; Hughitt, V. K.;
Ireland, J.; Mueller, D.; Somani, A.; Sommers, J.
Bibcode: 2010AGUFMSH23C1865T
Altcode:
To solve the issue of dealing with the large volume of data available
from AIA, there are a number of ways to get access to SDO data. With
Helioviewer, the Heliophysics Event Knowledgebase, the Virtual Solar
Observatory, and the PI-provided tools, scientists and other interested
parties have a number of ways to find and obtain data of interest. We
present an overview of the differences between the various systems,
and a flow chart to help determine which one might be of the most
benefit for a given situation.
Title: JHelioviewer: Open-Source Software for Discovery and Image
Access in the Petabyte Age (Invited)
Authors: Mueller, D.; Dimitoglou, G.; Langenberg, M.; Pagel, S.; Dau,
A.; Nuhn, M.; Garcia Ortiz, J. P.; Dietert, H.; Schmidt, L.; Hughitt,
V. K.; Ireland, J.; Fleck, B.
Bibcode: 2010AGUFMSH22A..05M
Altcode:
The unprecedented torrent of data returned by the Solar Dynamics
Observatory is both a blessing and a barrier: a blessing for making
available data with significantly higher spatial and temporal
resolution, but a barrier for scientists to access, browse and
analyze them. With such staggering data volume, the data is bound
to be accessible only from a few repositories and users will have to
deal with data sets effectively immobile and practically difficult to
download. From a scientist's perspective this poses three challenges:
accessing, browsing and finding interesting data while avoiding
the proverbial search for a needle in a haystack. To address
these challenges, we have developed JHelioviewer, an open-source
visualization software that lets users browse large data volumes
both as still images and movies. We did so by deploying an efficient
image encoding, storage, and dissemination solution using the JPEG
2000 standard. This solution enables users to access remote images at
different resolution levels as a single data stream. Users can view,
manipulate, pan, zoom, and overlay JPEG 2000 compressed data quickly,
without severe network bandwidth penalties. Besides viewing data, the
browser provides third-party metadata and event catalog integration
to quickly locate data of interest, as well as an interface to the
Virtual Solar Observatory to download science-quality data. As part of
the Helioviewer Project, JHelioviewer offers intuitive ways to browse
large amounts of heterogeneous data remotely and provides an extensible
and customizable open-source platform for the scientific community.
Title: Automated Detection of Oscillating Regions in the Solar
Atmosphere
Authors: Ireland, J.; Marsh, M. S.; Kucera, T. A.; Young, C. A.
Bibcode: 2010SoPh..264..403I
Altcode: 2010SoPh..tmp..127I; 2010SoPh..tmp..115I; 2010arXiv1007.0975I
Recently observed oscillations in the solar atmosphere have been
interpreted and modeled as magnetohydrodynamic wave modes. This has
allowed for the estimation of parameters that are otherwise hard
to derive, such as the coronal magnetic-field strength. This work
crucially relies on the initial detection of the oscillations, which
is commonly done manually. The volume of Solar Dynamics Observatory
(SDO) data will make manual detection inefficient for detecting all
of the oscillating regions. An algorithm is presented that automates
the detection of areas of the solar atmosphere that support spatially
extended oscillations. The algorithm identifies areas in the solar
atmosphere whose oscillation content is described by a single, dominant
oscillation within a user-defined frequency range. The method is based
on Bayesian spectral analysis of time series and image filtering. A
Bayesian approach sidesteps the need for an a-priori noise estimate
to calculate rejection criteria for the observed signal, and it also
provides estimates of oscillation frequency, amplitude, and noise,
and the error in all of these quantities, in a self-consistent
way. The algorithm also introduces the notion of quality measures to
those regions for which a positive detection is claimed, allowing for
simple post-detection discrimination by the user. The algorithm is
demonstrated on two Transition Region and Coronal Explorer (TRACE)
datasets, and comments regarding its suitability for oscillation
detection in SDO are made.
Title: JHelioviewer: Taming The Torrent Of SDO Data
Authors: Mueller, Daniel; Langenberg, M.; Pagel, S.; Schmidt, L.;
Garcia Ortiz, J. P.; Dimitoglou, G.; Hughitt, V. K.; Ireland, J.;
Fleck, B.
Bibcode: 2010AAS...21640224M
Altcode: 2010BAAS...41..877M
Space missions generate an ever-growing amount of data, as impressively
highlighted by the Solar Dynamics Observatory's (SDO) expected return
of 1.4 TByte/day. In order to fully exploit their data, scientists
need to be able to browse and visualize many different data products
spanning a large range of physical length and time scales. So far, the
tools available to the scientific community either require downloading
all potentially relevant data sets beforehand in their entirety or
provide only movies with a fixed resolution and cadence. For SDO,
the former approach is prohibitive due to the shear data volume, while
the latter does not do justice to the high resolution and cadence of
the images. To address this challenge, we have developed JHelioviewer,
a JPEG 2000-based visualization and discovery software for solar image
data. Using the very efficient lossy compression mode of JPEG 2000,
a full-size SDO image can be compressed to 1 MByte at good visual
quality for browsing purposes. JHelioviewer will make the vast amount
of SDO images available to the worldwide community in this format,
which is already being used for all SOHO images. JHelioviewer is
a cross-platform application that offers movie streaming, real-time
frame-by-frame image processing, feature/event overlays and will enable
users to access SDO science data via a VSO interface. JHelioviewer uses
the JPEG 2000 Interactive Protocol (JPIP) and OpenGL. The random code
stream access of JPIP minimizes data transfer by streaming image data in
a region-of-interest and quality-progressive way, while OpenGL enables
rapid hardware-accelerated image processing and rendering. Currently
focused on solar physics data, JHelioviewer can easily be adapted
for use in other areas of space and earth sciences. This poster will
illustrate the new and expanded functionality of JHelioviewer and
highlight the advantages of JPEG 2000 as a new compression standard
for solar image data.
Title: The Helioviewer Project: Browsing, Visualizing and Accessing
Petabytes of Solar Data
Authors: Mueller, Daniel; Hughitt, V. K.; Langenberg, M.; Ireland, J.;
Pagel, S.; Schmidt, L.; Garcia Ortiz, J. P.; Dimitoglou, G.; Fleck, B.
Bibcode: 2010AAS...21640223M
Altcode: 2010BAAS...41..876M
After its successful launch, NASA's Solar Dynamics Observatory
(SDO) will soon return more than 1 Terabyte worth of images per
day. This unprecedented torrent of data will pose an entirely new
set of challenges with respect to data access, data browsing and
searching for interesting data while avoiding the proverbial search
for "a needle in a haystack". In order to fully exploit SDO's wealth
of data and connect it to data from other solar missions like SOHO,
scientists need to be able to interactively browse and visualize many
different data products spanning a large range of physical length and
time scales. So far, all tools available to the scientific community
either require downloading all potentially relevant data sets beforehand
in their entirety or provide only movies with a fixed resolution and
cadence. The Helioviewer project offers a solution to these challenges
by providing a suite of tools that are based on the new JPEG 2000
compression standard and enable scientists and the general public alike
to intuitively browse visualize and access petabytes of image data
remotely: - JHelioviewer, a cross-platform application that offers
movie streaming and real-time processing using the JPEG 2000 Interactive
Protocol (JPIP) and OpenGL, as well as feature/event overlays. -
helioviewer.org, a web-based image and feature/event browser. -
Server-side services to stream movies of arbitrary spatial and temporal
resolution in a region-of-interest and quality-progressive form, a
JPEG 2000 image database and a feature/event server. All the services
can be accessed through well-documented interfaces (APIs). - Code
to convert images into JPEG 2000 format. This presentation will
give an overview of the Helioviewer Project, illustrate new features
and highlight the advantages of JPEG 2000 as a data format for solar
physics that has the potential to revolutionize the way high-resolution
image data are disseminated and analyzed.
Title: Observing the High Energy Sun with CGRO/COMPTEL
Authors: Young, C. Alex; Ireland, J.; de Nolfo, G. A.; Ryan, J. M.
Bibcode: 2010AAS...21640433Y
Altcode: 2010BAAS...41..905Y
Despite many observations of solar flares with spacecraft and
ground-based instruments, the underlying physics that drives particle
acceleration is still not well understood. Understanding the role of
energetic particles in the flare process and identifying the relevant
processes behind energetic particle acceleration requires sensitive
observations that cover a wide range in energy in photon emission and,
if possible, neutron emission. The COMPton TELescope (COMPTEL) aboard
the Compton Gamma Ray Observatory (CGRO) provided unprecedented, and
as yet unsurpassed, sensitivity to γ rays in the 0.7 to 30 MeV energy
range and neutrons in the 20 to 150 MeV energy range. This, combined
with its nine years of operation, has produced a unique data set of
observations for almost a complete solar cycle. Analysis of some of
these data has provided many new and exciting results for high energy
solar astrophysics, but these data have been largely unexplored. In
this work we present both past and new results from this rich dataset.
Title: Bayesian Analysis of RHESSI Flare Spectra
Authors: Ireland, Jack; Holman, G. D.; Tolbert, A. K.; Dennis, B. R.;
Schwartz, R. A.
Bibcode: 2010AAS...21640402I
Altcode: 2010BAAS...41..899I
We use a Bayesian/Markov chain Monte Carlo (MCMC) posterior analysis
to determine credible intervals (error estimates) to the parameter
values of emission models. We model two RHESSI spectra, one from
the X1.9 flare of 23 July 2002 and the other from the X4.8 flare
of 19 January 2005, as an isothermal component plus a non-thermal
bremsstrahlung photon spectrum produced in thick-target interactions
by an electron distribution that is a double power law above a low
energy cutoff. Each model has seven parameters. The parameter and
error estimates from the Bayesian/MCMC approach are compared to two
conventional fitting and error estimation techniques, Monte Carlo
and chi-squared mapping. We find that the Bayesian/MCMC approach
estimates that the low energy cutoff of the 19 January 2005 spectrum
is in the range 98-114 keV with 95% probability, in agreement with
conventional analyses. For the 23 July 2002 spectrum, the Bayesian/MCMC
approach finds a 95% probability that the low energy cutoff is below
32 keV, and that the probability distribution is approximately flat
below 25 keV, indicating that there is insufficient information to
further define the low energy cutoff energy below 25 keV, in intuitive
agreement with expectations from examining the inferred photon flux
which begins to be thermally dominated around 25-30 keV. In contrast
with this expectation, the Monte Carlo technique yields a peaked low
energy cutoff frequency distribution, with 95% of the distribution in
the range 24-35 keV. Chi-squared mapping gives a 95% probability upper
limit of 33 keV. These results are explained in terms of the
relative location of the low energy cutoff in the electron spectrum
compared to the thermal contribution and the way each of the three
methods explore the parameter search space.
Title: Solar Mashups: Interacting With, Extending, And Embedding
Helioviewer.org And Jhelioviewer
Authors: Hughitt, V. Keith; Ireland, J.; Müller, D.; Langenberg,
M.; Pagel, S.; Schmidt, L.; Harper, J.; Dimitoglou, G.; Fleck, B.
Bibcode: 2010AAS...21640225H
Altcode: 2010BAAS...41..877H
Helioviewer.org is a JPEG 2000-driven web application for searching
and displaying heterogeneous solar data sets, including both image
and catalog information. Helioviewer.org has been written from the
ground up with extensibility in mind. The result of this effort is a
rich Application Programming Interface (API) from which third-party
applications can interact with Helioviewer.org. In addition to being
able to launch Helioviewer.org with a specified state (by giving
it a time and a set of instruments, wavelengths, etc), it is also
possible to generate composite images and movies, and to search for
catalog data from the Heliophysics Event Knowledgebase (HEK). We are
developing our software so that you will be able to embed instances
of Helioviewer.org in your own web pages, in much the same way that
it is now possible to embed Google Maps (tm) into any webpage. This
will make it very easy to overlay your data with that provided by
the Helioviewer Project. JHelioviewer, Helioviewer.org's Java-based
counterpart, shares many of the same features as Helioviewer.org, but
also offers some new ones when it comes to extensibility, including a
custom plugin architecture that supports custom image filters, overlay
layers, GUI components, and more. Both of the projects are free to
use and completely open-source, and anyone is welcome to contribute
to their development.
Title: Preface
Authors: Ireland, J.; Young, C. A.; Leibacher, J.
Bibcode: 2010SoPh..262..233I
Altcode: 2010SoPh..tmp...46I; 2010SoPh..tmp...58I
No abstract at ADS
Title: JHelioviewer: Exploring Petabytes of Solar Images
Authors: Mueller, Daniel; Fleck, Bernhard; Dimitoglou, George; Garcia
Ortiz, Juan Pablo; Schmidt, Ludwig; Hughitt, Keith; Ireland, Jack
Bibcode: 2010cosp...38.2880M
Altcode: 2010cosp.meet.2880M
Space missions generate an ever-growing amount of data, as impressively
highlighted by the Solar Dynamics Observatory's (SDO) expected return
of 1.4 TByte/day. In order to fully ex-ploit their data, scientists
need to be able to browse and visualize many different data products
spanning a large range of physical length and time scales. So far, the
tools available to the scientific community either require downloading
all potentially relevant data sets beforehand in their entirety or
provide only movies with a fixed resolution and cadence. For SDO,
the former approach is prohibitive due to the shear data volume,
while the latter does not do justice to the high resolution and
cadence of the images. To address this challenge, we have developed
JHelioviewer, a JPEG 2000-based visualization and discovery software
for solar image data. JHelioviewer makes the vast amount of SDO images
available to the worldwide community, lets users browse more than
14 years worth of images from the Solar and Heliospheric Observatory
(SOHO) and facilitates browsing and analysis of complex time-dependent
data sets from mul-tiple sources in general. The user interface for
JHelioviewer is a multi-platform Java client that communicates with a
remote server via the JPEG 2000 interactive protocol JPIP. The random
code stream access of JPIP minimizes data transfer and can encapsulate
metadata as well as multiple image channels in one data stream. This
presentation will illustrate the features of JHelioviewer and highlight
the advantages of JPEG 2000 as a new data compression standard.
Title: Bayesian analysis of RHESSI spectra
Authors: Ireland, J.; Holman, G.; Dennis, B. R.; Tolbert, A. K.;
Schwartz, R. A.
Bibcode: 2009AGUFMSH21C..08I
Altcode:
We use Bayesian posterior analysis to determine credible intervals to
the parameter values of flare models of RHESSI data. Two flare spectra,
from the 23 July 2002 and 19 January 2005 events are considered. The
Bayesian credible interval (an upper and lower limit to a parameter
value, plus the probability that the true value lies between those
limits) is compared to the standard error found using conventional
analysis techniques. Of particular interest is the low energy
cutoff. The Bayesian approach allows us to quote an upper limit to
the low energy cutoff with the probability that the low energy cutoff
is below that upper limit. The implications of a Bayesian analysis on
our understanding of these flare events are discussed. Extensions to
the current approach are also discussed.
Title: Helioviewer.org: Browsing Very Large Image Archives Online
Using JPEG 2000
Authors: Hughitt, V. K.; Ireland, J.; Mueller, D.; Dimitoglou, G.;
Garcia Ortiz, J.; Schmidt, L.; Wamsler, B.; Beck, J.; Alexanderian,
A.; Fleck, B.
Bibcode: 2009AGUFMSH51B1279H
Altcode:
As the amount of solar data available to scientists continues to
increase at faster and faster rates, it is important that there exist
simple tools for navigating this data quickly with a minimal amount
of effort. By combining heterogeneous solar physics datatypes such
as full-disk images and coronagraphs, along with feature and event
information, Helioviewer offers a simple and intuitive way to browse
multiple datasets simultaneously. Images are stored in a repository
using the JPEG 2000 format and tiled dynamically upon a client's
request. By tiling images and serving only the portions of the image
requested, it is possible for the client to work with very large
images without having to fetch all of the data at once. In addition
to a focus on intercommunication with other virtual observatories
and browsers (VSO, HEK, etc), Helioviewer will offer a number of
externally-available application programming interfaces (APIs) to
enable easy third party use, adoption and extension. Recent efforts
have resulted in increased performance, dynamic movie generation,
and improved support for mobile web browsers. Future functionality
will include: support for additional data-sources including RHESSI,
SDO, STEREO, and TRACE, a navigable timeline of recorded solar events,
social annotation, and basic client-side image processing.
Title: JHelioviewer: Visualizing Large Sets of Solar Images Using
JPEG 2000
Authors: Muller, D.; Fleck, B.; Dimitoglou, G.; Caplins, B. W.;
Amadigwe, D. E.; García Ortiz, J. P.; Wamsler, B.; Alexanderian,
A.; Hughitt, V. K.; Ireland, J.
Bibcode: 2009CSE....11...38M
Altcode: 2009arXiv0906.1582M
All disciplines that work with image data-from astrophysics to medical
research and historic preservation-increasingly require efficient ways
to browse and inspect large sets of high-resolution images. Based on
the JPEG 2000 image-compression standard, the JHelioviewer solar image
visualization tool lets users browse petabyte-scale image archives as
well as locate and manipulate specific data sets.
Title: A Novel Approach to Discovery and Access to Solar Data in
the Petabyte Age
Authors: Mueller, Daniel; Dimitoglou, G.; Hughitt, V. K.; Ireland,
J.; Wamsler, B.; Fleck, B.
Bibcode: 2009SPD....40.1706M
Altcode:
Space missions generate an ever-growing amount of data, as impressively
highlighted by SDO's expected data rate of 1.4 TByte/day. In order
to fully exploit their data, scientists need to be able to browse
and visualize many different data products spanning a large range
of physical length and time scales. So far, the tools available to
the scientific community either require downloading all potentially
relevant data sets beforehand in their entirety or provide only
movies with a fixed resolution and cadence. To facilitate browsing and
analysis of complex time-dependent data sets from multiple sources,
we are developing JHelioviewer, a JPEG 2000-based visualization and
discovery infrastructure for solar image data. Together with its
web-based counterpart helioviewer.org, JHelioviewer offers intuitive
ways to browse large amounts of heterogeneous data remotely and allows
users to search related event data bases. The user interface for
JHelioviewer is a multi-platform Java client that can both communicate
with a remote server via the JPEG 2000 interactive protocol JPIP
and open local data. The random code stream access of JPIP minimizes
data transfer and can encapsulate meta data as well as multiple image
channels in one data stream. This presentation will illustrate some
of the features of JHelioviewer and the advantages of JPEG 2000 as a
new data compression standard.
Title: Automated Detection of Oscillating Areas in the Solar
Atmosphere
Authors: Ireland, Jack; Marsh, M. S.; Kucera, T. A.; Young, A.
Bibcode: 2009SPD....40.1517I
Altcode:
Recently observed oscillations in the solar atmosphere have been
interpreted and modeled as magnetohydrodynamic wave modes. This
has allowed the estimation of parameters that are otherwise hard
to derive, such as the coronal magnetic field strength. This work
crucially relies on the initial detection of the waves, which is
commonly done manually. The volume of Solar Dynamics Observatory
(SDO) data will make manual detection inefficient for detecting all
the oscillating regions. An algorithm is presented which automates the
detection of areas of the solar surface that support spatially extended
oscillations. The method is based on Bayesian spectral analysis of
time series and image filtering. A Bayesian approach sidesteps the
need for an a priori noise estimate to calculate rejection criteria
for the observed signal, and also provides estimates of oscillation
frequency, amplitude and noise, and the error in all these quantities,
in a self-consistent way. The algorithm also introduces the notion
of quality measures to those regions for which a positive detection
is claimed, allowing simple post-detection discrimination by the
user. The algorithm is demonstrated on Transition Region and Coronal
Explorer (TRACE) datasets, and comments regarding its suitability for
oscillation detection in SDO are made.
Title: Helioviewer.org: An Open-source Tool for Visualizing Solar Data
Authors: Hughitt, V. Keith; Ireland, J.; Schmiedel, P.; Dimitoglou,
G.; Mueller, D.; Fleck, B.
Bibcode: 2009SPD....40.1502H
Altcode:
As the amount of solar data available to scientists continues to
increase at faster and faster rates, it is important that there exist
simple tools for navigating this data quickly with a minimal amount
of effort. By combining heterogeneous solar physics datatypes such
as full-disk images and coronagraphs, along with feature and event
information, Helioviewer offers a simple and intuitive way to browse
multiple datasets simultaneously. Images are stored in a repository
using the JPEG 2000 format and tiled dynamically upon a client's
request. By tiling images and serving only the portions of the image
requested, it is possible for the client to work with very large
images without having to fetch all of the data at once. Currently,
Helioviewer enables users to browse the entire SOHO data archive,
updated hourly, as well as data feature/event catalog data from
eight different catalogs including active region, flare, coronal
mass ejection, type II radio burst data. In addition to a focus on
intercommunication with other virtual observatories and browsers (VSO,
HEK, etc), Helioviewer will offer a number of externally-available
application programming interfaces (APIs) to enable easy third party
use, adoption and extension. Future functionality will include:
support for additional data-sources including TRACE, SDO and STEREO,
dynamic movie generation, a navigable timeline of recorded solar events,
social annotation, and basic client-side image processing.
Title: The Helioviewer Project: Discovery For Everyone Everywhere
Authors: Ireland, Jack; Hughitt, K.; Müller, D.; Dimitoglou, G.;
Schmiedel, P.; Fleck, B.
Bibcode: 2009SPD....40.1501I
Altcode:
The Helioviewer Project: discovery for everyone everywhere There is
an ever increasing amount of solar and heliospheric data gathered
from multiple sources such as space-based facilities and ground based
observatories. There are also multiple feature and event catalogs
arising from human and computer based detection methods. The Helioviewer
Project is developing a suite of technologies to allow users around the
world to visualize, browse and access these heterogeneous datasets in an
intuitive and highly customizable fashion. Helioviewer technologies
are based on the JPEG2000 file format, an extremely flexible format that
allows for the efficient transfer of data (and meta-data, such as FITS
keywords) between client and server. Rather then having to download an
entire image and then examine the small portion- for example, an active
region - that you are interested in, the JPEG2000 file format lets you
preferentially download only those portions you are interested in. This
dramatically reduces the amount of data transferred, making possible
responsive and flexible scientific discovery applications that can
browse populous archives of large images, such as those from the Solar
Dynamics Observatory. In addition, the Helioviewer Project is
designed to be flexible and extensible to data sources as they become
available. Helioviewer.org (www.helioviewer.org) works seamlessly with
the Virtual Solar Observatory (VSO) whilst an application programming
interface (API) is being developed for interaction with the Solar
Dynamics Observatory Heliophysics Event Knowledgebase. After a
short introduction to the underlying technology, a live demonstration
of the web application www.helioviewer.org will be given. We will also
comment on other client applications (Jhelioviewer, a Java-based browse
tool), and the application of Helioviewer technology to existing and
future solar and heliospheric data and feature/event repositories. This
project is funded by NASA VxO and LWS awards and an ESA science award.
Title: Solar Image Analysis and Visualization
Authors: Ireland, J.; Young, C. A.
Bibcode: 2009siav.book.....I
Altcode:
No abstract at ADS
Title: Automated detection of oscillations in extreme ultraviolet
imaging data
Authors: Ireland, J.; Marsh, M. S.; Kucera, T. A.; Young, C. A.
Bibcode: 2008AGUFMSH13A1507I
Altcode:
The corona is now known to support many different types of
oscillation. Initial detection of these oscillations currently
relied on manual labor. With the advent of much higher cadence EUV
(extreme ultraviolet) data at better spatial resolution, sifting
through the data manually to look for oscillatory material becomes
an onerous task. Further, different observers tend to see different
behavior in the data. To overcome these problems, we introduce a
Bayesian probability-based automated method to detect areas in EUV
images that support oscillations. The method is fast and can handle
time series data with even or uneven cadences. Interestingly, the
Bayesian approach allows us to generate a probability that a given
frequency is present without the need for an estimate of the noise in
the data. We also generate simple and intuitive "quality measures" for
each detected oscillation. This will allow users to select the "best"
examples in a given dataset automatically. The method is demonstrated
on existing datasets (EIT, TRACE, STEREO). Its application to Solar
Dynamics Observatory data is also discussed. We also discuss some of
the problems in detecting oscillations in the presence of a significant
background trend which can pollute the frequency spectrum.
Title: Helioviewer: A Web 2.0 Tool for Visualizing Heterogeneous
Heliophysics Data
Authors: Hughitt, V. K.; Ireland, J.; Lynch, M. J.; Schmeidel, P.;
Dimitoglou, G.; Müeller, D.; Fleck, B.
Bibcode: 2008AGUFMSM11B1617H
Altcode:
Solar physics datasets are becoming larger, richer, more numerous and
more distributed. Feature/event catalogs (describing objects of interest
in the original data) are becoming important tools in navigating these
data. In the wake of this increasing influx of data and catalogs there
has been a growing need for highly sophisticated tools for accessing and
visualizing this wealth of information. Helioviewer is a novel tool for
integrating and visualizing disparate sources of solar and Heliophysics
data. Taking advantage of the newly available power of modern web
application frameworks, Helioviewer merges image and feature catalog
data, and provides for Heliophysics data a familiar interface not unlike
Google Maps or MapQuest. In addition to streamlining the process of
combining heterogeneous Heliophysics datatypes such as full-disk images
and coronagraphs, the inclusion of visual representations of automated
and human-annotated features provides the user with an integrated
and intuitive view of how different factors may be interacting on the
Sun. Currently, Helioviewer offers images from The Extreme ultraviolet
Imaging Telescope (EIT), The Large Angle and Spectrometric COronagraph
experiment (LASCO) and the Michelson Doppler Imager (MDI) instruments
onboard The Solar and Heliospheric Observatory (SOHO), as well as
The Transition Region and Coronal Explorer (TRACE). Helioviewer also
incorporates feature/event information from the LASCO CME List, NOAA
Active Regions, CACTus CME and Type II Radio Bursts feature/event
catalogs. The project is undergoing continuous development with many
more data sources and additional functionality planned for the near
future.
Title: Multiresolution Analysis of Active Region Magnetic Structure
and its Correlation with the Mount Wilson Classification and Flaring
Activity
Authors: Ireland, J.; Young, C. A.; McAteer, R. T. J.; Whelan, C.;
Hewett, R. J.; Gallagher, P. T.
Bibcode: 2008SoPh..252..121I
Altcode: 2008arXiv0805.0101I; 2008SoPh..tmp..134I
Two different multiresolution analyses are used to decompose the
structure of active-region magnetic flux into concentrations of
different size scales. Lines separating these opposite polarity
regions of flux at each size scale are found. These lines are used as
a mask on a map of the magnetic field gradient to sample the local
gradient between opposite polarity regions of given scale sizes. It
is shown that the maximum, average, and standard deviation of the
magnetic flux gradient for α,β,βγ, and βγδ active-regions
increase in the order listed, and that the order is maintained over
all length scales. Since magnetic flux gradient is strongly linked
to active-region activity, such as flares, this study demonstrates
that, on average, the Mt. Wilson classification encodes the notion
of activity over all length scales in the active-region, and not
just those length scales at which the strongest flux gradients are
found. Further, it is also shown that the average gradients in the
field, and the average length-scale at which they occur, also increase
in the same order. Finally, there are significant differences in the
gradient distribution, between flaring and non-flaring active regions,
which are maintained over all length scales. It is also shown that the
average gradient content of active-regions that have large flares (GOES
class "M" and above) is larger than that for active regions containing
flares of all flare sizes; this difference is also maintained at all
length scales. All of the reported results are independent of the
multiresolution transform used. The implications for the Mt. Wilson
classification of active-regions in relation to the multiresolution
gradient content and flaring activity are discussed.
Title: Bayesian Analysis of Solar Oscillations
Authors: Marsh, M. S.; Ireland, J.; Kucera, T.
Bibcode: 2008ApJ...681..672M
Altcode: 2008arXiv0804.1447M
A Bayesian probability-based approach is applied to the problem
of detecting and parameterizing oscillations in the upper solar
atmosphere for the first time. Due to its statistical origin, this
method provides a mechanism for determining the number of oscillations
present, gives precise estimates of the oscillation parameters
with a self-consistent statistical error analysis, and allows the
oscillatory model signals to be reconstructed within these errors. A
highly desirable feature of the Bayesian approach is the ability to
resolve oscillations with extremely small frequency separations. The
code is applied to SOHO CDS O V λ629 observations and resolves four
distinct P4,P5,P6, and P7
p-modes within the same sunspot transition region. This suggests that
a spectrum of photospheric p-modes is able to propagate into the
upper atmosphere of the Sun and Sun-like stars, and places precise
observational constraints on models of umbral eigenmodes.
Title: Radiative and magnetic properties of solar active
regions. I. Global magnetic field and EUV line intensities
Authors: Fludra, A.; Ireland, J.
Bibcode: 2008A&A...483..609F
Altcode:
Context: The relationships between the photospheric magnetic flux
and either the X-ray or extreme ultraviolet emission from the solar
atmosphere have been studied by several authors. Power-law relations
have been found between the total magnetic flux and X-ray flux or
intensities of the chromospheric, transition region, and coronal
emission lines in solar active regions. These relations were then
used to infer the mechanism of the coronal heating.
Aims: We
derive accurate power laws between EUV line intensities and the total
magnetic flux in solar active regions and discuss their applications. We
examine whether these global power laws are capable of providing
the diagnostics of the coronal heating mechanism.
Methods:
This analysis is based on EUV lines recorded by the Coronal Diagnostic
Spectrometer (CDS) on SOHO for 48 solar active regions, as they crossed
the central meridian in years 1996-1998. Four spectral lines are used:
He I 584.3 Å (3×104 K), O V 629.7 Å (2.2×105
K), Mg IX 368.06 Å (9.5×105 K), and Fe XVI 360.76 Å
(2.0×106 K). In particular, the Fe XVI 360.76 Å line, seen
only in areas of enhanced heating in active regions or bright points,
has not been used before for this analysis.
Results: Empirical
power laws are established between the total active region intensity
in the lines listed above and the total magnetic flux. We demonstrate
the usefulness of some spatially integrated EUV line intensities, I_T,
as a proxy for the total magnetic flux, Φ, in active regions. We point
out the approximate, empirical nature of the I_T-Φ relationships and
discuss the interpretation of the global power index. Different power
index values for transition region and coronal lines are explained
by their different dependence on pressure under the assumption of
hydrostatic loop models. However, the global power laws are dominated by
the size of the active regions, and we demonstrate for the first time
the difficulties in uniquely relating the power index in the global
IT - Φ relationship to the power index for individual loops
and comment on results obtained by other authors. We caution against
using global power laws to infer the coronal heating mechanism without a
detailed knowledge of the distributions of the magnetic flux densities
and instrumental response as a function of temperature. Despite these
uncertainties, we show that the intensities of the transition region
lines in individual loops depend on the photospheric magnetic flux
density, φ, through I_tr ∝ φδ_t, δt < 1,
and the coronal line Fe XVI, I_Fe ∝ φδ_c, δc
> 1, and under the assumption of hydrostatic loops we can place a
constraint on the coronal heating models, obtaining the volumetric
heating rate, EH (erg cm-3 s-1),
EH ∝ φ^γ , where 0.6 < γ < 1.1.
Title: A Bayesian Analysis of MHD Waves in the Lower Atmosphere
Authors: Marsh, M. S.; Ireland, J.; Kucera, T.
Bibcode: 2008IAUS..247...48M
Altcode: 2007IAUS..247...48M
Magneto-hydrodynamic wave modes propagating from the solar
photosphere into the corona have the potential to be exploited as an
observational tool in an analogous way to the use of acoustic waves
in helio/terrestrial seismology. In regions of strong magnetic field
photospheric p-modes are thought to undergo mode conversion to slow
magneto-acoustic waves, and that these slow magnetoacoustic p-modes
may be waveguided from the photosphere into the solar corona along
the magnetic field. A Bayesian analysis technique is applied to
observations which suggests four distinct p-modes may be resolved in
the transition region.
Title: Multi-scale structure of active region magnetic fields
correlated with flaring activity
Authors: Ireland, J.; Young, C. A.; McAteer, R. J.; Whelan, C. M.;
Hewett, R.; Gallagher, P. T.
Bibcode: 2008AGUSMSH43B..03I
Altcode:
Two multi-scale analyses are used to decompose active region magnetic
fields into objects of different size scales, allowing one to examine
the structure of the active region field at different size scales. Lines
separating opposite polarity groupings of flux at different size scales
are found. It is shown that the magnetic field gradients for α,
β, βγ, and βγδ active regions increases in the order listed,
and that the order is maintained over all object size scales. Hence
for a given Mt. Wilson classification, essentially the same field
gradient information is present at all size scales, when compared to
any other Mt. Wilson classification. It is also shown that on average,
flaring and non-flaring active regions have a different field gradient
content, and that the difference between the flaring and non-flaring
active regions is size scale dependent. This suggests that the gradient
distribution on smaller size scales is a better indicator of flaring
activity when compared to larger size scales.
Title: Multiscale Analysis of Active Region Evolution
Authors: Hewett, R. J.; Gallagher, P. T.; McAteer, R. T. J.; Young,
C. A.; Ireland, J.; Conlon, P. A.; Maguire, K.
Bibcode: 2008SoPh..248..311H
Altcode:
Flows in the photosphere of solar active regions are turbulent in
nature. Because magnetic fields are frozen into the plasma on the
solar surface, magnetograms can be used to investigate the processes
responsible for structuring active regions. Here, a continuous wavelet
technique is developed, analyzed, and used to investigate the multiscale
structure of an evolving active region using magnetograms obtained by
the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric
Observatory (SOHO). The multiscale structure was measured using a 2D
continuous wavelet technique to extract the energy spectrum of the
region over the time scale of 13 days. Preliminary evidence of an
inverse cascade in active region NOAA 10488 is presented as well as
a potential relationship between energy scaling and flare productivity.
Title: Multifractal Properties of Evolving Active Regions
Authors: Conlon, P. A.; Gallagher, P. T.; McAteer, R. T. J.; Ireland,
J.; Young, C. A.; Kestener, P.; Hewett, R. J.; Maguire, K.
Bibcode: 2008SoPh..248..297C
Altcode:
Magnetohydrodynamic turbulence is thought to be responsible for
producing complex, multiscale magnetic field distributions in solar
active regions. Here we explore the multiscale properties of a number of
evolving active regions using magnetograms from the Michelson Doppler
Imager (MDI) on the Solar and Heliospheric Observatory (SOHO). The
multifractal spectrum was obtained by using a modified box-counting
method to study the relationship between magnetic-field multifractality
and region evolution and activity. The initial emergence of each
active region was found to be accompanied by characteristic changes
in the multifractal spectrum. Specifically, the range of multifractal
structures (Ddiv) was found to increase during emergence,
as was their significance or support (Cdiv). Following this,
a decrease in the range in multifractal structures occurred as the
regions evolved to become large-scale, coherent structures. From the
small sample considered, evidence was found for a direct relationship
between the multifractal properties of the flaring regions and their
flaring rate.
Title: Correlation of multi-resolution analyses of active region
magnetic field structure with flare activity
Authors: Ireland, J.; Young, A.; McAteer, J.; Whelan, C.; Hewett,
R. J.; Gallagher, P. T.
Bibcode: 2007AGUFMSH13A1094I
Altcode:
Two multi-resolution analyses are used to decompose active region
magnetic fields into objects of different lengthscales, allowing
one to examine the structure of the active region field at different
lengthscales. Lines separating opposite polarity groupings of flux
at different lengthscales are found (a generalization of the notion
of a magnetic neutral line). It is shown that the average magnetic
field gradient for alpha, beta, beta-gamma, and beta-gamma-delta
active regions increases in the order listed, and that the order is
maintained over all length-scales. Since magnetic field gradient is
strongly linked to active region activity, such as flares, this study
demonstrates that, on average, the Mt. Wilson classification encodes
the notion of activity over all lengthscales in the active region, and
not just those lengthscales at which the strongest field gradients are
found. Properties of these generalized neutral lines are also correlated
with GOES flare activity in a search for an indicator of flare activity.
Title: Two New Approaches to Determining Parameter Values to Emission
Spectra From RHESSI
Authors: Schwartz, R.; Ireland, J.
Bibcode: 2007AGUFMSH13A1097S
Altcode:
We examine two new approaches to determining parameter values to
emission spectra from RHESSI. Simulated annealing removes much of the
bias inherent in initializing commonly used deterministic routines
through implementing a parameter space search minimizing a suitable
cost function (such as sum of squares of differences between data and
a parameterized curve). This search gradually moves from being a full
random search to a directed search where only parameter values which
minimize the cost function are accepted. In comparison, Markov Chain
Monte Carlo methods are used to sample from the Bayesian posterior
distribution constructed from prior information on the observation (such
as the number of emission lines present and likely parameter values)
as well as the data itself. Parameter values can then be assigned by
constructing the appropriate averages from the data. These methods
have the advantage of sidestepping many of the problems of traditional
analysis routines (for example, ill-conditioned matrices) whilst
allowing the easy inclusion of other information, such as parameter
constraints. Both approaches are applied to RHESSI spectroscopic data,
and are compared to more commonly used routines. RHESSI is comprised of
separate detectors which allows us to conduct 9 independent measurements
of the same solar flux over any time interval. Since these new methods
return important information about the dispersion in a parameter from
counting statistics, then the multi-detector sample will also contain
important insight into the sources of systematic deviations.
Title: Multi-scale Tools for Solar Image Processing
Authors: Young, C.; Ireland, J.; McAteer, R.; Gallagher, P. T.;
Byrne, J.
Bibcode: 2007AGUFMSH13A1093Y
Altcode:
The important information contained in solar image data exists on many
different time and spatial scales. This makes multi-scale transforms
such as wavelets and curvelets very appropriate tools. These and other
multi- scale transforms are used in several different types of image
processing including image enhancement, feature detection, deconvolution
and noise reduction. We present an overview of multi-scale transforms
and show some of their applications to solar image data.
Title: Investigation of Coronal Loop Temperatures using Three EUV
Filters and Implications for Future Work with Solar-B
Authors: Noglik, J. B.; Walsh, R. W.; Ireland, J.
Bibcode: 2007ASPC..369..303N
Altcode:
In 2002 Chae et al. proposed a two filter ratio method for determining
unambiguous temperature values for the plasma in the solar corona. When
applying this method to SOHO/EIT it was found that outside the range
of 0.7 - 4 MK the errors for the instrument response functions were
so large that the values could not be trusted. This paper analyses
a SOHO/EIT data set of loops at the solar limb. It was found that
none of the points taken from along the coronal structure sat on the
colour-colour curve. This could be due to a number of different reasons
such as the time lapse between the three EUV images, the fairly poor
resolution of EIT, plasma flows along the loop or perhaps looking
through a multi-thermal atmosphere. Considering the latter, using a
simple two temperature approach, it was found that it is possible to
reproduce our results in this way.
Title: Simulated Annealing and Bayesian Posterior Distribution
Analysis Applied to Spectral Emission Line Fitting
Authors: Ireland, Jack
Bibcode: 2007SoPh..243..237I
Altcode:
Spectral-line fitting problems are extremely common in all
remote-sensing disciplines, solar physics included. Spectra in
solar physics are frequently parameterized by using a model for the
background and the emission lines, and various computational techniques
are used to find values to the parameters given the data. However,
the most commonly-used techniques, such as least-squares fitting,
are highly dependent on the initial parameter values used and are
therefore biased. In addition, these routines occasionally fail
because of ill-conditioning. Simulated annealing and Bayesian posterior
distribution analysis offer different approaches to finding parameter
values through a directed, but random, search of the parameter
space. The algorithms proposed here easily incorporate any other
available information about the emission spectrum, which is shown to
improve the fit. Example algorithms are given and their performance is
compared to a least-squares algorithm for test data - a single emission
line, a blended line, and very low signal-to-noise-ratio data. It is
found that the algorithms proposed here perform at least as well or
better than standard fitting practices, particularly in the case of
very low signal-to-noise ratio data. A hybrid simulated annealing and
Bayesian posterior algorithm is used to analyze a Mg x line contaminated
by an O IV triplet, as observed by the Coronal Diagnostic Spectrometer
onboard SOHO. The benefits of these algorithms are also discussed.
Title: The Bursty Nature of Solar Flare X-Ray Emission
Authors: McAteer, R. T. James; Young, C. Alex; Ireland, Jack;
Gallagher, Peter T.
Bibcode: 2007ApJ...662..691M
Altcode:
The complex and highly varying temporal nature of emission from an X4.8
flare is studied across seven X-ray energy bands. A wavelet transform
modulus maxima method is used to obtain the multifractal spectra of
the temporal variation of the X-ray emission. As expected from the
Neupert effect, the time series of the emission at low energies (3-6,
6-12 keV; thermal) is smooth. The peak Hölder exponent, around 1.2,
for this low-energy emission is indicative of a signal with a high
degree of memory and suggestive of a smooth chromospheric evaporation
process. The more bursty emission at higher energies (100-300, 300-800
keV; nonthermal) is described by a multifractal spectrum that peaks at a
smaller Hölder exponent (less than 0.5 for the largest singularities),
indicative of a signal with a low degree of memory. This describes an
antipersistent walk and indicates an impulsive, incoherent driving
source. We suggest that this may arise from bursty reconnection,
with each reconnection event producing a different and uncorrelated
nonthermal particle source. The existence of a power-law scaling
of wavelet coefficients across timescales is in agreement with the
creation of a fractal current sheet diffusion region.
Title: Wavelet Analysis of Active Region Magnetic Structure
Authors: Ireland, Jack; Young, C. A.; Gallagher, P. T.; McAteer,
R. T. James; Whelan, C.; Hewett, R. J.
Bibcode: 2007AAS...210.9322I
Altcode: 2007BAAS...39..214I
A wavelet analysis is used to decompose active region magnetic
fields into regions of different lengthscales, allowing one to
examine the structure of the active region field at different
lengthscales. Linesseparating opposite polarity groupings of flux
at different lengthscales are found; these lines can be seen as a
generalization of the notion of a magnetic neutral line. It is shown
that the average magnetic field gradient for alpha, beta, beta-gamma,
and beta-gamma-delta active regions increases in the order listed,
and that the order is maintained over all length-scales. Further,
the standard deviation and maximum of the magnetic field gradient,
as well as the length of these generalized neutral lines, all share
the same property. Since magnetic field gradient is strongly linked
to active region activity, such as flares, this study demonstrates
that, on average, the Mt. Wilson classification encodes the notion
of activity over all lengthscales in the active region, and not
just those lengthscales at which the strongest field gradients are
found. This study uses the multiscale analysis toolkit Mkit developed
by C. A. Young and presented elsewhere at this meeting.
Title: Robust Imaging with RHESSI Data
Authors: Schwartz, Richard A.; Ireland, J.
Bibcode: 2007AAS...210.9304S
Altcode: 2007BAAS...39..211S
The analysis software for use with RHESSI data produces images using
one of several algorithms like CLEAN or PIXON after a simple selection
of a few control parameters. It's all quite automatic. Simple tools are
provided to extract the flux from a region. There is, however, little to
guide the analyst in determining robustness of the result. For example,
how much would random deviations in the incident counts perturb the
result. This presentation will illustrate methods that use elements
of the existing software to evaluate the robustness of any RHESSI
image by creating images using count rates sampled from a probability
distribution consistent with the original data.
Title: Solar Activity Monitoring
Authors: Gallagher, Peter T.; McAteer, R. T. James; Young, C. Alex;
Ireland, Jack; Hewett, Russell J.; Conlon, Paul
Bibcode: 2007ASSL..344...15G
Altcode:
No abstract at ADS
Title: A Statistical Model for the Occurrence Times of Coronal Mass
Ejections and Solar Flares
Authors: Hugeback, A. B.; Young, C.; Ireland, J.
Bibcode: 2006AGUFMSH21A0317H
Altcode:
The rate of occurrence of coronal mass ejections (CMEs) and solar
flares is of interest to solar and geomagnetic physicists, as better
descriptions of time trends in these processes may lead to more accurate
predictions of geomagnetic storms and a better understanding of the
process by which magnetic energy is released in the solar corona. In
recent years, there has been wide spread debate about whether CMEs
and solar flares are temporally associated. This paper presents a
statistical model for the superimposed (or joint) process in order to
provide insight toward the nature of the correlation between the two
individual processes. The temporal relationship between CME velocity
and flare intensity is also explored.
Title: Investigation of a Color-Color Method to Determine Solar
Atmospheric Temperatures along Plasma Loops
Authors: Noglik, J. B.; Walsh, R. W.; Ireland, J.
Bibcode: 2006ASPC..354..339N
Altcode:
Recent interest in establishing the heating mechanism in solar
coronal loops has centered on determining the fundamental plasma
properties within the loops, e.g. T(s), and ρ(s). This approach
has so far prooved to be difficult. Aschwanden et al.~(2000) used
single filter ratio techniques and found evidence for heating weighted
towards the loop base. Priest et al.~(2000) used Yohkoh observations
and a corresponding heating form and found that the heat was most
likely uniformly distributed, whilst Reale (2002) found cases of apex
dominated heating. This paper examines a new method proposed by Chae
et al. (2002), which takes two filter ratios (TRACE 195/171~Å and
284/195~Å). When plotted against each other, the two ratios provide
a color-color curve for determining a wide range of unambiguous
plasma temperatures. We used this method on SOHO-EIT data of a flare
loop on the north east solar limb in order to obtain the temperature
profile along the structure. In doing so, we find Chae's method to be
troublesome with many data-points sitting off the color-color curve. We
discuss how this may be due to a multi-thermal atmosphere with more
than one loop along the observational line of sight.
Title: Multiscale Solar Image Processing
Authors: Young, C. B.; Byrne, J.; Ireland, J.; Gallagher, P. T.;
McAteer, R. J.
Bibcode: 2006AGUFMSH23B0369Y
Altcode:
Wavelets have been very successfully used as a tool for noise reduction
and general processing of images. Despite this, wavelets have inherent
limitations with 2-D data. Wavelets are well suited for describing
point singularities but much of the interesting information in images
is described by edges, lines or curves. Newly developed multiscale
transforms address some of these issues. The ridgelet transform takes
the multiscale concept of wavelets but applies it to 1-D objects (lines)
instead of 0-D objects (points). The curvelet transform likewise
applies to multiscale curves. We present a preliminary study of the
use of these new multiscale transforms with solar image data. These
data include TRACE EUV images and LASCO coronagraph images.
Title: The Complex Sun: Turbulence and Complexity of the Solar
atmosphere
Authors: McAteer, R. T. James; Gallagher, Peter T.; Ireland, J.;
Young, C Alex; Hewett, Russell J.; Conlon, P.
Bibcode: 2006ESASP.617E.137M
Altcode: 2006soho...17E.137M
No abstract at ADS
Title: Toward RHESSI Spectroscopic Imaging: I, Spectroscopy
Authors: Ireland, Jack; Young, C. A.; van Dyk, D.
Bibcode: 2006SPD....37.0604I
Altcode: 2006BAAS...38..226I
We examine two new approaches to determining parameter values to
emission spectra from RHESSI and the Coronal Diagnostic Spectrometer
(CDS) on board SoHO. Simulated annealing removes much of the bias
inherent in initializing commonly used deterministic routines through
implementing a parameter space search minimizing a suitable cost
function (such as sum of squares of differences between data and a
parameterized curve). This search gradually moves from being a full
random search to a directed search where only parameter values which
minimize the cost function are accepted. In comparison, Markov Chain
Monte Carlo methods are used to sample from the Bayesian posterior
distribution constructed from prior information on the observation
(such as the number of emission lines present and likely parameter
values) as well as the data itself. Parameter values can then be
assigned by constructing the appropriate averages from the data.These
methods have the advantage of sidestepping many of the problems of
traditional analysis routines (for example, ill-conditioned matrices)
whilst allowing the easy inclusion of other information, such as
parameter constraints. Both approaches are applied to CDS and RHESSI
spectroscopic data, and are compared to more commonly used routines.
Title: Toward RHESSI Spectroscopic Imaging II : Imaging
Authors: Young, C. A.; Ireland, J.; van Dyk, D. A.; Willett, R. M.
Bibcode: 2006SPD....37.3703Y
Altcode:
The Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) has
provided Solar physics with an unprecedented view of high-energy
solar flares. RHESSI has observed flares providing high resolution
x-ray and gamma-ray spectra and the first spatially resolved gamma-ray
images of flares. Despite its successes, RHESSI data analysis has yet
to obtain joint high resolution spectroscopy and imaging. Currently,
spectroscopy and imaging with RHESSI are disjoint processes. This work
is part 2 of the 2 part process leading to a joint spectroscopic imaging
algorithm. Here we present two new statistical imaging techniques and
their application with RHESSI data. These techniques are designed
to take advantage of Poisson nature of the data in the low count
regime. This minimizes the loss of data due to the binning required
by current imaging methods. We discuss these techniques in the context
of Spectroscopic Imaging algorithms for RHESSI.
Title: How Complex Are Solar Flare Hrx Lightcurves? A Multiscalar
Multifractal Approach.
Authors: McAteer, R. T. J.; Young, C.; Ireland, J.; Gallagher, P. T.
Bibcode: 2006SPD....37.0824M
Altcode: 2006BAAS...38..235M
A wavelet transform modulus maxima approach to the calculation of
the singularity spectrum is applied to hard X-ray (7 energy bands
from 3--800keV) lightcurves from an X4.8 flare on 23 July 2002. The
multifractality of each lightcurve is discussed in terms of the
Hausdorff dimension, D, of the Holder exponent, h, of each detected
singularity. In addition to a general discussion of the technique, we
show results showing a general increase in complexity of lightcurves
at higher energies
Title: Multiscale Structure of Active Region Magnetic Fields
Authors: Hewett, Russell J.; Gallagher, P. T.; McAteer, R.; Young,
C.; Ireland, J.
Bibcode: 2006SPD....37.0301H
Altcode: 2006BAAS...38..222H
Flows in the photosphere of solar active regions are in a state ofhighly
developed turbulence. As magnetic fields are frozen into theplasma in
the solar surface, magnetograms can therefore be used toinvestigate
the processes responsible for structuring active regions.Here, the
multiscale structure of a large sample of active regionmagnetograms from
the Michelson Doppler Imager (MDI) onboard theSolar and Heliospheric
Observatory (SOHO) are investigated. Initialresults regarding the
relationship between multiscale structuring andactive region evolution
and flaring activity is discussed.
Title: Multifractal Analysis of Solar Magnetograms
Authors: Conlon, Paul; McAteer, R. T.; Gallagher, P. T.; Ireland,
J.; Young, C. A.; Young, C. A.
Bibcode: 2006SPD....37.0303C
Altcode: 2006BAAS...38Q.222C
Magnetohydrodynamic turbulence is thought to be responsible for
structuring sunspot magnetic fields. Here we explore the selfsimilar
and multi-scaling properties of this turbulence using multi-fractal
methods. The multi-fractal spectrum was obtained from full disk
Michelos Doppler Imager magnetograms, to study the relationship
between magnetic field multifractality and flaring and non-flaring
regions. In particular, box counting and wavelet based techniques
where investigated. The discrete box counting method was found to
be inadequate for these purposes, primarily due to discretization
errors. Wavelet based methods, on the other hand, where found to be
more stable for diagnosing turbulence in active region magnetic fields.
Title: Wavelet analysis of Active Region structure
Authors: Ireland, J.; Young, C. A.; Whelan, C.; Gallagher, P. T.;
McAteer, R. T. J.; Hewett, R. J.
Bibcode: 2006cosp...36.2595I
Altcode: 2006cosp.meet.2595I
Active regions are known to consist of complex magnetic fields as
evinced by both fractal and multifractal studies In contrast the Mt
Wilson classification of active regions is relatively simple yet is
useful in predicting the likelihood of flaring events since it considers
the overall geometrical structure of the active region In particular
neutral lines are especially important in evaluating the likelihood
of flare events occurring Wavelet analysis techniques in conjunction
with edge detection methods are applied to the problem of diagnosing
the gross geometrical structure of active region magnetic field Active
region fields are decomposed into their constituent parts using wavelet
techniques and edge detection methods are used to characterize the
neutral lines present A statistical analysis is presented outlining
the utility of this approach in automatically generating a Mt Wilson
classification for a given active region
Title: Statistics of the Quiet Sun Intensity Distribution
Authors: Young, C. A.; Ireland, J.; Bewsher, D.
Bibcode: 2005ESASP.600E..75Y
Altcode: 2005ESPM...11...75Y; 2005dysu.confE..75Y
No abstract at ADS
Title: Applying the CRAMÉR-RAO Lower Bound to Spectroscopic
Measurements
Authors: Ireland, J.
Bibcode: 2005ESASP.600E..61I
Altcode: 2005dysu.confE..61I; 2005ESPM...11...61I
No abstract at ADS
Title: Investigation of a Colour-Colour Method to Determine Solar
Atmospheric Temperatures Using Soho/eit Data
Authors: Noglik, J. B.; Walsh, R. W.; Ireland, J.
Bibcode: 2005ESASP.596E..77N
Altcode: 2005ccmf.confE..77N
No abstract at ADS
Title: Indirect calculation of the magnetic reconnection rate from
flare loops
Authors: Noglik, J. B.; Walsh, R. W.; Ireland, J.
Bibcode: 2005A&A...441..353N
Altcode:
High time resolution Transition Region And Coronal Explorer (TRACE) 171
and 195 Å observations of the evolution of flare loops on 1999 March
18 have been investigated. Given the location of the magnetic loops on
the northeast solar limb and the cadence of the TRACE observations (~50
s), an estimation of the footpoint velocity due to ongoing reconnection
was undertaken. This was achieved by calculating the velocity at which
successive loops brighten in the emission lines during the postflare
phase. A typical footpoint velocity of 1.5 km s-1 ±0.7
km s-1 is obtained and a reconnection rate of ~0.001-0.03
is determined using the method outlined in Isobe et al. (2002, ApJ,
566, 528). This value for the reconnection rate is consistent with
the regime outlined by Petschek's model for magnetic reconnection.
Title: Statistics of Active Region Complexity: A Large-Scale Fractal
Dimension Survey
Authors: McAteer, R. T. James; Gallagher, Peter T.; Ireland, Jack
Bibcode: 2005ApJ...631..628M
Altcode:
A quantification of the magnetic complexity of active regions using a
fractal dimension measure is presented. This fully automated approach
uses full-disk MDI magnetograms of active regions from a large data set
(2742 days of the SOHO mission, 9342 active region images) to compare
the calculated fractal dimension of each region to both its Mount
Wilson classification and flare rate. Each Mount Wilson class exhibits
a similar fractal dimension frequency distribution, possibly suggesting
a self-similar nature of all active regions. Solar flare productivity
exhibits an increase in both the frequency and GOES X-ray magnitude
of flares from regions with higher fractal dimension. Specifically, a
lower threshold fractal dimension of 1.2 and 1.25 exists as a necessary,
but not sufficient, requirement for an active region to produce M-
and X-class flares, respectively, within 24 hr of the observation.
Title: Automated Boundary-extraction And Region-growing Techniques
Applied To Solar Magnetograms
Authors: McAteer, R. T. James; Gallagher, Peter T.; Ireland, Jack;
Young, C. Alex
Bibcode: 2005SoPh..228...55M
Altcode:
We present an automated approach to active region extraction from
full-disc MDI longitudinal magnetograms. This uses a region-growing
technique in conjunction with boundary-extraction to define a number
of enclosed contours as belonging to separate regions of magnetic
significance on the solar disc. This provides an objective definition
of active regions and areas of plage on the Sun. A number of parameters
relating to the flare potential of each region are discussed.
Title: Statistics of the quiet Sun intensity distribution.
Authors: Ireland, J.; Young, C.; Bewsher, D.
Bibcode: 2005AGUSMSP21B..11I
Altcode:
The statistics of the quiet Sun intensity distribution present an
interesting challenge. Some authors find that the observed distribution
is adequately represented by a two component model, which seems to fit
well with the notion of a network and internetwork being physically
distinct. Other authors find that a single component model fits
the intensity distribution data well, which seems to suggest that
the network and internetwork emission may in fact be due to the same
process. This paper examines the evidence for both these points of view,
using CDS EUV data and a mixture modeling technique. Some comments
are also made on the nature of the mechanism which may create the
observed distributions.
Title: From Raw Data to Flare Predictions: A Fully Automated Technique
Authors: McAteer, R. T.; Gallagher, P. T.; Ireland, J.; Young, A.
Bibcode: 2005AGUSMSP42A..06M
Altcode:
With the large volume of solar data which already exists, and expected
in the near future with SDO, automated techniques are becoming
increasingly vital. We present a fully automated active region
extraction routine based on boundary extraction and region growing
techniques applied to full disc MDI longitudinal magnetograms. Once
extracted, any number of image processing techniques can be applied to
the data leading to the possibility of automated classification. We
discuss a large scale (9 years of MDI data, ~10,000 active region
images) fractal survey of this data. This quantifies the meaning of
magnetic complexity, relating lower threshold fractal dimension to
the onset of large flares.
Title: Representation of Sun Spots with Shapelets
Authors: Young, C.; Gallagher, P. T.; Ireland, J.; McAteer, R.
Bibcode: 2005AGUSMSP11A..07Y
Altcode:
Shapelets are complete set of orthonormal functions that can be used to
represent most images. These functions are Gauss-Hermite polynomials and
are the eigenfunctions of the 2D harmonic oscillator. They were first
used in image processing to study the shape of galaxies. Shapelets have
properties that allow one to compute quantities such as chirality,
shear and asymmetry in images. We use these functions to represent
magnetograms of sunspots, allowing us to calculate a large set of
descriptive quantities including those previously mentioned. These
quantities are then correlated with the current classification schemes
used to type sunspots.
Title: Precision Limits to Emission-Line Profile Measuring Experiments
Authors: Ireland, J.
Bibcode: 2005ApJ...620.1132I
Altcode:
Spectra, such as astrophysical spectra, can provide detailed
diagnostics on the state of their emitting volume. Emission-line
diagnostics are found by assuming a model for the spectral emission
line and then fitting the model to the data. It is shown for Poisson
noisy emission-line data, via the application of Cramér-Rao lower
bounds, that there are limits to the precision that line fitting can
achieve. The limits depend on the spectral line model and the noise
properties of the data. A Cramér-Rao lower bound treatment introduces
a framework in which questions of line fitting in particular and
spectrometers in general may be posed. Some example applications
are given and their implications for the design of spectrometric
observations are discussed.
Title: Determining the Temperature Profile Along a Plasma Loop II:
Detecting Spatial Variations in the Heat Input
Authors: Walsh, R. W.; Noglik, J. B.; Ireland, J.
Bibcode: 2004ESASP.575..562W
Altcode: 2004soho...15..562W
No abstract at ADS
Title: SOHO 15 Workshop - Coronal Heating
Authors: Walsh, R. W.; Ireland, J.; Danesy, D.; Fleck, B.
Bibcode: 2004ESASP.575.....W
Altcode: 2004soho...15.....W
No abstract at ADS
Title: Indirect Calculation of the Magnetic Reconnection Rate from
Flare Loops
Authors: Noglik, J. B.; Walsh, R. W.; Ireland, J.
Bibcode: 2004ESASP.575..491N
Altcode: 2004soho...15..491N
No abstract at ADS
Title: Determining the Temperature Profile Along a Plasma Loop I:
Investigating a Colour-Colour Method for Soho/EIT
Authors: Noglik, J. B.; Walsh, R. W.; Ireland, J.
Bibcode: 2004ESASP.575..557N
Altcode: 2004soho...15..557N
No abstract at ADS
Title: Precision Limits in Line Profile Fitting Experiments
Authors: Ireland, J.
Bibcode: 2004ESASP.575..587I
Altcode: 2004soho...15..587I
No abstract at ADS
Title: Applying the Cramer-Rao Lower Bound to Spectroscopic
Measurements
Authors: Ireland, J.
Bibcode: 2004AAS...204.7608I
Altcode: 2004BAAS...36..807I
Solar spectra, through emission line models, can provide detailed
diagnostics on the state of their emitting volume. Estimates of the
emission line model parameters are found by fitting the model to the
data. It is shown, via the application of Cramer-Rao lower bounds,
that there are calculable lower limits to the achievable precision
with which we can know the parameter estimates. The limits depend on
how much is known about the spectrum prior to the fit, the spectral
line model, the model spectrometer and the noise in the data. A
Cramer-Rao lower bound analysis introduces a theoretical framework
in which questions of line fitting in particular, and spectrometers
in general, may be posed. Some example applications are given and
their implication for the design of spectrometric observations are
discussed. This work is funded by NASA, contract number NNH04CC31C.
Title: A Search for Photospheric Sources of Coronal Longitudinal
Oscillations
Authors: Ireland, J.; De Moortel, I.; Walsh, R. W.; Moretti, P. F.
Bibcode: 2004ESASP.547...57I
Altcode: 2004soho...13...57I
It has recently been shown that longitudinal intensity fluctuations
observed in TRACE 171 Å loops come in what appear to be two separate
populations. These populations are differentiated by their period, and
are clustered distinctly around 3 and 5 minute periods. The 3 minute
fluctuations appear to be rooted in sunspots, whereas the 5 minute
sunspots are not. This study presents two test cases in the search
for a photospheric source to these oscillations. A wavelet analysis
is presented in the search for a fluctuating magnetic component since
previous studies show that a magnetic fluctuation may be intermittent. A
Fourier analysis is used to look in the intensity and Doppler regions of
the same area of interest. Some comments are made on the photosphere in
relation to the search for the driver of the as yet unobserved driver
of longitudinal coronal oscillations.
Title: Applying fragmentation models to the solar atmosphere
Authors: Ireland, J.; Young, C. A.; March, K.; Adam, J. -P.
Bibcode: 2004IAUS..223..387I
Altcode: 2005IAUS..223..387I
Recent observational work has shown that the emission in different
layers of the solar atmosphere can de described statistically. For
example, Pauluhn et al. (2000) show that the frequency distribution
of quiet Sun emission in EUV lines is well fit by a lognormal
distribution. In addition, Parnell (2002) has shown that the frequency
distribution of discrete magnetic elements in the quiet Sun is well
fit by a Weibull distribution. These distributions arise naturally from
fragmentation studies of materials such as polymers and sediments. It is
suggested that fragmentation and its related phenomena may be of use in
describing the physics of how the above distributions appear on the Sun.
Title: Longitudinal Oscillations in Coronal Loops - Joint Observations
with SOHO/CDS and TRACE
Authors: Marsh, M. S.; Walsh, R. W.; De Moortel, I.; Ireland, J.
Bibcode: 2004ESASP.547..519M
Altcode: 2004soho...13..519M
Joint Observing Program (JOP) 83 Solar and Heliospheric
Observatory/Coronal Diagnostic Spectrometer (SOHO/CDS) and Transition
Region and Coronal Explorer (TRACE) data is analysed for evidence of
propagating intensity oscillations along loop structures in the solar
corona. A propagating intensity oscillation with a minimum estimated
speed of 50-195 km s is observed within a TRACE 171 Å coronal loop
using a running difference method. Co-spatial and co-temporal CDS
and TRACE observations of this loop are analysed using a wavelet
analysis method. The TRACE data shows a propagating oscillation with
a period of 300 s. This period is also observed with CDS suggesting
propagating oscillations at chromospheric, transition region and
coronal temperatures in the He I, O V and Mg IX lines.
Title: Spatially-Resolved Diagnostics of Coronal Heating in Solar
Active Regions
Authors: Fludra, A.; Ireland, J.
Bibcode: 2004ESASP.547..341F
Altcode: 2004soho...13..341F
We study the relationship between EUV spectral line intensities and the
photospheric magnetic field in solar active regions, using magnetograms
from SOHO-MDI and EUV spectra of the Fe XVI 360.8 Å line ( K) and the O
V 629.7 A line (220,000 K) from the Coronal Diagnostic Spectrometer on
SOHO, recorded for several active regions. Two complementary analysis
methods are compared - a global analysis applied to the coronal line
emission (Fe XVI), and a spatially-resolved analysis of the transition
region emission (O V). We overlay and compare spatial patterns of
the O V emission and the magnetic flux concentrations, with a spatial
resolution, and search for a relationship between the local O V line
intensity and the photospheric magnetic flux density in each active
region. While this dependence exhibits a certain amount of scatter,
it can be represented by a power law fit. The average power index from
all regions is . Applying static loop models, we derive the dependence
of the volumetric heating rate on the magnetic flux density, , and
compare it to the dependence predicted by the coronal heating models.
Title: Diagnostics of Coronal Heating in Solar Active Regions
Authors: Fludra, A.; Ireland, J.
Bibcode: 2004IAUS..219..478F
Altcode: 2003IAUS..219E.244F
We study the relationship between EUV spectral line intensities emitted
at transition region temperatures and the photospheric magnetic
field in solar active regions. We use magnetograms from SOHO/MDI
and EUV spectra of the O V 629.7 A line (220000 K) from the Coronal
Diagnostic Spectrometer on SOHO recorded for 25 active regions. We
overlay and compare spatial patterns of the OV emission and the
magnetic flux concentrations with a 2''x2'' spatial resolution and
search for a relationship between the local OV line intensity and the
photospheric magnetic flux density in each active region. While this
dependence exhibits a certain amount of scatter it can be represented
by a power law fit. We find that the power indeces are similar in
all regions. Applying static loop models we derive the dependence of
the heating rate on the magnetic flux density and compare it to the
dependence predicted by the coronal heating models. This spatially
resolved analysis extends the previous work of Fludra and Ireland
(2002 2003) who studied the relationship between area-integrated
coronal line intensities and the total magnetic flux.
Title: The Magnetic Field and EUV Line Intensities in Solar Active
Regions
Authors: Fludra, A.; Ireland, J.
Bibcode: 2003csss...12..220F
Altcode:
Relationships between the photospheric magnetic flux and intensities of
spectral lines emitted from the solar atmosphere have been extensively
studied by several authors. Power-law relations have been found between
the total magnetic flux and total intensities of the chromospheric,
transition region and coronal emission lines in active regions. This
approach is applied to extreme ultraviolet lines recorded by the
Coronal Diagnostic Spectrometer (CDS) on SOHO for 50 solar active
regions, as they crossed the central meridian in years 1996-1998. Four
spectral lines are examined: ion{He}{1} 584.3 Å (2× 104 K),
ion{O}{5} 629.7 Å (2.2 × 105 K), ion{Mg}{9} 368.06 Å (9.5
× 105 K), and ion{Fe}{16} 360.76 Å (2.0 × 106
K). In particular, the ion{Fe}{16} 360.76 Å line, seen only in areas
of enhanced heating in active regions or bright points, has not been
used before for this analysis. Empirical relations are established
between the total active region intensity in ion{Fe}{16} and ion{O}{5}
lines, and the total magnetic flux and between the spatially-averaged
intensities and the magnetic flux density. The dependence of the
coronal loop heating rate on the magnetic flux density is derived and
its implications for the coronal heating models are discussed.
Title: Joint observations of propagating oscillations with SOHO/CDS
and TRACE
Authors: Marsh, M. S.; Walsh, R. W.; De Moortel, I.; Ireland, J.
Bibcode: 2003A&A...404L..37M
Altcode:
Joint Observing Program (JOP) 83 Solar and Heliospheric
Observatory/Coronal Diagnostic Spectrometer (SOHO/CDS) and Transition
Region and Coronal Explorer (TRACE) data is analysed for evidence of
propagating intensity oscillations along loop structures in the solar
corona. A propagating intensity oscillation with a minimum estimated
speed of 50-195 km s-1 is observed within a TRACE 171
Å coronal loop using a running difference method. Co-spatial and
co-temporal CDS and TRACE observations of this loop are analysed
using a wavelet analysis method. The TRACE data shows a propagating
oscillation with a period of ~300 s. This period is also observed with
CDS suggesting propagating oscillations at chromospheric, transition
region and coronal temperatures in the He I, O V and Mg Ix lines.
Title: Some theoretical and algorithmic ideas in spectral line
fitting problems
Authors: Ireland, J.; McIntosh, S. W.
Bibcode: 2003SPD....34.0302I
Altcode: 2003BAAS...35..808I
We take another look at the issue of fitting spectral lines from two
different viewpoints. Firstly, we present a theoretical framework
that enables the exploration of spectrometer precisions. The theory
enables the discussion of theoretical precision limits to model
spectrometers. Some applications of the theory are presented and
discussed with reference to the Coronal Diagnostic Spectrometer
(CDS) and Solar Ultraviolet Measurements of Emitted Radiation
(SUMER) instruments on board the Solar and Heliospheric Observatory
(SOHO). Secondly, we discuss the application of genetic and simulated
annealing algorithms to line fitting problems in the context of the
theoretical framework described above. Such algorithms are of utility
in providing unbiased fits in a wide variety of spectra where more
traditional fitting routines have difficulty converging. This work is
funded via a NASA NRA 01-OSS-01 award.
Title: Inversion of the intensity-magnetic field relationship in
solar active regions
Authors: Fludra, A.; Ireland, J.
Bibcode: 2003A&A...398..297F
Altcode:
We discuss the relationship between the EUV spectral line intensities
and the photospheric magnetic flux in solar active regions. Since the
histograms of the magnetic flux density in active region plages can
be approximated by an exponential function, the equation describing
how the observed total line intensity integrated over an active region
area arises from the magnetic field, can be approximated by a Laplace
integral. We use this property to solve an inverse problem and derive
a function relating the line intensity from individual loops to the
photospheric magnetic flux density at their footpoints. We propose a
simple model in which the intensity of a coronal line Fe XVI 360.8 Å
in an individual coronal loop is proportional to the footpoint magnetic
flux density to the power of delta and explore how well the value of
delta is constrained by the observations. Using EUV spectra from the
Coronal Diagnostic Spectrometer (CDS) on SOHO and magnetograms from
SOHO Michelson Doppler Imager for 26 active regions without sunspots,
we find that the value of delta depends on the magnetic flux density
threshold used to define active region magnetic area. When even the
weakest fields are included, we obtain delta =1.3, where 1.0 <
delta < 1.6 with 90% confidence. This result can be used to provide
constraints on coronal heating models.
Title: The heating of the solar corona
Authors: Walsh, R. W.; Ireland, J.
Bibcode: 2003A&ARv..12....1W
Altcode:
The heating of the solar corona has been a fundamental astrophysical
issue for over sixty years. Over the last decade in particular,
space-based solar observatories (Yohkoh, SOHO and TRACE) have revealed
the complex and often subtle magnetic-field and plasma interactions
throughout the solar atmosphere in unprecedented detail. It is
now established that any energy release mechanism is magnetic in
origin - the challenge posed is to determine what specific heat
input is dominating in a given coronal feature throughout the solar
cycle. This review outlines a range of possible magnetohydrodynamic
(MHD) coronal heating theories, including MHD wave dissipation and MHD
reconnection as well as the accumulating observational evidence for
quasi-periodic oscillations and small-scale energy bursts occurring
in the corona. Also, we describe current attempts to interpret plasma
temperature, density and velocity diagnostics in the light of specific
localised energy release. The progress in these investigations expected
from future solar missions (Solar-B, STEREO, SDO and Solar Orbiter)
is also assessed.
Title: An overview of longitudinal oscillations in coronal loops
Authors: De Moortel, I.; Hood, A. W.; Ireland, J.; Walsh, R. W.
Bibcode: 2002ESASP.506..509D
Altcode: 2002svco.conf..509D; 2002ESPM...10..509D
High cadence TRACE observations show that outward propagating
intensity disturbances are a common feature in large, quiescent coronal
loops. An overview is given of geometric and physical parameters of
such propagating disturbances observed in 38 coronal loops. We found
that loops that are situated above sunspot regions display intensity
oscillations with periods centred around 3 minutes, whereas oscillations
in 'non-sunspot' loops show periods centred around 5 minutes. The
observed longitudinal oscillations are interpreted as propagating
slow magneto-acoustic waves and we show that the disturbances are
not flare-driven but are most likely caused by an underlying driver
exciting the loop footpoints. We present a simple theoretical model
to explain the observed features.
Title: Observational evidence of underlying driving of longitudinal
oscillations in coronal loops
Authors: De Moortel, I.; Ireland, J.; Hood, A. W.; Walsh, R. W.
Bibcode: 2002ESASP.505..211D
Altcode: 2002IAUCo.188..211D; 2002solm.conf..211D
We give an overview of both geometric and physical parameters of
propagating disturbances in coronal loops, using high cadence TRACE
data (JOP83 & JOP144). The majority of these outward propagating
oscillations are found in the footpoints of large diffuse coronal loop
structures, close to active regions. The disturbances travel outward
with a propagation speed v = 122±43 km s-1. The variations
in intensity are estimated to be of the order of 4.1±1.5%, compared
to the background brightness and are found to be damped very quickly,
within 8.9±4.4 Mm along the loop. Using a wavelet analysis, periods in
the 282±93 seconds range are obtained. However, it was found that loops
that are situated above sunspot regions display intensity oscillations
with a period smaller than 200 seconds, whereas oscillations in
'non-sunspot' loops show periods larger than 200 seconds. This result
provides evidence that the underlying oscillations can propagate
through the transition region and into the corona. We conclude that
the observed longitudinal oscillations are not flare-driven but are
most likely caused by an underlying driver exciting the loop footpoints.
Title: The magnetic fields and the heating of active regions
Authors: Fludra, A.; Ireland, J.
Bibcode: 2002ESASP.505..405F
Altcode: 2002IAUCo.188..405F; 2002solm.conf..405F
Fludra and Ireland (2002) established empirical power-laws between
the EUV line intensity averaged over the active region area and
the magnetic flux density, using SOHO/MDI magnetograms and two EUV
spectral lines, O V 629.7 Å (2.2×105K) and Fe XVI 360.76
Å (2.0×106K), recorded by the SOHO Coronal Diagnostic
Spectrometer for 45 active regions. These relationships were used to
derive the heating rate as a function of the magnetic flux density. In
this paper we examine a subset of 26 active regions without sunspots, to
investigate the change in these relationships in the absence of strong
sunspot magnetic fields. We find a reduced power index in the power-law
dependence between the average line intensities and the magnetic flux
density. This translates as a reduced power index in the dependence
of the heating rate on the magnetic flux density, EH ∝
B0.9, and affirms that most of the DC models of coronal
heating, predicting an EH ∝ B2 dependence,
are incompatible with our observations.
Title: Examination of the photospheric magnetic field underlying
longitudinally oscillating coronal loops
Authors: Ireland, J.; Walsh, R. W.; De Moortel, I.; Moretti, P. F.
Bibcode: 2002ESASP.505..429I
Altcode: 2002IAUCo.188..429I; 2002solm.conf..429I
Longitudinally oscillating coronal loops have been seen in TRACE 171
Å data in many different quiescent active regions. The oscillation
is thought to be an example of an outwardly propagating slow
magneto-acoustic wave. However, the source of these waves is as
yet unknown. In the context of SOHO Joint Observing Program 144, we
search for a possible photospheric driver to these waves. We examine
the photospheric longitudinal magnetic flux underlying an oscillating
loop observed between 1200-1300 UT on June 7th 2001. The field was
imaged using the Kanzelhöhe Magneto-Optical Filter instrument and the
SOHO Michelson Doppler Imager (MDI). The dynamics of the photospheric
magnetic field underlying these loops is discussed in the context of
possible mechanisms causing the observed coronal oscillations.
Title: Longitudinal intensity oscillations in coronal loops observed
with TRACE II. Discussion of Measured Parameters
Authors: De Moortel, I.; Hood, A. W.; Ireland, J.; Walsh, R. W.
Bibcode: 2002SoPh..209...89D
Altcode:
In this paper, we give a detailed discussion of the parameters of
longitudinal oscillations in coronal loops, described in Paper I. We
found a surprising absence of correlations between the measured
variables, with the exception of a relation between the estimated
damping length and the period of the intensity variations. Only for
2 out of the 38 cases presented in Paper I did we find a significant
perturbation in the 195 Å TRACE data. The loops supporting the
propagating disturbances were typically stable, quiescent loops and
the total luminosity of the analyzed structures generally varied by
no more than 10%. The observed density oscillations are unlikely to be
flare-driven and are probably caused by an underlying driver exciting
the loop footpoints. It was demonstrated that the rapid damping of
the perturbations could not simply be explained as a consequence
of the decreasing intensity along the loops. However, we found that
(slightly enhanced) thermal conduction alone could account for the
observed damping lengths and wavelengths, and, additionally, explain
the correlation between propagation period and damping length.
Title: Longitudinal intensity oscillations in coronal loops observed
with TRACE I. Overview of Measured Parameters
Authors: De Moortel, I.; Ireland, J.; Walsh, R. W.; Hood, A. W.
Bibcode: 2002SoPh..209...61D
Altcode:
In this paper we aim to give a comprehensive overview of geometric
and physical properties of longitudinal oscillations in large coronal
loops. The 38 examples of propagating disturbances were obtained
from the analysis of high cadence, 171 Å TRACE data (JOP 83 and JOP
144). The majority of these outward propagating oscillations are found
in the footpoints of large diffuse coronal loop structures, close to
active regions. The disturbances travel outward with a propagation
speed of the order of v≈122±43 km s−1. The variations
in intensity are estimated to be roughly 4.1±1.5% of the background
loop brightness. The propagating disturbances are found to be damped
very quickly and are typically only detected in the first 8.9±4.4
Mm along the loop. Using a wavelet analysis, periods of the order
of 282±93 s are found and the energy flux was estimated as 342±126
erg cm−2 s−1. We found highly filamentary
behavior in the lower part of the coronal loops and showed that the
intensity oscillations can be present for several consecutive hours,
with a more or less constant period. It is evident that the longitudinal
oscillations are a widespread, regularly occurring coronal phenomena. A
companion paper is devoted to the interpretation and discussion of
the results.
Title: Application of wavelet analysis to transversal coronal loop
oscillations
Authors: Ireland, J.; De Moortel, I.
Bibcode: 2002A&A...391..339I
Altcode:
There as yet remain few examples of well observed, transversal
oscillations in coronal loops. Such oscillations have the potential
to yield much information on the nature of the solar corona, as
demonstrated by the analysis of Nakariakov et al. (\cite{nak})
of a transversely oscillating loop observed in the TRACE 171 Å
passband on 14th July, 1998. Their analysis extracts a decaying loop
oscillation signal from the data which is then considered in the light
of the substantial body of theoretically and computationally derived
knowledge of the dynamics of coronal loops. The analysis presented in
this paper approaches the reduction of the same dataset using wavelet
techniques described by De Moortel & Hood (\cite{demhood}) and De
Moortel et al. (\cite{dhi}). The authors show that the value of the
decay exponent N in a decaying oscillating time series of the form exp
(-ktN) is measurable from a wavelet transform of the time
series (for some decay constant k and time t). The application of
these techniques shows that the value of the decay exponent in the
14th July, 1998 event is not well determined by the data, i.e., the
associated error is very large. Since the value of the decay exponent
implies the presence of particular decay mechanisms and not others,
the large error associated with the exponent value implies that a wide
range of mechanisms should be considered when discussing the physics
behind this event. Comments are also made on the time dependence of
the oscillation wavelet scale. Two additional examples of transversal
coronal loop oscillations are also analysed.
Title: Preliminary description of Kanzelhöhe/MDI magnetograms and
the search for sources of coronal oscillations
Authors: Ireland, J.; Walsh, R. W.; De Moortel, I.; Moretti, P. F.
Bibcode: 2002ESASP.508..299I
Altcode: 2002soho...11..299I
Many examples of transverse (Schrijver et al., 2002; Aschwanden
et al., 2002) and longitudinal coronal loop oscillations have now
been observed in TRACE 171 Å data (see De Moortel et al., 2002
at this meeting for examples of longitudinal oscillations). These
oscillations hold the promise of telling us much about the physics of
the corona. However, the mechanisms describing these distinct phenomena
are as yet unclear. Magnetogram data from MDI and Kanzelhöhe taken
as part of SOHO Joint Observing 144 allows us to use the spatial
resolution of MDI and temporal resolution of Kanzelhöhe to probe the
photospheric magnetic field at likely footpoint sources of coronal
loop oscillations at length and time scales not available to either
instrument separately. Variations in the photospheric magnetic field
are analysed in conjunction with co-temporally observed TRACE 171 Å
derived time series.
Title: Trace observations of propagating slow magneto-acoustic
disturbances in coronal loops
Authors: De Moortel, I.; Ireland, J.; Walsh, R. W.
Bibcode: 2002ESASP.508..275D
Altcode: 2002soho...11..275D
We study propagating disturbances in 38 coronal loops and give an
overview of their properties using high cadence, 171 Å, TRACE data
(JOP 83 & JOP 144). The majority of these outward propagating
oscillations are found in the footpoints of large diffuse coronal loop
structures, close to active regions. The disturbances travel outward
with a propagation speed of the order of v ≍ 119+/-39 km/s. The
variations in intensity are estimated to be roughly 4.1+/-1.6% of the
background brightness and the propagating disturbances are found to
be damped very quickly, within 8.6+/-3.8 Mm along the loop. Using a
wavelet analysis, periods of the order of 282+/-93 seconds are found
and the energy flux was estimated as 346+/-132 ergs/cm2s. It
is suggested that these oscillations are slow magneto-acoustic waves
propagating along the lower part of large, quiescent, coronal loops.
Title: Coronal heating in active regions
Authors: Fludra, A.; Ireland, J.
Bibcode: 2002ESASP.508..267F
Altcode: 2002soho...11..267F
Many theoretical models of coronal heating predict a different
dependence of the heating rate on the magnetic field strength. This
property can be used to test these models by studying relationships
between the photospheric magnetic flux and intensities of spectral
lines emitted from the solar atmosphere. We use SOHO/MDI magnetograms
and Extreme Ultraviolet lines recorded by the SOHO Coronal Diagnostic
Spectrometer for 50 solar active regions, as they crossed the central
meridian in years 1996-1998. We use two spectral lines: O V 629.7 Å
(2.2×105K) and Fe XVI 360.76 Å (2.0×106K). We
establish empirical power-laws between the total line intensity
integrated over the active region area and the total magnetic flux,
and derive the dependence of line intensities on the magnetic flux
density for an average individual coronal loop. The heating rate is
then derived as a function of the magnetic flux density and a comparison
is made with the coronal heating models.
Title: The detection of 3 & 5 min period oscillations in
coronal loops
Authors: De Moortel, I.; Ireland, J.; Hood, A. W.; Walsh, R. W.
Bibcode: 2002A&A...387L..13D
Altcode:
High cadence, 171 Alfvén A, TRACE observations show that outward
propagating intensity disturbances are a common feature in large,
quiescent coronal loops. These oscillations are interpreted as
propagating slow magneto-acoustic waves. Using a wavelet analysis, we
found periods of the order of 282 +/- 93 s. However, a careful study of
the location of the footpoints revealed a distinct separation between
those loops that support oscillations with periods smaller than 200 s
and periods larger than 200 s. It was found that loops that are situated
above sunspot regions display intensity oscillations with a period
of the order of 172 +/- 32 s, whereas oscillations in ``non-sunspot''
loops show periods of the order of 321 +/- 74 s. We conclude that the
observed longitudinal oscillations are not flare-driven but are most
likely caused by an underlying driver exciting the loop footpoints. This
result suggests that the underlying oscillations can propagate through
the transition region and into the corona.
Title: Coronal seismology through wavelet analysis
Authors: De Moortel, I.; Hood, A. W.; Ireland, J.
Bibcode: 2002A&A...381..311D
Altcode:
This paper expands on the suggestion of De Moortel & Hood
(\cite{DeMoortel00}) that it will be possible to infer coronal plasma
properties by making a detailed study of the wavelet transform of
observed oscillations. TRACE observations, taken on 14 July 1998, of a
flare-excited, decaying coronal loop oscillation are used to illustrate
the possible applications of wavelet analysis. It is found that a decay
exponent n ~ 2 gives the best fit to the double logarithm of the wavelet
power, thus suggesting an e-varepsilon t^2 damping profile
for the observed oscillation. Additional examples of transversal loop
oscillations, observed by TRACE on 25 October 1999 and 21 March 2001,
are analysed and a damping profile of the form e-varepsilon
t^n, with n ~ 0.5 and n ~ 3 respectively, is suggested. It is
demonstrated that an e-varepsilon t^n damping profile of
a decaying oscillation survives the wavelet transform, and that the
value of both the decay coefficient varepsilon and the exponent n can
be extracted by taking a double logarithm of the normalised wavelet
power at a given scale. By calculating the wavelet power analytically,
it is shown that a sufficient number of oscillations have to be present
in the analysed time series to be able to extract the period of the
time series and to determine correct values for both the damping
coefficient and the decay exponent from the wavelet transform.
Title: The solar corona in cycle 23
Authors: Fludra, A.; Ireland, J.; Del Zanna, G.; Thompson, W. T.
Bibcode: 2002AdSpR..29..361F
Altcode:
The Coronal Diagnostic Spectrometer (CDS) on SOHO has been recording
EUV spectra and monitoring time variability of EUV line intensities,
electron temperature and density in the low solar corona during the
rising part of Cycle 23. The four-year data set includes daily synoptic
observations in four EUV lines along the central meridian since April
1996 and weekly diagnostic observations above the polar coronal holes
since July 1997. The history of line intensities along the central
meridian, and radial profiles of electron temperature and density above
the polar regions at heights up to 1.15 R⊙ are derived. EUV
line intensities and photospheric magnetic flux are also calculated
for 50 active regions observed from 1996 to June 1998. Variability of
temperature, density, and EUV spectral line intensities in the polar
coronal holes, quiet sun and active regions with the solar cycle is
discussed. Power-law relationships among the EUV line intensities from
the CDS synoptic data, and also between the EUV line intensities and
magnetic field flux in active regions are presented.
Title: Active Region EUV Intensities, Magnetic Flux and Coronal
Heating
Authors: Ireland, J.; Fludra, A.
Bibcode: 2001AGUFMSH11A0692I
Altcode:
Several authors have previously noted the existence of power law
relationships between the total unsigned photospheric magnetic
flux and the intensities of a variety of spectral lines emitted by
active regions. Applying this approach to more recent datasets, it
is shown that power law relationships exist for extreme ultraviolet
(EUV) emission data observed by the Coronal Diagnostic Spectrometer
(CDS) and photospheric flux as measured by the Michelson Doppler
Imager (MDI), both on-board the Solar and Heliospheric Observatory
(SOHO). Four spectral lines are examined, covering a wide range of
temperatures: He I 584.3 Å (2x 104~K), O V 629.7 Å (2.2
x 105~K), Mg IX 368.06 Å (9.5 x 105~K), and
Fe XVI 360.76 Å (2.0 x 106~K). Relations are established
between total EUV intensities and photospheric magnetic flux as well
as average EUV intensity and magnetic flux density. Comments are also
made on the viability of various coronal heating models in the light
of these results.
Title: EUV Line Intensities and the Magnetic Field in Solar Active
Regions
Authors: Ireland, J.; Fludra, A.
Bibcode: 2001IAUS..203..276I
Altcode:
The Coronal Diagnostic Spectrometer on SOHO carries out daily synoptic
observations of the Sun, recording four EUV spectra : He I 584 Å, O
V 630 Å, Mg IX 368 Å and Fe XVI 360 Å, over a 4 arcmin-wide strip
along the solar central meridian. A study has been made of 55 active
regions and bright points appearing in the CDS synoptic dataset in years
1996-1998. Using the CDS dataset and the MDI full disk magnetograms
we study the correlation of the chromospheric, transition region and
coronal emission with the photospheric magnetic field for meridional
active regions, probing the relation between the radiative output and
magnetic observables. We establish empirical, quantitative relations
among intensities of different lines, and between intensities and the
magnetic field flux. This work extends the study of Schrijver (1985,
1987) to a larger sample of active regions and different EUV lines. We
discuss the implications of this study for coronal heating models.
Title: An Observational Test for Solar Atmospheric Heating
Authors: van Driel-Gesztelyi, L.; Démoulin, P.; Ireland, J.; Thompson,
B.; Fludra, A.; Oláh, K.; Kövári, Zs.; Harra, L. K.; Mandrini,
C. H.; Bocchialini, K.; Orlando, S.
Bibcode: 2001IAUS..203..514V
Altcode:
We study the evolution of the emissivity and heating correlated with
magnetic observables of an active region from its birth throughout
its decay during seven solar rotations (July-Dec. 1996). Taking one
"snapshot" per g:wq: Command not found. time of flares, we analyse
multi-wavelength and multi-instrument data obtained from SOHO (MDI,
EIT, CDS and SUMER), Yohkoh (SXT), GOES, SOLSTICE and 10.7 cm radio
data from DRAO, Canada. We utilise our results to test the validity
of coronal heating models. We find that models which are based on
the dissipation of stressed, current-carrying magnetic fields are in
better agreement with the observations than the models which attribute
coronal heating to the dissipation of MHD waves.
Title: Observation of oscillations in coronal loops
Authors: De Moortel, I.; Walsh, R. W.; Ireland, J.
Bibcode: 2000AIPC..537..216D
Altcode: 2000wdss.conf..216D
High cadence TRACE data (JOP 83) in the 171 Å bandpass are used to
report on several examples of outward propagating oscillations in the
footpoints of large diffuse coronal loop structures close to active
regions. The disturbances travel outward with a propagation speed
between 70 and 160 km s-1. The variations in intensity are
of the order of 2%-4%, compared to the background brightness and these
get weaker as the disturbance propagates along the structure. From a
wavelet analysis at different positions along the structures, periods
in the 200-400 seconds range are found. It is suggested that these
oscillations are slow magneto-acoustic waves propagating along the
loop, carrying an estimated energy flux of 4×102 ergs
cm-2 s-1. .
Title: Quiet Sun Oscillation Packets
Authors: Ireland, J.; McIntosh, S. W.; Fleck, B.
Bibcode: 2000SPD....31.0132I
Altcode: 2000BAAS...32..807I
This paper combines the novel techniques of wavelet analysis
and genetic algorithms to exploit SOHO-SUMER (Solar Ultraviolet
Measurements of Emitted Radiation) data in a new way. The data consists
of time series in O I 1306.03 Angstroms, Si II 1309.28 Angstroms,
C I 1311.36 Angstroms, C II 1334.53 Angstroms, He I 584 Angstroms,
O I 1152 Angstroms, and C III 1176 Angstroms tracking specific pieces
of quiet Sun westward across the disk. To analyse this data, genetic
algorithms (McIntosh et. al, A.& A. Suppl. Ser., 132, 145, 1998)
are used to fit quiet Sun emission spectra, allowing the unbiassed
determination of spectral properties such as total line intensity
and Doppler velocity. Time series of line intensity and Doppler
velocity are formed which are then analysed using wavelet techniques,
permitting the distinguishing of distinct oscillation wave packets in
the time series. Correlations of wave packets between different lines
and physical quantities are discussed, as are the distributions of
oscillation packets seen.
Title: Observation of oscillations in coronal loops
Authors: De Moortel, I.; Ireland, J.; Walsh, R. W.
Bibcode: 2000A&A...355L..23D
Altcode:
On March 23rd 1999, a set of TRACE observations in the 171 Alfvén A
(Fe Ix) bandpass was made of active region AR 8496. A wavelet analysis
of a bright loop-footpoint to the south west of this active region
displays outward propagating perturbations with periods 180-420
seconds at approximately 70-165 km s-1. We suggest that
these oscillations are slow magneto-acoustic waves propagating along
the loop, carrying an estimated energy flux of 4 x 102
ergs cm-2 s-1.
Title: Coronal heating events in high-cadence TRACE data
Authors: Ireland, Jack; Wills-Davey, Meredith; Walsh, Robert W.
Bibcode: 1999SoPh..190..207I
Altcode:
On March 23rd 1999 a set of TRACE (Transition Region and Coronal
Explorer) observations were taken in support of Solar and Heliospheric
Observatory (SOHO) / TRACE Joint Observing Program 83. The program
is designed to look for coronal heating mechanisms operating at high
cadence and to observe their dynamical effects on coronal loop density,
temperature and magnetic structure. We present here a study of 27 small,
dynamic brightening events seen in this data. These events are seen
in the quiet-Sun areas surrounding the active region. The data itself
consists of 157 171 Å 512×512 arc sec images at 1 arc sec resolution
and 9 second cadence, a previously unavailable combination of cadence,
resolution and image size. Three classes of events are introduced:
complex, intermediate and simple. All three classes share the property
of being dynamic on small time and length scales but differ in the
complexity of their behavior. We find that the brightenings across all
classes exhibit variations as part of a distribution of time scales
(90-400 s) peaked around 228 s. The brightenings are no more than
5 arc sec in diameter. Motions between brightenings occur on time
scales from 9 to 90 s and on length scales no greater than 10 arc
sec. These motions have velocities estimated to be in the range 89-174
km s−1. The position of these events in the spectrum of
previously observed coronal heating events is discussed.
Title: Wavelet Analysis Of Active Region Oscillations
Authors: Ireland, J.; Walsh, R. W.; Priest, E. R.; Harrison, R. A.
Bibcode: 1999ESASP.446..363I
Altcode: 1999soho....8..363I
The wavelet transform is applied to the analysis of active region
oscillations. The localised (in time) nature of the wavelet transform
allows us to study both the duration of any statistically significant
oscillations as well as their period. Time series arising from SOHO
(Solar and Heliospheric Observatory) CDS-NIS (Coronal Diagnostic
Spectrometer Normal Incidence Spectrometer) active region observations
on 14th-15th November 1996 are used to demonstrate the applicability of
wavelet methods. High cadence (approximately 14 seconds) observations
were made in He I 584.33 Angstroms (log T = 4.3, T being the electron
temperature), O V 629.73 Angstroms(log T = 5.3), Mg IX 368.06 Angstroms
(log T = 6.0), Fe XVI 360.76 Angstroms (log T = 6.4) provide detailed
intensity information on the active region over a wide range of
temperatures. The distribution of statistically significant periods
found varies from line to line, as does their duration.
Title: SunBlock '99: Young Scientists Investigate the Sun
Authors: Walsh, R. W.; Pike, C. D.; Mason, H.; Young, P.; Ireland,
J.; Galsgaard, K.
Bibcode: 1999ESASP.446..693W
Altcode: 1999soho....8..693W
SunBlock `99 is a Web-based Public Understanding of Science and
educational project which seeks to present the very latest solar
research as seen through the eyes of young British scientists. These
``solar guides'' discuss not only their scientific interests, but also
their extra-curricular activities and the reasons they chose scientific
careers; in other words the human face of scientific research. The
SunBlock '99 pages gather a range of solar images and movies from
current solar space observatories and discuss the underlying physics
and its relationship to the school curriculum. The instructional level
is pitched at UK secondary school children (aged 13-16 years). It is
intended that the material should not only provide a visually appealing
introduction to the study of the Sun, but that it should help bridge
the often wide gap between classroom science lessons and the research
scientist `out in the field'. SunBlock '99 is managed by a team from
the Rutherford Appleton Laboratory and the Universities of St Andrews
and Cambridge, together with educational consultants. The production
has, in part, been sponsored by PPARC and the Millennium Mathematics
Project. Web site addresss: http://www.sunblock99.org.uk
Title: A wavelet analysis of active region oscillations
Authors: Ireland, J.; Walsh, R. W.; Harrison, R. A.; Priest, E. R.
Bibcode: 1999A&A...347..355I
Altcode:
The wavelet transform is applied to the analysis of active region
oscillations. The localised (in time) nature of the wavelet transform
allows us to study both the duration of any statistically significant
oscillations as well as their period. Time series arising from SOHO
(Solar and Heliospheric Observatory) CDS-NIS (Coronal Diagnostic
Spectrometer Normal Incidence Spectrometer) active region observations
on 14th-15th November 1996 are used to demonstrate the applicability of
wavelet methods. High cadence (approximately 14 seconds) observations
were made in {He I} 584.33 Ä (log Te=4.3), {O V} 629.73 Ä
(log Te=5.3), {Mg IX} 368.06 Ä (log Te=6.0),
{Fe XVI} 360.76 Ä (log Te=6.4) provide detailed intensity
information on the active region over a wide range of temperatures. The
distribution of statistically significant periods found varies from
line to line, as does their duration.
Title: Phase mixing of Alfvén waves in a stratified and open
atmosphere
Authors: De Moortel, I.; Hood, A. W.; Ireland, J.; Arber, T. D.
Bibcode: 1999A&A...346..641D
Altcode:
Phase mixing was introduced by Heyvaerts and Priest (1983) as a
mechanism for heating the plasma in the open magnetic field regions
of coronal holes. Here the basic process is modified to include a
stratified atmosphere in which the density decreases with height. We
present an analytical solution in the case of zero dissipation and
use a numerical code in the non-zero dissipation case to describe the
effect of stratification on phase mixing. The exponential damping
behaviour derived by Heyvaerts and Priest is largely confirmed in
the non stratified limit. However, it is shown that the decrease in
density lengthens the oscillation wavelengths and thereby reduces the
generation of transverse gradients. Furthermore we found that in a
stratified atmosphere the perturbed magnetic field and velocity behave
quite differently depending on whether we consider resistivity or
viscosity. Ohmic heating is spread out over a greater height range in
a stratified medium whereas viscous heating is not strongly influenced
by the stratification.
Title: Realisation of 3-dimensional data sets.
Authors: Brown, D.; Galsgaard, K.; Ireland, J.; Verwichte, E.;
Walsh, R.
Bibcode: 1999joso.proc..211B
Altcode:
The visualisation of three-dimensional objects on two dimensions is a
very common problem, but is a tricky one to solve. Every discipline
has its way of solving it. The artist uses light-shade interaction,
perspective, special colour coding. The architect produces projections
of the object. The cartographer uses both colour-coding and shading to
represent height elevations. There have been many attempts in the last
century by the entertainment industry to produce a three-dimensional
illusion, in the fifties it was fashionable to have 3d movies which
utilize the anaglyph method. Nowadays one can buy "Magic Eye" postcards
which show a hidden three dimensional picture if you stare at it half
cross-eyed. This poster attempts to demonstrate how some of these
techniques can be applied to three-dimensional data sets that can
occur in solar physics.
Title: Spectral decomposition by genetic forward modelling
Authors: McIntosh, S. W.; Diver, D. A.; Judge, P. G.; Charbonneau,
P.; Ireland, J.; Brown, J. C.
Bibcode: 1998A&AS..132..145M
Altcode:
We discuss the analysis of real and simulated line spectra using
a genetic forward modelling technique. We show that this Genetic
Algorithm (GA) based technique experiences none of the user bias
or systematic problems that arise when faced with poorly sampled or
noisy data. An important feature of this technique is the ease with
which rigid a priori constraints can be applied to the data. These
constraints make the GA decomposition much more accurate and stable,
especially at the limit of instrumental resolution, than decomposition
algorithms commonly in use.
Title: Visualization of three-dimensional datasets
Authors: Ireland, Jack; Walsh, Robert W.; Galsgaard, Klaus
Bibcode: 1998SoPh..181...87I
Altcode:
The effective visualization of three-dimensional (3d) datasets, both
observationally and computationally derived, is an increasing problem
in solar physics. We present here plots of computational data derived
from the 3d reconstruction of the magnetic field of a loop system,
rendered as anaglyphs. By combining images of the same 3d object
from two slightly different angles a realistic and useful 3d effect
is obtained, aiding data visualization. The application of the same
technique to real solar data (such as from the Coronal Diagnostic
Spectrometer (CDS) on board the Solar and Heliospheric Observatory
(SOHO)) is discussed.
Title: Preliminary Results for Coronal Magnetic Fields as Suggested
by MDI Magnetograms
Authors: Walsh, R. W.; Ireland, J.; Mackay, D. H.; Galsgaard, K.;
Longbottom, A. W.
Bibcode: 1998ASPC..155..371W
Altcode: 1998sasp.conf..371W
No abstract at ADS
Title: Heating of coronal loops by phase-mixing.
Authors: Hood, A. W.; Gonzalez-Delgado, D.; Ireland, J.
Bibcode: 1997A&A...324...11H
Altcode:
A simple, self similar solution for the heating of coronal loops is
presented. It is shown that the Heyvaerts-Priest model gives a good
description of phase mixing in a certain class of coronal loops. In
addition, under typical coronal conditions the ohmic heating, due to
phase mixing, can provide magnetic energy on a timescale comparable
with the coronal radiative time. Thus, it is possible that phase
mixing can maintain a hot coronal loop for large Lundquist number. If
the photospheric motions continually excite coronal loops, then phase
mixing could contribute to a background level of coronal heating for
very large Lundquist number.
Title: Phase-mixing in Dissipative Alfvén Waves
Authors: Ireland, Jack; Priest, Eric R.
Bibcode: 1997SoPh..173...31I
Altcode:
The phase-mixing mechanism first proposed as a coronal heating mechanism
by Heyvaerts and Priest (1983) is examined using a length-scale analysis
adapted from Cally (1991). This allows parameter ranges other than
those studied by Heyvaerts and Priest (1983) to be described, together
with a detailed examination of the transfer of energy to both longer
and shorter length-scales as the Alfvén wave front evolves in the
solar corona. The results of Heyvaerts and Priest (1983) are largely
confirmed, but with some notable differences. Energy initially at
smaller length-scales decays faster than their rate, because the
plasma is more strongly dissipative at smaller length-scales. The
full inclusion of diffusion across field lines also leads to smoother
Alfvén wavefronts.
Title: Heating of coronal holes by phase mixing.
Authors: Hood, A. W.; Ireland, J.; Priest, E. R.
Bibcode: 1997A&A...318..957H
Altcode:
A two-dimensional, analytical, self-similar solution to the Alfven
wave phase mixing equations is presented for a coronal hole model. The
solution shows clearly that the damping of the waves with height follows
the scaling predicted by Heyvaerts & Priest at low heights, before
switching to an algebraic decay at large heights. The ohmic dissipation
is calculated and it is shown that the maximum dissipation occurs at a
height that scales with η^1/3^. However, the total Ohmic dissipation
is, of course, independent of the resistivity. Using realistic solar
parameters it appears that phase mixing is a viable mechanism for
heating the lower corona provided either the frequency of photospheric
motions is sufficiently large or the background Alfven velocity is
sufficiently small.
Title: Active Region Blinkers: Transient Events in the Solar
Atmosphere
Authors: Walsh, R. W.; Ireland, J.; Harrison, R. A.; Priest, E. R.
Bibcode: 1997ESASP.404..717W
Altcode: 1997cswn.conf..717W
No abstract at ADS
Title: Periodicities in Active Regions
Authors: Ireland, J.; Walsh, R. W.; Harrison, R. A.; Priest, E. R.
Bibcode: 1997ESASP.404..433I
Altcode: 1997cswn.conf..433I
No abstract at ADS
Title: Wave heating of the solar corona and SoHO
Authors: Ireland, J.
Bibcode: 1996AnGeo..14..485I
Altcode: 1996AnG....14..485I
A short introduction is given to some wave-heating mechanisms applicable
to the solar corona. Their relevance to the capabilities of the SoHO
mission is briefly discussed.