Author name code: freeland
ADS astronomy entries on 2022-09-14
author:"Freeland, Samuel L." OR author:"Freeland, Sam"
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Title: The Future Of SolarSoft
Authors: Hurlburt, N.; Freeland, S. L.; Timothy, S.; Shirts, P.;
Slater, G.
Bibcode: 2021AAS...23821301H
Altcode:
The IDL-based SolarSoft (SSW, SSWIDL) software library and distribution
framework continues to be used by a substantial fraction of solar
physics researchers, even as other solar physics software packages
such as Python-based SunPy grow in usage. In a 2020 survey of
researchers in the field of solar physics, 73% of respondents
reported using IDL compared to 66% who use Python*. The overwhelming
majority of solar physicists using IDL use SolarSoft. In particular,
SolarSoft now supports the latest missions in the Heliophysics System
Observatory, including the Parker Solar Probe, Solar Orbiter, and
GOES 16 and 17 missions. In addition, SolarSoft is used in the data
production pipelines of many current missions, including SDO, IRIS,
and Hinode. SolarSoft is used for generating much of the content
of the Heliospheric Events Knowledgebase (HEK). Given the field's
enduring embrace of solarsoft and the value it provides, we are
working to provide additional tools to integrate SolarSoft with the
latest developments in scientific data analysis, image processing, and
software package distribution systems. SSWIDL versions for reading and
writing imagery, data, and metadata in the latest and most efficient
formats are being developed. The current software distribution system
is being augmented to use Git. Seamless access to both SolarSoft
and SunPy tools in one interface will allow researchers to work in a
single environment. SSWIDL support for running on Jupyter notebooks,
and Jupyter-based interactive tutorials are being developed. Here
we present the current status of these and other tools. *Bobra
et al, 2020, 'A Survey of Computational Tools in Solar Physics',
10.1007/s11207-020-01622-2 10.1007/s11207-020-01622-2
Title: An Evolving Solar Data Environment
Authors: Hurlburt, Neal; Freeland, Sam; Timmons, Ryan
Bibcode: 2019ASPC..521..687H
Altcode: 2018arXiv180611210H
The rapid growth of solar data is driving changes in the typical
workflow and algorithmic approach to solar data analysis. We present
recently deployed tools to aid this evolution and layout the path for
future development. The majority of space-based datasets including
those from the multi-petabyte Solar Dynamics Observatory and the Hinode
and Interface Region Imaging Spectrograph (IRIS) missions are made
available to the community through a common API with support in IDL
(via SolarSoft), Python/SunPy and other emerging languages. Stellar
astronomers may find the IRIS data particularly useful for research
into stellar chromospheres and for interpreting UV spectra.
Title: Instrument Calibration of the Interface Region Imaging
Spectrograph (IRIS) Mission
Authors: Wülser, J. -P.; Jaeggli, S.; De Pontieu, B.; Tarbell,
T.; Boerner, P.; Freeland, S.; Liu, W.; Timmons, R.; Brannon, S.;
Kankelborg, C.; Madsen, C.; McKillop, S.; Prchlik, J.; Saar, S.;
Schanche, N.; Testa, P.; Bryans, P.; Wiesmann, M.
Bibcode: 2018SoPh..293..149W
Altcode:
The Interface Region Imaging Spectrograph (IRIS) is a NASA small
explorer mission that provides high-resolution spectra and images of
the Sun in the 133 - 141 nm and 278 - 283 nm wavelength bands. The
IRIS data are archived in calibrated form and made available to the
public within seven days of observing. The calibrations applied to
the data include dark correction, scattered light and background
correction, flat fielding, geometric distortion correction, and
wavelength calibration. In addition, the IRIS team has calibrated the
IRIS absolute throughput as a function of wavelength and has been
tracking throughput changes over the course of the mission. As a
resource for the IRIS data user, this article describes the details
of these calibrations as they have evolved over the first few years
of the mission. References to online documentation provide access to
additional information and future updates.
Title: An innovative browser-based data exploration tool with
simultaneous scrolling in time and wavelength domains
Authors: Slater, Gregory L.; Schiff, David; De Pontieu, Bart; Tarbell,
Theodore D.; Freeland, Samuel L.
Bibcode: 2017SPD....4810624S
Altcode:
We present Cruiser, a new web tool for the precision interactive
blending of image series across time and wavelength domains. Scrolling
in two dimensions enables discovery and investigation of similarities
and differences in structure and evolution across multiple
wavelengths. Cruiser works in the latest versions of standards compliant
browsers on both desktop and IOS platforms. Co-aligned data cubes
have been generated for AIA, IRIS, and Hinode SOT FG, and image data
from additional instruments, both space-based and ground-based, can be
data sources. The tool has several movie playing and image adjustment
controls which will be described in the poster and demonstrated on a
MacOS notebook and iPad.
Title: Comparison of 30 THz impulsive burst time development to
microwaves, Hα, EUV, and GOES soft X-rays
Authors: Miteva, R.; Kaufmann, P.; Cabezas, D. P.; Cassiano, M. M.;
Fernandes, L. O. T.; Freeland, S. L.; Karlický, M.; Kerdraon, A.;
Kudaka, A. S.; Luoni, M. L.; Marcon, R.; Raulin, J. -P.; Trottet,
G.; White, S. M.
Bibcode: 2016A&A...586A..91M
Altcode: 2015arXiv151201763M
The recent discovery of impulsive solar burst emission in the 30 THz
band is raising new interpretation challenges. One event associated with
a GOES M2 class flare has been observed simultaneously in microwaves,
Hα, EUV, and soft X-ray bands. Although these new observations confirm
some features found in the two prior known events, they exhibit time
profile structure discrepancies between 30 THz, microwaves, and hard
X-rays (as inferred from the Neupert effect). These results suggest a
more complex relationship between 30 THz emission and radiation produced
at other wavelength ranges. The multiple frequency emissions in the
impulsive phase are likely to be produced at a common flaring site lower
in the chromosphere. The 30 THz burst emission may be either part of a
nonthermal radiation mechanism or due to the rapid thermal response to
a beam of high-energy particles bombarding the dense solar atmosphere.
Title: 3-D Reconstruction of Structure and Dynamics of Coronal
Twistors From STEREO and SDO Imagery
Authors: Slater, G. L.; Freeland, S. L.
Bibcode: 2014AGUFMSH13A4071S
Altcode:
Although observed anecdotally for decades in H-alpha and EUV, so-called
coronal 'tornadoes' have only recently become the focus of systematic
and quantitative study and modeling. This increased focus has primarily
been driven by data from the SDO observatory and more recently the IRIS
observatory and ground-based telescopes. These ubiquitous magnetic
structures differ in appearance and apparent dynamics depending upon
position on the sun relative to the observer and upon observational
wavelength. One of the key outstanding questions is whether they are
actually rotating structures. Progress has been made using spectroscopic
observations (IRIS, etc.) but the question is still not settled. We
will present true stereographic movies of a set of these structures
at various locations on the sun, using combinations of simultaneous
STEREO and SDO imagery, in order to address the question of the actual
motion of the structures.
Title: The Interface Region Imaging Spectrograph (IRIS)
Authors: De Pontieu, B.; Title, A. M.; Lemen, J. R.; Kushner, G. D.;
Akin, D. J.; Allard, B.; Berger, T.; Boerner, P.; Cheung, M.; Chou,
C.; Drake, J. F.; Duncan, D. W.; Freeland, S.; Heyman, G. F.; Hoffman,
C.; Hurlburt, N. E.; Lindgren, R. W.; Mathur, D.; Rehse, R.; Sabolish,
D.; Seguin, R.; Schrijver, C. J.; Tarbell, T. D.; Wülser, J. -P.;
Wolfson, C. J.; Yanari, C.; Mudge, J.; Nguyen-Phuc, N.; Timmons,
R.; van Bezooijen, R.; Weingrod, I.; Brookner, R.; Butcher, G.;
Dougherty, B.; Eder, J.; Knagenhjelm, V.; Larsen, S.; Mansir, D.;
Phan, L.; Boyle, P.; Cheimets, P. N.; DeLuca, E. E.; Golub, L.;
Gates, R.; Hertz, E.; McKillop, S.; Park, S.; Perry, T.; Podgorski,
W. A.; Reeves, K.; Saar, S.; Testa, P.; Tian, H.; Weber, M.; Dunn, C.;
Eccles, S.; Jaeggli, S. A.; Kankelborg, C. C.; Mashburn, K.; Pust, N.;
Springer, L.; Carvalho, R.; Kleint, L.; Marmie, J.; Mazmanian, E.;
Pereira, T. M. D.; Sawyer, S.; Strong, J.; Worden, S. P.; Carlsson,
M.; Hansteen, V. H.; Leenaarts, J.; Wiesmann, M.; Aloise, J.; Chu,
K. -C.; Bush, R. I.; Scherrer, P. H.; Brekke, P.; Martinez-Sykora,
J.; Lites, B. W.; McIntosh, S. W.; Uitenbroek, H.; Okamoto, T. J.;
Gummin, M. A.; Auker, G.; Jerram, P.; Pool, P.; Waltham, N.
Bibcode: 2014SoPh..289.2733D
Altcode: 2014arXiv1401.2491D; 2014SoPh..tmp...25D
The Interface Region Imaging Spectrograph (IRIS) small explorer
spacecraft provides simultaneous spectra and images of the photosphere,
chromosphere, transition region, and corona with 0.33 - 0.4 arcsec
spatial resolution, two-second temporal resolution, and 1 km
s−1 velocity resolution over a field-of-view of up to
175 arcsec × 175 arcsec. IRIS was launched into a Sun-synchronous
orbit on 27 June 2013 using a Pegasus-XL rocket and consists of a
19-cm UV telescope that feeds a slit-based dual-bandpass imaging
spectrograph. IRIS obtains spectra in passbands from 1332 - 1358 Å,
1389 - 1407 Å, and 2783 - 2834 Å, including bright spectral lines
formed in the chromosphere (Mg II h 2803 Å and Mg II k 2796 Å) and
transition region (C II 1334/1335 Å and Si IV 1394/1403 Å). Slit-jaw
images in four different passbands (C II 1330, Si IV 1400, Mg II k
2796, and Mg II wing 2830 Å) can be taken simultaneously with spectral
rasters that sample regions up to 130 arcsec × 175 arcsec at a variety
of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to
emission from plasma at temperatures between 5000 K and 10 MK and will
advance our understanding of the flow of mass and energy through an
interface region, formed by the chromosphere and transition region,
between the photosphere and corona. This highly structured and dynamic
region not only acts as the conduit of all mass and energy feeding
into the corona and solar wind, it also requires an order of magnitude
more energy to heat than the corona and solar wind combined. The
IRIS investigation includes a strong numerical modeling component
based on advanced radiative-MHD codes to facilitate interpretation of
observations of this complex region. Approximately eight Gbytes of data
(after compression) are acquired by IRIS each day and made available
for unrestricted use within a few days of the observation.
Title: Coordinated IRIS science using the Heliophysics Event
Knowledgebase
Authors: Hurlburt, Neal E.; Freeland, Sam; Timmons, Ryan; De Pontieu,
Bart
Bibcode: 2014AAS...22431301H
Altcode:
We have recently enhanced the capabilities of the Heliophysics Event
Knowledgebase (HEK) to support the complex datasets being produced
by the Interface Region Imaging Spectrograph (IRIS). This includes
tools to incorporate observations from the Solar Dynamics Observatory
and ground-based facilities to generate composite data products. We
will discuss the system and its recent evolution and demonstrate its
ability to support coordinated science investigations.
Title: The Association of Solar Flares with Coronal Mass Ejections
During the Extended Solar Minimum
Authors: Nitta, N. V.; Aschwanden, M. J.; Freeland, S. L.; Lemen,
J. R.; Wülser, J. -P.; Zarro, D. M.
Bibcode: 2014SoPh..289.1257N
Altcode: 2013arXiv1308.1465N
We study the association of solar flares with coronal mass ejections
(CMEs) during the deep, extended solar minimum of 2007 - 2009, using
extreme-ultraviolet (EUV) and white-light (coronagraph) images from the
Solar Terrestrial Relations Observatory (STEREO). Although all of the
fast (v>900 km s−1), wide (θ>100∘) CMEs
are associated with a flare that is at least identified in GOES soft
X-ray light curves, a majority of flares with relatively high X-ray
intensity for the deep solar minimum (e.g. ≳1×10−6
W m−2 or C1) are not associated with CMEs. Intense
flares tend to occur in active regions with a strong and complex
photospheric magnetic field, but the active regions that produce
CME-associated flares tend to be small, including those that have no
sunspots and therefore no NOAA active-region numbers. Other factors
on scales similar to and larger than active regions seem to exist that
contribute to the association of flares with CMEs. We find the possible
low coronal signatures of CMEs, namely eruptions, dimmings, EUV waves,
and Type III bursts, in 91 %, 74 %, 57 %, and 74 %, respectively, of
the 35 flares that we associate with CMEs. None of these observables
can fully replace direct observations of CMEs by coronagraphs.
Title: Further Investigation into the Biosynthetic Pathways of the
20 Standard Amino Acids of the Genetic Code
Authors: Onyilagha, J. C.; Trice, K.; Freeland, S.
Bibcode: 2014LPI....45.1875O
Altcode:
The biosynthesis pathways of the 20 amino acids of the genetic code
were investigated to provide more information into the origin of the
standard genetic code.
Title: STEREO/ Extreme Ultraviolet Imager (EUVI) Event Catalog 2006
- 2012
Authors: Aschwanden, Markus J.; Wülser, Jean-Pierre; Nitta, Nariaki
V.; Lemen, James R.; Freeland, Sam; Thompson, William T.
Bibcode: 2014SoPh..289..919A
Altcode: 2013arXiv1306.3180A
We generated an event catalog with an automated detection algorithm
based on the entire EUVI image database observed with the two Solar
Terrestrial Relations Observatory (STEREO)-A and -B spacecraft over
the first six years of the mission (2006 - 2012). The event catalog
includes the heliographic positions of some 20 000 EUV events,
transformed from spacecraft coordinates to Earth-based coordinates,
and information on associated GOES flare events (down to the level
of GOES A5-class flares). The 304 Å wavelength turns out to be the
most efficient channel for flare detection (79 % of all EUVI event
detections), while the 171 Å (4 %), 195 Å (10 %), and the 284 Å
channel (7 %) retrieve substantially fewer flare events, partially
due to the suppressing effect of EUV dimming, and partially due
to the lower cadence in the later years of the mission. Due to the
Sun-circling orbits of STEREO-A and -B, a large number of flares have
been detected on the farside of the Sun, invisible from Earth, or seen
as partially occulted events. The statistical size distributions of
EUV peak fluxes (with a power-law slope of αP=2.5±0.2)
and event durations (with a power-law slope of αT=2.4±0.3)
are found to be consistent with the fractal-diffusive self-organized
criticality model. The EUVI event catalog is available on-line at
secchi.lmsal.com/EUVI/euvi_autodetection/euvi_events.txt and may serve
as a comprehensive tool to identify stereoscopically observed flare
events for 3D reconstruction and to study occulted flare events.
Title: Soft X-ray Fluxes of Major Flares Far Behind the Limb as
Estimated Using STEREO EUV Images
Authors: Nitta, N. V.; Aschwanden, M. J.; Boerner, P. F.; Freeland,
S. L.; Lemen, J. R.; Wuelser, J. -P.
Bibcode: 2013SoPh..288..241N
Altcode: 2013arXiv1304.4163N
With increasing solar activity since 2010, many flares from the backside
of the Sun have been observed by the Extreme Ultraviolet Imager (EUVI)
on either of the twin STEREO spacecraft. Our objective is to estimate
their X-ray peak fluxes from EUVI data by finding a relation of the EUVI
with GOES X-ray fluxes. Because of the presence of the Fe XXIV line at
192 Å, the response of the EUVI 195 Å channel has a secondary broad
peak around 15 MK, and its fluxes closely trace X-ray fluxes during
the rise phase of flares. If the flare plasma is isothermal, the EUVI
flux should be directly proportional to the GOES flux. In reality,
the multithermal nature of the flare and other factors complicate
the estimation of the X-ray fluxes from EUVI observations. We discuss
the uncertainties, by comparing GOES fluxes with the high cadence EUV
data from the Atmospheric Imaging Assembly (AIA) on board the Solar
Dynamics Observatory (SDO). We conclude that the EUVI 195 Å data can
provide estimates of the X-ray peak fluxes of intense flares (e.g.,
above M4 in the GOES scale) to small uncertainties. Lastly we show
examples of intense flares from regions far behind the limb, some of
which show eruptive signatures in AIA images.
Title: The detection of a bright 30 THz impulsive solar burst
Authors: White, Stephen M.; Kaufmann, P.; Freeland, S. L.; Marcon,
R.; Fernandes, L. T.; Kudaka, A. S.; de Souza, R. V.; Marun, A.;
Valio, A.; Raulin, J.; Gimenez de Castro, C.
Bibcode: 2013SPD....4440206W
Altcode:
One of the last unexplored wavelength frontiers for solar flares is
in the range of submillimeter to infrared wavelengths. We report the
detection of an intense impulsive burst at 30 THz using a new imaging
system. The 30 THz emission exhibited remarkable time coincidence with
peaks observed at microwave, mm/submm, visible, EUV and hard X-ray
wavelengths. The 30 THz burst location matches a weak white-light
feature, an intense EUV knot, and a hard X-ray source. The two spatial
structures at EUV are not time coincident, and appear to correspond to
two successive peaks at 30 THz and submm, the second one without time
correspondence with the impulsive component. The coincidence with a
white-light feature is consistent with heating below the temperature
minimum in the atmosphere. However, there are problems in attributing
the heating to accelerated electrons. The peak 30 THz flux is several
times larger than the usual microwave peak near 9 GHz, attributed
to non-thermal electrons in the corona. The 30 THz emission could
be consistent with an optically thick spectrum increasing from low
to high frequencies. It might be part of the same spectral component
found at sub-THz frequencies whose nature remains mysterious. Further
observations at these wavelengths will provide a new window for flare
studies.
Title: A Bright Impulsive Solar Burst Detected at 30 THz
Authors: Kaufmann, P.; White, S. M.; Freeland, S. L.; Marcon, R.;
Fernandes, L. O. T.; Kudaka, A. S.; de Souza, R. V.; Aballay, J. L.;
Fernandez, G.; Godoy, R.; Marun, A.; Valio, A.; Raulin, J. -P.;
Giménez de Castro, C. G.
Bibcode: 2013ApJ...768..134K
Altcode: 2013arXiv1303.5894K
Ground- and space-based observations of solar flares from radio
wavelengths to gamma-rays have produced considerable insights but
raised several unsolved controversies. The last unexplored wavelength
frontier for solar flares is in the range of submillimeter and infrared
wavelengths. Here we report the detection of an intense impulsive burst
at 30 THz using a new imaging system. The 30 THz emission exhibited
remarkable time coincidence with peaks observed at microwave, mm/submm,
visible, EUV, and hard X-ray wavelengths. The emission location
coincides with a very weak white-light feature, and is consistent with
heating below the temperature minimum in the atmosphere. However, there
are problems in attributing the heating to accelerated electrons. The
peak 30 THz flux is several times larger than the usual microwave peak
near 9 GHz, attributed to non-thermal electrons in the corona. The
30 THz emission could be consistent with an optically thick spectrum
increasing from low to high frequencies. It might be part of the same
spectral component found at sub-THz frequencies whose nature remains
mysterious. Further observations at these wavelengths will provide a
new window for flare studies.
Title: SolarSoft: Programming and data analysis environment for
solar physics
Authors: Freeland, S. L.; Handy, B. N.
Bibcode: 2012ascl.soft08013F
Altcode:
SolarSoft is a set of integrated software libraries, data bases,
and system utilities which provide a common programming and data
analysis environment for Solar Physics. The SolarSoftWare (SSW)
system is built from Yohkoh, SOHO, SDAC and Astronomy libraries and
draws upon contributions from many members of those projects. It is
primarily an IDL based system, although some instrument teams integrate
executables written in other languages. The SSW environment provides
a consistent look and feel at widely distributed co-investigator
institutions to facilitate data exchange and to stimulate coordinated
analysis. Commonalities and overlap in solar data and analysis goals are
exploited to permit application of fundamental utilities to the data
from many different solar instruments. The use of common libraries,
utilities, techniques and interfaces minimizes the learning curve
for investigators who are analyzing new solar data sets, correlating
results from multiple experiments or performing research away from
their home institution.
Title: Automated Solar Flare Statistics in Soft X-Rays over 37 Years
of GOES Observations: The Invariance of Self-organized Criticality
during Three Solar Cycles
Authors: Aschwanden, Markus J.; Freeland, Samuel L.
Bibcode: 2012ApJ...754..112A
Altcode: 2012arXiv1205.6712A
We analyzed the soft X-ray light curves from the Geostationary
Operational Environmental Satellites over the last 37 years (1975-2011)
and measured with an automated flare detection algorithm over 300,000
solar flare events (amounting to ≈5 times higher sensitivity than the
NOAA flare catalog). We find a power-law slope of α F =
1.98 ± 0.11 for the (background-subtracted) soft X-ray peak fluxes
that is invariant through three solar cycles and agrees with the
theoretical prediction α F = 2.0 of the fractal-diffusive
self-organized criticality (FD-SOC) model. For the soft X-ray flare
rise times, we find a power-law slope of α T = 2.02 ±
0.04 during solar cycle minima years, which is also consistent with
the prediction α T = 2.0 of the FD-SOC model. During
solar cycle maxima years, the power-law slope is steeper in the
range of α T ≈ 2.0-5.0, which can be modeled by
a solar-cycle-dependent flare pile-up bias effect. These results
corroborate the FD-SOC model, which predicts a power-law slope of
α E = 1.5 for flare energies and thus rules out significant
nanoflare heating. While the FD-SOC model predicts the probability
distribution functions of spatio-temporal scaling laws of nonlinear
energy dissipation processes, additional physical models are needed
to derive the scaling laws between the geometric SOC parameters and
the observed emissivity in different wavelength regimes, as we derive
here for soft X-ray emission. The FD-SOC model also yields statistical
probabilities for solar flare forecasting.
Title: Heliophysics Event Knowledgebase for the Solar Dynamics
Observatory (SDO) and Beyond
Authors: Hurlburt, N.; Cheung, M.; Schrijver, C.; Chang, L.; Freeland,
S.; Green, S.; Heck, C.; Jaffey, A.; Kobashi, A.; Schiff, D.; Serafin,
J.; Seguin, R.; Slater, G.; Somani, A.; Timmons, R.
Bibcode: 2012SoPh..275...67H
Altcode: 2010arXiv1008.1291H
The immense volume of data generated by the suite of instruments
on the Solar Dynamics Observatory (SDO) requires new tools for
efficient identifying and accessing data that is most relevant for
research. We have developed the Heliophysics Events Knowledgebase
(HEK) to fill this need. The HEK system combines automated data mining
using feature-detection methods and high-performance visualization
systems for data markup. In addition, web services and clients are
provided for searching the resulting metadata, reviewing results,
and efficiently accessing the data. We review these components and
present examples of their use with SDO data.
Title: Data Discovery and Access via the Heliophysics Events
Knowledgebase (HEK)
Authors: Somani, A.; Hurlburt, N. E.; Schrijver, C. J.; Cheung, M.;
Freeland, S.; Slater, G. L.; Seguin, R.; Timmons, R.; Green, S.;
Chang, L.; Kobashi, A.; Jaffey, A.
Bibcode: 2011AGUFMSM21A1989S
Altcode:
The HEK is a integrated system which helps direct scientists to solar
events and data from a variety of providers. The system is fully
operational and adoption of HEK has been growing since the launch of
NASA's SDO mission. In this presentation we describe the different
components that comprise HEK. The Heliophysics Events Registry (HER)
and Heliophysics Coverage Registry (HCR) form the two major databases
behind the system. The HCR allows the user to search on coverage event
metadata for a variety of instruments. The HER allows the user to
search on annotated event metadata for a variety of instruments. Both
the HCR and HER are accessible via a web API which can return search
results in machine readable formats (e.g. XML and JSON). A variety
of SolarSoft services are also provided to allow users to search the
HEK as well as obtain and manipulate data. Other components include
- the Event Detection System (EDS) continually runs feature finding
algorithms on SDO data to populate the HER with relevant events, -
A web form for users to request SDO data cutouts for multiple AIA
channels as well as HMI line-of-sight magnetograms, - iSolSearch,
which allows a user to browse events in the HER and search for specific
events over a specific time interval, all within a graphical web page,
- Panorama, which is the software tool used for rapid visualization of
large volumes of solar image data in multiple channels/wavelengths. The
user can also easily create WYSIWYG movies and launch the Annotator
tool to describe events and features. - EVACS, which provides a JOGL
powered client for the HER and HCR. EVACS displays the searched for
events on a full disk magnetogram of the sun while displaying more
detailed information for events.
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: Insights into Filament Eruption Onset from Solar Dynamics
Observatory Observations
Authors: Sterling, Alphonse C.; Moore, R. L.; Freeland, S. L.
Bibcode: 2011SPD....42.0904S
Altcode: 2011BAAS..43S.0904S
We examine the buildup to and onset of an active region filament
confined eruption of 2010 May 12, using EUV imaging data from the Solar
Dynamics Observatory (SDO) Atmospheric Imaging Array and line-of-sight
magnetic data from the SDO Helioseismic and Magnetic Imager. Over the
hour preceding eruption the filament undergoes a slow rise averaging
3 km/s, with a step-like trajectory. Accompanying a final rise step 20
minutes prior to eruption is a transient preflare brightening, occurring
on loops rooted near the site where magnetic field had canceled over
the previous 20 hr. Flow-type motions of the filament are relatively
smooth with speeds 50 km/s prior to the preflare brightening and appear
more helical, with speeds 50-100 km/s, after that brightening. After
a final plateau in the filament's rise, its rapid eruption begins,
and concurrently an outer shell "cocoon" of the filament material
increases in emission in hot EUV lines, consistent with heating in
a newly formed magnetic flux rope. The main flare brightenings start
5 minutes after eruption onset. The main flare arcade begins between
the legs of an envelope-arcade loop that is nearly orthogonal to the
filament, suggesting that the flare results from reconnection among
the legs of that loop. This progress of events is broadly consistent
with flux cancellation leading to formation of a helical flux rope
that subsequently erupts due to onset of a magnetic instability and/or
runaway tether cutting. A full description of this work appears in
ApJ Letters 2011, 731, L3. NASA supported this work through its Solar
Physics Supporting Research and Technology, Sun-Earth Connection
Guest Investigator, and Living With a Star Targeted Research &
Technology programs.
Title: Insights into Filament Eruption Onset from Solar Dynamics
Observatory Observations
Authors: Sterling, Alphonse C.; Moore, Ronald L.; Freeland, Samuel L.
Bibcode: 2011ApJ...731L...3S
Altcode:
We examine the buildup to and onset of an active region filament
confined eruption of 2010 May 12, using EUV imaging data from the Solar
Dynamics Observatory (SDO) Atmospheric Imaging Array and line-of-sight
magnetic data from the SDO Helioseismic and Magnetic Imager. Over the
hour preceding eruption the filament undergoes a slow rise averaging
~3 km s-1, with a step-like trajectory. Accompanying a
final rise step ~20 minutes prior to eruption is a transient preflare
brightening, occurring on loops rooted near the site where magnetic
field had canceled over the previous 20 hr. Flow-type motions of the
filament are relatively smooth with speeds ~50 km s-1
prior to the preflare brightening and appear more helical, with
speeds ~50-100 km s-1, after that brightening. After a
final plateau in the filament's rise, its rapid eruption begins,
and concurrently an outer shell "cocoon" of the filament material
increases in emission in hot EUV lines, consistent with heating in
a newly formed magnetic flux rope. The main flare brightenings start
~5 minutes after eruption onset. The main flare arcade begins between
the legs of an envelope-arcade loop that is nearly orthogonal to the
filament, suggesting that the flare results from reconnection among
the legs of that loop. This progress of events is broadly consistent
with flux cancellation leading to formation of a helical flux rope
that subsequently erupts due to onset of a magnetic instability and/or
runaway tether cutting.
Title: A comparison of space weather analysis techniques used to
predict the arrival of the Earth-directed CME and its shockwave
launched on 8 April 2010
Authors: Davis, C. J.; de Koning, C. A.; Davies, J. A.; Biesecker,
D.; Millward, G.; Dryer, M.; Deehr, C.; Webb, D. F.; Schenk, K.;
Freeland, S. L.; Möstl, C.; Farrugia, C. J.; Odstrcil, D.
Bibcode: 2011SpWea...9.1005D
Altcode: 2011SpWea...901005D
The Earth-directed coronal mass ejection (CME) of 8 April 2010
provided an opportunity for space weather predictions from both
established and developmental techniques to be made from near-real
time data received from the SOHO and STEREO spacecraft; the STEREO
spacecraft provide a unique view of Earth-directed events from outside
the Sun-Earth line. Although the near-real time data transmitted by
the STEREO Space Weather Beacon are significantly poorer in quality
than the subsequently downlinked science data, the use of these data
has the advantage that near-real time analysis is possible, allowing
actual forecasts to be made. The fact that such forecasts cannot be
biased by any prior knowledge of the actual arrival time at Earth
provides an opportunity for an unbiased comparison between several
established and developmental forecasting techniques. We conclude that
for forecasts based on the STEREO coronagraph data, it is important
to take account of the subsequent acceleration/deceleration of each
CME through interaction with the solar wind, while predictions based
on measurements of CMEs made by the STEREO Heliospheric Imagers would
benefit from higher temporal and spatial resolution. Space weather
forecasting tools must work with near-real time data; such data, when
provided by science missions, is usually highly compressed and/or
reduced in temporal/spatial resolution and may also have significant
gaps in coverage, making such forecasts more challenging.
Title: SDO Data Access And Analysis
Authors: Somani, A.; Hurlburt, N. E.; Schrijver, C. J.; Cheung, C.;
Freeland, S. L.; Slater, G. L.; Seguin, R.; Timmons, R.; Green, S.;
Chang, L.; Kobashi, A.; Jaffey, A.
Bibcode: 2010AGUFMSH23C1870S
Altcode:
The Heliophysics Event Knowledgebase (HEK), Event Detection System
(EDS), iSolSearch, Panorama, Event Viewer and Control Software (EVACS),
and a variety of SolarSoft routines all work together to provide a
suite of tools to facilitate access and analysis of SDO data. The
HEK, which consists of the Heliophysics Event Registry (HER) and
the Heliophysics Coverage Registry (HCR), uses XML formats built
upon the IVOA VOEvent specification to ingest, store, and search
events. Web services and SolarSoft routines are available to make
use of these functions. The EDS is one of the sources that provides
events for ingest into the HEK. The EDS continuously runs feature
finding modules on SDO data. It's a distributed system that allows
it to keep up with SDO's data rate. iSolSearch allows the user to
browse the events in the HER and search for events given a specific
time interval and other constraints. Panorama is the software tool
used for rapid visualization of large volumes of solar image data
in multiple channels/wavelengths. With the EVACS front-end GUI tool,
Panorama allows the user to, in real-time, change channel pixel scaling,
weights, alignment, blending and colorization of data. The user can
also easily create WYSIWYG movies and launch the Annotator tool to
describe events and features the user observes in the data. Panorama
can also be used to drive clustered HiperSpace walls using the CGLX
toolkit. Panorama harnesses the power of the GPU and OpenGL fragment
shaders to enable stunning visualization. EVACS provides a JOGL powered
GUI that the user can search both the HER and HCR with. EVACS displays
the searched for events on a full disk magnetogram of the sun while
displaying more detailed information for events. EVACS can also be used
to launch Panorama with a selected set of FITS or PRGB files, as well
as control many aspects of Panorama. A host of SolarSoft routines are
available to not only access functions of the HEK, but to also access
metadata and/or image data from the Joint Science Operations Center
(JSOC). Routines are also provided to create cutout images and movies
of SDO data. A data order web page is provided to allow a casual user
to order cutouts or full disk images. This page will make use of both
the SSW cutout service as well as the JSOC cutout service.
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: An Invitation to the Improved Yohkoh Legacy data Archive
Authors: Takeda, A.; Acton, L. W.; McKenzie, D.; Yoshimura, K.;
Freeland, S. L.
Bibcode: 2010AGUFMSH11B1645T
Altcode:
The Yohkoh Legacy data Archive (YLA) is a unique source of solar X-ray
images and spectra obtained with the Yohkoh satellite(1991-2001). The
archive consists of four levels of data products from raw to highly
value added, with ample amount of documentation and user-friendly web
interface (http://solar.physics.montana.edu/ylegacy). The YLA is also
unique in that quality and variety of the products and services have
been constantly improved through these nine years after the completion
of the satellite mission. Our recent improvements are: (1) Completion of
the stray light correction, applied to the data after the SXT entrance
filter failure in 1992. (2) Completion of the satellite attitude data
correction. (3) E-mail based individual user support (E-consultant
service). (4) New FITS header definition with World Coordinate System
compliance. (5) Update of SXT response function based on the latest
atomic data and models (Chianti 6.0.1). (6) Introduction of a new
data category, Level 3, for co-aligned composite images suitable for
browsing in movie mode. The main body of our archive (data from the
Soft X-ray Telescope) are provided in both Yohkoh-specific (XDA) and
FITS formats. The XDA format is convenient for analysis with existing
SSW/Yohkoh software that runs under IDL. The more general FITS format
enables use of advanced SSW applications developed in the various
missions after Yohkoh. FITS products do not specifically require IDL
to read and view images, which allows our products to be accessed from
a wide range of communities. Our products can be accessed through our
quick-look and data-search web services, and also through the Virtual
Solar Observatory data search. Since 2009, YLA is funded as one of
NASA's Resident Archives in Virtual Observatories for Heliophysics Data
program. Through the funds, we take responsibility for maintaining
the best corrected data sets, and providing the easy access and user
support. The top page of the YLA web interface
Title: An Alternative View of the "Masuda" Flare
Authors: Nitta, Nariaki V.; Freeland, Samuel L.; Liu, Wei
Bibcode: 2010ApJ...725L..28N
Altcode:
The limb flare on 1992 January 13, the so-called Masuda flare,
has stimulated scientists to refine theory of solar flares based on
two-dimensional magnetic reconnection. This is primarily because of
the hard X-ray (HXR) source seen above the clearly defined flare loop,
and the outward motions in soft X-rays (SXRs) interpreted as "plasmoid"
ejections. We have revisited Yohkoh HXR and SXR data for this and other
limb flares and found that the Masuda flare is still unique in terms of
the location and spectral properties of the coronal HXR source. However,
the outward motions in SXR outside the flare loop may not be as simply
characterized as plasmoid ejections as in other flares, nor are they
particularly fast. The motions appear complex partly because we also see
trans-equatorial loops in motion, one of whose legs anchors close to the
main flare loop. It is possible that these large-scale loops represent
post-flare loops, and that the flare may also be explained in terms of
three-dimensional quadrupolar reconnection, similar to those flares
where a pair of two loops exchange their footpoints through magnetic
reconnection. It appears that expansion and brightening of large-scale
loops offset from the main flare loop are not common, possibly providing
a reason for the unusual coronal HXR source in the Masuda flare.
Title: Precursors of CMEs in coronal images
Authors: Freeland, S. L.; Slater, G. L.; Nitta, N. V.
Bibcode: 2010AGUFMSH43B1824F
Altcode:
For many years we have tried to find key observational signatures
primarily in low coronal images (such as SOHO EIT) that are useful for
predicting coronal mass ejections (CMEs). The signatures are isolated
in an automated way. It is also important to estimate the spatial and
kinematic properties of the white-light CME on the basis of its earlier
signatures as captured in EUV and X-ray images. In this presentation,
we give examples to demonstrate how low coronal observations help
us predict or understand the spatial and kinematic properties of
CMEs. We discuss how SDO AIA observations, either on their own or
in combination with data from other experiments (such as STEREO),
may improve our capability to predict CMEs and their properties.
Title: An Introduction to the Heliophysics Event Knowledgebase
Authors: Hurlburt, Neal E.; Cheung, M.; Schrijver, C.; Chang, L.;
Freeland, S.; Green, S.; Heck, C.; Jaffey, A.; Kobashi, A.; Schiff,
D.; Serafin, J.; Seguin, R.; Slater, G.; Somani, A.; Timmons, R.
Bibcode: 2010AAS...21640222H
Altcode: 2010BAAS...41T.876H
The immense volume of data generated by the suite of instruments on
SDO requires new tools for efficiently identifying and accessing data
that are most relevant to research investigations. We have developed
the Heliophysics Events Knowledgebase (HEK) to fill this need. The
system developed to support the HEK combines automated datamining using
feature detection methods; high-performance visualization systems for
data markup; and web-services and clients for searching the resulting
metadata, reviewing results and efficient access to the data. We will
review these components and present examples of their use with SDO data.
Title: Coronal Dimming And Waves Observed In Flare-Associated CMEs
Authors: Nitta, Nariaki; Aschwanden, M.; Freeland, S.; Lemen, J.;
Wuelser, J.; Zarro, D.
Bibcode: 2010AAS...21640614N
Altcode: 2010BAAS...41..882N
The relationship between solar flares and coronal mass ejections
(CMEs) is still an active area of research. It is studied from
various aspects. Our goal is to understand the importance of magnetic
reconnection in launching CMEs and that of magnetic field environment
of the flaring regions to determine how eruptive flares are. We have
studied the association of solar flares during 2007-2009 with CMEs,
using primarily extreme-ultraviolet (EUV) and inner coronagraphic
images from the Solar Terrestrial Relations Observatory (STEREO). While
energetic CMEs tend to accompany a flare, flares with relatively high
soft X-ray intensity for the extended solar minimum conditions are often
found without an associated CME, even though the underlying photospheric
magnetic field is strong and complex. In contrast, some of the regions
hosting flare-associated CMEs have weak photospheric field, sometimes
not even classified as active regions because of no sunspots. Out of
several signatures in low coronal images previously raised as proxies
for CMEs, large-scale dimming that persists for at least an hour is
found to be a sufficient condition. Waves in EUV images, on the other
hand, may not necessarily signal an appreciable CME that is still
clearly observed beyond, for example, 5 Rsun, unless the concurrent
dimming is substantial. This suggests that waves detected in EUV images
may have more than one origins. We present the result of the survey
and discuss a number of well-observed cases focusing on the properties
of the flares and CMEs with respect to the extents of dimming and wave.
Title: The Heliophysics Event Knowledgebase for the Solar Dynamics
Observatory - A User's Perspective
Authors: Slater, Gregory L.; Cheung, M.; Hurlburt, N.; Schrijver,
C.; Somani, A.; Freeland, S. L.; Timmons, R.; Kobashi, A.; Serafin,
J.; Schiff, D.; Seguin, R.
Bibcode: 2010AAS...21641505S
Altcode: 2010BAAS...41S.825S
The recently launched Solar Dynamics Observatory (SDO) will
generated over 2 petabytes of imagery in its 5 year mission. The
Heliophysics Events Knowledgebase (HEK) system has been developed to
continuously build a database of solar features and events contributed
by a combination of machine recognition algorithms run on every single
image, and human interactive data exploration. Access to this growing
database is provided through a set of currently existing tools as well
as an open source API. We present an overview of the user interface
tools including illustrative examples of their use.
Title: Detailed Design of the Heliophysics Event Knowledgebase (HEK)
Authors: Somani, Ankur; Seguin, R.; Timmons, R.; Freeland, S.;
Hurlburt, N.; Kobashi, A.; Jaffey, A.
Bibcode: 2010AAS...21641504S
Altcode: 2010BAAS...41R.825S
We present the Heliophysics Event Registry (HER) and the Heliophysics
Coverage Registry (HCR), which serve as two components of the
Heliophysics Event Knowledgebase (HEK). Using standardized XML formats
built upon the IVOA VOEvent specification, events can be ingested,
stored, and later searched upon. Various web services and SolarSoft
routines are available to aid in these functions. One source of
events for the HEK is an automated Event Detection System (EDS) that
continuously runs feature finding modules on SDO data. Modules are
primarily supplied by the Smithsonian Astrophysical Observatory-led
Feature Finding Team. The distributed system will keep up with SDO's
data rate and issue space weather alerts in near-real time. Some modules
will be run on all data while others are run in response to certain
solar phenomena found by other modules in the system. Panorama is
a software tool used for rapid visualization of large volumes of solar
image data in multiple channels/wavelengths. With the EVACS front-end
GUI tool, Panorama allows the user to, in real-time, change channel
pixel scaling, weights, alignment, blending and colorization of the
data. The user can also easily create WYSIWYG movies and launch the
Annotator tool to describe events and features the user observes in the
data. Panorama can also be used to drive clustered HiperSpace walls
using the CGLX toolkit. The Event Viewer and Control Software
(EVACS) provides a GUI that the user can search both the HER and HCR
with. By specifying a start and end time and selecting the types of
events and instruments that are of interest, EVACS will display the
events on a full disk image of the sun while displaying more detailed
information for the events. As mentioned, the user can also launch
Panorama via EVACS.
Title: CME-related Phenomena and Solar Flares
Authors: Nitta, Nariaki; Aschwanden, Markus; Freeland, Samuel; Lemen,
James; Wuelser, Jean-Pierre; Zarro, Dominic
Bibcode: 2010cosp...38.1792N
Altcode: 2010cosp.meet.1792N
The relationship between solar flares and coronal mass ejections
(CMEs) is still an active area of research. It is studied from
various aspects. Our goal is to understand the importance of magnetic
reconnection in launching CMEs and that of magnetic field environment
of the flaring regions to determine how eruptive flares are. We have
studied the association of solar flares dur-ing 2007-2009 with CMEs,
using primarily extreme-ultraviolet (EUV) and inner coronagraphic
images from the Solar Terrestrial Relations Observatory (STEREO). While
energetic CMEs tend to accompany a flare, flares with relatively high
soft X-ray intensity for the extended solar minimum conditions are often
found without an associated CME, even though the underlying photospheric
magnetic field is strong and complex. In contrast, some of the regions
hosting flare-associated CMEs have weak photospheric field, sometimes
not even classified as active regions because of no sunspots. Out of
several signatures in low coronal images previously raised as proxies
for CMEs, large-scale dimming that persists for at least an hour is
found to be a sufficient condition. Waves in EUV images, on the other
hand, may not necessarily signal an appreciable CME that is still
clearly observed beyond, for example, 5 Rsun, unless the concur-rent
dimming is substantial. This suggests that waves detected in EUV images
may have more than one origins. We present the result of the survey
and discuss a number of well-observed cases focusing on the properties
of the flares and CMEs with respect to the extents of dimming and wave.
Title: Estimation of coronal magnetic field using the type II radio
burst associated with a fast CME
Authors: Gopalswamy, Nat; Yashiro, Seiji; Akiyama, Sachiko; Freeland,
Samuel; Davila, Joseph; Howard, Russell; Bougeret, J. -L.
Bibcode: 2010cosp...38.1808G
Altcode: 2010cosp.meet.1808G
The 2008 March 25 coronal mass ejection (CME) was the second
fastest among the 10 type II producing CMEs in the STEREO era. The
CME was accompanied by a EUV wave and a shock discernible in the
white-light data. The type II burst was observed in the metric and
decameter-hectometer (DH) wavelength domains. The type II burst ended in
the DH domain when the CME speed started declining at a heliocentric
distance where the Alfven speed reached its peak value. Under the
scenario that the type II burst was caused by a CME-driven shock,
we see that the end of the type II burst corresponds to a significant
weakening of the shock, making it subcritical. The standoff distance
between the flux rope structure and the shock significantly increased at
the time of the shock weakening. From the observed standoff distance,
we estimated the upstream Alfvenic Mach number and hence the coronal
magnetic field. The magnetic field derived (0.04 G) is consistent with
typical quiet solar atmosphere at 7 solar radii.
Title: The CME-Flare Relation Revisited With STEREO Observations
Authors: Nitta, Nariaki; Aschwanden, M.; Freeland, S.; Lemen, J.;
Wuelser, J.; Zarro, D.
Bibcode: 2009SPD....40.2105N
Altcode:
We study the association of solar flares since March 2007 with coronal
mass ejections (CMEs), using images taken by the EUV Imager (EUVI),
COR1 and COR2 coronagraphs on board STEREO. This is done by searching
EUVI data for low coronal signatures attributable to CMEs, such as
dimming, EUV waves and eruptions, following them to COR1 and COR2
fields of view. Base and running difference images (after correcting
for differential rotation) as well as raw images in all the four
filters of EUVI on STEREO A and STEREO B are viewed as movies to find
the CME-related signatures. The COR1 data are particularly helpful for
connecting the EUVI signatures with CMEs observed by COR2. Only 2 (out
of 11) M-class flares and 7 (out of 64) C-class flares are convincingly
associated with CMEs traceable beyond 5 Rs. There are also a handful
of less intense (B-class and A-class) flares associated with CMEs. We
discuss the "calibration" of the low coronal signatures with actual
CMEs, quantitatively re-defining them to be used as reliable proxies
for CMEs. Radio observations are also found to be of use to distinguish
flares associated and not associated with CMEs. Lastly we consider the
CME association of flares in terms of the the following items about the
flaring active regions: their basic properties, their relations with
more global field, and local (spatial or temporal) changes therein. This
study may help us understand the effect of (reconnection-driven)
flare processes on the initiation and subsequent dynamics of CMEs.
Title: The SOHO/LASCO CME Catalog
Authors: Gopalswamy, N.; Yashiro, S.; Michalek, G.; Stenborg, G.;
Vourlidas, A.; Freeland, S.; Howard, R.
Bibcode: 2009EM&P..104..295G
Altcode: 2009EM&P..tmp....8G
Coronal mass ejections (CMEs) are routinely identified in the images
of the solar corona obtained by the Solar and Heliospheric Observatory
(SOHO) mission’s Large Angle and Spectrometric Coronagraph (LASCO)
since 1996. The identified CMEs are measured and their basic attributes
are cataloged in a data base known as the SOHO/LASCO CME Catalog. The
Catalog also contains digital data, movies, and plots for each CME,
so detailed scientific investigations can be performed on CMEs and
the related phenomena such as flares, radio bursts, solar energetic
particle events, and geomagnetic storms. This paper provides a brief
description of the Catalog and summarizes the statistical properties
of CMEs obtained using the Catalog. Data products relevant to space
weather research and some CME issues that can be addressed using the
Catalog are discussed. The URL of the Catalog is: <ExternalRef>
<RefSource>http://cdaw.gsfc.nasa.gov/CME_list</RefSource>
<RefTarget Address="http://cdaw.gsfc.nasa.gov/CME_list"
TargetType="URL"/> </ExternalRef>.
Title: EUV Wave Reflection from a Coronal Hole
Authors: Gopalswamy, N.; Yashiro, S.; Temmer, M.; Davila, J.; Thompson,
W. T.; Jones, S.; McAteer, R. T. J.; Wuelser, J. -P.; Freeland, S.;
Howard, R. A.
Bibcode: 2009ApJ...691L.123G
Altcode:
We report on the detection of EUV wave reflection from a coronal
hole, as observed by the Solar Terrestrial Relations Observatory
mission. The EUV wave was associated with a coronal mass ejection
(CME) erupting near the disk center. It was possible to measure the
kinematics of the reflected waves for the first time. The reflected
waves were generally slower than the direct wave. One of the important
implications of the wave reflection is that the EUV transients are
truly a wave phenomenon. The EUV wave reflection has implications for
CME propagation, especially during the declining phase of the solar
cycle when there are many low-latitude coronal holes.
Title: Coronal Mass Ejections Associated With Impulsive Solar Flares -
Observations With SECCHI EUVI On STEREO
Authors: Nitta, N. V.; Lemen, J. R.; Wuelser, J.; Aschwanden, M. J.;
Freeland, S. L.; Zarro, D. M.
Bibcode: 2008AGUFMSH13B1538N
Altcode:
Long-duration flares, sometimes referred to as Long Decay Events (LDEs),
are known to be unmistakable signatures of coronal mass ejections
(CMEs), and often of fast and large ones. Short-duration or impulsive
flares, on the other hand, do not as frequently accompany CMEs,
even though X-ray plasmoid ejections seen in some of these flares may
suggest that all flares are eruptive irrespective of durations. Some
of these ejections in X-ray or EUV images could be failed ejections,
however, meaning that they do not move into interplanetary medium. A
complementary, and perhaps more reliable signature of a CME in the
low corona may be large-scale dimming typically observed at 1-2
MK. We report on high cadence observations of SECCHI EUVI on STEREO
that show this phenomenon in weak impulsive flares more frequently
than expected. We systematically study flare periods with good data
coverage. In order to avoid false dimming, we use both base and running
difference images after carefully co-aligning the image pairs. Some
of the dimming events were observed in more than one channel and
at two widely separated view angles, letting us better understand
the nature of dimming especially in terms of the associated CME. We
discuss how the properties of dimming are reflected in CME parameters,
how to distinguish the impulsive flares with large- scale effects from
those that are confined, and whether similar events could account for
orphan ICMEs without a clearly associated CME near the Sun.
Title: Relation between Coronal Mass Ejection, Type II Radio Burst,
and EUV Wave during the 2008 March 25 STEREO Event
Authors: Gopalswamy, N.; Yashiro, S.; Akiyama, S.; Freeland, S.;
Thompson, W. T.; Davila, J. M.; Howard, R. A.; Kaiser, M. L.; Bougeret,
J. -
Bibcode: 2008AGUFMSH12A..02G
Altcode:
STEREO and SOHO observations of the March 25, 2008 coronal mass ejection
(CME) provide an excellent opportunity to study its early evolution
from multiple view points. The CME was fast (980 km/s) and wide (112
degrees) from the east limb of the Sun as viewed by SOHO. The STEREO
spacecraft were separated by about 50 degrees, so the CME was a disk
event for the STEREO-behind spacecraft and a behind-the-limb event
for STEREO-ahead. The CME was associated with a well defined EUV wave
as observed by the STEREO/EUVI instrument, a metric type II burst,
and a multi-component type II burst observed by the STEREO/WAVES and
Wind/WAVES instruments. One of the important aspect of this CME is
that it was well observed by STEREO/SECCHI inner coronagraph (COR1)
when the metric type II burst was in progress, so we are able to obtain
the shock height with respect t the CME. This enabled us to infer the
connection the coronal shock driven by the CME (inferred from type II
burst) and the EUV wave. It appears that the EUV wave steepened into
a shock and produced the type II burst. The multiple components of
the type II burst were not harmonically related, so we examined the
circumstances of the eruption. CME was ejected in the region between
two streamers, so the CME-driven shock is likely to simultaneously
encounter high and low- density regions of the corona, thus producing
type II bursts at widely separated frequencies. This paper summarizes
these observations and explains how the CME, type II radio burst,
and EUV waves all fit together.
Title: Developing a Heliophysics Event Knowledgebase for Solar
Dynamics Observatory
Authors: Schrijver, K.; Hurlburt, N.; Mark, C.; Freeland, S.; Green,
S.; Jaffey, A.; Kobashi, A.; Schiff, D.; Seguin, R.; Slater, G.;
Somani, A.; Timmons, R.
Bibcode: 2008AGUFMSM11B1619S
Altcode:
The Solar Dynamics Observatory will generated over 2 petabytes
of imagery in its 5 year mission. In order to improve scientific
productivity and to reduce system requirements , we have developed a
system for data markup to identify -interesting" datasets and direct
scientists to them through an event-based querying system. The SDO
Heliophysics Event Knowledgebase (HEK) will enable caching of commonly
accessed datasets within the Joint Science Operations Center (JSOC) and
reduces the (human) time spent searching for and downloading relevant
data. We present an overview of our HEK including the ingestion of
images, automated and manual tools for identifying and annotation
features within the images, and interfaces and webtools for querying
and accessing events and their associated data. informatcs/hpkb
Title: The Atmospheric Imaging Array Feature and Event System (AFES)
for SDO
Authors: Hurlburt, N.; Freeland, S.; Cheung, M.; Schrijver, C.
Bibcode: 2008AGUSMSM21A..07H
Altcode:
The great data volumes involved in Solar Dynamics Observatory impose
the need to have efficient means to access, process and transport
data products that goes beyond basic data discovery. In order to
reduce system requirements and to improve scientific productivity,
we pre-package Ðinterestingî datasets and direct scientists to them
through an event-based querying system. This will enable caching of
commonly accessed datasets within the Joint Science Operations Center
(JSOC) and reduces the (human) time spent searching for and downloading
relevant data. This system leverages the infrastructure developed
for the Hinode Observation System (http://sot.lmsal.com/sot-data)
and incorporates elements of the evolving heliophysics knowledgebase
(http://www.lmsal.com/helio-informatics/hpkb). We present the details
of the AFES including the ingestion of images, automated and manual
tools for identifying and annotation features within the images, and
interfaces and webtools for querying and accessing events and their
associated data. This work has been supported by NASA through contract
NNG04AE00C and Lockheed Martin Research Funds.
Title: The Collaborative Heliophysics Observatory
Authors: Hurlburt, N.; Freeland, S.; Cheung, M.; Bose, P.
Bibcode: 2007AGUFMSH51A0256H
Altcode:
The Collaborative Heliophysics Observatory (CHO) would provide a robust
framework and enabling tools to fully utilize the VOs for scientific
discovery and collaboration. Scientists across the realm of heliophysics
would be able to create, use and share applications -- either as
services using familiar tools or through intuitive workflows -- that
orchestrate access to data across all virtual observatories. These
applications can be shared freely knowing that proper recognition of
data and processing components are acknowledged; that erroneous use
of data is flagged; and that results from the analysis runs will in
themselves be shared Ð all in a transparent and automatic fashion. In
addition, the CHO would incorporate cross-VO models and tools to weave
the various virtual observatories into a unified system. These provide
starting points for interactions across the solar/heliospheric and
heliospheric/magnetospheric boundaries.
Title: A New X-ray Bright Point Catalog From Honode XRT images As An
Application of Feature Recognition Methods and Emerging Heliophysics
Knowledge Base Systems
Authors: Slater, Gregory L.; Freeland, S. L.; Weber, M. A.
Bibcode: 2007AAS...210.9420S
Altcode: 2007BAAS...39R.220S
A new effort is underway to process the rapidly growing volume of
solar observational data by using automated feature recognition and
cataloguing software (c.f., Schrijver et al SPD 2007 or Hurlburt et
al, SPD 2007). We apply a particular set of feature recognition tools
called FINDSTUFF, available within the SolarSoft IDL framework, to the
problem of automatically extracting X-Ray Bright Point (XBP) features
from images recorded by the XRT instrument aboard the recently launched
Japanese Hinode satellite. The extracted events are automatically
catalogued by the FINDSTUFF software. The events are converted into
standardized XML format as VOEvents, and these XML event files in
turn are automatically deposited in the Heliophysics Knowledge Base
(HKB) being developed at Lockheed Martin in collaboration with other
institutions (c.f., Hurlburt et al, SPD 2007). In addition to providing
a very useful end-to-end test of the Heliophysics Knowledge Base Project
(Schrijver et al), the catalogue yields a valuable scientific database
of XBPs extracted from high resolution XRT images. We discuss the
aspects of our processing pipeline which are generally applicable
to many feature archiving projects; we demonstrate how the final
Heliophysics Knowledge Base may be queried to explore the XBP archive;
we compare our catalogue of XBPs with previously generated ones; and we
provide examples of discoveries made with massively autonomous feature
extraction (MAFE). The U.S. XRT team is supported by NASA contracts
from NASA to SAO (XRT), while the SOT team is supported by NASA contract
number NNM07AA01C. Hinode is an international project supported by JAXA,
NASA, PPARC and ESA. We are grateful to the Hinode team for all their
efforts in the design, development and operation of the mission.
Title: An Observation Knowledgebase for Hinode Data
Authors: Hurlburt, Neal E.; Freeland, S.; Green, S.; Schiff, D.;
Seguin, R.; Slater, G.; Cirtain, J.
Bibcode: 2007AAS...210.7203H
Altcode: 2007BAAS...39..179H
We have developed a standards-based system for the Solar Optical and
X Ray Telescopes on the Hinode orbiting solar observatory which can
serve as part of a developing Heliophysics informatics system. Our
goal is to make the scientific data acquired by Hinode more accessible
and useful to scientists by allowing them to do reasoning and flexible
searches on observation metadata and to ask higher-level questions of
the system than previously allowed. The Hinode Observation Knowledgebase
relates the intentions and goals of the observation planners (as-planned
metadata) with actual observational data (as-run metadata), along with
connections to related models, data products and identified features
(follow-up metadata) through a citation system. Summaries of the data
(both as image thumbnails and short "film strips") serve to guide
researchers to the observations appropriate for their research, and
these are linked directly to the data catalog for easy extraction
and delivery. The semantic information of the observation
(Field of view, wavelength, type of observable, average cadence
etc.) is captured through simple user interfaces and encoded using
the VOEvent XML standard (with the addition of some solar-related
extensions). These interfaces merge metadata acquired automatically
during both mission planning and an data analysis (see Seguin
et. al. 2007 at this meeting) phases with that obtained directly
from the planner/analyst and send them to be incorporated into the
knowledgebase. The resulting information is automatically rendered
into standard categories based on planned and recent observations,
as well as by popularity and recommendations by the science team. They
are also directly searchable through both and web-based searches and
direct calls to the API. Observations details can also be rendered as
RSS, iTunes and Google Earth interfaces. The resulting system provides
a useful tool to researchers and can act as a demonstration for larger,
more complex systems.
Title: Testing the Validity of Bayesian Block Segmentation of Active
Region Light Curves Using High Cadence Soft X-ray Image Sequences
Authors: Slater, G.; Freeland, S.
Bibcode: 2006AGUFMSH23A0333S
Altcode:
Using GOES SXI image series with approximately two minute cadence,
we extract soft X-ray light curves for multiple active regions. From
these light curves we extract flare lists, including events to a lower
threshold than is possible with traditional GOES XRS time series. The
flare lists for each active region are used to segment the time series
for each region using the Bayesian Blocks technique. The validity of
the technique is then tested by examining the flare distributions with
each Bayesian block.
Title: CoSEC: Connecting Living With a Star Research
Authors: Hurlburt, N.; Freeland, S.; Bose, P.; Zimdars, A.; Slater, G.
Bibcode: 2006AGUFMSH11A0372H
Altcode:
The Collaborative Sun-Earth Connector (CoSEC) provide the means for
heliophysics researchers to compose the data sources and processing
services published by their peers into processing workflows that
reliably generate publication-worthy data. It includes: composition
of computational and data services into easy-to- read workflows with
data quality and version traceability; straightforward translation
of existing services into workflow components, and advertisement of
those components to other members of the CoSEC community; annotation
of published services with functional attributes to enable discovery
of capabilities required by particular workflows and identify peer
subgroups in the CoSEC community; and annotation of published services
with nonfunctional attributes to enable selection on the basis of
quality of service (QoS). We present an overview and demonstration
of the CoSEC system, discuss applications, the lessons learned and
future developments.
Title: Active Region Light Curves From Full Disk Solar Images
Authors: Slater, Gregory L.; Freeland, S. L.
Bibcode: 2006SPD....37.0813S
Altcode: 2006BAAS...38..232S
We have developed algorithms to extract the boundaries of active regions
from time series of full disk solar images and to associate the region
boundaries extracted from sequential images. Using these data, we have
constructed light curves for individual active regions in different
wavelengths. These light curves may be used to evaluate the brightness
fluctuation distributions of active regions in multiple wavelengths,
which in turn can be used for flare prediction, in particular by the
method of Wheatland. There are several advantages to using continuous
active region light curves rather then discrete time series of
"tagged" flares: the continuous light curves contain a more complete
history of the brightness fluctuation spectrum than discrete flare
lists; the individual light curves include fluctuations down to a
significantly lower intensity than flare lists; and since the method
may be readily applied to any full disk image archive, light curves
may be obtained from any number of wavelengths, and the differences in
active region brightness fluctuations across the various wavelengths
may be investigated. We present preliminary light curve databases
extracted from full disk image archives from GOES-12 SXI and SoHO EIT
(195 A), which were selected for their relatively high time cadence,
and we generate event statistics distributions from them which may be
used in Wheatland's event statistics method of flare prediction. The
technique should prove valuable for use with imagery from future solar
telescopes, such as the AIA suite aboard the Solar Dynamics Observatory,
which will provide continuous high cadence and high resolution full
disk images at multiple wavelengths.
Title: SolarSoft Web Services
Authors: Freeland, S.; Hurlburt, N.
Bibcode: 2005AGUFMIN31B1152F
Altcode:
The SolarSoft system (SSW) is a set of integrated software libraries,
databases, and system utilities which provide a common programming
and data analysis environment for solar physics. The system includes
contributions from a large community base, representing the efforts of
many NASA PI team MO&DA teams,spanning many years and multiple NASA
and international orbital and ground based missions. The SSW general use
libraries include Many hundreds of utilities which are instrument and
mission independent. A large subset are also SOLAR independent, such
as time conversions, digital detector cleanup, time series analysis,
mathematics, image display, WWW server communications and the like. PI
teams may draw on these general purpose libraries for analysis and
application development while concentrating efforts on instrument
specific calibration issues rather than reinvention of general use
software. By the same token, PI teams are encouraged to contribute
new applications or enhancements to existing utilities which may have
more general interest. Recent areas of intense evolution include space
weather applications, automated distributed data access and analysis,
interfaces with the ongoing Virtual Solar Observatory efforts, and
externalization of SolarSoft power through Web Services. We will
discuss the current status of SSW web services and demonstrate how
this facilitates accessing the underlying power of SolarSoft in more
abstract terms. In this context, we will describe the use of SSW
services within the Collaborative Sun Earth Connector environment.
Title: Using the Collaborative Sun-Earth Connector for integrating
data systems
Authors: Hurlburt, N.; Freeland, S.; Slater, G.; Bentley, R.; Hill,
F.; Bose, P.
Bibcode: 2005AGUSMSH43B..05H
Altcode:
We demonstrate the coupling of disjoint data systems into virtual
collaborative operations using the Collaborative Sun-Earth Connector
(CoSEC). In addition to demonstrating possible interactions between
Virtual observatories, we will present how individual missions and
researchers can integrate their systems with space science services
already incorporated into CoSEC. We present more advanced concepts of
how to create collaborative data environments using upcoming solar
missions as examples. This research has been supported through NASA
contract NNH04CC00C.
Title: Collaborative Virtual Observatories using CoSEC
Authors: Hurlburt, N.; Bose, P.; Freeland, S.; Woodward, M.; Slater, G.
Bibcode: 2004AAS...204.5208H
Altcode: 2004BAAS...36..755H
The ``Virtual Observatories" (VOs) movement is underway to organize
space science data into discipline-based VOs. These would provide
easy, online access to large volumes of data. We extend this idea to
include interactions between these VOs, creating collaborative virtual
observatories. The Collaborative Sun-Earth Connector (CoSEC) is used
as a test bed for this concept. We demonstrate possible interactions
between Virtual observatories by integrating the prototype Virtual Solar
Observatory (VSO) and European Grid of Solar Observations (EGSO) with
space science services already incorporated into CoSEC. In addition
we present more advanced concepts of how Collaborative Observatories
might increase the scientific productivity. This research has
been supported through NASA contract NNH04CC00C.
Title: Collaborative Observatories for ILWS
Authors: Hurlburt, N.; Bose, P.; Freeland, S.; Slater, G.; Woodward, M.
Bibcode: 2004cosp...35.3217H
Altcode: 2004cosp.meet.3217H
The success of the ILWS program depends upon the successful integration
of data from a wide variety of sources which span the heliosphere,
electromagnetic spectrum and physics. A motion is underway to
organize these data into discipline-based "Virtual Observatories"
(V0s), which would provide easy, online access to large volumes
of data. We extend this idea to include interactions between these
VOs,creating collaborative observatories. The Collaborative Sun-Earth
Connector (CoSEC) is used as a testbed for this concept. We demonstrate
possible interactions between Virtual observatories by integrating the
prototype Virtual Solar Observatory (VSO) and European Grid of SOlar
Obseravtions (EGSO) with space science services already incorporated
into CoSEC. In addition we present more advanced concepts of how
Collaborative Observatories might increase the scientific productivity
of the ILWS program. This research has been supported through NASA
contract NNH04CC00C.
Title: CoSEC: Coordinated Web Services and Infrastructure for Living
with a Star
Authors: Hurlburt, N.; Freeland, S.; Bose, P.; Woodward, M.
Bibcode: 2003SPD....34.0309H
Altcode: 2003BAAS...35..809H
The Collaborative Sun-Earth Connector (CoSEC) will offer a testbed
for developing and deploying data and modeling services for the space
science community. We will demonstrate the concept using the current
prototype, www.lmsal.com/cosec, and offer templates and tools for
expanding the prototype with existing space science data and models
using the SolarSoft framework. In addition we will discuss how CoSEC
to relates to other projects, including the Virtual Solar Observatory
and the European Grid of Solar Observations. This research has
been supported through NASA grant NAG5-10784.
Title: The Collaborative Sun-Earth Connector
Authors: Hurlburt, N.; Freeland, S.; Bose, P.
Bibcode: 2002AGUFMSH51A0420H
Altcode:
The Collaborative Sun-Earth Connector fuses data from a variety of
instruments, including images, spectra and in situ measurements,
to unveil the essential elements of space weather. We demonstrate
a prototype system for such coordinated, distributed data analysis
based upon software agent technologies and SolarSoft (Freeland
and Handy 1998). Researchers use the system to develop process maps
which merge distributed data archives and servers into a virtual data
analysis system. Sophisticated image and time-series processing can be
coordinated between data centers while minimizing the amount of data
transferred between them and optimizing the delivery of pertinent
and refined data to the requestor. We describe how CoSEC relates to
and can leverage related efforts from the Virtual Solar Observatory
and the European Grid of Solar Observatories and examine how it can
transition to a comprehensive data analysis system for upcoming LWS
and SEC missions. Freeland, S. and Handy, B., 1998 Sol. Phys. 182,497
This research is funded by NASA through grant NAG5-10784.
Title: TRACE, SOHO/EIT, and SOHO/MDI Observations of AR0030, Including
Rotating Sunspots and the July 15, 2002 X3.0 Flare in Ultraviolet
and Extreme Ultraviolet
Authors: Nightingale, R. W.; Shine, R. A.; Alexander, D.; Freeland,
S. L.; Frank, Z. A.; Brown, D. S.
Bibcode: 2002AGUFMSH52A0467N
Altcode:
On July 15, 2002 TRACE and several SOHO instruments observed an X3.0
flare in AR0030 near 2000 UT. During this period TRACE was primarily
observing in its 1600Å ultraviolet (UV) channel (most sensitive
to temperatures around 100,000 K in the flare). The 195Å extreme
ultraviolet (EUV) channel of SOHO/EIT (which is most sensitive to about
1.6 MK) will be utilized in this poster, in addition to the magnetic
field measurements of SOHO/MDI during this event period. TRACE followed
the active region for over 10 days, starting about 4 days before the
flare. Broadband white light TRACE images of the photosphere indicate
that one or more of the sunspots were rotating, a possible precursor to
the flare. Images and movies of AR0030 in the various wavelengths will
be shown. The flare region was so intense in the TRACE UV that it is
very difficult to show both the quiescent and flaring regions, so the UV
movie will focus on the flaring plasma with its 2 eruptions. In the EIT
EUV, more coronal structure away from the flare can be seen. Analysis
of the rotational rates of the sunspots will be given along with their
possible coupling to the flare. This work was supported by NASA under
contract NAS5-38099.
Title: Semantic Composition of Distributed Solar Data and Analysis
Services For Coordinated E-Science
Authors: Hurlburt, N. E.; Freeland, S.; Bose, P.; Woodward, M.
Bibcode: 2002AAS...200.6002H
Altcode: 2002BAAS...34..742H
The success of NASA's Living with a Star Program depends upon
coordinated, distributed data systems which share many features with
the Virtual Observatory. Data from a variety of instruments including
images, spectra and in situ measurements must be fused to unveil the
complexities of space weather. We demonstrate a prototype system for
such coordinated, distributed data analysis based upon software agents
technologies and SolarSoft (Freeland and Handy 1998). Researchers use
the system to develop process maps which merge distributed data archives
and servers into a virtual data analysis system. Sophisticated image and
time-series processing can be coordinated between data centers while
minimizing the amount of data transferred between them and optimizing
the delivery of pertinent and refined data to the requestor. Freeland,
S. and Handy, B., 1998 Sol. Phys. 182,497
Title: The Yohkoh Public Outreach Project
Authors: Larson, M. B.; Slater, T.; McKenzie, D.; Acton, L.; Alexander,
D.; Lemen, J.; Freeland, S.; Metcalf, T.
Bibcode: 2002mwoc.conf..117L
Altcode:
The NASA funded Yohkoh Public Outreach Project (YPOP) began in 1995
with the goal of providing public access to high quality Yohkoh
SXT data via the World Wide Web. The project utilizes the intrinsic
excitement of the SXT data, and in particular the SXT movies, to develop
science learning tools and classroom activities. The WWW site at URL:
http://www.lmsal.com/YPOP/ uses a movie theater theme to highlight
available Yohkoh movies in a format that is entertaining and inviting
to non-scientists and well received by scientists. We will discuss
the wide range of people YPOP has reached over the past six years,
as well as lessons learned during the development of the project.
Title: The Yohkoh Public Outreach Project: A Space Science Resource
for Formal and Informal Education
Authors: Lemen, J. R.; Alexander, D.; Metcalf, T. R.; Freeland, S. L.;
Acton, L. W.; Larson, M.; McKenzie, D.; Slater, T.
Bibcode: 2001AGUFMED12A0160L
Altcode:
The Yohkoh Public Outreach Project (YPOP) is a NASA-funded web site
maintained by scientists and educators at Lockheed Martin Solar and
Astrophysics Lab. and Montana State University. YPOP includes a range
of activities for youngsters, parents, teachers and anyone interested
in learning more about the Sun. YPOP utilizes a number of approaches
to the dissemination of solar data which incorporates elements of both
formaleducation, via a number of lesson plans and classroom activities,
and informal education, via access to the latest solar images, a
solar tour, and updated movies. This combination has proved extremely
effective in providing quality access to scientific data for a broad
audience with a wide range of interests. The Yohkoh Public Outreach
Project can be found at http://www.LMSAL.com/YPOP.
Title: A Prototype Problem-Solving Environment for Living With a
Star Data
Authors: Hurlburt, N.; Freeland, S.; Shine, R.; Bose, P.
Bibcode: 2001AGUFMSH31A0702H
Altcode:
The Living With a Star program aims to understanding our space
environment as a unified system. For this approach to be successful,
the scientific working environment must present the LWS components
as a unified whole. We present an architecture and data assimilation
environment which addresses this critical issue. The goal of our
Problem-Solving Environment for Living With a Star (PSELWS) project is
to place the users of the data at center stage -- providing a virtual
workbench with the tools, and infrastructure needed for seamless,
timely and efficient access to the various data sources.
Title: Automated Search for Limb-Occulted Flares
Authors: Freeland, S.; Hudson, H.
Bibcode: 2001AGUSM..SP51A07F
Altcode:
Limb-occulted flares give instruments with limited spatial resolution
or limited dynamic range an opportunity to study coronal processes
without the competition of bright sources in the lower atmosphere,
for example at the footpoints of coronal loops. We have created an
automated search procedure for Yohkoh soft X-ray and hard X-ray data
and have tested it for the 1999 data, finding a total of 59 candidate
events that occurred quite near the limb. The procedure produces a Web
page for each candidate event, including images and lightcurves plus a
set of parameters intended to guide the distinction between front-side
and back-side events. The initial application of the search will be
to develop a comprehensive list of coronal hard X-ray events from the
first 11 years of Yohkoh observations.
Title: SolarSoft
Authors: Freeland, S.; Bentley, R.
Bibcode: 2000eaa..bookE3390F
Altcode:
The SolarSoft system (SSW) is a set of integrated software libraries,
databases, and system utilities which provide a common programming
and data analysis environment for solar physics. The SolarSoft
environment provides a consistent look and feel at widely distributed
co-investigator institutions to facilitate data exchange and to
stimulate coordinated analysis. Commonalities and overlap in sola...
Title: Evolution of the Solar Corona From Cycle 22 to Cycle 23 As
Revealed by X-ray Limb Synoptic Maps
Authors: Slater, G. L.; Freeland, S. L.; LaBonte, B. J.; Li, J.;
Acton, L. W.
Bibcode: 2000SPD....31.0228S
Altcode: 2000BAAS...32..815S
How does the solar corona vary within a solar cycle? We present time
series observations assembled from the Yohkoh Soft X-ray Telescope
(SXT) full mission image database which reveal coronal structures in the
inner corona that are not easily identifiable in individual images. We
have generated limb synoptic maps prepared from SXT data taken over
8 years (1992 through 1999). This period covers the decay phase of
solar cycle 22 and the rise phase of solar cycle 23. The SXT images
have recently been re-calibrated using more precise techniques. We
will address such topics as the variation of the polar coronal holes,
the lifetimes of active regions and associated streamers, and the
nature of polar plumes in the two phases of the solar cycle.
Title: The transition region and coronal explorer
Authors: Handy, B. N.; Acton, L. W.; Kankelborg, C. C.; Wolfson, C. J.;
Akin, D. J.; Bruner, M. E.; Caravalho, R.; Catura, R. C.; Chevalier,
R.; Duncan, D. W.; Edwards, C. G.; Feinstein, C. N.; Freeland, S. L.;
Friedlaender, F. M.; Hoffmann, C. H.; Hurlburt, N. E.; Jurcevich,
B. K.; Katz, N. L.; Kelly, G. A.; Lemen, J. R.; Levay, M.; Lindgren,
R. W.; Mathur, D. P.; Meyer, S. B.; Morrison, S. J.; Morrison, M. D.;
Nightingale, R. W.; Pope, T. P.; Rehse, R. A.; Schrijver, C. J.;
Shine, R. A.; Shing, L.; Strong, K. T.; Tarbell, T. D.; Title, A. M.;
Torgerson, D. D.; Golub, L.; Bookbinder, J. A.; Caldwell, D.; Cheimets,
P. N.; Davis, W. N.; Deluca, E. E.; McMullen, R. A.; Warren, H. P.;
Amato, D.; Fisher, R.; Maldonado, H.; Parkinson, C.
Bibcode: 1999SoPh..187..229H
Altcode:
The Transition Region and Coronal Explorer (TRACE) satellite, launched
2 April 1998, is a NASA Small Explorer (SMEX) that images the solar
photosphere, transition region and corona with unprecedented spatial
resolution and temporal continuity. To provide continuous coverage
of solar phenomena, TRACE is located in a sun-synchronous polar
orbit. The ∼700 Mbytes of data which are collected daily are made
available for unrestricted use within a few days of observation. The
instrument features a 30-cm Cassegrain telescope with a field of view
of 8.5×.5 arc min and a spatial resolution of 1 arc sec (0.5 arc sec
pixels). TRACE contains multilayer optics and a lumogen-coated CCD
detector to record three EUV wavelengths and several UV wavelengths. It
observes plasmas at selected temperatures from 6000 K to 10 MK with
a typical temporal resolution of less than 1 min.
Title: Making YOHKOH SXT Images Available to the Public: The YOHKOH
Public Outreach Project
Authors: Larson, M. B.; McKenzie, D.; Slater, T.; Acton, L.; Alexander,
D.; Freeland, S.; Lemen, J.; Metcalf, T.
Bibcode: 1999AAS...194.7024L
Altcode: 1999BAAS...31..941L
The NASA funded Yohkoh Public Outreach Project (YPOP) provides public
access to high quality Yohkoh SXT data via the World Wide Web. The
products of this effort are available to the scientific research
community, K-12 schools, and informal education centers including
planetaria, museums, and libraries. The project utilizes the intrinsic
excitement of the SXT data, and in particular the SXT movies, to develop
science learning tools and classroom activities. The WWW site at URL:
http://solar.physics.montana.edu/YPOP/ uses a movie theater theme to
highlight available Yohkoh movies in a format that is entertaining and
inviting to non-scientists. The site features informational tours of
the Sun as a star, the solar magnetic field, the internal structure
and the Sun's general features. The on-line Solar Classroom has proven
very popular, showcasing hand-on activities about image filtering,
the solar cycle, satellite orbits, image processing, construction of a
model Yohkoh satellite, solar rotation, measuring sunspots and building
a portable sundial. The YPOP Guestbook has been helpful in evaluating
the usefulness of the site with over 300 detailed comments to date.
Title: Observations of Coronal Structures Above an Active Region by
EIT and Implications for Coronal Energy Deposition
Authors: Neupert, W. M.; Newmark, J.; Delaboudinière, J. -P.;
Thompson, B. J.; Catura, R. C.; Moses, J. D.; Gurman, J. B.;
Portier-Fozzani, F.; Gabriel, A. H.; Artzner, G.; Clette, F.; Cugnon,
P.; Maucherat, A. J.; Defise, J. M.; Jamar, C.; Rochus, P.; Dere,
K. P.; Howard, R. A.; Michels, D. J.; Freeland, S.; Lemen, J. R.;
Stern, R. A.
Bibcode: 1998SoPh..183..305N
Altcode:
Solar EUV images recorded by the EUV Imaging Telescope (EIT) on SOHO
have been used to evaluate temperature and density as a function of
position in two largescale features in the corona observed in the
temperature range of 1.0-2.0 MK. Such observations permit estimates
of longitudinal temperature gradients (if present) in the corona and,
consequently, estimates of thermal conduction and radiative losses
as a function of position in the features. We examine two relatively
cool features as recorded in EIT's Fe ix/x (171 Å) and Fe xii (195 Å)
bands in a decaying active region. The first is a long-lived loop-like
feature with one leg, ending in the active region, much more prominent
than one or more distant footpoints assumed to be rooted in regions of
weakly enhanced field. The other is a near-radial feature, observed
at the West limb, which may be either the base of a very high loop
or the base of a helmet streamer. We evaluate energy requirements to
support a steady-state energy balance in these features and find in
both instances that downward thermal conductive losses (at heights
above the transition region) are inadequate to support local radiative
losses, which are the predominant loss mechanism. The requirement that a
coronal energy deposition rate proportional to the square of the ambient
electron density (or pressure) is present in these cool coronal features
provides an additional constraint on coronal heating mechanisms.
Title: Data Analysis with the SolarSoft System
Authors: Freeland, S. L.; Handy, B. N.
Bibcode: 1998SoPh..182..497F
Altcode:
The SolarSoftWare (SSW) system is a set of integrated software
libraries, databases and system utilities which provide a common
programming and data analysis environment for solar physics. Primarily
an IDL based system, SSW is a collection of common data management
and analysis routines derived from the Yohkoh and SOHO missions,
the Solar Data Analysis Center, the astronomy libraries and other
packages. The SSW environment is designed to provide a consistent look
and feel at co-investigator institutions and facilitate sharing and
exchange of data. The SSW system minimizes the learning curve when
doing research away from the home institution or when correlating
results from multiple experiments.
Title: SOLARSOFT - an Analysis Environment for Solar Physics
Authors: Bentely, R. D.; Freeland, S. L.
Bibcode: 1998ESASP.417..225B
Altcode: 1998cesh.conf..225B
No abstract at ADS
Title: Movies of flares observed by YOHKOH/HXT
Authors: Lemen, J. R.; Alexander, D.; Metcalf, T. R.; Freeland, S. L.;
Nitta, N.
Bibcode: 1997SPD....28.0169L
Altcode: 1997BAAS...29..892L
The Yohkoh Hard X-ray Telescope (HXT) has revealed new information
about solar flares by providing high spatial resolution (5 arcsec)
images in four energy bands covering 14 to 99 keV. The comparison of
images obtained in hard X-rays with those obtained with the Yohkoh Soft
X-ray Telescope (SXT) has led to important interpretations of flare
heating mechanisms (e.g., Masuda et al, 1994, Nature, 374, 495). The
HXT images are formed by reconstructing data obtained from 64 detectors
located behind a bi-grid modulation pattern. Reconstruction algorithms
using Maximum Entropy and PIXON methods have been successfully applied
to the HXT data (Alexander and Metcalf, 1997, ApJ, submitted). At the
recent HXT Coordinated Data Analysis Workshop held in January 1997, new
calibration data for the response of the grids were incorporated and an
error in the application of the reconstruction algorithms was identified
and corrected (see Kosugi et al 1997 in these proceedings). As a result,
it is now possible to reconstruct the HXT images semi-automatically to
produce quick-look movies. We are in the process of generating movies
for all flares obtained with the HXT using an MEM reconstruction. The
automated procedure selects time intervals on the basis of the count
rate statistics. We present a selection of reconstructed images and
movies from this on-going project. We expect that the ability to view
easily time sequences from many flares observed with the HXT will
provide new insights for flare studies.
Title: Using the WWW to Make YOHKOH SXT Images Available to the
Public: The YOHKOH Public Outreach Project
Authors: Larson, M.; McKenzie, D.; Slater, T.; Acton, L.; Alexander,
D.; Freeland, S.; Lemen, J.; Metcalf, T.
Bibcode: 1997SPD....28.0231L
Altcode: 1997BAAS...29..898L
The Yohkoh Public Outreach Project (YPOP) is funded by NASA as one of
the Information Infrastructure Technology and Applications Cooperative
Agreement Teams to create public access to high quality Yohkoh SXT data
via the World Wide Web. These products are being made available to the
scientific research community, K-12 schools, and informal education
centers including planetaria, museums, and libraries. The project aims
to utilize the intrinsic excitement of the SXT data, and in particular
the SXT movies, to develop science learning tools and classroom
activities. The WWW site at URL: http://www.space.lockheed.com/YPOP/
uses a movie theater theme to highlight available Yohkoh movies in a
non-intimidating and entertaining format for non-scientists. The site
features lesson plans, 'solar' activities, slide shows and, of course,
a variety of movies about the Sun. Classroom activities are currently
undergoing development with a team of scientists and K-12 teachers
for distribution in late 1997. We will display the products currently
online, which include a solar classroom with activities for teachers,
background resources, and a virtual tour of our Sun.
Title: Automated He II 304A Limb Feature Detection
Authors: Freeland, S. L.; Slater, G. L.; Lemen, J. R.
Bibcode: 1997SPD....28.0220F
Altcode: 1997BAAS...29..896F
We describe algorithms and software designed to automatically identify,
catalog, and extract the prominence features from cleaned, full disk
He II 304A images of the solar atmosphere recorded by the The Extreme
Ultraviolet Imaging Telescope (EIT) aboard the Solar and Heliospheric
Observatory (SoHO). Sequences of partial frame images extracted in
this manner will be presented, together with parameters automatically
derived from the data, such as limb location, 'center of mass' location,
and apparent radial velocity of the features. It has been observed that
limb prominences show up exceptionally well in the 304A images, which
therefore provide excellent candidates for automated feature recognition
software. Specifically, these 'above the limb' prominence features
are highly contrasted with the surrounding pixels in individual 304A
images. When assembled into three dimensional data cubes, the growth,
shrinkage, and possible eruption of prominences are identifiable with
software. Moreover, for events identified as eruptive, the 304A signal
might provide a valuable proxy to identify and extract corresponding
events in less "well behaved" data sets, including those of EIT at
other wavelengths, Yohkoh/SXT, and SOHO/LASCO. The software design
permits near real time execution in anticipation that identification
of eruptive prominence events will provide some future predictive or
automated notification value. To optimize use of existing software
capabilities and to facilitate cross reference with other data
sets, we use the SolarSoft system as our development environment [
http://www.space.lockheed.com/solarsoft/ ].
Title: Observations of Coronal Features by EIT above an Active Region
by EIT and Implications for Coronal Heating
Authors: Neupert, W. M.; Newmark, J.; Thompson, B. J.; Catura, R.;
Moses, J. D.; Portier-Fozzani, F.; Delaboudiniere, J. P.; Gabriel, A.;
Artzner, G.; Clette, F.; Cugnon, P.; Maucherat, A.; Defise, J. M.;
Jamar, C.; Rochus, P.; Howard, R.; Michels, D.; Dere, K.; Freeland,
S.; Lemen, J.; Stern, R.; Gurman, J.
Bibcode: 1997SPD....28.0115N
Altcode: 1997BAAS...29..881N
The EUV Imaging Telescope (EIT) on the SOHO provides the capability
for multi-wavelength imaging of the corona in four spectral bands,
centered at 171, 195, 284, and 304 Angstroms, using multilayer telescope
technology. These bands encompass coronal temperatures from 1 MK
to 2.5 MK as well as the upper chromosphere, at about 60,000 K. In
particular, nearly simultaneous imaging in the 171 and 195 Angstrom
bands, the former including major Fe IX and Fe X emission lines, the
latter including a strong Fe XII line, provides a capability to infer
the morphology and characteristics of the corona at temperatures of
1.0 - 1.7 MK. We have examined the corona in this temperature range
over an active region observed from SOHO from May - September, 1996 and
find that low-lying loops (below a density scale height of 75,000 km,
characteristic of Fe X) vary little in brightness and temperature along
their length. For features extending to greater heights, however, both
brightness gradients and temperature gradients are observed. Preliminary
analysis of the observations when the region was on the West limb
on September 30 indicates a small positive temperature gradient of
approximately 0.5 K/km in one loop system that extended above 100,000
km. On the other hand, a nearly radial feature extending to the edge of
the EIT FOV was isothermal or had at most a slight negative temperature
gradient. Such measurements may have application to the modeling of
coronal loops and streamers and the processes of coronal heating and
solar wind acceleration.
Title: Using the World Wide Web to Make YOHKOH SXT Images Available
to the Public: The YOHKOH Public Outreach Project
Authors: McKenzie, D.; Larson, M. B.; Slater, T.; Acton, L.; Alexander,
D.; Freeland, S.; Lemen, J.; Metcalf, T.
Bibcode: 1997ESASP.404..561M
Altcode: 1997cswn.conf..561M
No abstract at ADS
Title: A Long-Duration Solar Flare with Mass Ejection and Global
Consequences
Authors: Hudson, H. S.; Acton, L. W.; Freeland, S. L.
Bibcode: 1996ApJ...470..629H
Altcode:
We report observations of a long-duration flare with mass ejection
from the corona, using the Yohkoh soft X-ray telescope (SXT). This
flare occurred 1994 November 13 near disk center during quiet solar
conditions, with excellent temporal coverage of both the core activity
in the active region itself and of the global corona. The initial
X-ray images reveal two arcades of cusped magnetic loops, connected
via a series of thin loops. These loops rise rapidly during the
increasing phase of soft X-ray flare brightness. In its final state,
the flare has the configuration of postflare loops with a cusp. Large
regions of the X-ray corona appear to empty during the evolution of the
event. We suggest that this corresponds a coronal mass ejection (CME)
seen in soft X-rays. Its detection in the SXT images is consistent with
the finding that material participating in a CME exists at elevated
coronal temperatures (2.8 x 106 K in this case) before
the ejection. We estimate a mass >4 x 1014 g for the
ejected material. The X-ray morphology of the event has strong points
of similarity with the classical reconnection picture of long-duration
event (LDE) formation, but there are significant discrepancies: there
is no observed inward flow during the rise phase, the expansions are
multiple and appear to be nonradial, and none of the observed motions
suggest a reconnection jet. We note the subsequent occurrence of very
large scale coronal disturbances, including regions near the boundaries
of coronal holes at both poles. We suggest that this global disturbance
implies a perturbation reaching as far outward as the heliospheric
neutral sheet. The exciter would require a horizontal velocity of
approximately 200 km s-1 in such a case, consistent with
the projected velocity of the plasma cloud that we identify with a
CME in the process of launching.
Title: Yohkoh/SXT soft x-ray observations of sudden mass loss from
the solar corona
Authors: Hudson, H. S.; Acton, L. W.; Alexander, D.; Freeland, S. L.;
Lemen, J. R.; Harvey, K. L.
Bibcode: 1996AIPC..382...88H
Altcode:
With soft X-ray imaging we can study the entire coronal volume, except
for cold inclusions such as prominences, as a function of time. This
should allow us to observe the origins of coronal mass ejections. We
report here an initial survey of the Yohkoh/SXT observations at the
times of reported or apparent mass ejections: three LDE flare events
and two large-scale arcade formations. For each of the events we
can easily detect sudden coronal dimming, which we interpret as the
launch interval of a CME. In one of the flare events we have found
a well-defined plasma cloud, apparently formed from a set of loop
structures, which rises and disappears during the growth phase of the
flare emission. Its mass amounted to some 4×1014 g with
a density of 3×108 cm-3 and a temperature of
2.8 MK before its disappearance.
Title: Observations of the South coronal hole from EIT and YOHKOH
Authors: Handy, B. N.; Catura, R.; Freeland, S.; Lemen, J.; Stern,
R.; Gurman, J. B.; Delaboudiniere, J. P.; Artzner, G.; Gabriel, A.;
Maucherat, A.; Defise, J. M.; Jamar, C.; Rochus, P.; Clette, F.;
Cugnon, P.; Howard, R.; Michels, D.; Moses, J. D.; Dere, K.; Cyr,
O. C. St.; Catura, R.; Freeland, S.; Lemen, J.; Stern, R.; Neupert,
W.; Einfalt, E.; Newmark, J.
Bibcode: 1996AAS...188.0206H
Altcode: 1996BAAS...28..821H
The Extreme ultraviolet Imaging Telescope (EIT) on board the
SOHO spacecraft is capable of studying solar transition region,
chomospheric and coronal plasmas over bandpasses optimized for He II
304 Angstroms (0.08 MK), Fe IX/X 171, 173 Angstroms (0.8 - 1.0 MK),
Fe XII 195 Angstroms (1.5 MK), and Fe XV 284 Angstroms (2.0 - 2.5
MK) with 2.5 arcsecond spatial resolution. This telescope in concert
with the Yohkoh/SXT instrument allows us to simultaneously observe
solar structures at temperatures ranging from less than 0.1MK in the
transition region to over 3MK in the solar corona. EIT has had several
opportunities to observe the South coronal hole with high spatial and
temporal resolution. We compare observations from EIT and SXT with
an eye towards correlating temporal variations over the range of
wavelengths, activity of polar crown filament systems and relating
large-scale morphology of the X-ray corona to the transition region
in He II.
Title: There's No Such Thing as the Quiet Sun: EUV Movies from SOHO
Authors: Gurman, J. B.; Delaboudiniere, J. P.; Artzner, G.; Gabriel,
A.; Maucherat, A.; Defise, J. M.; Jamar, C.; Rochus, P.; Clette, F.;
Cugnon, P.; Howard, R.; Michels, D.; Moses, J. D.; Dere, K.; Cyr,
O. C. St.; Catura, R.; Freeland, S.; Lemen, J.; Stern, R.; Neupert,
W.; Einfalt, E.; Newmark, J.
Bibcode: 1996AAS...188.3718G
Altcode: 1996BAAS...28..880G
We present unique time series of high-resolution solar images from the
normal-incidence Extreme ultraviolet Imaging Telescope (EIT) on board
the SOHO spacecraft. With a pixel scale of 2.6 arc sec and a detector
dynamic range of > 10(4) , the EIT can be used to study the dynamics
of chromospheric and coronal features in multilayer bandpasses optimized
for He II 304 Angstroms (0.08 MK), Fe IX/X 171, 173 Angstroms (0.8 -
1.0 MK), Fe XII 195 Angstroms (1.5 MK), and Fe XV 284 Angstroms (2.0 -
2.5 MK). Among the most striking features of the digital movies we will
display are: the dynamic nature of small-scale loop features in the
polar coronal holes, the constant activity of the polar crown filament
systems, the locations of the bases of polar plumes, the presence
of dark (scattering) filament material in the coronal emission line
images, and the evolution of a unique, linear, dark feature in a young
active region. The latter feature is suggestive of the ``coronal void''
observed in the electron scattering corona by Macqueen et al./ (1983).
Title: Observations of the south coronal hole from EIT and Yohkoh.
Authors: Handy, B. N.; Catura, R.; Freeland, S.; Lemen, J.; Stern,
R.; Gurman, J. B.; Delaboudinière, J. P.; Artzner, G.; Gabriel,
A.; Maucherat, A.; Defise, J. M.; Jamar, C.; Rochus, P.; Clette, F.;
Cugnon, P.; Howard, R.; Michels, D.; Moses, J. D.; Dere, K.; St. Cyr,
O. C.; Neupert, W.; Einfalt, E.; Newmark, J.
Bibcode: 1996BAAS...28Q.821H
Altcode:
No abstract at ADS
Title: Yohkoh/SXT soft x-ray observations of sudden mass loss from
the solar corona
Authors: Hudson, H. S.; Acton, L. W.; Alexander, D.; Freeland, S. L.;
Lemen, J. R.; Harvey, K. L.
Bibcode: 1995sowi.confR..58H
Altcode:
Direct X-ray observations allow us to estimate the hot coronal mass
before and after a flare or other disturbance of the type leading to
a coronal mass ejection. The sudden disappearance of a large coronal
structure (scale greater than 105 km) gives evidence that an ejection
has occurred, if the time scales are much shorter than the conductive
or radiative cooling times for such structures. A flare also typically
adds large amounts of new material to the corona via evaporation
resulting from the coronal energy release. This provides a competing
mechanism that makes the estimation of the total mass loss somewhat
difficult. We note that the X-ray observations have the advantage of
covering the entire corona rather than the limb regions unlike the
coronagraph observations. We have identified two examples of coronal
mass disappearances. before and during long duration flare events on
21 Feb. 1992 (on the E limb) and 13 Nov. 1994 (near disk center). In
latter case the total mass amounted to some 4 x 1014 g with a
density of 3 x 108cm-3 and a temperature of 2.8 MK
before its disappearance. This corresponds to a radiative cooling time
of some 104 S. much longer than the observed time of disappearance. We
therefore suggest that these sudden mass disappearances correspond with
coronal mass ejections (CMEs), and suggest that further data analysis
will be able to confirm this by comparison with optical observations
of specific CMEs.
Title: Inference of 3-dimensional structure underlying large-scale
coronal events observed by YOHKOH and ULYSSES
Authors: Slater, G. L.; Freeland, S. L.; Hoeksema, T.; Zhao, X.;
Hudson, H. S.
Bibcode: 1995sowi.confQ..63S
Altcode:
The Yohkoh/SXT images provide full-disk coverage of the solar corona,
usually extending before and after one of the large-scale eruptive
events that occur in the polar crown These produce large arcades of
X-ray loops, often with a cusp-shaped coronal extension, and are known
to be associated with coronal mass ejections. The Yohkoh prototype of
such events occurred 12 Nov. 1991. This allows us to determine heights
from the apparent rotation rates of these structures. In comparison v
with magnetic-field extrapolations from Wilcox Solar Observatory. use
use this tool to infer the three dimensional structure of the corona
in particular cases: 24 Jan. 1992, 24 Feb. 1993, 14 Apr. 1994, and 13
Nov. 1994. The last event is a long-duration flare event.
Title: Hα surges and associated Soft X-ray loops
Authors: Schmieder, B.; Shibata, K.; van Driel-Gesztelyi, L.;
Freeland, S.
Bibcode: 1995SoPh..156..245S
Altcode:
A recurrent Hα surge was observed on 7 October, 1991 on the western
solar limb with the Meudon MSDP spectrograph. The GOES satellite
recorded X-ray subflares coincident with all three events. During
two of the surges high-resolutionYohkoh Soft X-ray Telescope (SXT)
images have been taken. Low X-ray loops overlying the active region
where the surges occurred were continuously restructuring. A flare
loop appeared at the onset of each surge event and somewhat separated
from the footpoint of the surge. The loops are interpreted as causally
related to the surges. It is suggested that surges are due to magnetic
reconnection between a twisted cool loop and open field lines. Cold
plasma bubbles or jets squeezed among untwisting magnetic field
lines could correspond to the surge material. No detection was made
of either X-ray emission along the path of the surges or X-ray jets,
possibly because of the finite detection threshold of theYohkoh SXT.
Title: Eclipses of the solar X-ray corona by Mercury and the Moon.
Authors: Hudson, H.; Freeland, S.; Lemen, J.; Kosugi, T.; Soma, M.;
Watanabe, T.; Hara, H.; Shimizu, T.
Bibcode: 1994BAAS...26..795H
Altcode:
No abstract at ADS
Title: The Yohkoh Software and Database System
Authors: Morrison, M. D.; Freeland, S. L.; Lemen, J. R.; Acton, L. W.;
Bentley, R. D.
Bibcode: 1993BAAS...25R1188M
Altcode:
No abstract at ADS
Title: Yohkoh-SXT Observations from the Spartan and Nixt Max91
Campaign
Authors: Morrison, M.; Bruner, M.; Freeland, S.; Lemen, J.; Linford,
G.; Nitta, N.; Slater, G.; Strong, K.; Hara, H.; Kano, R.; Shimizu,
T.; Tsuneta, S.; Hudson, H.; Ogawara, Y.; Kosugi, T.; Sakao, T.;
Watanabe, T.; Takeda, A.; Acton, L.
Bibcode: 1993BAAS...25.1213M
Altcode:
No abstract at ADS
Title: The Soft X-ray Telescope for the SOLAR-A mission
Authors: Tsuneta, S.; Acton, L.; Bruner, M.; Lemen, J.; Brown, W.;
Caravalho, R.; Catura, R.; Freeland, S.; Jurcevich, B.; Morrison,
M.; Ogawara, Y.; Hirayama, T.; Owens, J.
Bibcode: 1991SoPh..136...37T
Altcode:
The Soft X-ray Telescope (SXT) of the SOLAR-A mission is designed
to produce X-ray movies of flares with excellent angular and time
resolution as well as full-disk X-ray images for general studies. A
selection of thin metal filters provide a measure of temperature
discrimination and aid in obtaining the wide dynamic range required for
solar observing. The co-aligned SXT aspect telescope will yield optical
images for aspect reference, white-light flare and sunspot studies,
and, possibly, helioseismology. This paper describes the capabilities
and characteristics of the SXT for scientific observing.
Title: Impulsive Phase Soft X-Ray Blueshifts at a Loop Footpoint
Authors: Zarro, Dominic M.; Slater, Gregory L.; Freeland, Samuel L.
Bibcode: 1988ApJ...333L..99Z
Altcode:
Solar Maximum Mission (SMM) observations of a solar flare that occurred
on May 24, 1987 are described. The event was noteworthy in that it was
observed during the impulsive phase with the SMM X-ray Poly-chromator
(XRP) pointed at a location associated with the chromospheric footpoints
of a system of coronal loops. Density-sensitive line ratios at the
flare site imply an initially large electron density of 5 x 10 to
the 12th/cu cm, which decreased an order of magnitude during the
flare. Spectral scans of the soft X-ray Mg XI line at the site reveal
asymmetric blueshifted (200 km/s) profiles concurrent with impulsive
hard X-ray emission. The blueshift amplitude was correlated with
the intensity of hard X-rays (with a phase delay of about 30 s) and
showed fluctuations on a time scale comparable with the variation of
hard X-ray emission. These observations are interpreted as evidence
for chromospheric evaporation produced by heating and expansion of
footpoint plasma.
Title: SMM X-ray polychromator
Authors: Strong, Keith T.; Haisch, Bernhard M.; Lemen, James R.;
Acton, L. W.; Bawa, H. S.; Claflin, E. S.; Freeland, S. L.; Slater,
G. L.; Kemp, D. L.; Linford, G. A.
Bibcode: 1988lock.reptR....S
Altcode:
The range of observing and analysis programs accomplished with the
X-Ray Polychromator (XRP) instruments during the decline of solar
cycle 21 and the rise of the solar cycle 22 is summarized. Section
2 describes XRP operations and current status. This is meant as
a guide on how the instrument is used to obtain data and what its
capabilities are for potential users. The science section contains
a series of representative abstracts from recently published papers
on major XRP science topics. It is not meant to be a complete list
but illustrates the type of science that can come from the analysis
of the XRP data. There then follows a series of appendixes that
summarize the major data bases that are available. Appendix A is a
complete bibliography of papers and presentations produced using XRP
data. Appendix B lists all the spectroscopic data accumulated by the
Flat Crystal Spectrometer (FCS). Appendix C is a compilation of the
XRP flare catalogue for events equivalent to a GOES C-level flare or
greater. It lists the start, peak and end times as well as the peak
Ca XIX flux.
Title: Recent Solar Observations from the X-Ray Polychromator on
the Repaired SMM Satellite
Authors: Saba, J. L. R.; Slater, G. L.; Levay, M. X.; Smith, K. L.;
Strong, K. T.; Bentley, R. D.; Lemen, J. R.; Caffey, R. R.; Freeland,
S. L., Jr.; Mathur, D. P.; Phillips, K. J. H.; Waters, T. A.
Bibcode: 1984BAAS...16..726S
Altcode:
No abstract at ADS