Author name code: hick
ADS astronomy entries on 2022-09-14
author:"Hick, P. Paul"
------------------------------------------------------------------------
Title: ASHI, an All Sky Heliospheric Imager Designed to Maximize
the Scientific Return from Structures Passing the Spacecraft
Authors: Jackson, Bernard; Buffington, Andrew; Bracamontes, Matthew;
Cota, Lucas; Volkow, Stuart; Hick, P.; Kahler, Stephen; Stephan, Ed;
Leblanc, Philippe; Quillin, Ron; Bisi, Mario
Bibcode: 2021AGUFMSH45E2407J
Altcode:
We have conceived, designed, and evaluated components for an All-Sky
Heliospheric Imager (ASHI), suitable for flight on future space
missions. ASHI is currently manifested on a DoD Space Test Program
ESPA ring in geosynchronous orbit where high satellite communication
downlink rates are relatively easy to provide. As a simple, light
weight (<5kg), and relatively inexpensive instrument, the ASHI
system has the principal objective of providing a minute-by-minute and
day-by-day near real time acquisition of precision photometric maps
of the inner heliosphere. The instrument's optical system is designed
to view a hemisphere of sky starting a few degrees from the Sun. A key
photometric specification for ASHI is 0.1% differential photometry in
one-degree sky bins at 90 degrees elongation that enables the three
dimensional (3-D) reconstruction of heliospheric density extending
outward from near the Sun. The ASHI system, unlike other operating or
planned heliospheric imagers, is intended to maximize the scientific
return of heliospheric structures that pass the spacecraft. This will
allow density structure measured in-situ to be extended outward into
the surrounding plasma. This is especially important at Earth where
recent high-resolution Solar Mass Ejection Imager (SMEI) analyses have
shown some CMEs with a corrugated structure when they pass Earth. We
anticipate that velocity can also be determined from the 2-D sequence
of images by following the motion of the background structures using
correlation tracking techniques, and also using 3-D reconstruction
techniques along with density. This should also help determine the
extent to which this corrugated structure extends to CME velocity. An
instrument similar to that of the full space-borne ASHI system has
been tested this year on a NASA-sponsored topside balloon flight,
and it is our intent that a successful space-borne flight make inroads
into this result found in the SMEI analyses.
Title: Iterative Interplanetary Scintillation (IPS) Analyses During
the Parker Solar Probe Close Solar Solar Passes
Authors: Jackson, Bernard; Hick, P.; Buffington, Andrew; Fallows,
Richard; Odstrcil, Dusan; Bisi, Mario M.; Cota, Lucas; Tokumaru,
Munetoshi
Bibcode: 2021cosp...43E.947J
Altcode:
We at the University of California, San Diego (UCSD) have developed a
time-dependent three-dimensional (3-D) reconstruction technique that
provides volumetric maps of density and velocity by iteratively fitting
a kinematic or the ENLIL 3-D MHD model to interplanetary scintillation
(IPS) observations. This system is compared with NOAA- and NASA-provided
in-situ spacecraft measurements, and is used for real time predictions
of solar wind parameters at Earth or globally (see the UCSD website
https://ips.ucsd.edu). Currently used with data from ISEE, Japan, we
have also integrated this system with data from Worldwide IPS Stations
(WIPSS) network groups to increase both spatial and temporal coverage
when these data are available. Some of these stations, especially
LOFAR, centered in the Netherlands, currently operate in "campaign"
mode only during periods of interest when the Parker Solar Probe (PSP)
makes close passes to the Sun. The UCSD 3-D iterative reconstruction
technique is unique in its ability to provide a low-resolution seamless
extension of density and velocity parameters measured in situ, outward
into the surrounding interplanetary medium at the resolution of the
volumetric data. We here present analyses using archival data sets
from both ISEE and LOFAR, that also include both kinematic and ENLIL
models during PSP close passes of the Sun. These analyses also show
the location of Solar Orbiter within the 3-D reconstructed volumes.
Title: ASHI: An All Sky Heliospheric Imager using Thomson-scattered
Sunlight to Enable Near-Earth 3-D Plasma Reconstruction and Forecasts
Authors: Jackson, Bernard; Hick, P.; Buffington, Andrew; Kahler,
Stephen; Bisi, Mario M.; Bracamontes, Matthew; Volkow, Stuart; Adriany,
Kyle; Leblanc, Philippe; Stephan, Ed
Bibcode: 2021cosp...43E.745J
Altcode:
We have conceived, designed, and are now evaluating components for an
All-Sky Heliospheric Imager (ASHI), suitable to fly on future NASA
or DoD missions. ASHI's principal objective is the minute-by-minute
and day-by-day acquisition of a precision photometric map of the
inner heliosphere. The instrument's optical system is designed views a
hemisphere of sky starting a few degrees from the Sun. Two such imagers
on a single spacecraft, or a single imager whose spacecraft has a
180$^\circ$ rotation, can view nearly the whole sky. A key photometric
specification for ASHI is 0.1% differential photometry in a one-degree
sky bin at 90$^\circ$ elongation. This enables the three dimensional
(3-D) reconstruction of heliospheric density starting from near the Sun
and extending outward, with updates as heliospheric structures approach,
and pass the spacecraft. Velocity can also be ascertained from the 2-D
sequence of images, by following the motion of the background structures
using correlation tracking techniques. Solar Mass Ejection Imager (SMEI)
analyses using data from 2003 to 2011 have demonstrated the success
of this technique to provide density reconstructions: applying this to
ASHI data will yield an order-of-magnitude improvement in 3-D density
reconstructions (better than 2 x 2 degrees in latitude and longitude,
and a 2-hour time resolution near the spacecraft). Here we present the
latest results of the ASHI laboratory evaluations, nighttime full-sky
tests of the instrument data sets, and the instrument construction
to date.
Title: UCSD Iterative Tomography Analyses Applied to STEREO HI
Observations
Authors: Jackson, B. V.; Davies, J. A.; Bisi, M. M.; Cota, L. V.;
Buffington, A.; Hick, P. P.
Bibcode: 2020AGUFMSH0280007J
Altcode:
The STEREO spacecraft provide heliospheric imaging systems
particularly designed to maximize the scientific return of heliospheric
Thomson-scattering brightness data from a non-Earth perspective. To
aid in this analysis we have adapted the UCSD iterative tomography
analyses for use with STEREO Heliospheric Imager observations to
provide plasma densities of the inner heliosphere. These analyses
show all manner of solar wind features with unprecedented precision-
resolutions of a few degrees in latitude and longitude, solar distances
of a few hundredths of an AU, and temporal cadences of about one hour
in regions viewed by these instruments. Included in these are Stream
Interaction Regions (SIRs) and Interplanetary Coronal Mass Ejections
(ICMEs). These structures include shocked plasma density enhancements
in front of SIRs and ICMEs, enhanced density in SIRs and in slow ICME
sheath regions. They also show plasma voids in regions behind SIRs and
ICMEs. In this analysis we look carefully at the shape and evolution of
several plasma voids behind ICMEs as they evolve outward from close to
the solar surface until they reach 1 AU where they are measured in situ.
Title: The UCSD Iterative Interplanetary Scintillation (IPS) Analysis
Using an ENLIL 3-D MHD Model Kernel
Authors: Jackson, B. V.; Odstrcil, D.; Hick, P. P.; Buffington, A.;
Tokumaru, M.; Bisi, M. M.
Bibcode: 2019AGUFMSH43D3362J
Altcode:
We at the University of California, San Diego (UCSD) have developed a
time-dependent three-dimensional (3-D) reconstruction technique that
provides volumetric maps of density and velocity by iteratively
fitting 3-D MHD models to interplanetary scintillation (IPS)
observations. This system is compared with NOAA- and NASA-provided
in-situ spacecraft measurements, and is now being evaluated for use in
real time predictions of solar wind parameters (see the UCSD website
https://ips.ucsd.edu/ENLIL_prediction), in order to validate it in
various operating conditions. Unlike previous UCSD kinematic modeling,
this new tomographic analysis with a 3-D MHD kernel now includes
shock processes and the non-radial transport of structures from an
inner-boundary source surface placed at 0.1 AU. Magnetic fields are
extrapolated outward from the solar surface to support the iterative
procedure, and are shown to provide a low resolution several-day advance
prediction of GSM Bz and geomagnetic storms. Used currently with data
from ISEE, Japan, we have also integrated this system for use with data
from Worldwide IPS Stations (WIPSS) network groups to increase both
spatial and temporal coverage when these data are available. Some
of these stations, especially LOFAR centered in the Netherlands,
currently operate in "campaign" mode only during periods of interest
when current and upcoming NASA and ESA spacecraft (Parker Solar Probe,
BepiColombo, Solar Orbiter) make close passes to the Sun or planetary
encounters. Here, the UCSD 3-D iterative reconstruction technique is
unique in its ability to provide a low-resolution seamless extension
of density and velocity parameters measured in situ outward into the
surrounding interplanetary medium.
Title: ASHI: An All Sky Heliospheric Imager to Provide Space Weather
Forecasting Using Thomson-Scattered Sunlight
Authors: Jackson, B. V.; Buffington, A.; Leblanc, P.; Bracamontes,
M.; Foroughi-Shafiei, S.; Edara, J.; Hick, P. P.; Bisi, M. M.
Bibcode: 2019AGUFMSH33C3369J
Altcode:
We have conceived, designed, and are now evaluating components
for an All-Sky Heliospheric Imager (ASHI), to fly on future NASA
missions. ASHI's principal objective is the minute-by-minute and
day-by-day acquisition of a precision photometric map of the inner
heliosphere. The instrument's optical design views a hemisphere of
sky starting a few degrees from the Sun. Two such instruments on a
single spacecraft, or a single instrument if the spacecraft has a
180 degree rotation, can view nearly the whole sky. A key photometric
specification for ASHI is 0.1% differential photometry in a one-degree
sky bin at 90 degrees elongation. This enables the three dimensional
(3-D) reconstruction of heliospheric density starting from near the
Sun and extending outward, with updates as heliospheric structures
approach, and pass the spacecraft. Velocity can also be ascertained
from the imagery in 3-D, by following the motion of the background
structures using correlation tracking techniques. SMEI analyses have
demonstrated the success of this technique: a similar analysis for
ASHI data will yield an order-of-magnitude improvement in 3-D density
reconstructions (better than 2 x 2 degrees in latitude, and longitude,
and a 2-hour time resolution near the spacecraft). Here we will present
the latest results of the ASHI laboratory evaluations, and nighttime
full-sky tests of the instrument data sets.
Title: The UCSD Iterative Tomography Interplanetary Scintillation
(IPS) and In-situ Constraints on the ENLIL 3-D MHD Model
Authors: Jackson, Bernard V.; Odstrcil, Dusan; Hick, P. Paul;
Buffington, Andrew; Tokumaru, Munetoshi; Bisi, Mario M.
Bibcode: 2019shin.confE.120J
Altcode:
The University of California, San Diego (UCSD) has developed a
time-dependent three-dimensional (3-D) reconstruction technique that
provides volumetric maps of density and velocity by constraining
the ENLIL 3-D MHD model to fit interplanetary scintillation
(IPS) observations and NOAA-provided in-situ plasma parameters
at Earth in near real time. This system is compared with NOAA
and NASA-provided in-situ measurements of plasma and fields and
is now being evaluated for use in real time predictions of solar
wind parameters a few days ahead of the present on the UCSD website
https://ips.ucsd.edu/ENLIL_prediction. Unlike previous UCSD kinematic
modeling, this new tomographic analysis with a 3-D MHD kernel now
includes shock processes and the non-radial transport of structure
from the inner-boundary source surface at 0.1 AU. Magnetic fields
extrapolated outward from the solar surface support the iterative
procedure, and are shown to provide a low-resolution several-day
advance prediction of the background solar wind GSM Bz and geomagnetic
storms. Used currently with IPS data available from ISEE, Japan,
this type of programming will be especially important when more data
become available from Worldwide IPS Stations (WIPSS) network groups
and both spatial and temporal coverage is increased. Our modeling
system complements existing operating systems at different world Space
Weather Prediction Centers that currently use 3-D MHD modeling based
primarily on magnetograms and NASA spacecraft imagery.
Title: Tests of the UCSD Iterative Interplanetary Scintillation
(IPS) Analysis Using Time-Dependent 3-D MHD Models as Kernels
Authors: Jackson, Bernard V.; Yu, Hsiu-Shan; Hick, P. Paul;
Buffington, Andrew; Odstrcil, Dusan; Kim, Tae; Pogorelov, Nick;
Tokumaru, Munetoshi; Bisi, Mario M.
Bibcode: 2018shin.confE.193J
Altcode:
The heliospheric group at the University of California, San Diego
has developed a time-dependent three-dimensional (3-D) reconstruction
technique which provides volumetric maps of density and velocity by
iteratively fitting 3-D MHD models to interplanetary scintillation (IPS)
observations. We have applied a similar technique in near real time to
the IPS data for nearly 20 years. However, unlike the previous UCSD
kinematic modeling, this new tomographic analysis now includes shock
processes, as well as non-radial transport. Magnetic fields extrapolated
outward from the solar surface, and in-situ spacecraft measurements near
Earth can also be included to support the iterative procedure. Tests
show that both CME and stream-interacting heliospheric density and
velocity structures can be more accurately localized in extent relative
to the previous kinematic analysis as structures move outward from the
Sun. Shock sheath enhancements in front of high-speed heliospheric
structures are also shown to be limited in extent by the iterative
procedure. Examples of this analysis using ENLIL and the University
of Alabama Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS)
heliospheric 3-D MHD codes as kernels will be shown. These examples
can also refine poorly-known 3-D MHD variables (i.e., temperature), and
parameters (gamma) by fitting heliospheric remotely-sensed structures
near the solar surface, on their way through the heliosphere, and then
later at 1 AU near Earth.
Title: ASHI: An `All Sky' Heliospheric Imager for Viewing
Thomson-Scattered Light
Authors: Jackson, Bernard; Hick, P.; Buffington, Andrew; Bisi, Mario
M.; Yu, Hsiu-Shan; Edara, Jyothirmayi
Bibcode: 2018cosp...42E1581J
Altcode:
We have developed, and are now making a detailed design for an All-Sky
Heliospheric Imager (ASHI), to fly on future deep-space missions. ASHI's
principal long-term objective is acquisition of a precision photometric
map of the inner heliosphere as viewed from deep space. Photometers on
the twin Helios spacecraft, the Solar Mass Ejection Imager (SMEI) on
the Coriolis satellite, and the Solar-TErrestrial RElations Observatory
(STEREO) twin spacecraft Heliospheric Imagers (HIs), all indicate
an optimum instrument design for visible-light Thomson-scattering
observations. This design views a hemisphere of sky starting a few
degrees from the Sun. Two imagers can cover almost all of the whole
sky. A key photometric specification for ASHI is 0.1% differential
photometry: this enables the three dimensional (3-D) reconstruction of
density starting from near the Sun and extending outward. SMEI analyses
have demonstrated the success of this technique, and when employed by
ASHI, this will provide an order of magnitude better resolution in 3-D
density over time. We augment this analysis to include remotely-sensed
2-D velocity, and thus when these imagers are deployed in deep space
they can provide comparisons of both imaged density and velocity to
those measured in situ. We present recent progress in the instrument
design, its expected performance specifications, and the possibilities
for its deployment over the next few years.
Title: Bz Determinations and Forecasts Using UCSD Analysis Techniques
Authors: Jackson, Bernard; Hick, P.; Buffington, Andrew; Yu, Hsiu-Shan;
Zhao, Gary
Bibcode: 2018cosp...42E1580J
Altcode:
Since the middle of the last decade, UCSD has incorporated magnetic
field data in its ISEE IPS tomographic analysis. These data are
extrapolated upward from the solar surface using the Current Sheet
Source Surface (CSSS) model (Zhao & Hoeksema, 1995) provide
predictions of the interplanetary field in RTN coordinates. When
extrapolated to Earth, these fields can be displayed in a variety of
ways, including GSM fields in Bx, By, and Bz coordinates. The Bz GSM
field component gives a fair correlation with in-situ derived fields
near Earth of a few nano-Tesla variation that maximizes in spring
and fall as Russell and McPherron (1973) have shown, but even more
significantly its daily variation is shown to be correlated with
geomagnetic Kp and Dst indices. UCSD currently operates a website
that predicts these transient low-resolution GSM Bz field component
variations several days in advance. More challenging to predict are
large, short-lived magnetic field components that can be north-south
in RTN coordinates, and whose southward GSM Bz can provide the most
extreme geomagnetic effects. Here, the record for success is not as
clear, but there have been some inroads to these predictions from this
analysis that will be discussed.
Title: ASHI: An All Sky Heliospheric Imager for Viewing
Thomson-Scattered Light
Authors: Buffington, A.; Jackson, B. V.; Yu, H. S.; Hick, P. P.;
Bisi, M. M.
Bibcode: 2017AGUFMSH23D2689B
Altcode:
We have developed, and are now making a detailed design for an All-Sky
Heliospheric Imager (ASHI), to fly on future deep-space missions. ASHI's
principal long-term objective is acquisition of a precision photometric
map of the inner heliosphere as viewed from deep space. Photometers
on the twin Helios spacecraft, the Solar Mass Ejection Imager
(SMEI) upon the Coriolis satellite, and the Heliospheric Imagers
(HIs) upon the Solar-TErrestrial RElations Observatory (STEREO)
twin spacecraft, all indicate an optimum instrument design for
visible-light Thomson-scattering observations. This design views a
hemisphere of sky starting a few degrees from the Sun. Two imagers can
cover almost all of the whole sky. A key photometric specification
for ASHI is 0.1% differential photometry: this enables the three
dimensional reconstruction of density starting from near the Sun
and extending outward. SMEI analyses have demonstrated the success
of this technique: when employed by ASHI, this will provide an order
of magnitude better resolution in 3-D density over time. We augment
this analysis to include velocity, and these imagers deployed in deep
space can thus provide high-resolution comparisons both of direct
in-situ density and velocity measurements to remote observations of
solar wind structures. In practice we find that the 3-D velocity
determinations provide the best tomographic timing depiction of
heliospheric structures. We discuss the simple concept behind this,
and present recent progress in the instrument design, and its expected
performance specifications. A preliminary balloon flight of an ASHI
prototype is planned to take place next Summer.
Title: The variable nature of the solar wind
Authors: Jackson, B. V.; Yu, H. S.; Buffington, A.; Hick, P. P.
Bibcode: 2017AGUFMSH23D2684J
Altcode:
When analyzing LASCO C2 and STEREO SECCHI COR2 coronagraph images,
and using UCSD-developed two-dimensional (2D) correlation-tracking
techniques, we found that the observed outflow is not a static
well-ordered motion, but instead has highly variable speed
structures. This outward motion of structures is also observed over
the entire high-resolution STEREO HI-1 field of view, whether or not
a CME is present. We have recently exploited the correlation-tracking
techniques to measure the optical flow on HI-1A images. The analysis
yields a wealth of information about the outward motion of large-
and fine-scale structures in the heliosphere. These include the 2D
speed of features, the level of the correlation, the brightness of
the feature measured, and the structure non-radial 2D motion. Here
we present the analysis of a well-observed fast-moving CME and the
speed of different structures within it. The preliminary results of
the heliospheric velocity determination using HI-1A images show the
nature of the solar wind within the CME that is organized into a fast
and patchy high-speed front followed by a slower internal region. From
this we conclude that the Parker Solar Probe and ESA Solar Orbiter
will measure this highly-variable structure in situ within CMEs,
and we speculate that these structures will also show abundance and
magnetic field differences related to this high variability.
Title: An Iterative Interplanetary Scintillation (IPS) Analysis
Using Time-dependent 3-D MHD Models as Kernels
Authors: Jackson, B. V.; Yu, H. S.; Hick, P. P.; Buffington, A.;
Odstrcil, D.; Kim, T. K.; Pogorelov, N. V.; Tokumaru, M.; Bisi, M. M.;
Kim, J.; Yun, J.
Bibcode: 2017AGUFMSH21A2650J
Altcode:
The University of California, San Diego has developed an iterative
remote-sensing time-dependent three-dimensional (3-D) reconstruction
technique which provides volumetric maps of density, velocity, and
magnetic field. We have applied this technique in near real time for
over 15 years with a kinematic model approximation to fit data from
ground-based interplanetary scintillation (IPS) observations. Our
modeling concept extends volumetric data from an inner boundary placed
above the Alfvén surface out to the inner heliosphere. We now use this
technique to drive 3-D MHD models at their inner boundary and generate
output 3-D data files that are fit to remotely-sensed observations
(in this case IPS observations), and iterated. These analyses are
also iteratively fit to in-situ spacecraft measurements near Earth. To
facilitate this process, we have developed a traceback from input 3-D
MHD volumes to yield an updated boundary in density, temperature,
and velocity, which also includes magnetic-field components. Here
we will show examples of this analysis using the ENLIL 3D-MHD and
the University of Alabama Multi-Scale Fluid-Kinetic Simulation Suite
(MS-FLUKSS) heliospheric codes. These examples help refine poorly-known
3-D MHD variables (i.e., density, temperature), and parameters (gamma)
by fitting heliospheric remotely-sensed data between the region near
the solar surface and in-situ measurements near Earth.
Title: 3D-MHD Modeling Fit to Interplanetary Scintillation (IPS)
Observations
Authors: Jackson, Bernard Vernon; Yu, Hsiu-Shan; Hick, P. Paul;
Buffington, Andrew; Bisi, Mario M.; Odstrcil, Dusan; Kim, Tae;
Pogorelov, Nick; Tokumaru, Munetoshi; Kim, Jaehun; Yun, Jongyeon
Bibcode: 2017shin.confE.125J
Altcode:
The University of California, San Diego has developed an iterative
remote-sensing time-dependent three-dimensional (3D) reconstruction
technique which provides volumetric maps of density, velocity, and
magnetic field. We have applied this technique in near real time for
over 15 years with a kinematic model approximation to fit data from
ground-based interplanetary scintillation (IPS) observations. Our
modeling concept extends volumetric data from an inner boundary placed
above the Alfvén surface out to the inner heliosphere. We now use this
technique to drive 3D-MHD models at their inner boundary and generate
output 3D data files that are fit to remotely-sensed observations (in
this case IPS observations), and iterated. These analyses are also
iteratively fit to in-situ spacecraft measurements near Earth. To
facilitate this process, we have developed a traceback from input
3D-MHD volumes to yield an updated boundary in density, temperature,
and velocity, which also includes magnetic-field components. Here
we will show examples of this analysis using the ENLIL 3D-MHD and
the University of Alabama Multi-Scale Fluid-Kinetic Simulation Suite
(MS-FLUKSS) heliospheric codes.
Title: Observations and Analyses of Heliospheric Faraday Rotation of
a Coronal Mass Ejection (CME) Using the LOw Frequency ARray (LOFAR)
and Space-Based Imaging Techniques
Authors: Bisi, Mario Mark; Jensen, Elizabeth; Sobey, Charlotte;
Fallows, Richard; Jackson, Bernard; Barnes, David; Giunta, Alessandra;
Hick, Paul; Eftekhari, Tarraneh; Yu, Hsiu-Shan; Odstrcil, Dusan;
Tokumaru, Munetoshi; Wood, Brian
Bibcode: 2017EGUGA..1913243B
Altcode:
Geomagnetic storms of the highest intensity are general driven
by coronal mass ejections (CMEs) impacting the Earth's space
environment. Their intensity is driven by the speed, density, and,
most-importantly, their magnetic-field orientation and magnitude
of the incoming solar plasma. The most-significant magnetic-field
factor is the North-South component (Bz in Geocentric Solar Magnetic
- GSM - coordinates). At present, there are no reliable prediction
methods available for this magnetic-field component ahead of the
in-situ monitors around the Sun-Earth L1 point. Observations of Faraday
rotation (FR) can be used to attempt to determine average magnetic-field
orientations in the inner heliosphere. Such a technique has already
been well demonstrated through the corona, ionosphere, and also the
interstellar medium. Measurements of the polarisation of astronomical
(or spacecraft in superior conjunction) radio sources (beacons/radio
frequency carriers) through the inner corona of the Sun to obtain
the FR have been demonstrated but mostly at relatively-high radio
frequencies. Here we show some initial results of true heliospheric FR
using the Low Frequency Array (LOFAR) below 200 MHz to investigate
the passage of a coronal mass ejection (CME) across the line of
sight. LOFAR is a next-generation low-frequency radio interferometer,
and a pathfinder to the Square Kilometre Array (SKA) - LOW telescope. We
demonstrate preliminary heliospheric FR results through the analysis of
observations of pulsar J1022+1001, which commenced on 13 August 2014 at
13:00UT and spanned over 150 minutes in duration. We also show initial
comparisons to the FR results via various modelling techniques and
additional context information to understand the structure of the inner
heliosphere being detected. This observation could indeed pave the way
to an experiment which might be implemented for space-weather purposes
that will eventually lead to a near-global method for determining the
magnetic field throughout the inner heliosphere.
Title: Observations of Heliospheric Faraday Rotation of a CME Using
LOFAR and Space-Based Imaging
Authors: Bisi, M. M.; Jensen, P. E., E. A.; Sobey, C.; Fallows, R. A.;
Jackson, B. V.; Barnes, D.; Giunta, A. S.; Hick, P. P.; Eftekhari,
T.; Yu, H. S.; Odstrcil, D.; Tokumaru, M.; Wood, B. E.
Bibcode: 2016AGUFMSH11C2251B
Altcode:
The most-intense space weather at Earth consists of geomagnetic
storms where their intensity is driven by the speed, density,
and magnetic-field orientation of the incoming solar plasma. The
most-significant factor is the North-South component of magnetic field
(Bz in Geocentric Solar Magnetic - GSM - coordinates). At present,
there is no reliable prediction of this magnetic-field component ahead
of the in-situ monitors around the Sun-Earth L1 point. Observations
of Faraday rotation (FR) can be used to attempt to determine average
magnetic-field orientations in the inner heliosphere, a technique which
has already been well demonstrated through the corona, ionosphere, and
interstellar medium. Measurements of the polarization of astronomical
(or spacecraft in superior conjunction) radio sources (beacons/radio
frequency carriers) through the inner corona of the Sun to obtain
the FR have been demonstrated but mostly at relatively-high radio
frequencies. Here we show some initial results of true heliospheric FR
using the Low Frequency Array (LOFAR) below 200 MHz to investigate
the passage of a coronal mass ejection (CME) across the line of
sight. LOFAR is a next-generation low-frequency radio interferometer,
and a pathfinder to the Square Kilometre Array (SKA) - LOW telescope. We
demonstrate preliminary heliospheric FR results through the analysis
of observations of pulsar J1022+1001, which commenced on 13 August
2014 at 13:00UT and spanned over 150 minutes in duration. We also show
initial comparisons to the FR results via various modelling techniques
and additional context information to understand the structure of the
inner heliosphere being detected. This observation could pave the way
to an experiment which might be implemented for space-weather purposes
that will eventually lead to a near-global method for determining the
magnetic field throughout the inner heliosphere.
Title: Observations of the Variable Coronal Solar Wind, and its
Implications for Solar Probe Plus and Solar Orbiter
Authors: Jackson, B. V.; Yu, H. S.; Hick, P. P.; Buffington, A.
Bibcode: 2016AGUFMSH43B2565J
Altcode:
Solar wind observations from Ulysses show polar solar regions at solar
minimum to be uniform and non-structured. However, when analyzing LASCO
C2 and STEREO SECCHI COR2 coronagraph images, and using UCSD-developed
correlation-tracking techniques, we find the observed solar wind
outflow during these periods is not a static well-ordered motion,
but instead has highly-variable speed structures. These high-speed
polar structures are associated with slightly brighter (and also
patchy) coronal structures. When the high-speed patches are averaged
with the slower surrounding corona, the solar wind acceleration with
solar distance is observed consistently across the polar coronal hole
regions. This change in speed with distance is also consistent with
the outward flow speed observed in polar regions determined from mass
flux considerations and known coronagraph polarization brightness. From
this we conclude that Solar Probe Plus and Solar Orbiter will not only
be able to measure these structures in situ as variable wind, but they
may also be able to determine the key parameters associated with these
structures and how these parameters (abundances and magnetic fields)
are related to the solar wind acceleration that is observed remotely
in coronagraph observations.
Title: ASHI, an All Sky Heliospheric Imager for Future NASA Missions
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Yu, H. S.;
Bisi, M. M.
Bibcode: 2016AGUFMSH11C2276J
Altcode:
We wish to answer the scientific question: "What are the shapes and time
histories of heliospheric structures in the plasma parameters, density
and velocity as structures move outward from the Sun and surround the
spacecraft?" To provide answers to this question, we propose ASHI,
an All-Sky Heliospheric Imager for future NASA missions. ASHI's
primary applicability is to view the inner heliosphere from deep
space as a photometric system. The zodiacal-light photometers
on the twin Helios spacecraft, the Solar Mass Ejection Imager
(SMEI) on the Coriolis satellite, and the Heliospheric Imagers
(HIs) on the Solar-TErrestrial RElations Observatory (STEREO) twin
spacecraft, all point the way towards an optimum instrument for viewing
Thomson-scattering observations. The specifications for such systems
include viewing the whole sky starting beyond a few degrees of the Sun,
and covering a hemisphere or more of sky. With an imager mass of about
2.5 kg per system (scalable to lower values for instruments viewing
from closer than 1 AU), ten-minute exposures, 20 arc-second pointing,
and low power consumption, this type of instrument has been a popular
choice for recent NASA Mission concepts such as STEREO, Solar Orbiter,
Solar probe, and EASCO. A key photometric specification for such imagers
is 0.1% differential photometry which enables the 3-D reconstruction
of density starting from near the Sun and extending outward. A proven
concept using SMEI analyses, ASHI will provide an order of magnitude
better resolution in three dimensions over time. As a new item we intend
to include velocity in this concept, and for a heliospheric imager in
deep space, provide high-resolution comparisions of in-situ density
and velocity measurements obtained at the spacecraft, to structures
observed remotely.
Title: The UCSD Time-dependent Tomography and IPS use for Exploring
Space Weather Events
Authors: Yu, H. S.; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Tokumaru, M.; Odstrcil, D.; Kim, J.; Yun, J.
Bibcode: 2016AGUFMSH22B..06Y
Altcode:
The University of California, San Diego (UCSD) time-dependent,
iterative, kinematic reconstruction technique has been used and expanded
upon for over two decades. It provides some of the most-accurate
predictions and three-dimensional (3D) analyses of heliospheric
solar-wind parameters now available using interplanetary scintillation
(IPS) data. The parameters provided include reconstructions of
velocity, density, and three-component magnetic fields. Precise
time-dependent results are now obtained at any solar distance in the
inner heliosphere using ISEE (formerly STELab), Japan, IPS data sets,
and can be used to drive 3D-MHD models including ENLIL. Using IPS
data, these reconstructions provide a real-time prediction of the
global solar wind parameters across the whole heliosphere with a time
cadence of about one day (see http://ips.ucsd.edu). Here we compare
the results (such as density, velocity, and magnetic fields) from the
IPS tomography with different in-situ measurements and discuss several
specific space weather events that demonstrate the issues resulting
from these analyses.
Title: Determination of magnetic-field components from inner-corona
closed-loop propagation and IPS analysis
Authors: Jackson, Bernard; Tokumaru, Munetoshi; Gonzalez-Esparza,
Americo; Hick, P.; Buffington, Andrew; Hong, Sunhak; Bisi, Mario M.;
Kim, Jaehun; Yu, Hsiu-Shan
Bibcode: 2016cosp...41E.882J
Altcode:
We find that a portion of the interplanetary magnetic field measured
in situ near Earth is present from a direct outward mapping of closed
fields from the low solar corona. The Current-Sheet Source Surface
(CSSS) model (Zhao & Hoeksema, 1995 JGR 100, 19), extrapolate
magnetogram-derived fields upward from near the solar surface. Global
velocities and densities inferred from a combination of observations
of interplanetary scintillation (IPS), matched to in-situ velocities
and densities measured by spacecraft instrumentation, then provide an
accurate outward timing to 1 AU using the UCSD tomography model that
assumes conservation of mass and mass flux. All three field components
at 1 AU are present including the north-south (or Bn) component field,
and are compared with the appropriate ACE magnetometer in-situ (RTN)
field coordinate. A significant positive daily correlation variation
sometimes as high as 0.8 exists between these closed loop components
and those determined by in-situ measurement over the last ten years
for individual Carrington rotations. We determine that a consistent
small fraction of the static low-coronal component flux (∼2%),
that includes the Bn component, regularly escapes from closed-field
regions. However, this percentage of closed projected fields relative
to those measured in situ at Earth varies somewhat, indicating that a
more efficient process for this flux propagation exists at the peak of
the solar cycle than at its minimum. Since the Bn field provides the
major portion of the Geocentric Solar Magnetospheric (GSM) Bz field
component that couples most closely to the Earth's geomagnetic field,
the prospects of using this technique for space weather predictions
are being actively developed.
Title: The 2014 August 19 CME VarSITI ISEST Event Observed in ISEE
IPS Observations with the UCSD Time-dependent Tomography
Authors: YU, HSIU-SHAN; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Chang, O.; Tokumaru, M.
Bibcode: 2016shin.confE..28Y
Altcode:
The 2014 August 19 CME shows a large in-situ density response at
Earth, and is a well-observed event in Institute for Space-Earth
Environmental Research (ISEE), Japan, interplanetary scintillation
(IPS) analyses. This event is documented as a case-study example of
the many events that can be reconstructed and viewed in 3D, with time
extending from first measurements in coronagraph observations to their
in-situ manifestation at Earth. Here, as usual, we find that the UCSD
tomography IPS-reconstructed g-level images for this event have nearly
the same structure as was observed in coronagraph images three days
earlier, before the CME arrived at Earth. The density enhancement that
arrives at Earth is well-reproduced in Advanced Composition Explorer
(ACE) and Charge, Element and Isotope Analysis System (CELIAS) in-situ
data; the differences between these data sets and those from Wind
are shown. Although this is a slow event, and thus very well-observed
using only the ISEE radio observatory data, this study indicates how
a network of IPS sites around the world could also map the fastest
Earth-directed CMEs.
Title: Preliminary Analysis of Observations of Heliospheric Faraday
Rotation of a CME Using LOFAR
Authors: Bisi, Mario M.; Jensen, Elizabeth A.; Sobey, Charlotte;
Fallows, Richard A.; Jackson, Bernard V.; Barnes, David; Giunta,
Alessandra; Hick, P. Paul L.; Eftekhari, Tarraneh; Yu, Hsiu-Shan;
Odstrcil, Dusan; Tokumaru, Munetoshi
Bibcode: 2016shin.confE..34B
Altcode:
Observations of Faraday rotation (FR) can be used as a remote-sensing
method of determining magnetic fields which has been well demonstrated
through the corona, ionosphere, and interstellar medium. FR values
are obtained via observations of polarised radio sources with
well-documented characteristics (astronomical radio sources observed
are typically Pulsars). Measurements of the inner corona of the Sun
in FR have been shown from both spacecraft beacons and some natural
radio sources but at relatively-high radio frequencies. Here we show
some initial results of true heliospheric FR using the Low Frequency
Array (LOFAR) below 200 MHz to investigate the passage of a coronal
mass ejection (CME) across the line of sight. LOFAR is arguably
the most-advanced interferometer radio telescope at present with
wide-ranging radio-astronomy capabilities from imaging to beam forming
multiple beams on the sky. We demonstrate preliminary heliospheric FR
results through the analysis of observations of pulsar J1022+1001, which
commenced on 13 August 2014 at 13:00UT and spanned over 150 minutes
in duration. We also show initial comparisons to the FR results via
modelling techniques and additional context information to understand
the structure of the inner heliosphere being detected. This observation
could pave the way to a set of observations and modelling techniques
that might be implemented for space-weather purposes eventually leading
to a near-global method for determining the magnetic field throughout
the inner heliosphere. The most-intense space weather at Earth is
due to geomagnetic storms. They are driven by the speed, density, and
magnetic-field of the incoming plasma. The most-important determining
factor of the intensity of geomagnetic storms is that of the North-South
component of magnetic field (Bz in Geocentric Solar Magnetic - GSM
- coordinates). Currently, there is no reliable prediction of this
magnetic-field component until the incoming plasma from the Sun has
reached in-situ monitors around the L1 point and this provides only
15-60 minutes advanced warning.
Title: Exploration of SOLIS and GONG Data Sets Using the UCSD ISEE
IPS Time-Dependent Tomography and the CSSS Magnetic Field Model
Authors: Jackson, Bernard Vernon; Yu, Hsiu-Shan; Buffington, Andrew;
Hick, P. Paul; Nishimura, Nobuhiko; Nozaki, Nishiki; Tokumaru,
Munetoshi; Fujiki, Ken'ichi; Hayashi, Keiji
Bibcode: 2016shin.confE..54J
Altcode:
We investigate daily Synoptic Optical Long-term Investigations of the
Sun (SOLIS), and Global Oscillation Network Group (GONG) magnetograms
extrapolated into the corona using Current-Sheet Source Surface
(CSSS) modeling. The usual 'open-field' way to do this (Zhao &
Hoeksema, 1995 JGR 100, 19), and a closed-field extrapolation of the
interplanetary magnetic field developed using this same modeling
technique by the University of California, San Diego (UCSD), are
compared with one another and with ACE component RTN fields measured
near Earth. UCSD tomography (which assumes conservation of mass and
mass flux), together with interplanetary scintillation (IPS) data from
the Institute for Space-Earth Environmental Research (ISEE), Japan,
provide global velocities and an accurate timing outward from the
corona to Earth. Although the open-field technique generally gives a
better result for radial and tangential fields, we find that a portion
of the closed extrapolated fields measured in situ near Earth comes
from the direct outward mapping of closed fields at the low solar
corona. All three closed-field components are present at 1 AU, and
are compared with the appropriate magnetometer values. A significant
positive correlation exists between these closed loop components and
the in-situ measurements over the last ten years. We determine that a
small fraction of the static low-coronal component flux, that includes
the Bn (north-south) component, regularly escapes from closed-field
regions. The variation of this flux fraction is about a factor of
three from 1.5% to 4% during this period, relative to the magnitude
of the field components measured in situ near Earth: the implication
is that a relatively more efficient process for closed flux escape
occurs near solar maximum.
Title: Measurements and an empirical model of the Zodiacal brightness
as observed by the Solar Mass Ejection Imager (SMEI)
Authors: Buffington, Andrew; Bisi, Mario M.; Clover, John M.; Hick,
P. Paul; Jackson, Bernard V.; Kuchar, Thomas A.; Price, Stephan D.
Bibcode: 2016Icar..272...88B
Altcode:
The Solar Mass Ejection Imager (SMEI) provided near-full-sky broadband
visible-light photometric maps for 8.5 years from 2003 to 2011. At
a cadence of typically 14 maps per day, these each have an angular
resolution of about 0.5º and differential photometric stability of
about 1% throughout this time. When individual bright stars are removed
from the maps and an empirical sidereal background subtracted, the
residue is dominated by the zodiacal light. This sky coverage enables
the formation of an empirical zodiacal-light model for observations at
1 AU which summarizes the SMEI data. When this is subtracted, analysis
of the ensemble of residual sky maps sets upper limits of typically
1% for potential secular change of the zodiacal light for each of
nine chosen ecliptic sky locations. An overall long-term photometric
stability of 0.25% is certified by analysis of three stable sidereal
objects. Averaging the nine ecliptic results together yields a 1-σ
upper limit of 0.3% for zodiacal light change over this 8.5 year period.
Title: A 17 June 2011 polar jet and its presence in the background
solar wind
Authors: Yu, H. -S.; Jackson, B. V.; Yang, Y. -H.; Chen, N. -H.;
Buffington, A.; Hick, P. P.
Bibcode: 2016JGRA..121.4985Y
Altcode:
High-speed jet responses in the polar solar wind are enigmatic. Here we
measure a jet response that emanates from the southern polar coronal
hole on 17 June 2011 at the extreme speed of over 1200 km/s. This
response was recorded from the Sun-Earth line in Solar Dynamics
Observatory/Atmospheric Imaging Assembly (SDO/AIA) and Large Angle
and Spectrometric Coronagraph/C2 and both Solar TErrestrial RElations
Observatory Extreme Ultraviolet Imager and COR2 coronagraphs when the
three spacecraft were situated ~90° from one another. These certify
the coronal 3-D location of the response that is associated with an
existing solar plume structure and show its high speed to distances of
over 14 RS. This jetting is associated with magnetic flux
changes in the polar region as measured by the SDO/Helioseismic and
Magnetic Imager instrumentation over a period of several hours. The
fastest coronal response observed can be tracked to a time near the
period of greatest flux changes and to the onset of the brightest
flaring in AIA. This high-speed response can be tracked directly as a
small patch of outward moving brightness in coronal images as in Yu et
al. (2014) where three slower events were followed from the perspective
of Earth. This accumulated jet response has the largest mass and energy
we have yet seen in 3-D reconstructions from Solar Mass Ejection Imager
observations, and its outward motion is certified for the first time
using interplanetary scintillation observations. This jet response is
surrounded by similar high-speed patches, but these are smoothed out
in Ulysses polar measurements, we speculate about how these dynamic
activities relate to solar wind acceleration.
Title: Nova Light Curves From The Solar Mass Ejection Imager (SMEI)
- II. The extended catalog
Authors: Hounsell, R.; Darnley, M. J.; Bode, M. F.; Harman, D. J.;
Surina, F.; Starrfield, S.; Holdsworth, D. L.; Bewsher, D.; Hick,
P. P.; Jackson, B. V.; Buffington, A.; Clover, J. M.; Shafter, A. W.
Bibcode: 2016ApJ...820..104H
Altcode: 2015arXiv151203321H
We present the results from observing nine Galactic novae in eruption
with the Solar Mass Ejection Imager (SMEI) between 2004 and 2009. While
many of these novae reached peak magnitudes that were either at
or approaching the detection limits of SMEI, we were still able
to produce light curves that in many cases contained more data at
and around the initial rise, peak, and decline than those found in
other variable star catalogs. For each nova, we obtained a peak time,
maximum magnitude, and for several an estimate of the decline time
({t}{{2}}). Interestingly, although of lower quality than
those found in Hounsell et al., two of the light curves may indicate
the presence of a pre-maximum halt. In addition, the high cadence
of the SMEI instrument has allowed the detection of low-amplitude
variations in at least one of the nova light curves.
Title: 3D Analysis of Remote-Sensed Heliospheric Data for Space
Weather Forecasting
Authors: Yu, H. S.; Jackson, B. V.; Hick, P. P.; Buffington, A.;
Bisi, M. M.; Odstrcil, D.; Hong, S.; Kim, J.; Yi, J.; Tokumaru, M.;
Gonzalez-Esparza, A.
Bibcode: 2015AGUFMSH21B2396Y
Altcode:
The University of California, San Diego (UCSD) time-dependent iterative
kinematic reconstruction technique has been used and expanded upon
for over two decades. It currently provides some of the most accurate
predictions and three-dimensional (3D) analyses of heliospheric
solar-wind parameters now available using interplanetary scintillation
(IPS) data. The parameters provided include reconstructions of velocity,
density, and magnetic fields. Precise time-dependent results are
obtained at any solar distance in the inner heliosphere using current
Solar-Terrestrial Environment Laboratory (STELab), Nagoya University,
Japan IPS data sets, but the reconstruction technique can also
incorporate data from other IPS systems from around the world. With
access using world IPS data systems, not only can predictions using
the reconstruction technique be made without observation dead times
due to poor longitude coverage or system outages, but the program can
itself be used to standardize observations of IPS. Additionally, these
analyses are now being exploited as inner-boundary values to drive
an ENLIL 3D-MHD heliospheric model in real time. A major potential of
this is that it will use the more realistic physics of 3D-MHD modeling
to provide an automatic forecast of CMEs and corotating structures up
to several days in advance of the event/features arriving at Earth,
with or without involving coronagraph imagery or the necessity of
magnetic fields being used to provide the background solar wind speeds.
Title: Observations of Heliospheric Faraday Rotation (FR) and
Interplanetary Scintillation (IPS) with the LOw Frequency ARray
(LOFAR): Steps Towards Improving Space-Weather Forecasting
Capabilities
Authors: Bisi, M. M.; Fallows, R. A.; Sobey, C.; Eftekhari, T.;
Jensen, E. A.; Jackson, B. V.; Yu, H. S.; Hick, P. P.; Odstrcil, D.;
Tokumaru, M.
Bibcode: 2015AGUFMSH21B2399B
Altcode:
The phenomenon of space weather - analogous to terrestrial weather
which describes the changing pressure, temperature, wind, and humidity
conditions on Earth - is essentially a description of the changes in
velocity, density, magnetic field, high-energy particles, and radiation
in the near-Earth space environment including the effects of such
changes on the Earth's magnetosphere, radiation belts, ionosphere,
and thermosphere. Space weather can be considered to have two main
strands: (i) scientific research, and (ii) applications. The former
is self-explanatory, but the latter covers operational aspects which
includes its forecasting. Understanding and forecasting space weather
in the near-Earth environment is vitally important to protecting our
modern-day reliance (militarily and commercially) on satellites,
global-communication and navigation networks, high-altitude
air travel (radiation concerns particularly on polar routes),
long-distance power/oil/gas lines and piping, and for any future human
exploration of space to list but a few. Two ground-based radio-observing
remote-sensing techniques that can aid our understanding and forecasting
of heliospheric space weather are those of interplanetary scintillation
(IPS) and heliospheric Faraday rotation (FR). The LOw Frequency ARray
(LOFAR) is a next-generation 'software' radio telescope centered in
The Netherlands with international stations spread across central and
northwest Europe. For several years, scientific observations of IPS
on LOFAR have been undertaken on a campaign basis and the experiment
is now well developed. More recently, LOFAR has been used to attempt
scientific heliospheric FR observations aimed at remotely sensing
the magnetic field of the plasma traversing the inner heliosphere. We
present our latest progress using these two radio heliospheric-imaging
remote-sensing techniques including the use of three-dimensional (3-D)
modeling and reconstruction techniques using other, additional data
as input (such as IPS data from the Solar Terrestrial Environment
Laboratory - STELab) to support and better-interpret the LOFAR results.
Title: Measurements and an Empirical Model of the Zodiacal Brightness
as Observed by the Solar Mass Ejection Imager (SMEI)
Authors: Buffington, A.; Bisi, M. M.; Clover, J. M.; Hick, P. P.;
Jackson, B. V.; Kuchar, T. A.; Price, S. D.
Bibcode: 2015AGUFMSH53B2501B
Altcode:
The Solar Mass Ejection Imager (SMEI) has provided near-full-sky
broadband visible-light photometric maps for 8.5 years from 2003 to
2011. These have an angular resolution of about 0.5º and differential
photometric stability of about 1% per map throughout this time. When
individual bright stars are removed from the maps and an empirical
sidereal background subtracted, the residue is dominated by the
zodiacal light. This sky coverage enables the formation of an empirical
zodiacal-light model for observations at 1 AU which summarizes the
SMEI data. When this is subtracted, analysis of the ensemble of
residual sky maps sets upper limits of typically 1% for potential
secular change of the zodiacal light for each of nine chosen ecliptic
sky locations. An overall long-term photometric stability of 0.25%
is certified by analysis of three stable sidereal objects. Averaging
the nine ecliptic results together yields a 1-σ upper limit of 0.3%
for zodiacal light change over this 8.5 year period.
Title: Determination of the North-South Heliospheric Magnetic-Field
Component from Inner-Corona Closed-Loop Propagation
Authors: Jackson, B. V.; Yu, H. S.; Hick, P. P.; Buffington, A.;
Bisi, M. M.; Tokumaru, M.; Kim, J.; Hong, S.; Lee, B.; Yi, J.; Yun, J.
Bibcode: 2015AGUFMSH43C..03J
Altcode:
We find that a portion of the north-south interplanetary magnetic field
measured in situ near Earth is present from a direct outward mapping
of closed fields from the low solar corona. Using the Current-Sheet
Source Surface (CSSS) model (Zhao & Hoeksema, 1995 JGR 100, 19),
these lower coronal fields are extrapolated upward from near the solar
surface. Global velocities inferred from a combination of observations
of interplanetary scintillation (IPS) matched to in-situ velocities
and densities measured by spacecraft instrumentation provide an
accurate outward timing to 1 AU from a model assuming conservation
of mass and mass flux. The north-south field component at 1 AU is
compared with the appropriate ACE magnetometer in-situ Normal (RTN)
or Bn field coordinate (Jackson et al., 2015, ApJL, 803:L1). From a
significant positive correlation between this method of determining
the Bn field compared with in-situ measurements over a three-year
period during the last solar minimum, we find that a small fraction
of the low-coronal Bn component flux (~1%) regularly escapes from
closed-field regions. Since the Bn field provides the major portion
of the Geocentric Solar Magnetospheric (GSM) Bz field component that
couples most closely to the Earth's geomagnetic field, the prospects
for its determination using this technique for space weather use are
being actively developed by our many colleague groups.
Title: Comparison of Solar Wind Speeds Using Wavelet Transform and
Fourier Analysis in IPS Data
Authors: Aguilar-Rodriguez, E.; Mejia-Ambriz, J. C.; Jackson, B. V.;
Buffington, A.; Romero-Hernandez, E.; Gonzalez-Esparza, J. A.;
Rodriguez-Martinez, M.; Hick, P.; Tokumaru, M.; Manoharan, P. K.
Bibcode: 2015SoPh..290.2507A
Altcode: 2015SoPh..tmp..123A
The power spectra of intensity fluctuations in interplanetary
scintillation (IPS) observations can be used to estimate solar-wind
speeds in the inner heliosphere. We obtain and then compare IPS
spectra from both wavelet and Fourier analyses for 12 time series
of the radio source 3C48; these observations were carried out at
Japan's Solar-Terrestrial Environment Laboratory (STEL) facility, at
327 MHz. We show that wavelet and Fourier analyses yield very similar
power spectra. Thus, when fitting a model to spectra to determine
solar-wind speeds, both yield comparable results. Although spectra
from wavelet and Fourier closely match each other for solar-wind speed
purposes, those from the wavelet analysis are slightly cleaner, which
is reflected in an apparent level of intensity fluctuations that is
enhanced, being ≈ 13 % higher. This is potentially useful for records
that show a low signal-to-noise ratio.
Title: 3D Reconstruction of Interplanetary Scintillation (IPS)
Remote-Sensing Data: Global Solar Wind Boundaries for Driving
3D-MHD Models
Authors: Yu, H. -S.; Jackson, B. V.; Hick, P. P.; Buffington, A.;
Odstrcil, D.; Wu, C. -C.; Davies, J. A.; Bisi, M. M.; Tokumaru, M.
Bibcode: 2015SoPh..290.2519Y
Altcode: 2015SoPh..tmp...47Y
The University of California, San Diego, time-dependent analyses of the
heliosphere provide three-dimensional (3D) reconstructions of solar
wind velocities and densities from observations of interplanetary
scintillation (IPS). Using data from the Solar-Terrestrial
Environment Laboratory, Japan, these reconstructions provide a
real-time prediction of the global solar-wind density and velocity
throughout the whole heliosphere with a temporal cadence of about one
day (ips.ucsd.edu). Updates to this modeling effort continue: in the
present article, near-Sun results extracted from the time-dependent
3D reconstruction are used as inner boundary conditions to drive
3D-MHD models (e.g. ENLIL and H3D-MHD). This allows us to explore the
differences between the IPS kinematic-model data-fitting procedure and
current 3D-MHD modeling techniques. The differences in these techniques
provide interesting insights into the physical principles governing
the expulsion of coronal mass ejections (CMEs). Here we detail for the
first time several specific CMEs and an induced shock that occurred
in September 2011 that demonstrate some of the issues resulting from
these analyses.
Title: A 3D-MHD Model Interface Using Interplanetary Scintillation
(IPS) Observations
Authors: Jackson, Bernard V.; Yu, H. -S.; Hick, P. P.; Buffington,
A.; Odstrcil, D.; Kim, T. K.; Pogorelov, N. V.; Wu, C. -C.; Tokumaru,
M.; Kim, J.; Hong, S.
Bibcode: 2015shin.confE..95J
Altcode:
We at UCSD for over two decades have developed a remote-sensing
iterative time-dependent three-dimensional (3D) tomographic
reconstruction technique which provides volumetric maps of density,
velocity, and magnetic field. These extend from an inner boundary out to
nearly the whole inner heliosphere. This modeling requires a "traceback"
to the boundary, from any element within the heliospheric volume, which
specifies the element origin, time, and change from a 2D location on a
set of Carrington maps. Moreover, this process has recently included
a traceback from any input volume to yield an updated boundary in
velocity, density, temperature, and magnetic field components, based
on fitting to data from interplanetary scintillation (IPS) or other
remotely-sensed heliospheric measurements. This traceback from an
external volume is the most difficult step needed to implement a future
UCSD iterative tomographic analysis from any given solar-wind model. Up
to now, the iterative UCSD tomographic analysis (fitting STELab, Japan,
IPS data) has used an internal solar wind model that conserves mass
and mass flux, and as a first step allows an inner boundary to be
extracted to drive heliospheric 3D-MHD (magnetohydrodynamic) forward
models. Here, three examples are shown where this IPS inner boundary
has been used in this way: 1) Analysis of the 9-10 September 2014 halo
coronal mass ejections (CMEs) using the ENLIL 3D-MHD code at Earth and
at the Rosetta spacecraft situated at 3.7 AU; 2) Analysis of the period
during two halo CMEs on 24 September 2011 using the MS-FLUKSS UAH 3D-MHD
heliospheric code; 3) Analysis of the 15 March 2015 halo CME and its
associated three component magnetic fields with the NRL H3D-MHD code.
Title: A Determination of the North-South Heliospheric Magnetic
Field Component from Inner Corona Closed-loop Propagation
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Yu, H. -S.;
Bisi, M. M.; Tokumaru, M.; Zhao, X.
Bibcode: 2015ApJ...803L...1J
Altcode:
A component of the magnetic field measured in situ near the Earth in
the solar wind is present from north-south fields from the low solar
corona. Using the Current-sheet Source Surface model, these fields
can be extrapolated upward from near the solar surface to 1 AU. Global
velocities inferred from a combination of interplanetary scintillation
observations matched to in situ velocities and densities provide the
extrapolation to 1 AU assuming mass and mass flux conservation. The
north-south field component is compared with the same ACE in situ
magnetic field component—the Normal (Radial Tangential Normal)
Bn coordinate—for three years throughout the solar minimum of
the current solar cycle. We find a significant positive correlation
throughout this period between this method of determining the Bn field
compared with in situ measurements. Given this result from a study
during the latest solar minimum, this indicates that a small fraction
of the low-coronal Bn component flux regularly escapes from closed
field regions. The prospects for Space Weather, where the knowledge
of a Bz field at Earth is important for its geomagnetic field effects,
is also now enhanced. This is because the Bn field provides the major
portion of the Geocentric Solar Magnetospheric Bz field coordinate
that couples most closely to the Earth’s geomagnetic field.
Title: Using IPS Magnetic Modeling to Determine Bz
Authors: Jackson, B. V.; Yu, H. S.; Hick, P. P.; Buffington, A.;
Mejia-Ambriz, J. C.; Bisi, M. M.; Tokumaru, M.
Bibcode: 2014AGUFMSH21C4144J
Altcode:
Interplanetary scintillation (IPS) observations enable remote
determinations of velocity and density in the inner heliosphere
while also providing forecasts of these quantities. Using the global
velocities inferred from IPS, and through convection upward of magnetic
fields perpendicular to a source surface produced by the Current-Sheet
Source Surface (CSSS) modified potential model (Zhao and Hoeksema,
J. Geophys. Res., 100, 19, 1995), global long-duration radial and
tangential heliospheric field components can also be determined. In
order to better include short-term transient effects and derive a
value for the field normal to these components (Bn) during periods
where CMEs, are present, we have tested an extension to our current 3D
vector-field analysis. This extension adds closed fields from below the
source surface to the CSSS model values, and when traced outward from
the sub-Earth point, three magnetic field components are present. These
are compared to in-situ magnetic fields measured near Earth for several
periods throughout the current solar cycle from the minimum between
Solar Cycle 23 and 24 up until the present. We find a significant
positive correlation when using this extension to current analyses
including that of the Bn field for the test cases analyzed thus far.
Title: On the Dynamic Character of the Polar Solar Wind
Authors: Yu, H. S.; Jackson, B. V.; Hick, P. P.; Buffington, A.
Bibcode: 2014AGUFMSH13C4131Y
Altcode:
SOHO LASCO C2 and STEREO SECCHI COR 2 coronagraph images, when
analyzed using correlation tracking techniques, show a surprising
result in polar coronal hole regions ordinarily thought of as "quiet"
solar wind. Here what we observe is not the static well-ordered flow
and gradual acceleration expected of quiescent regions. Rather, the
coronagraph images show outflow in polar coronal holes as intermittent,
highly-variable solar wind speed structures. We compare measurements
of these structures in different simultaneously-measured coronagraph
images, and with coronal brightness. The distribution of structure
speeds shows a gradual decrease with speed in the overlap regions of
the two coronagraphs. Measurements of the mean speed derived versus
height shows the solar wind acceleration with position angle, and are
compared with mass flux and other determinations of solar wind outflow
over the large polar coronal hole regions. In this presentation we
give the most recent work on this ongoing analysis.
Title: The Dynamic Character of the Polar Solar Wind
Authors: Jackson, B. V.; Yu, H. -S.; Buffington, A.; Hick, P. P.
Bibcode: 2014ApJ...793...54J
Altcode:
The Solar and Heliospheric Observatory (SOHO) Large Angle and
Spectrometric Coronagraph C2 and Solar Terrestrial Relations
Observatory (STEREO) COR2A coronagraph images, when analyzed using
correlation tracking techniques, show a surprising result in places
ordinarily thought of as "quiet" solar wind above the poles in coronal
hole regions. Instead of the static well-ordered flow and gradual
acceleration normally expected, coronagraph images show outflow in polar
coronal holes consisting of a mixture of intermittent slow and fast
patches of material. We compare measurements of this highly variable
solar wind from C2 and COR2A images and show that both coronagraphs
measure essentially the same structures. Measurements of the mean
velocity as a function of height of these structures are compared with
mass flux determinations of the solar wind outflow in the large polar
coronal hole regions and give similar results.
Title: The UCSD Kinematic Global Solar Wind Boundary for use in
real-time ENLIL 3D-MHD Modeling
Authors: Yu, Hsiu-Shan; Jackson, Bernard; Hick, Paul; Buffington,
Andrew; Odstrcil, Dusan; Tokumaru, Munetoshi; Hong, Sunhak; Kim,
Jaehun; Kim, Yungkyu
Bibcode: 2014shin.confE..95Y
Altcode:
The UCSD IPS time-dependent iterative kinematic modeling technique has
been used and expanded-upon for over more than a decade to provide some
of the most accurate forecasts of heliospheric solar-wind parameters
now available. These parameters include global models of velocity,
density, and through convection upward of magnetic fields from the
solar surface, radial and tangential heliospheric fields. The precise
time-dependent results can be extracted at any solar distance and are
now being exploited as inner boundary values to drive the ENLIL and
other 3D-MHD models. For ENLIL, this data-driven modeling effort is
now available in real time. The advantage of this system is that it
uses the superior physics of 3D-MHD modeling to provide an automatic
forecast of CMEs and corotating structures several days in advance
of the present at Earth without using coronagraph observations. Here,
we explore the current differences between the IPS real-time kinematic
analyses and those from the ENLIL 3D-MHD modeling using IPS-derived
real-time boundaries.
Title: The UCSD Kinematic Global Solar Wind Analysis Tests of
Different Magnetogram Inputs using MAGIC
Authors: Jackson, Bernard V.; Hick, Paul; Buffington, Andrew; Yu,
Hsiu-Shan; Mejia-Ambriz, Julio; MacNeice, Peter
Bibcode: 2014shin.confE..96J
Altcode:
The UCSD IPS time-dependent iterative kinematic modeling technique has
been used and expanded-upon for over more than a decade to provide some
of the most accurate forecasts of heliospheric solar-wind parameters
now available. These parameters include global models of velocity,
density, and through convection upward of magnetic fields from near the
solar surface, radial and tangential heliospheric fields using the CSSS
Potential Field Model (Zhao and Hoeksema, 1995, JGR, 100, 19). The RTN
coordinate fields mapped to Earth and matched to in-situ measurements
from L1 spacecraft can accurately reproduce daily or longer-term average
field component values, but this accuracy depends on the magnetic field
inputs from different ground and space-based sources. Here we use inputs
provided by the newly-available MAGIC routine from the NASA-Goddard
Community Coordinate Modeling Center (CCMC) to evaluate the differences
present in the two RTN field coordinates. These are mapped to Earth
and compared with near-Earth spacecraft magnetic field measurements for
several different Carrington rotations from 2007 up to the present day.
Title: The Three-dimensional Analysis of Hinode Polar Jets using
Images from LASCO C2, the Stereo COR2 Coronagraphs, and SMEI
Authors: Yu, H. -S.; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Shimojo, M.; Sako, N.
Bibcode: 2014ApJ...784..166Y
Altcode:
Images recorded by the X-ray Telescope on board the Hinode spacecraft
are used to provide high-cadence observations of solar jetting
activity. A selection of the brightest of these polar jets shows
a positive correlation with high-speed responses traced into the
interplanetary medium. LASCO C2 and STEREO COR2 coronagraph images
measure the coronal response to some of the largest jets, and also the
nearby background solar wind velocity, thereby giving a determination
of their speeds that we compare with Hinode observations. When using
the full Solar Mass Ejection Imager (SMEI) data set, we track these
same high-speed solar jet responses into the inner heliosphere and from
these analyses determine their mass, flow energies, and the extent to
which they retain their identity at large solar distances.
Title: The Solar Mass Ejection Imager and Its Heliospheric Imaging
Legacy
Authors: Howard, T. A.; Bisi, M. M.; Buffington, A.; Clover, J. M.;
Cooke, M. P.; Eyles, C. J.; Hick, P. P.; Holladay, P. E.; Jackson,
B. V.; Johnston, J. C.; Kahler, S. W.; Kuchar, T. A.; Mizuno, D. R.;
Penny, A. J.; Price, S. D.; Radick, R. R.; Simnett, G. M.; Tappin,
S. J.; Waltham, N. R.; Webb, D. F.
Bibcode: 2013SSRv..180....1H
Altcode: 2013SSRv..tmp...71H
The Solar Mass Ejection Imager (SMEI) was the first of a new class of
heliospheric and astronomical white-light imager. A heliospheric imager
operates in a fashion similar to coronagraphs, in that it observes
solar photospheric white light that has been Thomson scattered by
free electrons in the solar wind plasma. Compared with traditional
coronagraphs, this imager differs in that it observes at much larger
angles from the Sun. This in turn requires a much higher sensitivity and
wider dynamic range for the measured intensity. SMEI was launched on the
Coriolis spacecraft in January 2003 and was deactivated in September
2011, thus operating almost continuously for nearly nine years. Its
primary objective was the observation of interplanetary transients,
typically coronal mass ejections (CMEs), and tracking them continuously
throughout the inner heliosphere. Towards this goal it was immediately
effective, observing and tracking several CMEs in the first month of
mission operations, with some 400 detections to follow. Along with this
primary science objective, SMEI also contributed to many and varied
scientific fields, including studies of corotating interaction regions
(CIRs), the high-altitude aurora, zodiacal light, Gegenschein, comet
tail disconnections and motions, and variable stars. It was also able
to detect and track Earth-orbiting satellites and space debris. Along
with its scientific advancements, SMEI also demonstrated a significantly
improved accuracy of space weather prediction, thereby establishing the
feasibility and usefulness of operational heliospheric imagers. In this
paper we review the scientific and operational achievements of SMEI,
discuss lessons learned, and present our view of potential next steps
in future heliospheric imaging.
Title: Inclusion of Real-Time In-Situ Measurements into the UCSD
Time-Dependent Tomography and Its Use as a Forecast Algorithm
Authors: Jackson, B. V.; Clover, J. M.; Hick, P. P.; Buffington, A.;
Bisi, M. M.; Tokumaru, M.
Bibcode: 2013SoPh..285..151J
Altcode: 2012SoPh..tmp..210J
The University of California, San Diego (UCSD) three-dimensional
(3D) time-dependent tomography program, used for over a decade to
reconstruct and forecast coronal mass ejections (CMEs), does so from
observations of interplanetary scintillation (IPS) taken using the
Solar-Terrestrial Environment Laboratory (STELab) radio arrays in
Japan. An earlier article (Jackson et al. in Solar Phys.265, 245,
2010) demonstrated how in-situ velocity measurements from the Advanced
Composition Explorer (ACE) space-borne instrumentation can be used
in addition to remote-sensing data to constrain a time-dependent
tomographic velocity solution. Here we extend this in-situ inclusion
to density measurements, and show how this constrains the tomographic
density solution. Supplementing remote-sensing observations with in-situ
measurements provides additional information to construct an iterated
solar-wind parameter that is propagated outward from near the solar
surface past the measurement location, and throughout the volume. As in
the case of velocity when this is done, the largest changes within the
volume are close to the radial directions around Earth that incorporate
the in-situ measurements; the inclusion significantly reduces the
uncertainty in extending these measurements to global 3D reconstructions
that are distant in time and space from the spacecraft. At Earth, this
analysis provides a finely tuned real-time result up to the latest time
for which in-situ measurements are available, and enables more-accurate
extension of these results near Earth to those remotely sensed. We show
examples of this new algorithm using real-time STELab IPS data that were
used in our forecasts throughout Carrington rotations 2010 through 2016,
and we provide one metric prescription that we have used to determine
the forecasting accuracy one, two, and three days in advance of the
time data become available to analyze from STELab. We show that the
accuracy is considerably better than assuming persistence of the same
signal over one to two days in advance of when the data are available.
Title: Heliospheric Solar Wind Forecasting Using Observations of
Interplanetary Scintillation (IPS)
Authors: Jackson, Bernard V.; Yu, Hsiu-Shan; Hick, Paul; Buffington,
Andrew; Mejia-Ambriz, Julio; Luckett, Nolan; Bisi, Mario
Bibcode: 2013shin.confE..86J
Altcode:
At the University of California, San Diego (UCSD), remote-sensing
analyses of the inner heliosphere have been regularly carried
out using radio interplanetary scintillation (IPS) data for
almost two decades. These analyses have measured and reconstructed
three-dimensional (3D) solar wind structure throughout this time period
where data have been available. These global results, especially using
the Solar-Terrestrial Environment Laboratory (STELab) IPS arrays,
provide a forecast of solar wind parameters and a time-dependent
inner boundary in density and velocity that is nearly complete over
the whole heliosphere for the major part of each year, and with a time
cadence of about one day. When using the IPS velocity analyses we can
accurately convect outwards the solar surface magnetic fields and thus
can provide values of the field (radial and tangential components)
throughout the global volume. In the inner heliosphere the results
of these 3D analyses of density, velocity, and vector magnetic field
have been forecast and compared successfully with in-situ measurements
obtained near Earth, STEREO, Mars, Venus, MESSENGER, and at the Ulysses
spacecraft. The resulting precise time-dependent measurements are
also used to provide an inner boundary of these parameters that can
be further extrapolated outward to the edge of the heliosphere using
current 3D-MHD modeling techniques.
Title: Using comet plasma tails to study the solar wind
Authors: Jackson, B. V.; Buffington, A.; Clover, J. M.; Hick, P. P.;
Yu, H. -S.; Bisi, M. M.
Bibcode: 2013AIPC.1539..364J
Altcode:
The plasma tails of comets have been used as probes of the solar wind
for many years, and well before direct solar wind measurements. Now,
analyses utilizing the much greater regularity and extent of comet
tails imaged from space detail outward solar wind flow much better
than was previously possible. These analyses mark the location of
the solar wind flow in three-dimensions over time much as do in-situ
measurements. Data from comet plasma tails using coronagraphs and
heliospheric white-light imagers provide a view closer to the Sun than
where spacecraft have ventured to date. These views show that this flow
is chaotic and highly variable, and not the benign regular outward
motion of a quiescent plasma. While this is no surprise to those who
study and characterize the solar wind in situ or use remotely-sensed
interplanetary scintillation (IPS) techniques, these spacecraft
images provide a visualization of this as never-before possible. Here
we summarize the results of an analysis that determines solar wind
velocity from multiple comet tails that were observed by the Solar Mass
Ejection Imager (SMEI) and also by the inner Heliospheric Imager (HI)
on board the Solar Terrestrial Relations Observatory Ahead (STEREOA)
spacecraft. Finally, we present results using a similar analysis that
measures this same behavior using coronagraph observations in the
low corona.
Title: Are Jets CMEs?
Authors: YU, HSIU-SHAN; Jackson, Bernard V.; Buffington, Andrew;
Hick, P. Paul
Bibcode: 2013shin.confE.165Y
Altcode:
The brightest jets observed by the Hinode XRT and the SDO/AIA
spacecraft instrumentation produce high-speed responses and enhanced
brightness that can be traced through coronagraph images and into the
heliosphere. Specifically, LASCO C2 and STEREO COR2 coronagraph images
measure the coronal responses to some of the largest jets, and analyses
using velocities from interplanetary scintillation (IPS) observations
and the Solar Mass Ejection Imager (SMEI) 3D reconstructions measure
these jet responses in the heliosphere. We determine the approximate
masses and energies for these large jet responses over polar coronal
hole regions, and relate them to the jet peak brightness spectrum
observed by Hinode during a three-week survey period in September
2007. We find in our analyses that jets contribute about 5% of the
total solar wind mass during this period. Assuming that a continuous
material outflow is associated with jets globally throughout the solar
cycle, jet responses provide a contribution of mass equivalent to CMEs
to the solar wind.
Title: Heliospheric Solar Wind Parameter Forecasting Using
Interplanetary Scintillation (IPS) Observations
Authors: Jackson, B. V.; Hick, P.; Buffington, A.; Yu, H.;
Mejia-Ambriz, J. C.; Luckett, N.; Bisi, M. M.
Bibcode: 2013AGUSMSH42B..02J
Altcode:
At the University of California, San Diego (UCSD), remote-sensing
analyses of the inner heliosphere have been regularly carried out using
radio interplanetary scintillation (IPS) data for almost two decades
employing data from the Solar-Terrestrial Environment Laboratory
(STELab), Japan, IPS arrays. More recently, several other world
locations have planned to join in this effort in order to provide
more complete coverage at times other than those above the celestial
meridian of the observing station. These analyses have measured and
reconstructed three-dimensional (3D) solar wind structure throughout the
time period when data are available. This enables a real-time forecast
of solar wind density and velocity outward from the observations that
is nearly complete over the whole heliosphere with a time cadence of
about one day. When using the IPS velocity analyses, we can accurately
convect outwards the solar surface background magnetic fields and thus
can provide values of the field (radial and tangential components)
throughout the global volume. In the inner heliosphere the results
of these 3D analyses of density, velocity, and vector magnetic field
have been forecast and compared successfully with in-situ measurements
obtained near Earth, at STEREO, at Mars, at Venus, at MESSENGER, and
at the Ulysses spacecraft. The resulting precise time-dependent results
can also be used to provide an inner boundary of these parameters that
can be further extrapolated outward to the edge of the heliosphere
using current 3D-MHD modeling techniques.
Title: Remote Sensing of Solar Wind Velocities using Interplanetary
Scintillation with MEXART and STELab Stations
Authors: Mejia-Ambriz, J. C.; Jackson, B. V.; Gonzalez-Esparza, A.;
Tokumaru, M.; Yu, H.; Buffington, A.; Hick, P.
Bibcode: 2013AGUSMSH52A..06M
Altcode:
Radio signals from compact radio sources are scattered by electron
density irregularities in the solar wind. This effect is registered
by radio telescopes as intensity fluctuations of the observed
radio source amplitude and known as Interplanetary Scintillation
(IPS). The Mexican Array Radio Telescope (MEXART) and the antennas
of Solar Terrestrial Environment Laboratory (STELab) are instruments
dedicated to studies of IPS signals. In this work we present a technique
(Manoharan and Ananthakrishnan, 1990) used to estimate solar wind
velocities applied to observations of MEXART and STELab using single
station spectra. Currently STELab uses a multi-station IPS technique to
determinate solar wind speeds. Here we compare velocities obtained with
a single station to those obtained using the multi-station technique
for a few strong radio sources using both techniques and with both
instruments. At the Center for Astrophysics and Space Sciences -
University of California, San Diego (CASS-UCSD), a tomography program
is able to reconstruct the dynamics of the inner heliosphere globally
using IPS measurements to give solar wind densities and velocities. We
show the incorporation of velocities provided by MEXART into this
program that has been used successfully for over a decade with STELab
IPS measurements.
Title: The Ability of Radio Heliospheric Remote Sensing Observations
to Provide Global Solar Wind Parameters
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Yu, H.; Bisi,
M. M.; Fallows, R.
Bibcode: 2012AGUFMSH41E..05J
Altcode:
Heliospheric remote sensing, in particular those using Interplanetary
Scintillation (IPS) observations, allow the 3-D reconstruction of solar
wind parameters globally. These parameters include velocity, density,
and by extrapolation from solar surface magnetogram observations, vector
magnetic field components. Since the year 2000, the Solar-Terrestrial
Environment Laboratory (STELab), Nagoya University, Japan, has provided
a source of IPS data with short-enough latency to enable forecasts of
these solar wind parameters throughout the inner heliosphere. Over time
these techniques have been improved upon with data from other radio
sites (Ootacamund - Ooty - India; and the European Incoherent SCATter
- EISCAT - radio telescopes based across Northern Scandinavia). Here
we review the improvements, limitations, and the potential future of
these techniques. In particular in one new development, the ability to
measure polarization from radio sources allows the possibility to use
Faraday rotation inputs to reconstruct heliospheric vector magnetic
fields without a reliance on solar surface magnetic field extrapolation.
Title: 3-D Reconstruction of the Inner Heliosphere From Remote-Sensing
Data: A Global Solar Wind Boundary that Includes CME Transient Effects
Authors: Jackson, B. V.; Yu, H.; Hick, P. P.; Buffington, A.
Bibcode: 2012AGUFMSH43C..04J
Altcode:
At UCSD, remote-sensing analyses of the inner heliosphere have been
regularly carried out using interplanetary scintillation (IPS) data for
almost two decades. These analyses have measured and reconstructed 3-D
solar wind structure throughout this time period. These global results,
especially using Solar-Terrestrial Environment Laboratory (STELab)
IPS observations, provide a time-dependent inner boundary in density
and velocity that is nearly complete over the whole heliosphere for the
major part of each year and with a time cadence of about one day. When
using the IPS velocity analyses we can accurately convect-outward
solar surface magnetic fields and thus provide values of the field
throughout the global volume. In the inner heliosphere results of these
3-D analyses of density, velocity, and vector magnetic field have been
compared successfully with in-situ measurements obtained near Earth,
STEREO, Mars, Venus, MESSENGER, and at the Ulysses spacecraft. The
resulting precise time-dependent inner boundary of these parameters
can be further extrapolated outward to the edge of the heliosphere
using current 3-D MHD modelling techniques. Here we present sample
determinations of this boundary for recent IPS data, and give the
details that allow the interpolation of these boundary values during IPS
"outage" periods when insufficient remote-sensing data are available
to provide complete daily coverage.
Title: Forecasting Transient Heliospheric Solar Wind Parameters at
the Locations of the Inner Planets
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Clover, J. M.;
Tokumaru, M.
Bibcode: 2012aogs...30...93J
Altcode: 2012agos...30...93J
Remotely-sensed interplanetary scintillation (IPS) from the
solar-terrestrial environment laboratory (STELab)system, and
Thomson-scattering observations from the U.S. Air Force/NASA Solar Mass
Ejection Imager (SMEI) allow the determination of solar wind parameters
at the locations of the inner planets. We show a 3D analysis technique
developed to provide daily-cadence transient solar wind forecasts of
velocity and density at Earth and the inner planets. These now include
in-situ measurements near Earth available in real time. Where in-situ
measurements are available these real-time analyses are compared with
the predicted values. Using the global velocity measurements available
from IPS analysis and daily updated magnetograms from the National Solar
Observatory, we are also able toproject outward solar-surfacemagnetic
fields in order to provide reasonable global in-situ magnetic-field
component trends from one day to the next. This paper summarizes the
analysis available and current progress in using the STELab, Japan
real-time data for validating these forecasts. A discussion is also
provided as to how we can derive more meaningful future information
from these remotely-sensed heliospheric measurements.
Title: The 3d Reconstructed Global Solar Wind Boundary from
Remote-Sensing IPS Data
Authors: Yu, Hsiu-Shan; Jackson, B. V.; Hick, P. P.; Buffington, A.;
Clover, J. M.; Tokumaru, Munetoshi
Bibcode: 2012shin.confE..32Y
Altcode:
At UCSD, remote-sensing analyses of the inner heliosphere have been
regularly carried out using interplanetary scintillation (IPS) data
for almost two decades. These analyses have measured and reconstructed
3D solar wind structure throughout this time period. These global
results, especially using Solar-Terrestrial Environment Laboratory
(STELab) IPS observations, provide a time-dependent inner boundary in
density and velocity that is nearly complete over the whole heliosphere
for the major part of each year and with a time cadence of about one
day. When using the volumetric velocity provided by UCSD time-dependent
tomography, we can accurately convect-outward solar surface magnetic
fields and thus provide values of the magnetic field throughout the
global volume. These resulting time-dependent 3D reconstructed results
of density, velocity, and vector magnetic field, which are available
from 15 solar radii out to 3.0 AU, have been compared successfully
with in-situ measurements obtained near Earth, STEREO, Mars, Venus,
MESSENGER, and at the Ulysses spacecraft. Here we present sample
determinations of these global solar wind boundary for 3D-MHD models
from recent IPS data.
Title: The 3d Global Forecast of Inner Heliosphere Solar Wind
Parameters from Remotely-Sensed IPS Data
Authors: Jackson, B. V.; Clover, J. M.; Hick, P. P.; Yu, Hsiu-Shan;
Buffington, A.; Tokumaru, Munetoshi
Bibcode: 2012shin.confE..15J
Altcode:
At UCSD, remote-sensing forecast analyses of the inner heliosphere
have been regularly carried out using interplanetary scintillation
(IPS) data. These analyses have measured and reconstructed the
3-D time-dependent solar wind structure for almost two decades
using Solar-Terrestrial Environment Laboratory (STELab) IPS
observations. More recently we have provided an even more accurate
3-D forecast analyses by incorporating in-situ spacecraft measurements
into the remotely-sensed volumes. When using the IPS velocity analyses
we can accurately convect-outward solar surface magnetic fields using
potential field model techniques, and thus also provide values of the
field throughout the global volume. This forecast analysis is being
operated in real time at the UCSD website http://ips.ucsd.edu, and at
the NASA Goddard Community Coordinated Modeling Center (CCMC) website:
http://iswa.ccmc.gsfc.nasa.gov:8080/IswaSystemWebApp/index.jsp? The
results of these time-dependent 3-D analyses of density, velocity,
and vector magnetic field are compared with in-situ measurements
obtained in real time near Earth, and are also displayed in real time
at all the other inner planets: Mercury, Venus and Mars as well as
at the locations of the STEREO A and B spacecraft. We display these
forecasts obtained from our UCSD website at this poster presentation,
and discuss a metric that we have devised to determine how well these
forecasts agree with ongoing in-situ measurements.
Title: Variable Stellar Object Detection and Light Curves from the
Solar Mass Ejection Imager (SMEI)
Authors: Hounsell, R. A.; Bode, M. F.; Darnley, M. J.; Harman, D. J.;
Hick, P. P.; Buffington, A.; Jackson, B. V.; Clover, J. M.; Shafter,
A. W.
Bibcode: 2012IAUS..285...91H
Altcode:
With the advent of surveys such as the Catalina Real-Time Transient
Survey, the Palomar Transient Factory, Pan-STARRS and Gaia,
the search for variable objects and transient events is rapidly
accelerating. There are, however important existing data-sets from
instruments not originally designed to find such events. One example
of such an instrument is the Solar Mass Ejection Imager (SMEI), an
all-sky space-based differential photometer which is able to produce
light curves of bright objects (m <= 8) with a 102-minute cadence. In
this paper we discuss the use of such an instrument for investigations
of novæ, and outline future plans to find other variable objects with
this hitherto untapped resource.
Title: A Study of Long-Term Heliospheric Brightness Using SMEI Data
Authors: Buffington, A.; Clover, J. M.; Hick, P. P.; Jackson, B. V.;
Bisi, M. M.
Bibcode: 2011AGUFMSH13B1970B
Altcode:
The Solar Mass Ejection Imager (SMEI) has been returning white-light
photometric maps of nearly the entire sky with a 102-minute cadence
for well over eight years. When the usual sidereal and zodiacal
backgrounds are removed, the residual maps are used to study
CME/ICME events. Moreover, the successful sidereal subtraction
provides a certification of SMEI's photometric accuracy over this
time period. Further, since the zodiacal background removal employs a
brightness model which does not vary with time, a search for potential
long-term changes in the residue can show whether the zodiacal cloud's
dust distribution varies within this portion of the present solar
cycle. We present results from studies using SMEI imagery along with
a concluded zodiacal-light model.
Title: SMEI and IPS 3-D CME Reconstructions, and What They Indicate
of Heliospheric Solar Wind Acceleration
Authors: Jackson, B. V.; Clover, J. M.; Hick, P. P.; Buffington, A.;
Bisi, M. M.; Tokumaru, M.
Bibcode: 2011AGUFMSH32A..05J
Altcode:
The remotely-sensed measurements of coronal mass ejections (CMEs) and
their interplanetary counterparts (ICMEs) from Solar Mass Ejection
Imager (SMEI) white-light brightness and radio interplanetary
scintillation (IPS) data can be used to provide limits on the
acceleration and deceleration of transients in the inner heliosphere. As
an intermediate measurement between the Sun and 1 AU, the limits
provided by remote sensing are convolved with line-of-sight effects and
CME/ICME `evolution' as each feature of the transient moves outward
from the Sun. Here we review a few of the popular events and studies
that have been presented to show how CME propagation proceeds in the
inner heliosphere. Often, the apparent acceleration shown can only be
provided by employing an assumption of the CME three-dimensional (3-D)
shape, which often changes with solar distance and CME visibility along
the line of sight. This assumption can often abrogate the original
acceleration measurement. In particular we concentrate here on the
analysis of two events during periods in 02-04 November 2003, and
also in January 2010 showing how each event provides significantly
different acceleration profiles depending on which structures are
identified in each transient. Finally, we highlight the strange case
of polar coronal jets (that are essentially miniature CMEs) frequently
observed to move outward in the polar coronal fast wind at speeds of
over three times ambient. These small solar wind transients seem to
have disappeared by the time they can be observed in Ulysses in-situ
data. Thus, a detailed study of these jets may provide an understanding
of smaller-scale CME/ICME deceleration processes.
Title: UCSD Time-Dependent Tomographic Forecasting with Interplanetary
Scintillation and White-Light Observations
Authors: Clover, J. M.; Jackson, B. V.; Hick, P. P.; Buffington, A.;
Tokumaru, M.; Fujiki, K.; Hirota, M.; Bisi, M. M.
Bibcode: 2011AGUFMSH31C2025C
Altcode:
The University of California, San Diego (UCSD) time-dependent tomography
program has been used successfully since the beginning of the year
2000 to remotely sense and forecast interplanetary scintillation (IPS)
observations of coronal mass ejections (CMEs). Recently, this program
has included real-time ACE data in the analysis. This more-efficiently
extends velocity and density measurements obtained near Earth in
real time to those derived from remotely-sensed observations, and
allows a far more efficient extrapolation from the present time
into the future. These analyses are now also used with real-time
extrapolations of radial and tangential magnetic fields from the
National Solar Observatory. The time-dependent program is also being
adapted to provide similar forecasts (but at higher spatial and temporal
resolutions) of heliospheric density using Thomson-scattering data from
the Solar Mass Ejection Imager (SMEI). Here, we describe the current
state of these IPS and SMEI real-time data pipelines and show their
usefulness. These demonstrate in near real-time the improved accuracy
of the remote-sensing fits with the inclusion of space-borne in-situ
density and velocity measurements during the current rising phase of
the solar cycle.
Title: Imaging Coronal Mass Ejections and Large-Scale Solar Wind
Structure Using Thomson-Scattering Measurements from SMEI
Authors: Jackson, B. V.; Clover, J. M.; Buffington, A.; Hick, P. P.;
Bisi, M. M.; Marubashi, K.; Webb, D. F.
Bibcode: 2011AGUFMSH21A1909J
Altcode:
In January 2010, two coronal mass ejections (CMEs) erupted from near
the solar east limb, the first on late 14 January 2010 and the second
on 17 January 2010. Both arrived at the Solar TErrestrial RElations
Observatory Behind spacecraft (STEREO-B) about six days later. We are
able to reconstruct the heliospheric density of both CME events in
three dimensions (3D) using data from the Solar Mass Ejection Imager
(SMEI) and our tomographic analysis. For each event, we isolate the
particular portion of the heliosphere attributed to the transient
CME density structure from the tomographic results, and then estimate
its extent. The structure of these events is shown in detail in the
three-dimensional reconstruction both as pseudo-coronagraph images
and later as density at the locations of STEREO-B and the Earth. The
first of these CMEs was associated with a magnetic cloud that had a
density enhancement near its center. By assuming that this density
enhancement extends along the loop, we can use the three-dimensional
density analysis to map the extent and orientation of this structure
in order to match it to existing magnetic-loop models and to use the
remote-sensing observations to constrain the various flux-rope models
determined using the in-situ measurements of the 14 January 2010 event.
Title: Observations of Polar-Region Jets and Their Manifestations
in the Solar Wind
Authors: Jackson, Bernard V.; Clover, John M.; Hick, P. Paul;
Buffington, Andrew; Linford, John C.; Shimojo, Masumi; Sako, Nobuharu
Bibcode: 2011shin.confE.170J
Altcode:
High-cadence images taken by the X-Ray Telescope (XRT) aboard Hinode
(Solar B), have shown that X-ray jets occur at very high frequency over
the polar regions of the Sun. Only the brightest of these explosive
events had been previously observed. It is possible that Alfven waves
generated by jets contribute greatly to the acceleration of the solar
wind; each jet provides a conduit for Alfven waves that add significant
energy to the corona by spreading outward from these localized areas
on the Sun. Here we explore the manifestations of the jet response in
the solar wind using observations from Hinode, the LASCO coronagraph,
and from 3D tomographic observations at greater heights above the
Sun. We attempt to quantify the jet response in the interplanetary
medium from these measurements, and to explore the diminution of this
response with solar radius.
Title: UCSD Time-Dependent Tomographic Forecasting with Interplanetary
Scintillation and White Light Observations
Authors: Clover, John M.; Jackson, Bernard V.; Hick, P. Paul;
Buffington, Andrew; Lindford, John C.
Bibcode: 2011shin.confE..20C
Altcode:
The University of California, San Diego (UCSD) time-dependent tomography
program has been used successfully since the beginning of the year
2000 to remotely sense and forecast interplanetary scintillation (IPS)
observations of coronal mass ejections. Recently, this program has
incorporated ACE data in the analysis to more efficiently extend,
in real time, near-Earth observations of velocity and density, to
those derived from remotely-sensed observations. This allows a more
efficient extrapolation from the present time into the future. The
time-dependent program has now also been adapted to provide forecasts
of heliospheric density using Thomson-scattered brightness from the
Solar Mass Ejection Imager (SMEI). Here we describe the current state
of these IPS and SMEI real-time data pipelines, and show examples of
the improved accuracy of the remote-sensing fits with the inclusion
of space-borne in-situ density and velocity measurements.
Title: Solar Mass Ejection Imager (SMEI) 3-D reconstruction of density
enhancements behind interplanetary shocks: In-situ comparison near
Earth and at STEREO
Authors: Jackson, B. V.; Hamilton, M. S.; Hick, P. P.; Buffington,
A.; Bisi, M. M.; Clover, J. M.; Tokumaru, M.; Fujiki, K.
Bibcode: 2011JASTP..73.1317J
Altcode:
SMEI and IPS remotely observe increased brightness and velocity
enhancements behind interplanetary shocks that are also seen in
situ. We use the UCSD time-dependent 3-D reconstruction technique
to map these enhancements, and compare them with measurements at the
SOHO, Wind, ACE, and STEREO spacecraft. The analyses of these shocks
from hour-averaged in-situ data show that the enhanced density column
associated with the shock response varies considerably between different
instruments, even for in-situ instruments located at L1
near Earth. The relatively-low-resolution SMEI 3-D reconstructions
generally show density enhancements, and within errors, the column
excesses match those observed in situ. In these SMEI 3-D reconstructions
from remotely-sensed data, the shock density enhancements appear not
as continuous broad fronts, but as segmented structures. This may
provide part of the explanation for the observed discrepancies between
the various in-situ measurements at Earth and STEREO, but not between
individual instruments near L1.
Title: Investigations of the July-August 2010 CME Event(s)
Authors: Bisi, Mario M.; Jackson, Bernard V.; Clover, John M.; Jensen,
Elizabeth A.; Mulligan, Tamitha M.; Manoharan, Periasamy K.; Hick,
P. Paul
Bibcode: 2011shin.confE.130B
Altcode:
A complex solar eruption (or set of eruptions) occurred at the start
of August 2010 releasing a disappearing filament and halo CME on an
Earth-wards trajectory launching from AR 1092. The first ICME arrived on
03 August followed by a second stronger ICME on 04; both were travelling
at speeds approximately twice that of the ambient solar wind of the
time. The ICMEs triggered a G2-class geomagnetic storm. Here, we look
at the 3-D reconstruction of the event(s) from Solar Mass Ejection
Imager (SMEI) white-light data, and where possible, interplanetary
scintillation (IPS) data. We also discuss flux-rope modelling results
as measured by ACE, VEX, and STEREO-B instrumentation. We will discuss
and attempt to pull together our findings in the context of the inner
heliosphere.
Title: Three-dimensional reconstruction of heliospheric structure
using iterative tomography: A review
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Bisi, M. M.;
Clover, J. M.; Tokumaru, M.; Kojima, M.; Fujiki, K.
Bibcode: 2011JASTP..73.1214J
Altcode:
Current perspective and in-situ analyses using data from NASA's twin
Solar TErrestrial RElations Observatory (STEREO) spacecraft have focused
studies on ways to provide three-dimensional (3-D) reconstructions of
coronal and heliospheric structure. Data from STEREO are proceeded
by and contemporaneous with many other types of data and analysis
techniques; most of the latter have provided 3-D information by relying
on remote-sensing information beyond those of the near corona (outside
10 RS). These include combinations of past data from the
Helios spacecraft and the Solwind coronagraphs and, continuing from the
past to the present, from observations of interplanetary scintillation
(IPS) and the Solar Mass Ejection Imager (SMEI) instrument. In this
article we review past and ongoing analyses that have led to a current
great wealth of 3-D information. When properly utilized, these analyses
can provide not only shapes of CME/ICMEs but also a characterization
of any solar wind structure or global outflow.
Title: The early outburst light curve of the 2011 eruption of the
Recurrent Nova T Pyxidis from Solar Mass Ejection Imager (SMEI)
observations
Authors: Hounsell, R.; Darnley, M. J.; Harman, D. J.; Bode, M. F.;
Clover, J. M.; Hick, P. P.; Buffington, A.; Jackson, B. V.; Osborne,
J.; Shafter, A. W.
Bibcode: 2011ATel.3373....1H
Altcode:
We report white light observations of the 2011 outburst of
Recurrent Nova T Pyxidis obtained using the USAF/NASA Solar Mass
Ejection Imager (SMEI) on board the Coriolis satellite (see Hounsell
et al., 2010 for details, all magnitudes quoted here are native
to the SMEI photometric system). The instrument has a peak quantum
efficiency at approximately 700 nm with a FWHM ~ 300 nm.
Title: The 3D Reconstruction of Heliospheric Density Using
Thomson-Scattering Observations - Current Progress and Future
Prospects
Authors: Jackson, Bernard V.; Clover, J. M.; Buffington, A.; Hick,
P. P.
Bibcode: 2011SPD....42.1401J
Altcode: 2011BAAS..43S.1401J
Three-dimensional reconstructions using Thomson-scattering observations
from the Air Force/NASA Solar Mass Ejection Imager (SMEI) provide
a determination of density in the inner heliosphere and allow its
forecast from these remote-sensing heliospheric data. Here we describe
our recent progress in providing density from this technique, and our
current success in this endeavor. We would like to provide the best
possible remote determinations of this heliospheric parameter. Here we
explore this possibility with the copious data available from the SMEI
imagery that can now be cleaned of auroral signals such that as many
as 10,000 lines of sight can be available on each 102-minute orbit. We
speculate on the degree to which these methods and results could be
used on future heliospheric missions, should such instruments on such
missions provide images as finely-calibrated as those from SMEI.
Title: Analysis of Epsilon Aurigae light curve from the Solar Mass
Ejection Imager
Authors: Clover, John; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Kloppenborg, B.; Stencel, R.
Bibcode: 2011AAS...21725702C
Altcode: 2011BAAS...4325702C
The Solar Mass Ejection Imager (SMEI) was launched aboard the Coriolis
spacecraft in 2003. It is equipped with 3 CCD cameras to measure the
brightness of Thomson-scattered electrons in the heliosphere. Each
CCD images a strip of the sky that is 3°x60°. The three cameras are
mounted on the satellite with their fields of view aligned end-to-end
so that SMEI sweeps nearly the entire sky each 102 minute orbit. SMEI
has now accumulated stellar time series for about 5700 bright stars,
including epsilon Aurigae, for each orbit where data is available. SMEI
data provide nearly year-round coverage of epsilon Aurigae. The baffled
SMEI optics provide more accurate photometric data than ground-based
observations, particularly at mid-eclipse when epsilon Aurigae is close
to the Sun. We present an analysis of the brightness variations of
the epsilon Aurigae system, before and during the eclipse. The
University of Denver participants are grateful for support under
NSFgrant 10-16678 and the bequest of William Hershel Womble in support
of astronomy at the University of Denver.
Title: Solar Mass Ejection Imager (SMEI) 3-D Reconstructions of CMEs,
CIRs and Interplanetary Shocks, and Comparison with In-situ Data
Authors: Jackson, B. V.; Clover, J. M.; Hick, P. P.; Buffington, A.;
Bisi, M. M.
Bibcode: 2010AGUFMSH31D..05J
Altcode:
The Solar Mass Ejection Imager (SMEI) has been operating since February
2003. At the University of California, San Diego (UCSD), a series
of editing steps and a tomography program removes zodiacal light,
high-energy-particle hits, and aurorae the SMEI data; and generates
reconstructed sky-map images and three-dimensional (3-D) volumetric
densities shortly after the SMEI CCD images become available. The
removal of a long-term base allows us to map the 3-D density extents of
coronal mass ejections (CMEs) and co-rotating structures, and measure
the density variations of these structures including estimates of their
continuity and the extent of density enhancements behind interplanetary
shocks. We match our analysis with the in-situ density columns that pass
the spacecraft near Earth as well as near the twin Solar TErrestrial
RElations Observatory (STEREO) spacecraft. Here we concentrate on
Thomson-scattered white-light SMEI observations of the 3 April 2010
halo CME, contrasting it to the studies of previous CME events that
provide similar Sun-to-Earth analyses.
Title: Remote-Sensing Studies of Heliospheric Solar-Wind Structure
Around Two Solar Minima
Authors: Bisi, M. M.; Clover, J. M.; Breen, A.; Jensen, E. A.; Fallows,
R.; Jackson, B. V.; Hick, P. P.; Rawlins, A.; Davies, J. A.; Owens,
M.; Xiong, M.; Buffington, A.; Grande, M.
Bibcode: 2010AGUFMSH41A1771B
Altcode:
Remote-sensing observations of the inner heliosphere are carried out
routinely using both the interplanetary scintillation (IPS) observations
of astronomical radio sources and also the Thomson-scattered white
light from heliospheric electrons. For these latter observations,
we use the Earth-orbiting Solar Mass Ejection Imager (SMEI: from
February 2003) aboard the Coriolis Satellite, and more recently using
the Heliospheric Imagers (HIs) aboard the Solar TErrestrial RElations
Observatory twin spacecraft (STEREO: from late 2006/early 2007). The
data sets from various IPS-capable systems as well as SMEI are used
with the University of California, San Diego (UCSD) three-dimensional
(3-D) tomographic-reconstruction and visualisation algorithms. We are
able to compare with in-situ measurements from multiple spacecraft
with these reconstruction results. This makes it possible to study the
structure of the inner heliosphere as a whole, including the isolation
of individual features or events such as interplanetary coronal mass
ejections (ICMEs) or stream interaction regions (SIRs). We look at the
global structure of the heliosphere during the current and previous
solar minima, and discuss similarities and differences between the
two solar cycles where possible.
Title: Imaging Coronal Mass Ejections and Large-Scale Solar Wind
Structure Using IPS and Thomson-Scattered Sunlight (Invited)
Authors: Clover, J. M.; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Bisi, M. M.; Tokumaru, M.; Fujiki, K.
Bibcode: 2010AGUFMSH52B..03C
Altcode:
The Solar Mass Ejection Imager (SMEI) observes Thomson-scattered
white light from heliospheric electrons across almost all of the sky
nearly all of the time since early 2003. Interplanetary scintillation
(IPS) observations of velocity and g-level provide similar structure
information but with a less-complete sky-and-time coverage. The
Solar TErrestrial RElations Observatory (STEREO) twin spacecraft
outer Heliospheric Imagers (HI-2) currently image the heliosphere in
Thomson-scattered light near the ecliptic plane far from Earth. The
Solar-Terrestrial Environment Laboratory (STELab) IPS observations
provide IPS velocity and g-level values, which in conjunction with our
tomographic reconstruction program, yield velocities and densities
of the inner heliosphere in three dimensions. The same tomographic
program substitutes SMEI Thomson-scattering brightness information for
the g-level values to derive heliospheric densities from these data
alone. We look at the global structure of the heliosphere concentrating
mainly on three events from 2007 through the rise phase of Solar Cycle
24. The first event, observed in both the IPS and SMEI defines the
three-dimensional velocity and density structure around the time of the
shock observed at Earth on 02:02 UT 17 December 2007. The second event,
seen only by SMEI, is that of the 23-26 April 2008 coronal mass ejection
(CME) and its interplanetary counterpart. The third event is the CME
(and its interplanetary counterpart) that took place 17 January 2010
and arrived at STEREO-B about four days later. For each event, we
isolate the particular portion of the heliosphere attributed to the
transient density structure using our tomographic technique, and then
estimate its extent.
Title: Type III Metric Radio-Wave Activity Prior to and During Active
Region Flaring and CMEs (Invited)
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Oberoi, D.;
Matthews, L. D.
Bibcode: 2010AGUFMSH54D..03J
Altcode:
From the time that type III metric radio-wave activity has been known,
and imaged, there has been a realization that this activity often
increases during, and for some events from a few minutes to several
hours prior to the major manifestations observed for a flare or Coronal
Mass Ejection (CME). We review these analyses from as long ago as the
observations from Culgoora, Australia, and more recently from the French
Nancay radio observatory. We find there can be precursor activity before
a flare or CME as indicated by the increasing numbers of isolated type
III bursts, and that this can be a maximum prior to the most obvious
manifestation of either the surface flare or the most obvious rapid
outward coronal motion of a CME. Current imaging measurements from the
Nancay radio array further clarify the location of this activity for
specific events such as the 26 April 2008 CME that was observed just
following the Whole Heliosphere Interval (WHI) near the time of solar
minimum. A plausible explanation for this precursor activity exists,
and we expect that this idea can be more fully tested using present-day
observations. As solar activity increases and more observations become
available from, for instance, the Murchison Widefield Array (MWA) now
under construction in Western Australia, far better worldwide temporal
coverage for this type of analysis will exist. In conjunction with
current NASA instrumentation such as the Solar TErrestrial RElations
Observatory (STEREO) and SOlar and Heliospheric Observatory (SOHO)
coronagraphs, and the Solar Dynamics Observatory (SDO), we expect a
significant improvement in our understanding of this unique flare and
CME precursor activity.
Title: SMEI 3D Reconstruction of a Coronal Mass Ejection Interacting
with a Corotating Solar Wind Density Enhancement: The 2008 April
26 CME
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Clover, J. M.;
Bisi, M. M.; Webb, D. F.
Bibcode: 2010ApJ...724..829J
Altcode:
The Solar Mass Ejection Imager (SMEI) has recorded the brightness
responses of hundreds of interplanetary coronal mass ejections (CMEs) in
the interplanetary medium. Using a three-dimensional (3D) reconstruction
technique that derives its perspective views from outward-flowing
solar wind, analysis of SMEI data has revealed the shapes, extents,
and masses of CMEs. Here, for the first time, and using SMEI data, we
report on the 3D reconstruction of a CME that intersects a corotating
region marked by a curved density enhancement in the ecliptic. Both the
CME and the corotating region are reconstructed and demonstrate that the
CME disrupts the otherwise regular density pattern of the corotating
material. Most of the dense CME material passes north of the ecliptic
and east of the Sun-Earth line: thus, in situ measurements in the
ecliptic near Earth and at the Solar-TErrestrial RElations Observatory
Behind spacecraft show the CME as a minor density increase in the solar
wind. The mass of the dense portion of the CME is consistent with
that measured by the Large Angle Spectrometric Coronagraph on board
the Solar and Heliospheric Observatory spacecraft, and is comparable
to the masses of many other three-dimensionally reconstructed solar
wind features at 1 AU observed in SMEI 3D reconstructions.
Title: A Heliospheric Imager for Deep Space: Lessons Learned from
Helios, SMEI, and STEREO
Authors: Buffington, A.; Jackson, B. V.; Hick, P. P.; Clover, J. M.;
Bisi, M. M.
Bibcode: 2010AGUFMSH41A1780B
Altcode:
The zodiacal-light photometers on the twin Helios spacecraft, the
Solar Mass Ejection Imager (SMEI) aboard the Coriolis spacecraft, and
the Heliospheric Imagers (HIs) on the twin Solar-TErrestrial RElations
Observatory (STEREO) spacecraft all point the way to optimizing future
remote-sensing Thomson-scattering observations from deep space. In the
future, such data could be provided by wide-angle viewing instruments
deployed on Solar Orbiter, Solar Probe Plus, and other deep-space
missions. Here, we present instrument specifications required for a
successful heliospheric imager, and the calibration measurements and
data-processing steps that enable the best use of these remote-sensing
systems. When properly designed and calibrated, data from these types
of instruments measure zodiacal-dust properties, and are used to
provide three-dimensional reconstructions of heliospheric electron
density over large volumes of the inner heliosphere. Such systems
measure fundamental properties of the inner heliospheric plasma,
provide context for the in-situ monitors on board spacecraft, and
perhaps most significantly, enable physics-based analyses of this
important segment of the Sun-Spacecraft connection.
Title: Exquisite Nova Light Curves from the Solar Mass Ejection Imager
(SMEI)
Authors: Hounsell, R.; Bode, M. F.; Hick, P. P.; Buffington, A.;
Jackson, B. V.; Clover, J. M.; Shafter, A. W.; Darnley, M. J.; Mawson,
N. R.; Steele, I. A.; Evans, A.; Eyres, S. P. S.; O'Brien, T. J.
Bibcode: 2010ApJ...724..480H
Altcode: 2010arXiv1009.1737H
We present light curves of three classical novae (CNe; KT Eridani, V598
Puppis, V1280 Scorpii) and one recurrent nova (RS Ophiuchi) derived
from data obtained by the Solar Mass Ejection Imager (SMEI) on board
the Coriolis satellite. SMEI provides near complete skymap coverage
with precision visible-light photometry at 102 minute cadence. The
light curves derived from these skymaps offer unprecedented temporal
resolution around, and especially before, maximum light, a phase of the
eruption normally not covered by ground-based observations. They allow
us to explore fundamental parameters of individual objects including
the epoch of the initial explosion, the reality and duration of any
pre-maximum halt (found in all three fast novae in our sample), the
presence of secondary maxima, speed of decline of the initial light
curve, plus precise timing of the onset of dust formation (in V1280
Sco) leading to estimation of the bolometric luminosity, white dwarf
mass, and object distance. For KT Eri, Liverpool Telescope SkyCamT
data confirm important features of the SMEI light curve and overall
our results add weight to the proposed similarities of this object to
recurrent rather than to CNe. In RS Oph, comparison with hard X-ray
data from the 2006 outburst implies that the onset of the outburst
coincides with extensive high-velocity mass loss. It is also noted
that two of the four novae we have detected (V598 Pup and KT Eri)
were only discovered by ground-based observers weeks or months after
maximum light, yet these novae reached peak magnitudes of 3.46 and
5.42, respectively. This emphasizes the fact that many bright novae
per year are still overlooked, particularly those of the very fast
speed class. Coupled with its ability to observe novae in detail even
when relatively close to the Sun in the sky, we estimate that as many
as five novae per year may be detectable by SMEI.
Title: A Summary of 3-D Reconstructions of the Whole Heliosphere
Interval and Comparison with in-Ecliptic Solar Wind Measurements
from STEREO, ACE, and Wind Instrumentation
Authors: Bisi, Mario M.; Jackson, B. V.; Clover, J. M.; Hick, P. P.;
Buffington, A.; Tokumaru, M.
Bibcode: 2010HiA....15..480B
Altcode:
We present a summary of results from simultaneous Solar-Terrestrial
Environment Laboratory (STELab) Interplanetary Scintillation
(IPS), STEREO, ACE, and Wind observations using three-dimensional
reconstructions of the Whole Heliosphere Interval - Carrington rotation
2068. This is part of the world-wide IPS community's International
Heliosphysical Year (IHY) collaboration. We show the global structure
of the inner heliosphere and how our 3-D reconstructions compare with
in-ecliptic spacecraft measurements.
Title: Three-Dimensional (3-D) Reconstruction of Solar-Wind Structure
at the Inner Planets and in the Inner Heliosphere
Authors: Bisi, M. M.; Jackson, B. V.; Wood, A. G.; Clover, J. M.;
Breen, A. R.; Fallows, R. A.; Jensen, E. A.; Tokumaru, M.; Fujiki,
K.; Hick, P. P.
Bibcode: 2010epsc.conf..882B
Altcode:
No abstract at ADS
Title: Three-Dimensional (3-D) Reconstructions of EISCAT IPS Velocity
Data in the Declining Phase of Solar Cycle 23
Authors: Bisi, M. M.; Jackson, B. V.; Breen, A. R.; Dorrian, G. D.;
Fallows, R. A.; Clover, J. M.; Hick, P. P.
Bibcode: 2010SoPh..265..233B
Altcode: 2010SoPh..tmp..129B; 2010SoPh..tmp..117B
The European Incoherent SCATter (EISCAT) radar has been used for
remote-sensing observations of interplanetary scintillation (IPS) for
a quarter of a century. During the April/May 2007 observing campaign,
a large number of observations of IPS using EISCAT took place to
give a reasonable spatial and temporal coverage of solar wind velocity
structure throughout this time during the declining phase of Solar Cycle
23. Many co-rotating and transient features were observed during this
period. Using the University of California, San Diego three-dimensional
(3-D) time-dependent computer assisted tomography (C.A.T.) solar-wind
reconstruction analysis, we show the velocity structure of the inner
heliosphere in three dimensions throughout the time interval of 20 April
through 20 May 2007. We also compare to white-light remote-sensing
observations of an interplanetary coronal mass ejection (ICME)
seen by the STEREO Ahead spacecraft inner Heliospheric Imager on 16
May 2007, as well as to in-situ solar-wind measurements taken with
near-Earth spacebourne instrumentation throughout this interval. The
reconstructions show clear co-rotating regions during this period,
and the time-series extraction at spacecraft locations compares well
with measurements made by the STEREO, Wind, and ACE spacecraft. This
is the first time such clear structures have been revealed using this
3-D technique with EISCAT IPS data as input.
Title: Faraday Rotation Response to Coronal Mass Ejection Structure
Authors: Jensen, E. A.; Hick, P. P.; Bisi, M. M.; Jackson, B. V.;
Clover, J.; Mulligan, T.
Bibcode: 2010SoPh..265...31J
Altcode: 2010SoPh..tmp...75J
We present the results from modeling the coronal mass ejection (CME)
properties that have an effect on the Faraday rotation (FR) signatures
that may be measured with an imaging radio antenna array such as the
Murchison Widefield Array (MWA). These include the magnetic flux rope
orientation, handedness, magnetic-field magnitude, velocity, radius,
expansion rate, electron density, and the presence of a shock/sheath
region. We find that simultaneous multiple radio source observations
(FR imaging) can be used to uniquely determine the orientation of
the magnetic field in a CME, increase the advance warning time on the
geoeffectiveness of a CME by an order of magnitude from the warning time
possible from in-situ observations at L1, and investigate
the extent and structure of the shock/sheath region at the leading
edge of fast CMEs. The magnetic field of the heliosphere is largely
"invisible" with only a fraction of the interplanetary magnetic-field
lines convecting past the Earth; remote sensing the heliospheric
magnetic field through FR imaging from the MWA will advance solar
physics investigations into CME evolution and dynamics.
Title: A Heliospheric Imager for Deep Space: Lessons Learned from
Helios, SMEI, and STEREO
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Bisi, M. M.;
Clover, J. M.
Bibcode: 2010SoPh..265..257J
Altcode: 2010SoPh..tmp..102J
The zodiacal-light photometers on the twin Helios spacecraft, the
Solar Mass Ejection Imager (SMEI) on the Coriolis spacecraft, and
the Heliospheric Imagers (HIs) on the Solar-TErrestrial RElations
Observatory (STEREO) twin spacecraft all point the way to optimizing
future remote-sensing Thomson-scattering observations from deep
space. Such data could be provided by wide-angle viewing instruments
on Solar Orbiter, Solar Probe, or other deep-space probes. Here, we
present instrument specifications required for a successful heliospheric
imager, and the measurements and data-processing steps that make the
best use of this remote-sensing system. When this type of instrument is
properly designed and calibrated, its data are capable of determining
zodiacal-dust properties, and of three-dimensional reconstructions
of heliospheric electron density over large volumes of the inner
heliosphere. Such systems can measure fundamental properties of the
inner heliospheric plasma, provide context for the in-situ monitors on
board spacecraft, and enable physics-based analyses of this important
segment of the Sun-spacecraft connection.
Title: From the Sun to the Earth: The 13 May 2005 Coronal Mass
Ejection
Authors: Bisi, M. M.; Breen, A. R.; Jackson, B. V.; Fallows, R. A.;
Walsh, A. P.; Mikić, Z.; Riley, P.; Owen, C. J.; Gonzalez-Esparza,
A.; Aguilar-Rodriguez, E.; Morgan, H.; Jensen, E. A.; Wood, A. G.;
Owens, M. J.; Tokumaru, M.; Manoharan, P. K.; Chashei, I. V.; Giunta,
A. S.; Linker, J. A.; Shishov, V. I.; Tyul'bashev, S. A.; Agalya, G.;
Glubokova, S. K.; Hamilton, M. S.; Fujiki, K.; Hick, P. P.; Clover,
J. M.; Pintér, B.
Bibcode: 2010SoPh..265...49B
Altcode: 2010SoPh..tmp..136B
We report the results of a multi-instrument, multi-technique,
coordinated study of the solar eruptive event of 13 May 2005. We
discuss the resultant Earth-directed (halo) coronal mass ejection
(CME), and the effects on the terrestrial space environment and
upper Earth atmosphere. The interplanetary CME (ICME) impacted the
Earth's magnetosphere and caused the most-intense geomagnetic storm
of 2005 with a Disturbed Storm Time (Dst) index reaching −263 nT
at its peak. The terrestrial environment responded to the storm on
a global scale. We have combined observations and measurements from
coronal and interplanetary remote-sensing instruments, interplanetary
and near-Earth in-situ measurements, remote-sensing observations and
in-situ measurements of the terrestrial magnetosphere and ionosphere,
along with coronal and heliospheric modelling. These analyses are used
to trace the origin, development, propagation, terrestrial impact, and
subsequent consequences of this event to obtain the most comprehensive
view of a geo-effective solar eruption to date. This particular event
is also part of a NASA-sponsored Living With a Star (LWS) study and
an on-going US NSF-sponsored Solar, Heliospheric, and INterplanetary
Environment (SHINE) community investigation.
Title: Inclusion of In-Situ Velocity Measurements into the
UCSD Time-Dependent Tomography to Constrain and Better-Forecast
Remote-Sensing Observations
Authors: Jackson, B. V.; Hick, P. P.; Bisi, M. M.; Clover, J. M.;
Buffington, A.
Bibcode: 2010SoPh..265..245J
Altcode: 2010SoPh..tmp...43J; 2010SoPh..tmp...55J
The University of California, San Diego (UCSD) three-dimensional
(3-D) time-dependent tomography program has been used successfully
for a decade to reconstruct and forecast coronal mass ejections
from interplanetary scintillation observations. More recently, we
have extended this tomography technique to use remote-sensing data
from the Solar Mass Ejection Imager (SMEI) on board the Coriolis
spacecraft; from the Ootacamund (Ooty) radio telescope in India;
and from the European Incoherent SCATter (EISCAT) radar telescopes
in northern Scandinavia. Finally, we intend these analyses to be
used with observations from the Murchison Widefield Array (MWA),
or the LOw Frequency ARray (LOFAR) now being developed respectively
in Australia and Europe. In this article we demonstrate how in-situ
velocity measurements from the Advanced Composition Explorer (ACE)
space-borne instrumentation can be used in addition to remote-sensing
data to constrain the time-dependent tomographic solution. Supplementing
the remote-sensing observations with in-situ measurements provides
additional information to construct an iterated solar-wind parameter
that is propagated outward from near the solar surface past the
measurement location, and throughout the volume. While the largest
changes within the volume are close to the radial directions that
incorporate the in-situ measurements, their inclusion significantly
reduces the uncertainty in extending these measurements to global
3-D reconstructions that are distant in time and space from the
spacecraft. At Earth, this can provide a finely-tuned real-time
measurement up to the latest time for which in-situ measurements are
available, and enables more-accurate forecasting beyond this than
remote-sensing observations alone allow.
Title: UCSD 3D Reconstruction of the 12 December 2008, 20 January
2009, and 3 April 2010 CMEs
Authors: Clover, John M.; Jackson, B. V.; Hick, P. Paul; Buffington,
A.; Amirbekian, N.
Bibcode: 2010shin.confE.142C
Altcode:
The Solar Mass Ejection Imager (SMEI) data base is available for the
three-dimensional (3-D) reconstruction of CME/ICMEs from early 2003 up
through the present. Here we concentrate upon analyses of three events,
on 12 December 2008, 20 January 2009, and 3 April 2010; and provide
comparisons with in-situ measurements during this interval. The
University of California, San Diego (UCSD) SMEI database includes
individual full-sky maps and orbit differences that preserve the
original instrument resolution and photometric precision. Higher-level
products (3-D reconstructions from the data, and 3-D tomographic
reconstructed images are also maintained by UCSD on its SMEI website
for the entire SMEI period of operation. The SMEI 3-D reconstruction
program is now also available for use at the Community Coordinated
Modeling Center (CCMC) located at the NASA/Goddard Space Flight Center.
Title: UCSD IPS 3-D time-dependent reconstruction of the global
solar wind during the last solar minimum
Authors: Jackson, Bernard V.; Clover, J. M.; Hick, P. Paul; Buffington,
A.; Amirbekian, Narek
Bibcode: 2010shin.confE.157J
Altcode:
The University of California, San Diego (UCSD) maintains an
interplanetary scintillation (IPS) data base from the Solar-Terrestrial
Environment Laboratory (STELab), Nagoya, Japan, from the mid-1990's up
to the present. UCSD's three-dimensional (3-D) reconstruction of these
data in time-dependent format is available to provide measurements
of global solar wind velocity and density for this entire period
with a time cadence of one day when data from STELab are available
(generally from April to December each year). Here we concentrate on
analyses of measurements obtained during the recent solar minimum, and
show time-dependent global solar wind velocity and density in several
coordinate formats (e.g., Sun-centered ecliptic and heliographic,
and as averaged per Carrington rotation). Velocity and density from
these reconstructions are combined to also provide global solar wind
dynamic pressure in these same formats. These analyses are used to
determine the global extent and change of the solar wind during the
last solar minimum. The current UCSD IPS 3-D reconstruction program
is now also available for use at the Goddard Spaceflight Community
Coordinated Modeling Center (CCMC) for analyses of specific time
intervals and ICMEs.
Title: Three-dimensional Reconstructions and Mass Determination of the
2008 June 2 LASCO Coronal Mass Ejection Using STELab Interplanetary
Scintillation Observations
Authors: Bisi, M. M.; Jackson, B. V.; Hick, P. P.; Buffington, A.;
Clover, J. M.; Tokumaru, M.; Fujiki, K.
Bibcode: 2010ApJ...715L.104B
Altcode:
We examine and reconstruct the interplanetary coronal mass ejection
(ICME) first seen in space-based coronagraph white-light difference
images on 2008 June 1 and 2. We use observations of interplanetary
scintillation (IPS) taken with the Solar-Terrestrial Environment
Laboratory (STELab), Japan, in our three-dimensional (3D) tomographic
reconstruction of density and velocity. The coronal mass ejection
(CME) was first observed by the LASCO C3 instrument at around 04:17 UT
on 2008 June 2. Its motion subsequently moved across the C3 field of
view with a plane-of-the-sky velocity of 192 km s-1. The 3D
reconstructed ICME is consistent with the trajectory and extent of the
CME measurements taken from the CDAW CME catalog. However, excess mass
estimates vary by an order of magnitude from Solar and Heliospheric
Observatory and Solar Terrestrial Relations Observatory coronagraphs
to our 3D IPS reconstructions of the inner heliosphere. We discuss the
discrepancies and give possible explanations for these differences as
well as give an outline for future studies.
Title: Solar Wind and CME Studies of the Inner Heliosphere Using
IPS Data from Stelab, ORT, and EISCAT
Authors: Bisi, M. M.; Jackson, B. V.; Fallows, R. A.; Dorrian, G. D.;
Manoharan, P. K.; Clover, J. M.; Hick, P. P.; Buffington, A.; Breen,
A. R.; Tokumaru, M.
Bibcode: 2010aogs...21...33B
Altcode:
Interplanetary scintillation (IPS) observations provide views of the
solar wind at all heliographic latitudes from near 1 A.U. down to fields
of view covered by coronagraphs. These observations can be used to
study the propagation of the solar wind and solar transients out into
interplanetary space, and also measure the inner-heliospheric response
to co-rotating solar structures and coronal mass ejections (CMEs). We
use a three dimensional (3D) reconstruction technique that obtains
perspective views from solar co-rotating plasma and outward-flowing
solar wind as observed from the Earth by iteratively fitting a kinematic
solar wind model to IPS data from various observing systems. Here
we use the model with both Solar Terrestrial Environment Laboratory
(STELab), Japan, and Ootacamund (Ooty) Radio Telescope (ORT), India,
IPS observations. This 3D modeling technique permits reconstructions
of the density and velocity structures of CMEs and other interplanetary
transients at a relatively coarse resolution for STELab and better for
Ooty; and is dependent upon the number of observations. We present
3D reconstructions of CME events around 4-8 November 2004 from Ooty
IPS observations and some preliminary reconstructions of STELab IPS
observations around the Whole Heliospheric Interval (WHI). We also
present some preliminary results of a CME observation by both the
European Incoherent SCATter (EISCAT) radar IPS observations and those
made by the Solar TErrestrial RElations Observatory (STEREO) of a CME
in May 2007.
Title: Solar Mass Ejection Imager (smei) and Interplanetary
Scintillation (ips) 3D-RECONSTRUCTIONS of the Inner Heliosphere
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Bisi, M. M.;
Clover, J. M.; Tokumaru, M.
Bibcode: 2010aogs...21..339J
Altcode:
The Solar Mass Ejection Imager (SMEI) direct white-light data as
well as higher-level data products are available on our UCSD Website
at http://smei.ucsd.edu/ from first light in early February 2003
to nearly the present day. These analyses provide densities in the
inner heliosphere, show many familiar CMEs in three dimensions (3D)
during this interval, and provide animations and individual images
of them. This 3D analysis is enhanced by use of interplanetary
scintillation (IPS) velocity observations to help provide the
overall form of the structures reconstructed. Our time-dependent 3D
reconstruction technique is discussed, and the different ways we test
and validate these 3D results. These checks include both internal
consistency checks, and comparisons with in situ measurements at
various near-Earth spacecraft, at Ulysses, at the STEREO spacecraft,
and from magnetic field data at Mars.
Title: Solar Wind Speed Inferred from Cometary Plasma Tails using
Observations from STEREO HI-1
Authors: Clover, John M.; Jackson, Bernard V.; Buffington, Andrew;
Hick, P. Paul; Bisi, Mario M.
Bibcode: 2010ApJ...713..394C
Altcode:
The high temporal and spatial resolution of heliospheric white-light
imagers enables us to measure the propagation of plasma tails of bright
comets as they travel through the interplanetary medium. Plasma tails
of comets have been recognized for many years as natural probes of
the solar wind. Using a new technique developed at the University
of California, San Diego to measure the radial motion of the plasma
tails, we measure the ambient solar wind speed, for the first time in
situ at comets 2P/Encke and 96P/Machholz. We determine the enhanced
solar wind speeds during an interplanetary coronal mass ejection
encounter with 2P/Encke and compare these to previously modeled
values, and also present solar wind speeds covering a range of
latitudes for 96P/Machholz. We here apply this technique using images
from the Sun-Earth Connection Coronal and Heliospheric Investigation
Heliospheric Imagers (HI-1) on board the Solar TErrestrial RElations
Observatory-Ahead spacecraft.
Title: The outburst light curve of Nova KT Eridani from Solar Mass
Ejection Imager (SMEI) observations
Authors: Hounsell, R.; Bode, M. F.; Hick, P.; Buffington, A.; Jackson,
B.; Clover, J.; Shafter, A. W.; Darnley, M. J.; Evans, A.; O'Brien,
T. J.; Eyres, S. P. S.
Bibcode: 2010ATel.2558....1H
Altcode:
We report white light observations of the initial outburst of Nova
Eridani 2009 obtained using the USAF/NASA Solar Mass Ejection Imager
(SMEI) on board the Coriolis satellite. KT Eri was discovered on 2009
November 25.54 UTC at magnitude 8.1 (CBET#2050). Its outburst was then
found on pre-discovery images with a peak magnitude of 5.4 on 2009
November 14.63 UT (IAUC#9098) and it has subsequently been detected as
a radio source (ATel#2434) and a luminous soft X-ray source (ATel#2423,
ATel#2418, ATel#2392).
Title: 3D Reconstruction of Density Enhancements Behind Interplanetary
Shocks from Solar Mass Ejection Imager White-Light Observations
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Bisi, M. M.;
Clover, J. M.; Hamilton, M. S.; Tokumaru, M.; Fujiki, K.
Bibcode: 2010AIPC.1216..659J
Altcode:
The Solar Mass Ejection Imager (SMEI) observes the increased brightness
from the density enhancements behind interplanetary shocks that
are also observed in situ near the Earth. We use the University
of California, San Diego (UCSD) time-dependent three-dimensional
(3D) reconstruction technique to map the extents of these density
enhancements. Here, we examine shock-density enhancements associated
with several well-known interplanetary coronal mass ejections (ICMEs)
including those on 30 May 2003 and on 21 January 2005. We compare these
densities with reconstructed velocities from the Solar-Terrestrial
Environment Laboratory (STELab) interplanetary scintillation (IPS)
observations for the 30 May 2003 ICME, and show the shock is present
at the front edge of the reconstructed high speed solar wind. The
SMEI analyses certify that the brightness enhancements observed behind
shocks identified and measured in situ near Earth are a direct response
to the plasma density enhancements that follow the shocked plasma.
Title: Large-Scale Heliospheric Structure during Solar-Minimum
Conditions using a 3D Time-Dependent Reconstruction Solar-Wind Model
and STELab IPS Observations
Authors: Bisi, M. M.; Jackson, B. V.; Hick, P. P.; Clover, J. M.;
Hamilton, S.; Tokumaru, M.; Fujiki, K.
Bibcode: 2010AIPC.1216..355B
Altcode:
Interplanetary scintillation (IPS) observations provide information
about a large portion of the inner heliosphere. We have used
Solar-Terrestrial Environment Laboratory (STELab) IPS velocity and
g-level observations with our three-dimensional (3D) reconstruction
model to determine velocities and densities of the inner heliosphere
in three dimensions. We present these observations using synoptic
maps generated from our time-dependent model that can measure changes
with durations of less than one day. These synopses show large-scale
stable solar-wind structure during solar-minimum conditions in
relation to transients that are present during this period. These
are also available as differences relative to the background. Here,
we concentrate primarily on data covering the 2007-2009 International
Heliophysical Year (IHY).
Title: Solar Mass Ejection Imager (SMEI) near real time images and
3-D reconstruction comparisons with multi-spacecraft observations
during the rising phase of Solar Cycle 24
Authors: Jackson, Bernard; Clover, John; Hick, P.; Buffington, Andrew;
Bisi, Mario
Bibcode: 2010cosp...38.1873J
Altcode: 2010cosp.meet.1873J
The Solar Mass Ejection Imager (SMEI) has been operating since February
2003. At the University of California, San Diego (UCSD) we are now able
to provide photometric images from SMEI in near real time. These are
available in quick-look form as orbit-to-orbit difference sky maps in a
variety of formats. A series of editing steps and a tomography program
cleans these data sets of aurora and provides three-dimensional (3-D)
volumetric density soon after the images become available, and allows us
to map the 3-D density extents of interplanetary coronal mass ejections
(ICMEs) and co-rotating structures. Here, we report on observations and
3-D reconstructions from SMEI during the current rising phase of Solar
Cycle 24. We match our analyses with in-situ densities from spacecraft
near Earth as well as at the two STEREO spacecraft. These include
both direct in-situ density variation comparisons and measurements of
columnar mass fluxes for different events. These comparisons show the
continuity of the structures that match in-situ density measurements
at each spacecraft, and their extensions beyond the ecliptic plane.
Title: Changes in gegenschein brightness with time, recorded by the
solar mass ejection imager (SMEI)
Authors: Buffington, Andrew; Jackson, Bernard; Hick, P.; Clover, John
Bibcode: 2010cosp...38..708B
Altcode: 2010cosp.meet..708B
The Solar Mass Ejection Imager (SMEI), operating since February 2003,
has provided photometric-quality visible-light maps covering nearly
the entire sky, at a rate of roughly 15 per day for more than seven
years. To measure the Gegenschein and characterize other aspects of
the zodiacal light, we combine these maps into daily averages after
subtracting individual bright stars, a residual sidereal background,
and finally an empirical zodiacal-light model. From averages of
the yearly brightness over the seven-year period, we find that the
Gegenschein brightness has been steadily decreasing by about 2 percent
per year. To confirm that this observation does not result from an error
in assessing the change in imager response over this time, we also
search for a potential brightness change of three comparably-bright
but presumably unchanging sidereal objects, the Andromeda Galaxy and
the two Magellanic Clouds. We find the brightness of these remains
constant over this seven-year time period to better than 1 percent.
Title: Measurements of Zodiacal-light brightness from the Solar Mass
Ejection Imager (SMEI)
Authors: Buffington, A.; Bisi, M. M.; Clover, J. M.; Hick, P. P.;
Jackson, B.
Bibcode: 2009AGUFMSH12A..06B
Altcode:
Observations from the Solar Mass Ejection Imager (SMEI), now spanning
over 6 years, provide unprecedented near-full-sky photometric maps each
102-minute orbit, using data from 3 unfiltered CCD cameras. SMEI’s
0.1% photometric precision enables observation of heliospheric
structures with surface brightness down to several S10’s (an S10
is the equivalent brightness of a 10th magnitude star spread over one
square degree). When individual bright stars and an empirical residual
sidereal background are removed from the maps, the residue is dominated
by the zodiacal light (ZL). The present work combines individual SMEI
sky maps to produce daily average maps, and uses the sequence of these
for both an empirical characterization of the ZL and an investigation
of its variation over time scales from several days to several years.
Title: Coronal Mass Ejections in the Declining and Minimum Phase
between Solar Cycles 23 and 24
Authors: Bisi, M. M.; Jackson, B.; Clover, J. M.; Tokumaru, M.;
Buffington, A.; Hick, P. P.; Fujiki, K.
Bibcode: 2009AGUFMSH43A..08B
Altcode:
The Solar Mass Ejection Imager (SMEI) observes Thomson-scattered
white light from heliospheric electrons across the sky all the time,
and observes heliospheric structure throughout a large portion of
the inner heliosphere all year round. Interplanetary scintillation
(IPS) observations of velocity and g-level provide similar structure
information but with sky and temporal coverage which is generally
less complete. We have used Solar-Terrestrial Environment Laboratory
(STELab) IPS observations to provide IPS velocity and g-level values
(a proxy for density), in conjunction with our three-dimensional (3D)
tomographic reconstruction program, to yield velocities and densities
of the inner heliosphere out to around 3 AU. A second determination
substitutes SMEI brightness information for the g-level values to
derive the heliospheric density. We look at the global structure
of the heliosphere throughout this time, concentrating on two time
intervals from 2008 (in the declining phase of solar cycle 23). The
first interval includes the 23-26 April 2008 coronal mass ejection
(CME) and its interplanetary counterpart seen best in SMEI data. The
second interval includes a CME (and its interplanetary counterpart)
that took place 02-06 June 2008. We try to isolate the particular
portion(s) of the heliosphere attributed to each event, and then
estimate their masses. We also compare our results with the STEREO
Heliospheric Imager data where possible.
Title: About the Solar Mass Ejection Imager (SMEI)
3D-Reconstruction-and-Display of Co-rotating Heliospheric Structure
during the Present Deep Solar Minimum
Authors: Jackson, B.; Bisi, M. M.; Hick, P. P.; Buffington, A.;
Clover, J. M.
Bibcode: 2009AGUFMSH11A1499J
Altcode:
Observations of the inner heliosphere from the Solar Mass Ejection
Imager (SMEI) since its launch in early 2003 have been used to
measure and map the outward flow of over 300 coronal mass ejections
(CMEs). Here, we report on observations and three-dimensional (3D)
reconstructions of co-rotating heliospheric structures observed by
SMEI during the present deep solar minimum. There is little evidence of
large, continuous density structures that co-rotate over the long term
(for durations of several weeks) throughout this solar minimum time
period. We compare the SMEI evidence of co-rotating density structures
with 3D reconstructions of interplanetary scintillation (IPS) velocity
observations, and generally with in-situ solar wind measurements
from the SOHO, Wind, ACE, and twin STEREO spacecraft. If we define
co-rotating heliospheric structure by these in-situ measurements or by
the IPS 3D-reconstruction velocity analyses, a general pattern emerges
for co-rotating heliospheric density structure in Thomson-scattering
observations. The density enhancements shown in brightness difference
images that co-rotate and that emanate from specific regions on the
Sun appear to expand to a far larger extent than a single heliospheric
current sheet region, or than the standing density structures near
their origin on the solar surface.
Title: Measurements of the Gegenschein brightness from the Solar
Mass Ejection Imager (SMEI)
Authors: Buffington, Andrew; Bisi, Mario M.; Clover, John M.; Hick,
P. Paul; Jackson, Bernard V.; Kuchar, Thomas A.; Price, Stephan D.
Bibcode: 2009Icar..203..124B
Altcode:
The Gegenschein is viewed by the Solar Mass Ejection Imager (SMEI),
which has provided near-full-sky broadband visible-light photometric
maps for over 5 years. These have an angular resolution of about 0.5°
and differential photometric stability of about 1% throughout this
time. When individual bright stars are removed from the maps and an
empirical sidereal background subtracted, the residue is dominated
by the zodiacal light. The unprecedented sky coverage and duration
of these measurements enables a definitive characterization of the
Gegenschein. This article describes the analysis method for these data,
presents a movie with time of the Gegenschein brightness distribution,
determines empirical formulae describing its average shape, and
discusses its variation with time. These measurements unambiguously
confirm previous reports that the Gegenschein surface-brightness
distribution has a decided peak in the antisolar point, which rises
above a broader background.
Title: The Large-Scale Structure of the Solar Wind during Solar
Minimum Conditions Using Three-Dimensional Reconstructions of
Interplanetary Scintillation Data
Authors: Bisi, Mario Mark; Jackson, Bernard V.; Clover, John M.;
Tokumaru, Munetoshi; Fujiki, Ken'ichi; Breen, Andrew R.; Fallows,
Richard A.; Buffington, Andrew; Hick, P. Paul
Bibcode: 2009shin.confE.149B
Altcode:
Interplanetary scintillation (IPS) observations provide information
about a large portion of the inner heliosphere. We use Solar-Terrestrial
Environment Laboratory (STELab) IPS velocity and g-level observations as
well as IPS velocity observations from the European Incoherent SCATter
(EISCAT) and EISCAT Svalbard Radar (ESR), with our three-dimensional
(3D) reconstruction data processing to determine velocities and
densities of the inner heliosphere. Here, we concentrate primarily on
results covering the 2007-2009 International Heliophysical Year (IHY)
which includes the Whole Heliosphere Interval (CR2068). We present
these using various forms of imaging from our time-dependent modelled
calculations that can measure changes with durations of less than a day,
and compare these with various spacecraft in-situ measurements. We
also present synoptic maps from the reconstructions. These maps
show large-scale solar wind structure during the somewhat unusual
solar-minimum conditions, in relation to transients that are present
during this period. These maps are also available as differences
relative to a Carrington-averaged background.
Title: Measurements of White-Light Images of Comet Plasma Tails as
a Proxy for Solar Wind Speed
Authors: Clover, John M.; Bisi, Mario M.; Buffington, Andrew; Jackson,
Bernard V.; Hick, P. Paul
Bibcode: 2009shin.confE..51C
Altcode:
The high temporal and spatial resolution of heliospheric white-light
imagers enables us to measure the changes in plasma tails of bright
comets. Plasma tails of comets have been recognized as natural
probes of the solar wind for many years, and thus using the technique
developed at the University of California, San Diego to measure the
changes in the plasma tails of comets, we obtain measurements for
the speed of the solar wind in situ. We present the results of this
technique used successfully on multiple comets observed by the Solar
Mass Ejection Imager (SMEI) and Heliospheric Imagers on board the
twin Solar TErrestrial RElations Observatory (STEREO) spacecraft,
and discuss future applications.
Title: The UCSD Solar Mass Ejection Imager (SMEI) and Interplanetary
Scintillation (IPS) 3D Reconstruction Analyses and Databases now at
the CCMC
Authors: Jackson, Bernard V.; Bisi, Mario M.; Clover, John M.; Hick,
P. Paul; Buffington, Andrew
Bibcode: 2009shin.confE..42J
Altcode:
Both the Solar Mass Ejection Imager (SMEI) and interplanetary
scintillation (IPS) data bases and 3D modeling are now available and
operate at the Community Coordinated Modeling Center (CCMC). We present
the current state of these instrument's databases that are maintained
and stored on UCSD/CASS Web servers. The IPS database is available for
real-time access from the Solar-Terrestrial Environment Laboratory
(STELab), Japan, and the UCSD IPS Web site provides a variety of
higher-level data products derived from these observations to help
in Space Weather Forecasting. The up-to-date UCSD SMEI database
includes individual SMEI CCD data frames from each of the three SMEI
cameras since first light in February 2003, as well as full-sky maps
in a sidereal reference frame that preserve the original instrument
resolution and photometric precision. Higher-level products from this
database and 3-D tomographic reconstruction images are also maintained
by UCSD on its SMEI website for the entire SMEI operation interval.
Title: Fabrication and test of a diamond-turned mirror suitable for
a spaceborne photometric heliospheric imager
Authors: Buffington, Andrew; Bach, Kirk G.; Bach, Bernhard W.; Bach,
Erich K.; Bisi, Mario M.; Hick, P. Paul; Jackson, Bernard V.; Klupar,
Peter D.
Bibcode: 2009SPIE.7438E..0OB
Altcode: 2009SPIE.7438E..17B
We have fabricated a diamond-turned low-mass version of a toroidal
mirror which is a key element for a spaceborne visible-light
heliospheric imager. This mirror's virtual image of roughly a hemisphere
of sky is viewed by a conventional photometric camera. The optical
system views close to the edge of an external protective baffle and does
not protrude from the protected volume. The sky-brightness dynamic range
and background-light rejection requires minimal wideangle scattering
from the mirror surface. We describe the manufacturing process for
this mirror, and present preliminary laboratory measurements of its
wide-angle scattering characteristics.
Title: Low-Resolution STELab IPS 3D Reconstructions of the Whole
Heliosphere Interval and Comparison with in-Ecliptic Solar Wind
Measurements from STEREO and Wind Instrumentation
Authors: Bisi, M. M.; Jackson, B. V.; Buffington, A.; Clover, J. M.;
Hick, P. P.; Tokumaru, M.
Bibcode: 2009SoPh..256..201B
Altcode:
We present initial 3D tomographic reconstructions of the inner
heliosphere during the Whole Heliosphere Interval (WHI) - Carrington
Rotation 2068 (CR2068) - using Solar-Terrestrial Environment Laboratory
(STELab) Interplanetary Scintillation (IPS) observations. Such
observations have been used for over a decade to visualise and
investigate the structure of the solar wind and to study in detail
its various features. These features include co-rotating structures as
well as transient structures moving out from the Sun. We present global
reconstructions of the structure of the inner heliosphere during this
time, and compare density and radial velocity with multi-point in situ
spacecraft measurements in the ecliptic; namely STEREO and Wind data,
as the interplanetary medium passes over the spacecraft locations.
Title: Three-Dimensional Reconstructions of the Solar Wind: During
Solar Minimum Conditions
Authors: Bisi, Mario; Jackson, B. V.; Hick, P. P. L.; Clover, J. M.;
Tokumaru, M.; Fujiki, K.; Fallows, R. A.; Breen, A. R.
Bibcode: 2009SPD....40.3203B
Altcode:
Interplanetary scintillation (IPS) observations provide information
about a vast region of the inner heliosphere. We use Solar-Terrestrial
Environment Laboratory (STELab) IPS velocity and g-level observations as
well as IPS velocity observations from the European Incoherent SCATter
(EISCAT) and EISCAT Svalbard Radar (ESR), with our three-dimensional
(3D) reconstruction model to determine velocities and densities of the
inner heliosphere. We present these observations using various forms
of imaging from our time-dependent model that can measure changes with
durations of less than a day and compare these with various spacecraft
in situ measurements. We concentrate on the current solar-minimum period
showing relatively-stable large-scale solar-wind structure during this
time in relation to transients that are also sometimes present. Data
primarily covers the 2007-2009 International Heliophysical Year (IHY)
which includes the Whole Heliosphere Interval (CR2068).
Title: 3D-Reconstruction of Density Enhancements Behind Interplanetary
Shocks from Solar Mass Ejection White-Light Observations
Authors: Jackson, Bernard V.; Hick, P. P. L.; Buffington, A.; Bisi,
M. M.; Clover, J. M.; Tokumaru, M.; Fujiki, K.
Bibcode: 2009SPD....40.2101J
Altcode:
The Solar Mass Ejection Imager (SMEI) observes the increased brightness
from the density enhancements behind interplanetary shocks that are
observed in situ near the Earth. We use the University of California,
San Diego time-dependent three-dimensional-reconstruction technique
to map the extents of these density enhancements. As examples,
we examine the shock density enhancements associated with several
well-known coronal mass ejections including the 28 October 2003
(Halloween storm) event. We compare these density enhancements with
reconstructed velocity observations from Solar-Terrestrial Environment
Laboratory interplanetary scintillation (IPS) observations when these
are available. Volumetric-differencing techniques available from the
SMEI analyses show that the outer portion of a larger increase in
heliospheric density is often what is observed in short-time image
brightness subtractions from these data.
Title: Coronal Mass Ejection Reconstructions from Interplanetary
Scintillation Data Using a Kinematic Model: A Brief Review
Authors: Bisi, M. M.; Jackson, B. V.; Hick, P. P.; Buffington, A.;
Clover, J. M.
Bibcode: 2009aogs...14..161B
Altcode:
Interplanetary scintillation (IPS) observations of multiple sources
provide a view of the solar wind at all heliographic latitudes from
around 1 AU down to coronagraph fields of view. These are used to
study the evolution of the solar wind and solar transients out into
interplanetary space, and also the inner-heliospheric response to
co-rotating solar structures and coronal mass ejections (CMEs). With
colleagues at the Solar Terrestrial Environment Laboratory (STELab),
Nagoya University, Japan, we have developed near-real-time access
of STELab IPS data for use in space-weather forecasting. We use a
three-dimensional (3D) reconstruction technique that obtains perspective
views of solar co-rotating plasma and of outward-flowing solar wind
crossing our lines of sight from the Earth to the radio sources. This is
accomplished by iteratively fitting a kinematic solar wind model to the
IPS observations. This 3D modeling technique permits reconstructions
of the density and speed structures of CMEs and other interplanetary
transients at a relatively coarse resolution. These reconstructions have
a 28-day solar-rotation cadence with 10° latitudinal and longitudinal
heliographic resolution for a co-rotational model, and a one-day
cadence and 20° latitudinal and longitudinal heliographic resolution
for a time-dependent model. These resolutions are restricted by the
numbers of lines of sight available for the reconstructions. When Solar
Mass Ejection Imager (SMEI) Thomson-scattered brightness measurements
are used, lines of sight are much greater in number so that density
reconstructions can be better resolved. Higher resolutions are also
possible when these analyses are applied to Ootacamund IPS data.
Title: Solar Wind 3D Reconstructions of the Whole Heliospheric
Interval
Authors: Bisi, M. M.; Jackson, B. V.; Clover, J. M.; Hick, P. P.;
Buffington, A.; Manoharan, P. K.; Tokumaru, M.
Bibcode: 2008AGUFMSH23A1617B
Altcode:
3D tomographic reconstructions of the inner heliosphere have been used
for over a decade to visualise and investigate the structure of the
solar wind and its various features such as transients and corotating
structures. Interplanetary scintillation (IPS) observations of the
solar wind have been carried out for a much longer period of time
revealing information on the structure of the solar wind and the
features within it. Here we present such 3D reconstructions using
IPS observations from the Solar Terrestrial Environment Laboratory
(STELab) and the Ootacamund (Ooty) Radio Telescope (ORT) of the Whole
Heliospheric Interval (WHI) Carrington Rotation 2068. This is part of
the world-wide IPS community's International Heliosphysical Year (IHY)
collaboration. We show the structure of the inner heliosphere during
this time and how our global reconstructions compare with deep-space
spacecraft measurements such as those taken by Wind, ACE, STEREO,
and Ulysses in terms of density and velocity.
Title: SMEI Remote Sensing and the 3D Reconstruction of Corotating
Heliospheric Structures
Authors: Jackson, B. V.; Bisi, M. M.; Hick, P. P.; Buffington, A.;
Clover, J. M.; Webb, D. F.; Tokumaru, M.; Manoharan, P. K.
Bibcode: 2008AGUFMSH13B1554J
Altcode:
We report observations and 3D reconstructions of corotating
heliospheric structures observed by the Solar Mass Ejection Imager
(SMEI). Observations of the inner heliosphere have been carried out
on a routine basis by SMEI since its launch in early 2003, and these
have been used to measure and map the outward flow of several-hundred
CMEs. Most of these observations use short-term variations of
brightness from one SMEI orbit to the next (every 102 minutes)
to track outward motion. The disadvantage of these orbit-to-orbit
analyses is that they cannot measure features that remain stationary
relative to the Sun-Earth line (or those which corotate with the Sun)
and change slowly over time periods of several days. At UCSD we provide
measurements of heliospheric structures relative to a long-term base
and, even in these observations, there is little evidence of long-term
stationary-standing density structures that corotate. By employing a
kinematic model of the solar wind, we reconstruct three-dimensional
(3D) solar wind structures from multiple observing lines of sight
through the outward-flowing solar wind. By including interplanetary
scintillation (IPS) velocity observations from STELab, Japan or from
Ooty, India we can extract both the solar wind density and velocity
from these analyses to compare with "ground truth" measurements from
multi-point, in-situ solar wind measurements from the STEREO, SOHO,
Wind, and ACE spacecraft. We define the heliospheric structures by
these 3D velocity analyses, and they show that while the velocities
map large regions near the ecliptic that corotate, the dense structures
that front and follow these regions are far more tenuous.
Title: Measurements of the Gegenschein brightness from the Solar
Mass Ejection Imager (SMEI)
Authors: Buffington, A.; Bisi, M. M.; Clover, J. M.; Hick, P.; Jackson,
B. V.
Bibcode: 2008AGUFMSH13B1561B
Altcode:
The Gegenschein is a faint diffuse component of the zodiacal light
centered upon the antisolar point; this has now been viewed by the
Solar Mass Ejection Imager (SMEI) for over 5 years. SMEI provides
unprecedented near-full-sky photometric maps each 102-minute orbit,
using data from 3 unfiltered CCD cameras. Its 0.1% photometric precision
enables observation over long periods of time, of heliospheric
structures having surface brightness down to several S10's (an S10
is the equivalent brightness of a 10th magnitude star spread over
one square degree). When individual bright stars are removed from the
maps and an empirical sidereal background subtracted, the residue is
dominated by the zodiacal light. The sky coverage and duration of these
measurements enables a definitive characterization. We describe the
analysis method for these data, characterize the average Gegenschein
brightness distribution, present empirical formulae describing its
shape, and discuss its variation with time.
Title: SMEI Observations of the Heliosphere During WHI
Authors: Jackson, B. V.; Bisi, M. M.; Hick, P. P.; Buffington, A.;
Clover, J. M.; Webb, D. F.
Bibcode: 2008AGUSMSH51A..08J
Altcode:
Solar Mass Ejection Imager (SMEI) observations of the inner heliosphere
have been carried out on a routine basis since early 2003. By employing
a kinematic model of the solar wind, we reconstruct three-dimensional
(3D) solar wind structures from multiple observing lines of sight
through the outward-flowing solar wind. These models allow us to extract
solar wind density and to compare these to "ground truth" measurements
from multi- point in-situ solar wind measurements from the STEREO,
SOHO, ACE, and the Wind spacecraft. This aids in improving the 3D
reconstruction technique by comparing these reconstructions at multiple
points in the inner heliosphere. Because our observations reveal the
global nature of heliospheric structures, this also leads to a better
understanding of the structure and dynamics of the interplanetary
environment around each spacecraft, and how these structures are
connected back to the Sun. During the Whole Heliosphere Interval (WHI)
SMEI will provide views and 3D reconstructions of the global heliosphere
that can be compared with ground-based and spacecraft observations.
Title: Numerical Simulations of Solar Wind Disturbances by Coupled
Models
Authors: Odstrcil, D.; Pizzo, V. J.; Arge, C. N.; Bissi, M. M.; Hick,
P. P.; Jackson, B. V.; Ledvina, S. A.; Luhmann, J. G.; Linker, J. A.;
Mikic, Z.; Riley, P.
Bibcode: 2008ASPC..385..167O
Altcode:
Numerical modeling plays a critical role in efforts to understand the
connection between solar eruptive phenomena and their impacts in the
near-Earth space environment and in interplanetary space. Coupling the
heliospheric model with empirical, observational, and numerical coronal
models is described. Results show background solar wind, evolution
of interplanetary transients, connectivity of magnetic field lines,
and interplanetary shocks approaching geospace.
Title: Observations of a comet tail disruption induced by the passage
of a CME
Authors: Kuchar, T. A.; Buffington, A.; Arge, C. N.; Hick, P. P.;
Howard, T. A.; Jackson, B. V.; Johnston, J. C.; Mizuno, D. R.; Tappin,
S. J.; Webb, D. F.
Bibcode: 2008JGRA..113.4101K
Altcode: 2008JGRA..11304101K
The Solar Mass Ejection Imager observed an extremely faint
interplanetary coronal mass ejection (ICME) as it passed Comet C/2001 Q4
(NEAT) on 5 May 2004, apparently causing a disruption of its plasma
tail. This is the first time that an ICME has been directly observed
interacting with a comet. SMEI's nearly all-sky coverage and image
cadence afforded unprecedented coverage of this rarely observed
event. The onset first appeared as a "kink" moving antisunward that
eventually developed knots within the disturbed tail. These knots
appeared to be swept up in the solar wind flow. We present the SMEI
observations as well as identify a likely SOHO/LASCO progenitor of the
CME. SMEI observed two other comets (C/2002 T7 [LINEAR] and C/2004 F4
[Bradfield]) and at least five similar events during a 35-d period
encompassing this observation. Although these had similar morphologies
to the 5 May NEAT event, SMEI did not observe any ICMEs in these
cases. Three of these were observed close to the heliospheric current
sheet indicating that a magnetic boundary crossing may have contributed
to the disruptions. However, there are no discernable causes in the
SMEI observations for the remaining two events.
Title: Analysis of Plasma-Tail Motions for Comets C/2001 Q4 (NEAT)
and C/2002 T7 (LINEAR) Using Observations from SMEI
Authors: Buffington, A.; Bisi, M. M.; Clover, J. M.; Hick, P. P.;
Jackson, B. V.; Kuchar, T. A.
Bibcode: 2008ApJ...677..798B
Altcode:
Comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) passed within ~0.3 AU
of Earth in April and May of 2004. Their tails were observed by the
Earth-orbiting Solar Mass Ejection Imager (SMEI) during this period. A
time series of photometric SMEI sky maps displays the motions and
frequent disruptions of the comet plasma tails. Ephemerides are
used to unfold the observing geometry; the tails are often seen
to extend ~0.5 AU from the comet nuclei. Having selected 12 of the
more prominent motions as "events" for further study, we introduce
a new method for determining solar wind radial velocities from
these SMEI observations. We find little correlation between these
and the changing solar wind parameters as measured close to Earth,
or with coarse three-dimensional reconstructions using interplanetary
scintillation data. A likely explanation is that the transverse sizes
of the solar wind perturbations responsible for these disruptions are
small, lesssim0.05 AU. We determine the radial velocities of these
events during the disruptions, using a technique only possible when
the observed comet tails extend over a significant fraction of an
AU. We find typical radial velocities during these events of 50-100
km s-1 lower than before or afterward. Time durations of
such events vary, typically from 3 to 8 hr, and correspond to comet
traversal distances ~106 km (0.007 AU). We conclude that
these large disturbances are primarily due to ubiquitous solar wind
flow variations, of which these measured events are a subset.
Title: Solar Mass Ejection Imager 3-D reconstruction of the 27-28
May 2003 coronal mass ejection sequence
Authors: Jackson, B. V.; Bisi, M. M.; Hick, P. P.; Buffington, A.;
Clover, J. M.; Sun, W.
Bibcode: 2008JGRA..113.0A15J
Altcode:
The Solar Mass Ejection Imager (SMEI) has recorded the
inner-heliospheric response in white-light Thomson scattering for many
hundreds of interplanetary coronal mass ejections (ICMEs). Some of these
have been observed by the Solar and Heliospheric Observatory (SOHO)
Large-Angle Spectroscopic Coronagraph (LASCO) instruments and also in
situ by near-Earth spacecraft. This article presents a low-resolution
three-dimensional (3-D) reconstruction of the 27-28 May 2003 halo CME
event sequence observed by LASCO and later using SMEI observations;
this sequence was also observed by all in situ monitors near Earth. The
reconstruction derives its perspective views from outward flowing
solar wind. Analysis results reveal the shape, extent, and mass of
this ICME sequence as it reaches the vicinity of Earth. The extended
shape has considerable detail that is compared with LASCO images and
masses for this event. The 3-D reconstructed density, derived from
the remote-sensed Thomson scattered brightness, is also compared with
the Advanced Composition Explorer (ACE) and Wind spacecraft in situ
plasma measurements. These agree well in peak and integrated total
value for this ICME event sequence when an appropriately enhanced
(∼20%) electron number density is assumed to account for elements
heavier than hydrogen in the ionized plasma.
Title: Three-dimensional reconstructions of the early November 2004
Coordinated Data Analysis Workshop geomagnetic storms: Analyses of
STELab IPS speed and SMEI density data
Authors: Bisi, M. M.; Jackson, B. V.; Hick, P. P.; Buffington, A.;
Odstrcil, D.; Clover, J. M.
Bibcode: 2008JGRA..113.0A11B
Altcode:
Combined interplanetary scintillation (IPS) and Solar Mass Ejection
Imager (SMEI) remote-sensing observations provide a view of the solar
wind at almost all heliographic latitudes and covering distances
from the Sun between 0.1 AU and 3.0 AU. They are used to study the
development of the solar wind and coronal transients as they move out
into interplanetary space, and also the inner heliospheric response to
the passage of corotating solar structures and coronal mass ejections
(CMEs). The observations take place in both radio scintillation level
and speed for IPS, and in Thomson-scattered white light brightness for
SMEI. With colleagues at the Solar Terrestrial Environment Laboratory
(STELab), Nagoya University, Japan, we have developed a data analysis
system for the STELab IPS data which can also be applied to SMEI white
light data. This employs a three-dimensional (3-D) reconstruction
technique that obtains perspective views from solar corotating plasma
and outward flowing solar wind as observed from the Earth by iterative
fitting of a kinematic solar wind model to the data. This 3-D modeling
technique permits reconstructions of the density and speed of CMEs
and other interplanetary transients at relatively coarse spatial
and temporal resolutions. For the time-dependent model (used here),
these typically range from 5° to 20° in latitude and longitude, with
a 1/2 to 1 day time cadence. For events during early November 2004
we compare these reconstructed structures with in situ measurements
from the ACE and Wind (near-Earth) spacecraft to validate the 3-D
tomographic reconstruction results and provide input to the ENLIL 3-D
magnetohydrodynamic (MHD) numerical model.
Title: Comparison of the extent and mass of CME events in the
interplanetary medium using IPS and SMEI Thomson scattering
observations
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Bisi, M. M.;
Kojima, M.; Tokumaru, M.
Bibcode: 2007A&AT...26..477J
Altcode:
No abstract at ADS
Title: IPS observations of the inner-heliosphere and their comparison
with multi-point in-situ measurements
Authors: Bisi, M. M.; Jackson, B. V.; Breen, A. R.; Fallows, R. A.;
Feynman, J.; Clover, J. M.; Hick, P. P.; Buffington, A.
Bibcode: 2007AGUFMSH33A1091B
Altcode:
Interplanetary scintillation (IPS) observations of the inner-heliosphere
have been carried out on a routine basis for many years using
metre-wavelength radio telescope arrays. By employing a kinematic
model of the solar wind, we reconstruct the three-dimensional (3D)
structure of the inner-heliosphere from multiple observing lines of
sight. From these reconstructions we extract solar wind parameters
such as velocity and density, and compare these to "ground truth"
measurements from multi-point in situ solar wind measurements from
ACE, Ulysses, STEREO, and the Wind spacecraft, particularly during
the International Heliophysical Year (IHY). These multi- point
comparisons help us improve our 3D reconstruction technique. Because
our observations show heliospheric structures globally, this leads to a
better understanding of the structure and dynamics of the interplanetary
environment around these spacecraft.
Title: Analysis and Interpretation of Comet Measurements from SMEI
Authors: Buffington, A.; Bisi, M. M.; Clover, J. M.; Hick, P. P.;
Jackson, B. V.
Bibcode: 2007AGUFMSH33A1080B
Altcode:
The Solar Mass Ejection Imager (SMEI) has observed several comets and
traced their plasma tails as far as 108 km from their nucleus. A time
sequence of SMEI orbital sky maps displays considerable tail motion and
disruption for several of these comets. Tracking these motions versus
time, when combined with ephemeris information about their distance
from the Earth allows a determination of solar wind speeds and their
variation with the location of the comet. In the case of comets C/2001
Q4 (NEAT) and C/2002 T7 (LINEAR), which passed within about 0.3 AU of
Earth in April and May of 2004, the SMEI observations show that speeds
during disruptions are typically 50 to 100 km s-1 less than speeds
before and after. Time durations of the disturbances vary between 3
and 8 hours, and correspond to distances traversed by the comets of
~106 km (0.007 AU). We compare these observations with interplanetary
scintillation (IPS) three-dimensional tomographic reconstructions and
find no evidence that the comet-tail features are due to large-scale
density or velocity structures. We also compare these with near-by
spacecraft measurements such as the Advanced Composition Explorer
(ACE), and find a similar result. This suggests that the comet-tail
disruptions are caused by small-scale changes in the solar wind acting
over distances that are short compared with 1 AU.
Title: Inner-heliosphere SMEI observations and their comparison with
multi-point in-situ measurements
Authors: Jackson, B. V.; Bisi, M. M.; Hick, P. P.; Buffington, A.;
Clover, J. M.; Feynman, J.
Bibcode: 2007AGUFMSH51B..03J
Altcode:
Solar Mass Ejection Imager (SMEI) observations of the inner heliosphere
have been carried out on a routine basis since shortly after its launch
on January 6, 2003. By employing a kinematic model of the solar wind,
we reconstruct three-dimensional (3D) solar wind structures from
multiple observing lines of sight through the outward-flowing solar
wind. This model allows us to extract solar wind densities from the
SMEI white-light observations and to compare these to multi-point in
situ "ground truth" solar wind measurements from instruments aboard
the Ulysses, STEREO, ACE, and Wind spacecraft. This facilitates
improvements to our 3D reconstruction technique by comparing these
reconstructions at multiple points in the inner-heliosphere. Our
observations show heliospheric structures globally, and because of
this, our reconstructions provide us with a better understanding of
the structure and dynamics of the interplanetary environment around
each spacecraft, and how these structures are connected back to the Sun.
Title: CME 3D Reconstructions Using Solar Mass Ejection Imager and
Interplanetary Scintillation Data
Authors: Jackson, Bernard V.; Bisi, M. M.; Hick, P. P.; Buffington, A.
Bibcode: 2007AAS...210.2923J
Altcode: 2007BAAS...39..141J
Solar Mass Ejection Imager (SMEI) and interplanetary scintillation (IPS)
observations provide a view of the solar wind at all solar elongations;
from 180 degrees anti-solar to as close to the Sun as coronagraph
fields of view. They can be used to study the evolution of the solar
wind and solar transients out into interplanetary space. In addition,
the inner heliospheric response to corotating solar structures and
coronal mass ejections (CMEs) can be measured, both in scintillation
level and in velocity when using IPS, and through Thomson Scattering
when using SMEI. We use a 3D reconstruction technique that obtains
perspective views from solar corotating plasma and outward-flowing
solar wind as observed from Earth, by iteratively fitting a kinematic
solar wind model to both SMEI and IPS observations. This 3D modeling
technique permits reconstructions of the density and velocity structures
of CMEs and other interplanetary transients. These reconstructions
have a temporal cadence and heliographic latitudinal and longitudinal
resolution predicated by the amount of data used for time-dependent
reconstructions, and can use data from a variety of IPS instruments
distributed around the Earth. We highlight the 3D analyses of these
different data sets using a series of CME events observed beginning on
the Sun 4-7 November 2004. We also apply this technique to determine
solar wind pressure (“ram” pressure) at Mars. Results are compared
with ram pressure observations derived from Mars Global Surveyor
magnetometer data for the years 1999 through 2004, and include a
reconstruction of a “back-side” event as seen by SOHO/LASCO.
Title: Analysis of Solar Wind Events Using Interplanetary
Scintillation Remote Sensing 3D Reconstructions and Their Comparison
at Mars
Authors: Jackson, B. V.; Boyer, J. A.; Hick, P. P.; Buffington, A.;
Bisi, M. M.; Crider, D. H.
Bibcode: 2007SoPh..241..385J
Altcode:
Interplanetary Scintillation (IPS) allows observation of the inner
heliospheric response to corotating solar structures and coronal mass
ejections (CMEs) in scintillation level and velocity. With colleagues
at STELab, Nagoya University, Japan, we have developed near-real-time
access of STELab IPS data for use in space-weather forecasting. We use
a 3D reconstruction technique that produces perspective views from
solar corotating plasma and outward-flowing solar wind as observed
from Earth by iteratively fitting a kinematic solar wind model to
IPS observations. This 3D modeling technique permits reconstruction
of the density and velocity structure of CMEs and other interplanetary
transients at a relatively coarse resolution: a solar rotational cadence
and 10° latitudinal and longitudinal resolution for the corotational
model and a one-day cadence and 20° latitudinal and longitudinal
heliographic resolution for the time-dependent model. This technique is
used to determine solar-wind pressure ("ram" pressure) at Mars. Results
are compared with ram-pressure observations derived from Mars Global
Surveyor magnetometer data (Crider et al.2003, J. Geophys. Res.108(A12),
1461) for the years 1999 through 2004. We identified 47 independent in
situ pressure-pulse events above 3.5 nPa in the Mars Global Surveyor
data in this time period where sufficient IPS data were available. We
detail the large pressure pulse observed at Mars in association with a
CME that erupted from the Sun on 27 May 2003, which was a halo CME as
viewed from Earth. We also detail the response of a series of West-limb
CME events and compare their response observed at Mars about 160° west
of the Sun - Earth line by the Mars Global Surveyor with the response
derived from the IPS 3D reconstructions.
Title: Solar Mass Ejection Imager (SMEI) observations of coronal
mass ejections (CMEs) in the heliosphere
Authors: Webb, D. F.; Mizuno, D. R.; Buffington, A.; Cooke, M. P.;
Eyles, C. J.; Fry, C. D.; Gentile, L. C.; Hick, P. P.; Holladay, P. E.;
Howard, T. A.; Hewitt, J. G.; Jackson, B. V.; Johnston, J. C.; Kuchar,
T. A.; Mozer, J. B.; Price, S.; Radick, R. R.; Simnett, G. M.; Tappin,
S. J.
Bibcode: 2006JGRA..11112101W
Altcode:
The Solar Mass Ejection Imager (SMEI) on the Coriolis spacecraft has
been obtaining white light images of nearly the full sky every 102
minutes for three years. We present statistical results of analysis
of the SMEI observations of coronal mass ejections (CMEs) traveling
through the inner heliosphere; 139 CMEs were observed during the first
1.5 years of operations. At least 30 of these CMEs were observed by
SMEI to propagate out to 1 AU and beyond and were associated with major
geomagnetic storms at Earth. Most of these were observed as frontside
halo events by the SOHO LASCO coronagraphs.
Title: An Empirical Description of Zodiacal Light as Measured by SMEI
Authors: Buffington, A.; Jackson, B. V.; Hick, P.; Price, S. D.
Bibcode: 2006AGUFMSH32A..06B
Altcode:
The SMEI visible-light cameras provide a photometric skymap for each
102-minute orbit with the objective to observe transient Coronal Mass
Ejections (CMEs). Zodiacal light is a significant contributor to these
maps and must be removed in the data-analysis in order to detect and
characterize the much fainter CMEs. We have analyzed over three years
of the SMEI calibration data that were taken at the highest spatial
resolution to derive the yearly averaged global distribution of zodiacal
light between solar elongations of 20 and 180 degrees. Residuals on
the individual sky maps from this global average provide information
on the detailed geometry of the clouds. We present preliminary results
of the analysis, including a characterization of the Gegenschein,
possible dust bands, and annual variations.
Title: The 20 January 2005 CME Solar Mass Ejection Imager (SMEI)
Analyses
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.
Bibcode: 2006AGUFMSH33A0396J
Altcode:
Solar Mass Ejection Imager (SMEI) brightness measurements are analyzed
to determine 3D volumetric densities for several CMEs including
that of the 20 January 2005 CME. Here we present analyses of these 3D
heliospheric volumetric solar wind density analyses. We use this system
to measure the distribution of structure and provide a 3D mass of the
ejecta associated with the large CMEs viewed in SMEI observations. In
the case of the 20 January 2005 CME, the primary mass moves to the
northwest of the Sun following the event observed earlier in LASCO
coronagraph observations. There are two other very large coronal
responses to the coronal energy input beginning around 6:30 UT near
the time of CME onset. One of these is the large and extremely prompt
Solar Energetic Particle (SEP) proton event observed at Earth beginning
about 6:50 UT. Another response is an outward-propagating fast shock
that arrives at Earth 34 hours following the event onset. A response
that may be attributed to this shock is observed slightly more than
5 days following this at the Ulysses spacecraft situated 5.3 AU from
the Sun, 17 degrees south of the ecliptic, and 27 degrees from the
Sun-Earth line to the west. SMEI observes the white-light response of
this shock at Earth in the interplanetary medium around the spacecraft,
and limits the shock extent in 3D.
Title: The Evolution of Comets in the Heliosphere as Observed by SMEI
Authors: Kuchar, T.; Buffington, A.; Howard, T.; Arge, C. N.; Webb,
D.; Jackson, B. V.; Hick, P. P.
Bibcode: 2006AGUFMSH32A..08K
Altcode:
Comet observations have been used as in situ probes of the heliospheric
environment since they were used to confirm the existence of the solar
wind. Changes in a comet tail's appearance are attributed to changes
in the solar wind flow. Large scale tail disruptions are usually
associated with boundary crossings of the current sheet or, more
rarely, impacts from coronal mass ejections. The Solar Mass Ejection
Imager (SMEI) observed three bright comets during April-May 2004:
Bradfield (C/2004 F4), LINEAR (C/2002 T7), and NEAT (C/2001 Q4). We
had previously reported several comet tail disconnection events (DEs)
for both NEAT and LINEAR. Investigation of the entire period further
reveals that these two comets showed continual changes in their
plasma tails. These changes are characterized by a "smokestack-like"
billowing effect punctuated by the disconnections. Bradfield however
was remarkably quiescent during this entire period. We present these
extended comet observations and offer an analysis and cause of the
similarities and disparities of these data.
Title: International Colloquium "Scattering and Scintillation in
Radio Astronomy" was held on June 19-23, 2006 in Pushchino, Moscow
region, Russia
Authors: Shishov, V. I.; Coles, W. A.; Rickett, B. J.; Bird,
M. K.; Efimov, A. I.; Samoznaev, L. N.; Rudash, V. K.; Chashei,
I. V.; Plettemeier, D.; Spangler, S. R.; Tokarev, Yu.; Belov, Yu.;
Boiko, G.; Komrakov, G.; Chau, J.; Harmon, J.; Sulzer, M.; Kojima,
M.; Tokumaru, M.; Fujiki, K.; Janardhan, P.; Jackson, B. V.; Hick,
P. P.; Buffington, A.; Olyak, M. R.; Fallows, R. A.; Nechaeva, M. B.;
Gavrilenko, V. G.; Gorshenkov, Yu. N.; Alimov, V. A.; Molotov, I. E.;
Pushkarev, A. B.; Shanks, R.; Tuccari, G.; Lotova, N. A.; Vladimirski,
K. V.; Obridko, V. N.; Gubenko, V. N.; Andreev, V. E.; Stinebring, D.;
Gwinn, C.; Lovell, J. E. J.; Jauncey, D. L.; Senkbeil, C.; Shabala, S.;
Bignall, H. E.; Macquart, J. -P.; Rickett, B. J.; Kedziora-Chudczer,
L.; Smirnova, T. V.; Rickett, B. J.; Malofeev, V. M.; Malov, O. I.;
Tyulbashev, S. A.; Jessner, A.; Sieber, W.; Wielebinski, R.
Bibcode: 2006astro.ph..9517S
Altcode:
Topics of the Colloquium: a) Interplanetary scintillation b)
Interstellar scintillation c) Modeling and physical origin of the
interplanetary and the interstellar plasma turbulence d) Scintillation
as a tool for investigation of radio sources e) Seeing through
interplanetary and interstellar turbulent media Ppt-presentations are
available on the Web-site: http://www.prao.ru/conf/Colloquium/main.html
Title: Preliminary three-dimensional analysis of the heliospheric
response to the 28 October 2003 CME using SMEI white-light
observations
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Wang, X.;
Webb, D.
Bibcode: 2006JGRA..111.4S91J
Altcode: 2006JGRA..11104S91J
The Solar Mass Ejection Imager (SMEI) has recorded the inner
heliospheric response in white-light Thomson scattering to the 28
October 2003 coronal mass ejection (CME). This preliminary report
shows the evolution of this particular event in SMEI observations, as
we track it from a first measurement at approximately 20° elongation
(angular distance) from the solar disk until it fades in the antisolar
hemisphere in the SMEI 180° field of view. The large angle and
spectrometric coronagraph (LASCO) images show a CME and an underlying
bright ejection of coronal material that is associated with an erupting
prominence. Both of these are seen by SMEI in the interplanetary
medium. We employ a three-dimensional (3-D) reconstruction technique
that derives its perspective views from outward flowing solar wind
to reveal the shape and extent of the CME. This is accomplished by
iteratively fitting the parameters of a kinematic solar wind density
model to both SMEI white-light observations and Solar-Terrestrial
Environment Laboratory (STELab), interplanetary scintillation (IPS)
velocity data. This modeling technique separates the true heliospheric
signal in SMEI observations from background noise and reconstructs the
3-D heliospheric structure as a function of time. These reconstructions
allow separation of the 28 October CME from other nearby heliospheric
structure and a determination of its mass. The present results are the
first utilizing this type of 3-D reconstruction with the SMEI data. We
determine an excess-over-ambient mass for the southward moving ejecta
associated with the prominence material of 7.1 × 1016
g and a total mass of 8.9 × 1016 g. Preliminary SMEI
white-light calibration indicates that the total mass of this CME
including possible associated nearby structures may have been as
much as ∼2.0 × 1017 g spread over much of the earthward
facing hemisphere.
Title: A Search for Early Optical Emission at Gamma-Ray Burst
Locations by the Solar Mass Ejection Imager (SMEI)
Authors: Buffington, Andrew; Band, David L.; Jackson, Bernard V.;
Hick, P. Paul; Smith, Aaron C.
Bibcode: 2006ApJ...637..880B
Altcode: 2005astro.ph.10159B
The Solar Mass Ejection Imager (SMEI) views nearly every point on the
sky once every 102 minutes and can detect point sources as faint as
R~10 mag. Therefore, SMEI can detect or provide upper limits for the
optical afterglow from gamma-ray bursts in the tens of minutes after
the burst, when different shocked regions may emit optically. Here we
provide upper limits for 58 bursts between 2003 February and 2005 April.
Title: Global 3-D Solar Wind Analysis of Halo CMEs Using
Interplanetary Scintillation (IPS) Remote Sensing and its Comparison
at Mars
Authors: Boyer, J. A.; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Yu, Y.; Crider, D. H.
Bibcode: 2005AGUFMSH43A1145B
Altcode:
The Interplanetary Scintillation (IPS) process allows observation
of the inner heliospheric response to CMEs in scintillation level
and velocity. With the help of our colleagues in STELab, Japan, we
have developed near real time access of these data for use in space
weather forecasting. We use a 3D reconstruction technique that obtains
perspective views from outward-flowing solar wind as observed from
Earth by iteratively fitting a kinematic solar wind model using the
IPS observations. This 3D modeling technique permits us to reconstruct
the density and velocity structure of CMEs, and other interplanetary
transient structure at low resolution (with a one day cadence, and at a
20 deg. latitudinal and longitudinal heliographic resolution). Here we
explore the use of this technique to reproduce the solar wind pressure
observed at Mars following the aftermath of halo (Earth-directed)
CMEs. These CMEs include one that erupted from the Sun on May 27,
2003 and another on October 28, 2003 both of which produced a large
response at Mars. In addition we explore the response at Mars and our
reconstruction of "backside" (as seen from Earth) halo CMEs.
Title: Solar Mass Ejection Imager (SMEI) Solar Wind 3-D Analysis of
the January 20, 2005 CME
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Yu, Y.; Webb, D.
Bibcode: 2005AGUFMSH21A..02J
Altcode:
The Solar Mass Ejection Imager (SMEI) has observed the inner
heliospheric response in white light from over 200 CMEs. One of these,
on January 20, 2005, produced one of the largest Solar Energetic
Particle events ever recorded. We show SMEI orbital difference images
and the 3D solar wind reconstruction of this well-observed CME, and
demonstrate how we can track its outward motion from approximately 20
deg. from the Sun until it vanishes in the SMEI field of view in the
direction of the Ulysses spacecraft. Our 3D reconstruction technique
is used to obtain perspective views from outward-flowing solar wind
as observed from Earth by iteratively fitting a kinematic solar wind
density model using the SMEI white light observations. This 3D modeling
technique permits us to separate the heliospheric response in SMEI
from background noise, and to estimate the 3D structure and transient
heliospheric components of the CME and its speed and mass. We then
determine the total energy of the CME that can be used as input to
determine the total energy output of the event. More information about
the spatial extent and energetics of this CME event can be determined
by measurements in-situ from the Ulysses spacecraft that was beyond 5 AU
and about 35 degrees west of Earth. Ulysses first detected an extremely
fast CME response at the spacecraft 7 days following the event on the
Sun and the transient flow continued for several days. The SMEI 3D
reconstruction shows the event as it passes Earth to the west and helps
to disentangle the CME structure. This will allow a better understanding
of which portions of the CME intersect Ulysses, and the 3D trajectories
of several CMEs observed earlier in coronagraph and SMEI data.
Title: 3D CME Mass and Energy From Solar Mass Ejection Imager (SMEI)
and Interplanetary Scintillation (IPS) Data
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Yu, Y.
Bibcode: 2005AAS...20711108J
Altcode: 2005BAAS...37.1342J
White-light Thomson scattering observations from the Solar Mass Ejection
Imager (SMEI) have recorded the inner heliospheric response to several
hundred CMEs including the halo CMEs of May 28, 2003 and October 28,
2003, and numerous other heliospheric structures. We show the extent
of several well-observed CMEs in SMEI observations, and measure these
events from their first observations in SMEI approximately 20 degrees
from the solar disk until they vanish in the SMEI field of view. Several
portions of large CMEs can be observed in the interplanetary medium
associated with the initial coronal response and the underlying
erupting prominence structure observed by the LASCO coronagraphs
and other instruments. To enhance the images and understand the
outward propagation of these structures we use a 3D reconstruction
technique that obtains perspective views from outward-flowing solar
wind as observed from Earth, iteratively fitting a kinematic solar wind
density model to the SMEI white light observations and, when available,
also to the Solar-Terrestrial Environment Laboratory (STELab), Japan
interplanetary scintillation (IPS) velocity data. This 3D modeling
technique allows separating the heliospheric response in SMEI from
background noise, and estimating the 3D structure of the CME and its
mass. Pixel-to-pixel 3D comparison with the IPS velocity structure
gives the outward flow kinetic energy for these events.
Title: SMEI: A Spaceborne Observatory for Heliospheric Remote Sensing
Authors: Hick, P.; Jackson, B. V.; Buffington, A.; Yu, Y.
Bibcode: 2005AGUFMSH51C1219H
Altcode:
The Solar Mass Ejection Imager (SMEI) provides measurements of the
Thomson scattering brightness with near-full sky coverage from Earth
orbit. These observations allow three-dimensional reconstruction of the
solar wind density and velocity throughout the inner heliosphere. We
discuss how these observations provide context for in situ solar wind
observations from other "Great Observatory" satellites near Earth
(ACE), other planets (Mars Orbiter) and in deep space (Ulysses).
Title: Interactive visualization of solar mass ejection imager (SMEI)
volumetric data
Authors: Yu, Yang; Hick, P. P.; Jackson, Bernard V.
Bibcode: 2005SPIE.5901..335Y
Altcode:
We present a volume rendering system developed for the real time
visualization and manipulation of 3D heliospheric volumetric solar wind
density and velocity data obtained from the Solar Mass Ejection Imager
(SMEI) and interplanetary scintillation (IPS) velocities over the same
time period. Our system exploits the capabilities of the VolumePro
1000 board from TeraRecon, Inc., a low-cost 64-bit PCI board capable of
rendering up to a 512-cubed array of volume data in real time at up to
30 frames per second on a standard PC. Many volume-rendering operations
have been implemented with this system such as stereo/perspective
views, animations of time-sequences, and determination of coronal
mass ejection (CME) volumes and masses. In these visualizations we
highlight one time period where a halo CMEs was observed by SMEI to
engulf Earth on October 29, 2003. We demonstrate how this system is
used to measure the distribution of structure and provide 3D mass for
individual CME features, including the ejecta associated with the
large prominence viewed moving to the south of Earth following the
late October CME. Comparisons with the IPS velocity volumetric data
give pixel by pixel and total kinetic energies for these events.
Title: Space performance of the multistage labyrinthine SMEI baffle
Authors: Buffington, Andrew; Jackson, Bernard V.; Hick, P. P.
Bibcode: 2005SPIE.5901..325B
Altcode:
The Solar Mass Ejection Imager (SMEI) was launched on 6 January
2003, and shortly thereafter raised to a nearly circular orbit
at 840 km. Three SMEI CCD cameras on the zenith-nadir oriented
CORIOLIS spacecraft cover most of the sky beyond about 20°. from
the Sun, each 102-minute orbit. Data from this instrument provide
precision visible-light photometric sky maps. Once starlight and
other constant or slowly varying backgrounds are subtracted, the
residue is mostly sunlight that has been Thomson-scattered from
heliospheric electrons. These maps enable 3-dimensional tomographic
reconstruction of heliospheric density and velocity. This analysis
requires 0.1% photometry and background-light reduction below one
S10 (the brightness equivalent of a 10th magnitude star per square
degree). Thus 10-15 of surface-brightness reduction is
required relative to the solar disk. The SMEI labyrinthine baffle
provides roughly 10-10 of this reduction; the subsequent
optics system provides the remainder. We analyze data obtained over two
years in space, and evaluate the full system's stray-light rejection
performance.
Title: Low resolution three dimensional reconstruction of CMEs using
solar mass ejection imager (SMEI) data
Authors: Jackson, Bernard V.; Buffington, Andrew; Hick, P. P.; Wang,
Cindy X.
Bibcode: 2005SPIE.5901....1J
Altcode:
White-light Thomson scattering observations from the Solar Mass Ejection
Imager (SMEI) have recorded the inner heliospheric response to many
CMEs. Here we detail how we determine the extent of several CME events
in SMEI observations (including those of 28 May 28 and 28 October,
2003). We show how we are able to measure these events from their first
observations as close as 20° from the solar disk until they fade away
in the SMEI 180° field of view. We employ a 3D reconstruction technique
that provides perspective views from outward-flowing solar wind as
observed at Earth. This is accomplished by iteratively fitting the
parameters of a kinematic solar wind density model to the SMEI white
light observations and to Solar-Terrestrial Environment Laboratory
(STELab), interplanetary scintillation (IPS) velocity data. This 3D
modeling technique enables separating the true heliospheric response
in SMEI from background noise, and reconstructing the 3D heliospheric
structure as a function of time. These reconstructions allow both
separation of the 28 October CME from other nearby heliospheric
structure and a determination of its mass. Comparisons with LASCO for
individual CMEs or portions of them allow a detailed view of changes
to the CME shape and mass as they propagate outward.
Title: The SMEI real-time data pipeline: from raw CCD frames to
photometrically accurate full-sky maps
Authors: Hick, P.; Buffington, A.; Jackson, B. V.
Bibcode: 2005SPIE.5901..340H
Altcode:
The Solar Mass Ejection Imager (SMEI) records a photometric white-light
response of the interplanetary medium from Earth orbit over most of
the sky. We present the techniques required to process the SMEI data
in near real time from the raw CCD images to their final assembly
into photometrically accurate maps of the sky brightness of Thomson
scattered sunlight. Steps in the SMEI data processing include:
integration of new data into the SMEI data base; conditioning to
remove from the raw CCD images an electronic offset (pedestal) and a
temperature-dependent dark current pattern; placement ("indexing")
of the CCD images onto a high-resolution sidereal grid using known
spacecraft pointing information. During the indexing the bulk of
high-energy-particle hits (cosmic rays), space debris inside the field
of view, and pixels with a sudden state change ("flipper pixels") are
identified. Once the high-resolution grid is produced, it is reformatted
to a lower-resolution set of sidereal maps of sky brightness. From these
we remove bright stars, background stars, and a zodiacal cloud model
(their brightnesses are retained as additional data products). The
final maps can be represented in any convenient sky coordinate system,
e.g., Sun-centered Hammer-Aitoff or "fisheye" projections. Time series
at selected sidereal locations are extracted and processed further
to remove aurorae, variable stars and other unwanted signals. These
time series of the heliospheric Thomson scattering brightness (with
a long-term base removed) are used in 3D tomographic reconstructions.
Title: Very high altitude aurora observations with the Solar Mass
Ejection Imager
Authors: Mizuno, D. R.; Buffington, A.; Cooke, M. P.; Eyles, C. J.;
Hick, P. P.; Holladay, P. E.; Jackson, B. V.; Johnston, J. C.; Kuchar,
T. A.; Mozer, J. B.; Price, S. D.; Radick, R. R.; Simnett, G. M.;
Sinclair, D.; Tappin, S. J.; Webb, D. F.
Bibcode: 2005JGRA..110.7230M
Altcode: 2005JGRA..11007230M
The Solar Mass Ejection Imager (SMEI) is a sensitive scanning instrument
mounted on the Coriolis satellite that assembles an approximately
all-sky image of the heliosphere in red-biased visible light once
per orbit. Its lines of sight pass obliquely through the topside
ionosphere and magnetosphere. We present serendipitous observations
of a visual phenomenon detected at high altitudes (≥840 km) over
the auroral zones and polar caps. The phenomenon is observed in two
basic forms. The first, and more common, are periods of brief (1-3
min), nearly uniform illumination of the imager's field of view,
which we interpret as transits of the satellite through a luminous
medium. The second appear as localized filamentary structures, which
we interpret as columns of luminous material, viewed from a distance,
possibly extending to visible altitudes of 2000 km or higher. More than
1000 occurrences of these phenomena were recorded during the first
full year of operations. These observations are well correlated in
brightness and frequency with periods of enhanced geomagnetic activity.
Title: Preliminary Three Dimensional CME Mass and Energy Using Solar
Mass Ejection Imager (SMEI) Data
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Yu, Y.; Webb,
D.; Mizuno, D.; Kuchar, T.
Bibcode: 2005AGUSMSP44A..05J
Altcode:
White-light Thomson scattering observations from the Solar Mass Ejection
Imager (SMEI) have recorded the inner heliospheric response to several
hundred CMEs including the May 28, 2003 halo CME, the October 28,
2003 halo CME, and numerous other heliospheric structures. Here we
show the extent of several well-observed CMEs in SMEI observations,
and show how we are able to track events from their first measurements
in SMEI approximately 20° from the solar disk until they vanish from
the SMEI 180° field of view. Several portions of large CMEs observed
by the LASCO coronagraphs can be tracked into the interplanetary
medium associated with the initial CME response and the underlying
erupting prominence structure. We use a 3D reconstruction technique
that obtains perspective views from outward-flowing solar wind as
observed from Earth, iteratively fitting a kinematic solar wind density
model using the SMEI white light observations and, when available, the
Solar-Terrestrial Environment Laboratory (STELab), Japan interplanetary
scintillation (IPS) velocity data. This 3D modeling technique allows
us to separate the heliospheric response in SMEI from background noise,
and to estimate the 3D structure of the CME and its mass. For instance,
the analysis shows and tracks outward the northward portion of the loop
structure of the October 28, 2003 CME observed as a halo in LASCO images
that passes Earth on October 29. We determine an excess mass for this
structure of 6.7×1016g and a total mass including an ambient background
of 8.3×1016g. The very fast structure compared in a 3D pixel to pixel
comparison with the IPS velocity data gives a kinetic energy for the
northward portion of this event of 2.0×1034erg as it passes Earth.
Title: Comparative Analyses of the CSSS Calculation in the UCSD
Tomographic Solar Observations
Authors: Dunn, T.; Jackson, B. V.; Hick, P. P.; Buffington, A.; Zhao,
X. P.
Bibcode: 2005SoPh..227..339D
Altcode:
We describe a new method to derive the interplanetary magnetic field
(IMF) out to 1 AU from photospheric magnetic field measurements. The
method uses photospheric magnetograms to calculate a source surface
magnetic field at 15R⊙. Specifically, we use Wilcox Solar
Observatory (WSO) magnetograms as input for the Stanford Current-Sheet
Source-Surface (CSSS) model. Beyond the source surface the magnetic
field is convected along velocity flow lines derived by a tomographic
technique developed at UCSD and applied to interplanetary scintillation
(IPS) observations. We compare the results with in situ data smoothed by
an 18-h running mean. Radial and tangential magnetic field amplitudes
fit well for the 20 Carrington rotations studied, which are largely
from the active phase of the solar cycle. We show exemplary results
for Carrington rotation 1965, which includes the Bastille Day event.
Title: Three-dimensional structure of compound interplanetary
transients associated with 27-28 May 2003 coronal mass ejections
Authors: Tokumaru, M.; Kojima, M.; Fujiki, K.; Yamashita, M.; Jackson,
B. V.; Hick, P.
Bibcode: 2004AGUFMSH11A..01T
Altcode:
We have investigated the global features of interplanetary (IP)
disturbances associated with 27-28 May coronal mass ejection (CME)
events using interplanetary scintillation (IPS) measurements of
the Solar-Terrestrial Environment Laboratory (STEL). Our IPS data
taken between 2003 May 28 22h UT and May 29 7h UT showed a set of
complex feature of IP disturbances, and most of them are regarded as
IP consequences of two full-halo CMEs which occurred in association
with the X1.3/2B flare on May 27 23:07 UT and the X3.3 flare on May 28
00:27 UT. Some components of the IP disturbances were discriminated from
the IPS data by making the model fitting analysis iteratively. One of
the components was an Earth-directed one, which appears to correspond
to the IP shock observed by ACE on May 29 18:30 UT. Other components
were obliquely propagating ones, which either preceded or followed the
Earth-directed one. The global features deduced here are generally
in agreement with heliospheric reconstructions made from Solar Mass
Ejection Imager (SMEI) measurements.
Title: Heliospheric Photometric Images and 3D Reconstruction from
the Solar Mass Ejection Imager (SMEI) Data
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.
Bibcode: 2004AGUFMSH11A..02J
Altcode:
The Solar Mass Ejection Imager (SMEI) experiment is fixed to
the Coriolis spacecraft and views the sky above Earth using
sunlight-rejecting baffles and CCD camera technology. SMEI was
designed to provide precise photometric white light images over most
of the sky on each 102-minute Earth orbit. The brightness sky maps
of the inner heliosphere indicate a rich variety of electron density
structures that are produced by the material that propagates through
it and its interaction with ambient structures. We present some of
the preliminary results of the analysis of these photometric SMEI
observations derived by modeling the white light observations such
that most of the contaminant signals: stars, the zodiacal cloud and
high-energy particle variations are removed. We will also show some
of the 3D reconstructions that allow this contaminant signal removal
using both interplanetary scintillation (IPS) and SMEI data.
Title: Preliminary Three Dimensional Reconstruction of CMEs Using
Solar Mass Ejection Imager (SMEI) Data
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Wang, X.
Bibcode: 2004AAS...205.4305J
Altcode: 2004BAAS...36.1412J
White-light Thomson scattering observations from the Solar Mass Ejection
Imager (SMEI) have recorded the inner heliospheric response to the
October 28, 2003 CME. Here we detail the extent of this particular
CME event in SMEI observations, and we show how we are able to track
the event from its first measurement approximately 20o
from the solar disk until it fades away in the SMEI 180o
field of view. Several portions of this CME that can be tracked
into the interplanetary medium are associated with the initial
CME response and the underlying erupting prominence structure. We
employ a 3D reconstruction technique that provides perspective views
from outward-flowing solar wind as observed from Earth. This is
accomplished by iteratively fitting the parameters of a kinematic
solar wind density model to the SMEI white light observations and
to Solar-Terrestrial Environment Laboratory (STELab), interplanetary
scintillation (IPS) velocity data. This 3D modeling technique enables
separating the true heliospheric response in SMEI from background
noise, and reconstructing the 3D heliospheric structure as a function
of time. These reconstructions allow both separation of the 28 October
CME from other nearby heliospheric structure and a determination of
its mass. The preliminary SMEI white light calibration indicates
a total mass of 6 X 1016g for the ejecta associated
with the prominence eruption. The total mass of this CME including
possible associated nearby structures may have been as much as 2 X
1017g of inner heliospheric response spread over much of
the Earthward-facing hemisphere.
Title: Comparison of Solar Mass Ejection Imager (SMEI) White Light
Observations with IPS Velocity
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Kojima, M.;
Tokumaru, M.
Bibcode: 2004AGUFMSH21A0393J
Altcode:
The Solar Mass Ejection Imager (SMEI) experiment is fixed
to the Coriolis spacecraft and views the sky above Earth using
sunlight-rejecting baffles and CCD camera technology. SMEI was designed
to provide precise photometric white light images over most of the sky
on each 102-minute Earth orbit. The brightness sky maps of the inner
heliosphere indicate a rich variety of electron density structures
that are produced by the material that propagates through it and its
interaction with ambient structures. We present some of the preliminary
results of the analysis of these photometric SMEI observations derived
by 3D reconstructions that allow contaminant signal removal using both
interplanetary scintillation (IPS) velocities and SMEI data. We use
these analyses to compare preliminary SMEI tomographic white-light
results with IPS velocity for the same time intervals.
Title: Systematic Error Reduction and Photometric Calibration for
the Solar Mass Ejection Imager (SMEI)
Authors: Buffington, A.; Jackson, B. V.; Hick, P.
Bibcode: 2004AGUFMSH11A..07B
Altcode:
The Solar Mass Ejection Imager (SMEI) instrument provides white-light
photometric maps covering most of the sky each orbit of the Coriolis
spacecraft. The SMEI differential photometry specification is 0.1% for
each 1 square degree sky bin. A labyrinthine baffle reduces scattered
sunlight, but for a portion of the data a background residue must also
be subtracted to finally reach this specification. We describe this
process, and further discuss how bright stars are used to determine an
appropriate conversion from the CCD-camera data units to sky surface
brightness. Also, the CCD in the camera viewing closest to the Sun
operates significantly warmer than expected, which gives rise to
a changing population of "hot pixels". We describe a data-analysis
process which significantly alleviates the photometric impact of this.
Title: Photometric Calibration for the Solar Mass Ejection Imager
(SMEI)
Authors: Buffington, A.; Smith, A. C.; Jackson, B. V.; Hick, P. P.
Bibcode: 2004AAS...205.1007B
Altcode: 2004BAAS...36.1350B
The Solar Mass Ejection Imager (SMEI) was designed to record a
photometric white-light response of the interplanetary medium from
Earth over most of the sky in near real time, using Thomson scattered
sunlight. In its first two years the instrument has observed several
hundred Coronal Mass Ejections. Quantitative interpretations of these
data requires that the Analog Data Units (ADUs) of the instrument's CCD
responses be converted to an effective stellar brightness. The present
work provides a preliminary report on establishing this relationship. An appropriate unit here is an "S10", the equivalent brightness of
a 10th magnitude star spread over one square degree. The relationship
between ADUs and S10s is established by using the SMEI response to
bright stars having known visual magnitude and spectral type. These
latter are converted to a "SMEI magnitude" by integrating the various
star's spectra over the nominal SMEI bandpass, which extends between
0.4 and 1.1 microns and peaks at 0.7 microns, to obtain a spectral
scaling factor which is set to unity for G-type stars and relates
visual magnitudes to SMEI magnitudes. The final overall conversion
factor is then determined from the ADU measurements of the individual
stars. This work was supported in part by NSF contract ATM0331513
and NASA grant NAG 5-134543.
Title: Near Real-Time Photometric Data Processing for the Solar Mass
Ejection Imager (SMEI)
Authors: Hick, P. P.; Buffington, A.; Jackson, B. V.
Bibcode: 2004AAS...205.1006H
Altcode: 2004BAAS...36.1350H
The Solar Mass Ejection Imager (SMEI) records a photometric white-light
response of the interplanetary medium from Earth over most of the sky
in near real time. In the first two years of operation the instrument
has recorded the inner heliospheric response to several hundred CMEs,
including the May 28, 2003 and the October 28, 2003 halo CMEs. In
this preliminary work we present the techniques required to process
the SMEI data from the time the raw CCD images become available to
their final assembly in photometrically accurate maps of the sky
brightness relative to a long-term time base. Processing of the
SMEI data includes integration of new data into the SMEI data base; a
conditioning program that removes from the raw CCD images an electronic
offset ("pedestal") and a temperature-dependent dark current pattern; an
"indexing" program that places these CCD images onto a high-resolution
sidereal grid using known spacecraft pointing information. At this
"indexing" stage further conditioning removes the bulk of the the
effects of high-energy-particle hits ("cosmic rays"), space debris
inside the field of view, and pixels with a sudden state change
("flipper pixels"). Once the high-resolution grid is produced,
it is reformatted to a lower-resolution set of sidereal maps of sky
brightness. From these sidereal maps we remove bright stars, background
stars, and a zodiacal cloud model (their brightnesses are retained as
additional data products). The final maps can be represented in any
convenient sky coordinate system. Common formats are Sun-centered
Hammer-Aitoff or "fisheye" maps. Time series at selected locations
on these maps are extracted and processed further to remove aurorae,
variable stars and other unwanted signals. These time series (with a
long-term base removed) are used in 3D tomographic reconstructions. The data processing is distributed over multiple PCs running Linux,
and, runs as much as possible automatically using recurring batch jobs
('cronjobs'). The batch scrips are controlled by Python scripts. The
core data processing routines are written in several computer languages:
Fortran, C++ and IDL.
Title: Interactive Visualization of Solar Mass Ejection Imager (SMEI)
Volumetric Data
Authors: Wang, X.; Hick, P. P.; Jackson, B. V.
Bibcode: 2004AAS...205.1005W
Altcode: 2004BAAS...36.1350W
We present a volume rendering system developed for the real time
visualization and manipulation of 3D heliospheric volumetric solar wind
density and velocity data obtained from the Solar Mass Ejection Imager
(SMEI) and interplanetary scintillation (IPS) velocities over the same
time period. Our system exploits the capabilities of the VolumePro
1000 board from TeraRecon, Inc., a low-cost 64-bit PCI board capable of
rendering up to a 512-cubed array of volume data in real time at up to
30 frames per second on a standard PC. Many volume-rendering operations
have been implemented with this system such as stereo/perspective views,
animations of time-sequences, and determination of CME volumes and
masses. In these visualizations we highlight two time periods where
halo CMEs were observed by SMEI to engulf Earth, on May 30, 2003 and
on October 29, 2003. We demonstrate how this system is used to measure
the distribution of structure and provide 3D mass for individual CME
features, including the ejecta associated with the large prominence
viewed moving to the south of Earth following the late October CME.
Title: Zodiacal Light Analysis and Removal From the Solar Mass
Ejection Imager (SMEI) Data
Authors: Simon, S.; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Smith, A.
Bibcode: 2004AGUFMSH21A0398S
Altcode:
The Solar Mass Ejection Imager (SMEI) experiment provides white-light
photometric maps covering most of the sky each orbit of the Coriolis
spacecraft. The SMEI differential photometry specification is
0.1% for each 1 square degree sky bin, and was designed to provide
precise photometric white light images over most of the sky on each
102-minute Earth orbit in order to map heliospheric structures. One of
the brightest contaminant signals observed in SMEI is zodiacal light
brightness that must be modeled and subtracted from the data in order
to provide heliospheric sky maps free from large background changes. We
have devised a technique to remove zodiacal dust brightness from the
SMEI maps, and in order to do so accurately measure the asymmetry of
the equatorial dust to the ecliptic plane as well as the Gegenschein
brightness throughout the year. We present preliminary analyses of
these observations for specific intervals during the one and a half
year lifetime of SMEI.
Title: The Solar Mass-Ejection Imager (SMEI) Mission
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Altrock, R. C.;
Figueroa, S.; Holladay, P. E.; Johnston, J. C.; Kahler, S. W.; Mozer,
J. B.; Price, S.; Radick, R. R.; Sagalyn, R.; Sinclair, D.; Simnett,
G. M.; Eyles, C. J.; Cooke, M. P.; Tappin, S. J.; Kuchar, T.; Mizuno,
D.; Webb, D. F.; Anderson, P. A.; Keil, S. L.; Gold, R. E.; Waltham,
N. R.
Bibcode: 2004SoPh..225..177J
Altcode:
We have launched into near-Earth orbit a solar mass-ejection imager
(SMEI) that is capable of measuring sunlight Thomson-scattered from
heliospheric electrons from elongations to as close as 18∘
to greater than 90∘ from the Sun. SMEI is designed to
observe time-varying heliospheric brightness of objects such as coronal
mass ejections, co-rotating structures and shock waves. The instrument
evolved from the heliospheric imaging capability demonstrated by the
zodiacal light photometers of the Helios spacecraft. A near-Earth
imager can provide up to three days warning of the arrival of a mass
ejection from the Sun. In combination with other imaging instruments
in deep space, or alone by making some simple assumptions about the
outward flow of the solar wind, SMEI can provide a three-dimensional
reconstruction of the surrounding heliospheric density structures.
Title: Three-Dimensional Tomography of Interplanetary Disturbances
Authors: Jackson, Bernard V.; Hick, P. Paul
Bibcode: 2004ASSL..314..355J
Altcode:
We have developed a Computer Assisted Tomography (CAT) program
that modifies a three-dimensional kinematic heliospheric model
to fit interplanetary scintillation (IPS) or Thomson scattering
observations. The tomography program iteratively changes this
global model to least-squares fit the data. Both a corotating and
time-dependent model can be reconstructed. The short time intervals
of the time-dependent modeling (to shorter than 1 day) force the
heliospheric reconstructions to depend on outward solar wind motion
to give perspective views of each point in space accessible to the
observations, allowing reconstruction of interplanetary Coronal Mass
Ejections (CMEs) as well as corotating structures. We show these
models as velocity or density Carrington maps and remote views. We
have studied several events, including the 2000 July 14 Bastille-Day
halo CME and several intervals using archival Cambridge IPS data,
and we have also used archival Helios photometer data to reproduce
the heliosphere. We check our results by comparison with additional
remote-sensing observations, and in-situ observations from near-Earth
spacecraft. A comparison of these observations and the Earth forecasts
possible using them is available in real time on the World Wide Web
using IPS data from the Solar Terrestrial Environment Laboratory, Japan.
Title: The Solar Mass Ejection Imager (SMEI) and Its Potential as
a Precision Time-Series Photometer
Authors: Buffington, A.; Jackson, B. V.; Hick, P. P.; Penny, A.
Bibcode: 2004AAS...204.6910B
Altcode: 2004BAAS...36..795B
The Solar Mass Ejection Imager (SMEI) was launched in January 2003
into Earth orbit. SMEI is designed to observe heliospheric structures
illuminated by Thomson-scattered sunlight. The design specification for
SMEI is 0.1% in differential photometry for bright unresolved objects,
to enable star removal from the heliospheric maps. Such a near-Earth
imager will also provide photometric time-series measurements of these
stars as a by-product of this removal process. For each 101-minute
orbit, SMEI will deliver near complete sky maps having an expected
(1 sigma) photometric resolution of about the equivalent of an
11th magnitude star in a square degree. We will report on progress
in establishing the photometric calibrations for the SMEI cameras,
and discuss SMEI's potential for delivering photometric time-series
measurements, which data can then be applied to the study of variable
stars, eclipsing stellar systems, and to search for extrasolar planets
by the occultation method.
Title: The Solar Mass Ejection Imager (SMEI) Mission
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Kuchar, T.;
Mizuno, D.; Webb, D. F.
Bibcode: 2004AAS...204.1809J
Altcode: 2004BAAS...36..684J
The Solar Mass Ejection Imager (SMEI) was launched in January 2003
into Earth orbit. It observes sunlight that has Thomson-scattered from
heliospheric structures of time-varying density. SMEI is designed to
observe heliospheric structures such as coronal mass ejections (CMEs),
corotating structures and shock waves to elongations greater than 90
degrees from the Sun. Such a near-Earth imager can provide up to three
days warning of the arrival of a CME from the Sun. In combination
with other imaging instruments in deep space, or alone by making
some simple assumptions about the outward flow of the solar wind,
SMEI can provide 3D reconstructions of the heliospheric structures
that it observes. We show images of several CMEs observed with this
instrument and low-resolution reconstruction analyses using the SMEI
data for each event. The 3D reconstructions and heights for these
events are compared with elongation-time plots of the same CMEs to
estimate true speeds and line-of-sight locations for each CME.
Title: Coronal Mass Ejection Masses From CMEs Identified in
Interplanetary Scintillation (IPS) Tomography and LASCO Coronagraph
Images
Authors: Rappoport, S. A.; Jackson, B. V.; Hick, P. P.; Buffington,
A.; Vourlidas, A.
Bibcode: 2004AAS...204.3802R
Altcode: 2004BAAS...36..712R
To optimize the information from individual radio source observations
of the sky covering large elongations, we have developed a
Computer-Assisted Tomography (CAT) program. We fit STELab (Nagoya
University, Japan) interplanetary scintillation (IPS) observations to a
time-dependent, three-dimensional heliospheric model. These observations
allow us to create "sky maps" covering 10 to 80 degrees in elongation,
in which we can track CMEs observed earlier in LASCO coronagraph
images. These events have approximately the same shapes and extents as
observed closer to the Sun. Here we map several CMEs in 3-dimensions as
they move outward to 1 AU. Masses for each of the events are determined
from the reconstruction analysis and are compared with plane of the
sky masses obtained from calibrated LASCO coronagraph images.
Title: Comparative analyses of the CSSS magnetic field calculation
in the Univ. of California/San Diego tomographic solar wind model
with in situ spacecraft observations
Authors: Dunn, Tamsen; Hick, P. P.; Jackson, Bernard V.; Buffington,
Andrew; Zhao, Xue Pu
Bibcode: 2004SPIE.5171....6D
Altcode:
Our tomographic techniques developed over the last few years are based
on kinematic models of the solar wind. This allows us to determine the
large-scale three-dimensional extents of solar wind structures using
interplanetary scintillation (IPS) observations and Thomson scattering
brightness data in order to forecast their arrival at Earth in real
time. We are specifically interested in a technique that can be combined
with observations presently available from IPS velocity data and with
observations which will become available from the Solar Mass Ejection
Imager. In this paper, we introduce magnetic field projections from
solar surface magnetogram data using the Stanford Current-Sheet Source
Surface model at the source surface of our model and extrapolate the
magnetic field out to and beyond Earth. The results are compared with
in situ data. Real time projections of these data are available on our
web site at: http://cassfos02.ucsd.edu/solar/forecast/index_v_n.html
and http://cassfos02.ucsd.edu/solar/forecast/index_br_bt.html
Title: Visualization of remotely sensed heliospheric plasmas for
space weather applications
Authors: Wang, Xin; Hick, P. P.; Jackson, Bernard V.; Bailey, Mike
Bibcode: 2004SPIE.5171..280W
Altcode:
We demonstrate a software application designed for the display and
interactive manipulation of 3D heliospheric volume data, such as solar
wind density, velocity and magnetic field. The Volume Explorer software
exploits the capabilities of the Volume Pro 1000 (from TeraRecon,
Inc.), a low-cost 64-bit PCI board capable of rendering a 512-cubed
array of volume data in real time at up to 30 frames per second on a
standard PC. The application allows stereo and perspective views, and
animations of time-sequences. We show examples of three-dimensional
heliospheric volume data derived from tomographic reconstructions
based on heliospheric remote sensing observations of the heliospheric
density and velocity structure. Currently these reconstructions are
based on archival IPS and Thomson scattering data. In the near future
we expect to add reconstructions based on the all-sky observations
from the recently launched Solar Mass Ejection Imager.
Title: SMEI: design and development of an Earth-orbiting all-sky
coronagraph
Authors: Jackson, Bernard V.; Hick, P. P.; Buffington, Andrew; Gold,
Robert E.; Simnett, George M.; Eyles, Christopher J.; Cooke, Mark P.;
Waltham, Nicholas R.
Bibcode: 2004SPIE.5171....1J
Altcode:
The Air Force/NASA Solar Mass Ejection Imager (SMEI) launched January 6,
2003 is now recording whole sky data on each 100-minute orbit. Precise
photometric sky maps of the heliosphere around Earth are expected from
these data. The SMEI instrument extends the heritage of the HELIOS
spacecraft photometer systems that have recorded CMEs and other
heliospheric structures from close to the Sun into the anti-solar
hemisphere. SMEI rotates once per orbit and views the sky away
from Earth using CCD camera technology. To optimize the information
derived from this and similar instruments, a tomographic technique
has been developed for analyzing remote sensing observations of the
heliosphere as observed in Thomson scattering. The technique provides
3-dimensional reconstructions of heliospheric density. The tomography
program has been refined to analyze time-dependent phenomena such as
evolving corotating heliospheric structures and more discrete events
such as coronal mass ejections (CMEs), and this improved analysis is
being applied to the SMEI data.
Title: Heliospheric tomography: an algorithm for the reconstruction
of the 3D solar wind from remote sensing observations
Authors: Hick, P. P.; Jackson, Bernard V.
Bibcode: 2004SPIE.5171..287H
Altcode:
Over the past years we have developed a tomographic technique for
using heliospheric remote sensing observations (i.e. interplanetary
scintillation and Thomson scattering data) for the reconstruction of
the three-dimensional solar wind density and velocity in the inner
heliosphere. We describe the basic algorithm on which our technique
is based. To highlight the details of the reconstruction algorithm we
specifically emphasize the implementation of corotating tomography
using IPS g-level and IPS velocity observations as proxies for the
solar wind density and velocity, respectively. We provide some insight
into the modifications required to expand the technique into a fully
time-dependent tomography, and to use Thomson scattering brightness
(instead of g-level) as a proxy for the solar wind density.
Title: Tracking a major interplanetary disturbance with SMEI
Authors: Tappin, S. J.; Buffington, A.; Cooke, M. P.; Eyles, C. J.;
Hick, P. P.; Holladay, P. E.; Jackson, B. V.; Johnston, J. C.; Kuchar,
T.; Mizuno, D.; Mozer, J. B.; Price, S.; Radick, R. R.; Simnett,
G. M.; Sinclair, D.; Waltham, N. R.; Webb, D. F.
Bibcode: 2004GeoRL..31.2802T
Altcode: 2004GeoRL..3102802T
We present the first clear observations of an Earth-directed
interplanetary disturbance tracked by the Solar Mass Ejection Imager
(SMEI). We find that this event can be related to two halo CMEs seen at
the Sun about 2 days earlier, and which merged in transit to 1 AU. The
disturbance was seen about 16 hours before it reached Earth,and caused
a severe geomagnetic storm at the time which would have been predicted
had SMEI been operating as a real-time monitor. It is concluded that
SMEI is capable of giving many hours advance warning of the possible
arrival of interplanetary disturbances.
Title: The Solar Mass Ejection Imager (SMEI) Mission
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.; Holladay, P.;
Johnston, J. C.; Kahler, S. W.; Mozer, J.; Price, S.; Radick, R. R.;
Sinclair, D.; Simnett, G. M.; Eyles, C. J.; Cooke, M. P.; Tappin,
J.; Waltham, N. R.; Kuchar, T.; Mizuno, D.; Webb, D. F.
Bibcode: 2003AGUFMSH41B0457J
Altcode:
We have designed, built and launched into near-Earth orbit a Solar
Mass Ejection Imager (SMEI) capable of observing sunlight that
has Thomson-scattered from heliospheric structures of time-varying
density. SMEI is designed to observe heliospheric structures such
as coronal mass ejections, corotating structures and shock waves,
to elongations greater than 90° from the Sun. The instrument was
inspired by the heliospheric imaging capability demonstrated by the
zodiacal light photometers of the Helios spacecraft. The instrument
makes effective use of in situ solar wind data from spacecraft in the
vicinity of the imager by extending observations to the surrounding
environment and back to the Sun. A near-Earth imager can provide up to
three days warning of the arrival of a mass ejection from the Sun. In
combination with other imaging instruments in deep space, or alone by
making some simple assumptions about the outward flow of the solar wind,
SMEI can provide a tomographic analysis of the heliospheric structures
surrounding it.
Title: Space Performance of the Multistage Labyrinthine SMEI Baffle
Authors: Buffington, A.; Jackson, B. V.; Hick, P. P.
Bibcode: 2003AGUFMSH41B0459B
Altcode:
The Solar Mass Ejection Imager (SMEI) was launched on 6 January
2003, and shortly thereafter raised to a nearly circular orbit
at 840 km. Three SMEI CCD cameras on the zenith-oriented CORIOLIS
spacecraft cover most of the sky beyond about 20° from the Sun,
each 102-minute orbit. Data from this instrument will ultimately
provide precision visible-light photometric sky maps. Once starlight
and other constant or slowly varying backgrounds are subtracted,
the residue is mostly sunlight that has been Thomson-scattered from
heliospheric electrons. These maps will enable 3-dimensional tomographic
reconstruction of heliospheric density and velocity. This analysis
requires 0.1% photometry and background-light reduction below one
S10 (the brightness equivalent of a 10th magnitude star per square
degree). Thus 10-15 of surface-reduction is required
relative to the solar disk. The SMEI labyrinthine baffle provides
roughly 10-10 of this reduction; the subsequent optics
provides the remainder. We analyze data covering a range of angles
between the SMEI optical axis and the Sun, or the Moon, to evaluate
the full system's stray-light rejection performance.
Title: The Solar Mass Ejection Imager (SMEI)
Authors: Simnett, G. M.; Eyles, C. J.; Cooke, M. P.; Waltham, N. R.;
King, J. M.; Jackson, B. V.; Buffington, A.; Hick, P. P.; Holladay,
P. E.; Anderson, P. A.
Bibcode: 2003AGUFMSH41C..02S
Altcode:
The Solar Mass Ejection Imager (SMEI) has been designed to detect and
forecast the arrival of solar mass ejections and other heliospheric
structures which are moving towards the Earth. We describe the
instrument, which was launched into a Sun-synchronous polar orbit
on 6 January, 2003 on board the US DoD Coriolis spacecrafth. SMEI
contains three CCD cameras, sensitive over the optical waveband,
each with a field-of-view of 60 degrees x 3 degrees. The sensitivity
is such that it will detect changes in sky brightness equivalent to
a tenth magnitude star in one square degree of sky. Each camera takes
an image every 4s and the normal telemetry rate is 128 kbits/s. SMEI
has a photometric accuracy of around 0.1%. In addition to solar mass
ejections, images of stars and the zodiacal cloud are measured to this
photometric accuracy once/ orbit (102 minutes).
Title: Stellar Variability Studies with SMEI
Authors: Penny, A. J.; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Kahler, S. W.; Price, S.; Johnston, J. C.; Holladay, P.; Sinclair,
D.; Radick, R. R.; Mozer, J. C.; Anderson, P.; Simnett, G. M.; Eyles,
C. J.; Cooke, M. P.; Tappin, J.; Waltham, N. R.; Kuchnar, T.; Mizuno,
D.; Webb, D. F.
Bibcode: 2003AGUFMSH41C..08P
Altcode:
The Solar Mass Ejection Imager (SMEI) instrument images most of the sky
every 105 minutes. From this unique dataset, the brightnesses of stars
down to and below the eight magnitude can be measured to investigate
their variability. This paper presents the methods developed to extract
the stellar brightnesses, and the accuracies obtained as a function
of brightness and crowding. Example lightcurves are given.
Title: IPS/SMEI potential joint observations
Authors: Tokumaru, M.; Kojima, M.; Fujiki, K.; Jackson, B. V.; Hick, P.
Bibcode: 2003AGUFMSH41C..05T
Altcode:
Interplanetary scintillation (IPS) measurements are known as one
of remote-sensing techniques which enable us to gain access to
global features of the solar wind (e.g. quasi-stationary corotating
structures, transient streams associated with CMEs). We have carried
out a long-term collaboration on the reconstruction of the heliospheric
features from IPS measurements made with the 327 MHz four-station
system of the Solar-Terrestrial Environment Laboratory (STEL),
Nagoya University. Under the collaboration, we have developed the
computer-assisted tomography (CAT) analysis method, which allows us to
retrieve the 3D distribution of the solar wind velocity and density
from IPS data. We also have been making the real-time reconstruction
experiment of heliospheric features using STEL IPS data and the CAT
method. Based on these results, we propose here the joint observations
of IPS and SMEI. The SMEI is a powerful tool to investigate the global
heliospheric features, and its capability is complementary to one of
IPS observations; That is, SMEI observations provide a high-resolution
image of the solar wind density distribution, while IPS observations
provide reliable estimates of the solar wind velocity. Therefore, a
combination of IPS and SMEI observations is essential for achieving a
precise reconstruction of global heliospheric (velocity and density)
features by the CAT analysis.
Title: Interactive Visualization of Transient Solar Wind Phenomena
for Space Weather Applications
Authors: Wang, C. X.; Hick, P. P.; Jackson, B. V.
Bibcode: 2003AGUFMSH41B0458W
Altcode:
We present a volume rendering system developed for the visualization and
manipulation of 3D heliospheric volume data such as solar wind density,
velocity and magnetic field. Our system exploits the capabilities of
the VolumePro 1000 board from TeraRecon, Inc., a low-cost 64-bit PCI
board capable of rendering a 512-cubed array of volume data in real
time at up to 30 frames per second on a standard PC. Many operations
have been implemented such as stereo/perspective views, animations
of time-sequences, and determination of CME volumes and masses. We
will show examples of three-dimensional heliospheric volumes from
tomographic reconstructions of density and velocity using real-time
interplanetary scintillation (IPS) data. In the near future we expect
to add reconstructions based on the all-sky observations from the
recently launched Solar Mass Ejection Imager and employ our system to
interactively analyze and visualize the abundant information embedded
in these data.
Title: Recent Comparative Analyses of the CSSS UCSD Tomographic
Solar Wind Model with in situ Spacecraft Observations
Authors: Dunn, T.; Hick, P.; Jackson, B. V.; Buffington, A.
Bibcode: 2003AGUFMSH42B0526D
Altcode:
Our tomographic techniques developed over the last few years are based
on kinematic models of the solar wind. This allows us to determine
the large-scale three-dimensional extents of solar wind structures
using interplanetary scintillation (IPS) observations and Thomson
scattering brightness data in order to forecast their arrival at Earth
in real time. We are specifically interested in a technique that can
be combined with observations presently available from IPS velocity
data and with observations which are now becoming available from the
Solar Mass Ejection Imager. We use solar surface magnetogram data,
and a source surface provided by the Stanford Current-Sheet Source
Surface model, to provide input to the UCSD tomography program. The
UCSD tomography program extrapolates the magnetic field out to and
beyond Earth. The latest results are compared with in situ data.
Title: The Solar Mass Ejection Imager (Smei)
Authors: Eyles, C. J.; Simnett, G. M.; Cooke, M. P.; Jackson, B. V.;
Buffington, A.; Hick, P. P.; Waltham, N. R.; King, J. M.; Anderson,
P. A.; Holladay, P. E.
Bibcode: 2003SoPh..217..319E
Altcode:
We describe an instrument (SMEI) which has been specifically designed
to detect and forecast the arrival of solar mass ejections and other
heliospheric structures which are moving towards the Earth. Such
events may cause geomagnetic storms, with resulting radiation hazards
and disruption to military and commercial communications; damage
to Earth-orbiting spacecraft; and also terrestrial effects such as
surges in transcontinental power transmission lines. The detectors
are sensitive over the optical wave-band, which is measured using CCD
cameras. SMEI was launched on 6 January 2003 on the Coriolis spacecraft
into a Sun-synchronous polar orbit as part of the US DoD Space Test
Programme. The instrument contains three cameras, each with a field of
view of 60°×3°, which are mounted onto the spacecraft such that they
scan most of the sky every 102-min orbit. The sensitivity is such that
changes in sky brightness equivalent to a tenth magnitude star in one
square degree of sky may be detected. Each camera takes an image every
4 s. The normal telemetry rate is 128 kbits s−1. In order
to extract the emission from a typical large coronal mass ejection,
stellar images and the signal from the zodiacal dust cloud must be
subtracted. This requires accurate relative photometry to 0.1%. One
consequence is that images of stars and the zodiacal cloud will be
measured to this photometric accuracy once per orbit. This will enable
studies of transient zodiacal cloud phenomena, flare stars, supernovae,
comets, and other varying point-like objects.
Title: Time-dependent tomography of hemispheric features using
interplanetary scintillation (IPS) remote-sensing observations
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Kojima, M.;
Tokumaru, M.; Fujiki, K.; Ohmi, T.; Yamashita, M.
Bibcode: 2003AIPC..679...75J
Altcode:
We have developed a Computer Assisted Tomography (CAT) program that
modifies a time-dependent three-dimensional kinematic heliospheric model
to fit interplanetary scintillation (IPS) observations. The tomography
program iteratively changes this global model to least-squares fit
IPS data. The short time intervals of the kinematic modeling (~1 day)
force the heliospheric reconstructions to depend on outward solar wind
motion to give perspective views of each point in space accessible to
the observations, allowing reconstruction of interplanetary Coronal
Mass Ejections (CMEs) as well as corotating structures. We show these
models as velocity or density Carrington maps and remote views. We have
studied several events, including the July 14, 2000 Bastille-day halo
CME. We check our results by comparison with additional remote-sensing
observations, and observations from near-Earth spacecraft.
Title: Time-dependent tomography of heliospheric structures using
IPS and Thomson scattering observations
Authors: Jackson, Bernard V.; Hick, P. P.; Buffington, A.
Bibcode: 2003ESASP.535..823J
Altcode: 2003iscs.symp..823J
The Air Force/NASA Solar Mass Ejection Imager (SMEI) launched
January 6, 2003 is now recording whole sky data on each 100-minute
orbit. Precise photometric images of the heliosphere around Earth
are expected from these data. To optimize the information available
from this and similar instruments, we are developing a tomographic
technique for analyzing remote sensing observations of the heliosphere
using both interplanetary scintillation (IPS) and Thomson scattering
data. The technique provides a three-dimensional reconstruction of
heliospheric velocities and densities. We have refined our tomography
program to analyze time-dependent phenomena such as evolving corotating
heliospheric structures and more discrete events such as coronal mass
ejections (CMEs).
Title: Time-dependent tomography of heliospheric features using the
three-dimensional reconstruction techniques developed for the solar
mass ejection imager (SMEI)
Authors: Jackson, Bernard V.; Hick, Pierre P.; Buffington, Andrew
Bibcode: 2003SPIE.4853...23J
Altcode:
Precise photometric images of the heliosphere are expected from the
Air Force/NASA Solar Mass Ejection Imager (SMEI) now scheduled for
launch in February 2003, and the all-sky cameras proposed for other
NASA missions. To optimize the information available from these
instruments, we are developing tomographic techniques for analyzing
remote sensing observations of heliospheric density as observed in
Thomson scattering (e.g. using the Helios photometer data) for eventual
use with SMEI. We have refined the tomography program to enable us to
analyze time-dependent phenomena, such as the evolution of corotating
heliospheric structures and more discrete events such as coronal mass
ejections. Both types of phenomena are discerned in our data, and are
reconstructed in three dimensions. We use our tomography technique to
study the interaction of these phenomena as they move outward from the
Sun for several events that have been studied by multiple spacecraft
in situ observations and other techniques.
Title: Introduction of the CSSS magnetic field calculation into the
UCSD tomographic solar wind model
Authors: Dunn, Tamsen; Hick, Pierre P.; Jackson, Bernard V.; Zhao,
Xuepu
Bibcode: 2003SPIE.4853..504D
Altcode:
Tomographic techniques developed at UCSD over the last few years
incorporate a kinematic model of the solar wind to determine and
forecast the large-scale three-dimensional extents of velocity and
density using interplanetary scintillation (IPS) observations or Thomson
scattering brightness data. In this paper, we introduce magnetic field
calculations from the Stanford Current-Sheet Source Surface (CSSS)
model into our kinematic model. The CSSS model is used to extrapolate
the photospheric magnetic field to a source surface at 15 solar radii
(Rs). The UCSD kinematic model convects magnetic field
from 15 Rs out to and beyond Earth. We compare the results
with in situ data near Earth. The spatial relationship between the
heliospheric current sheet and coronal mass ejections (CMEs) is shown
in remote views of the inner heliosphere
Title: Calculations for and laboratory measurements of a multistage
labyrinthine baffle for SMEI
Authors: Buffington, Andrew; Jackson, Bernard V.; Hick, Pierre P.
Bibcode: 2003SPIE.4853..490B
Altcode:
The spaceborne Solar Mass Ejection Imager (SMEI) is scheduled for launch
into near-earth orbit (>800 km) in early 2003. Three SMEI CCD cameras
on the zenith-oriented CORIOLIS spacecraft cover most of the sky each
100-minute orbit. Data from this instrument will provide precision
visible-light photometric maps. Once starlight and other constant
or slowly varying backgrounds are subtracted, the residue is mostly
sunlight that has Thomson-scattered from heliospheric electrons. These
maps will enable 3-dimensional tomographic reconstruction of
heliospheric density and velocity. The SMEI design provides three
cameras, one of which views to within 18 degrees of the solar disk with
a field of view 60° long by 3° wide. Placed end-to-end, three fields
of view then cover a nearly 180° long strip that sweeps out the sky
over each orbit. The 3-dimensional tomographic analysis requires 0.1%
photometry and background-light reduction below one S10 (the brightness
equivalent of a 10th magnitude star per square degree). Thus 10-15
of surface-brightness reduction is required relative to the solar
disk. The SMEI labyrinthine baffle provides roughly 10-10 of
this reduction; the subsequent optics provides the remainder. We
describe the baffle design and present laboratory measurements of
prototypes that confirm performance at this level.
Title: Tomography of Heliospheric Features Developed for Smei
Authors: Jackson, Bernard V.; Hick, P. P.; Buffington, Andrew
Bibcode: 2003IAUJD...7E..23J
Altcode:
The Air Force/NASA Solar Mass Ejection Imager (SMEI) launched January 6
2003 is now recording whole sky data on each 100-minute orbit. Precise
photometric images of the heliosphere around Earth are expected from
these data. To optimize the information available from this and similar
instruments we are developing a tomographic technique for analyzing
remote sensing observations of the heliosphere as observed in Thomson
scattering. The technique provides three-dimensional reconstructions of
heliospheric density. We have refined our tomography program to analyze
time-dependent phenomena such as evolving corotating heliospheric
structures and more discrete events such as coronal mass ejections
(CMEs).
Title: The 3d Solar Wind Over the Solar Cycle Observed by IPS
Authors: Kojima, Masayoshi; Jackson, Bernard V.; Ohmi, Tomoaki; Hick,
Paul; Hayashi, Keiji; Tokumaru, Munetoshi; Fujiki, Ken-Ichi
Bibcode: 2003IAUJD...7E..25K
Altcode:
The interplanetary scintillation (IPS) method can observe the dynamics
and structure of the solar wind in three dimensions with a relatively
short time cadence. Because IPS observations are line-of-sight
integrations we have developed an IPS tomography analysis method that
can retrieve three-dimensional solar wind parameters as well as provide
better spatial resolutions than previous IPS techniques. Using the
IPS tomography analysis we have studied the solar cycle dependence
of the solar wind properties such as the velocity of fast solar wind
bimodal structure north-south asymmetry of fast wind and the origin of a
compact slow streamer. Solar wind structure is bimodal not only in the
solar minimum phase but also in the ascending and descending phases;
In solar minimum phase a small coronal hole in vicinity of an active
region emanates slow wind and a polar coronal hole also becomes the
source of slow wind when it shrinks to a small size at solar maximum;
the velocity of the fast wind does not change significantly when
a coronal hole changes its size in the descending and ascending
phases. We also introduce the three-dimensional dynamic nature of
interplanetary transient events that were observed with another new
technique: time-dependent tomography.
Title: Coronal Mass Ejections Identified in Interplanetary
Scintillation (IPS) Tomography and in LASCO Coronagraph Images
Authors: Rappoport, S. A.; Hick, P. P.; Jackson, B. V.
Bibcode: 2002AAS...201.8303R
Altcode: 2002BAAS...34.1242R
Coronal mass ejections (CMEs), including halo CMEs, can be observed in
interplanetary scintillation (IPS) data. To optimize the information
from radio source observations, we model them using a time-dependent
three-dimensional tomography program. We depict this heliospheric model
as a series of "sky map" images that cover elongations extending from
10 to 80 degrees. These IPS maps show CMEs observed earlier in the
LASCO coronagraph images with approximately the same shapes and extents
that were seen closer to the Sun. Here, a series of these CME events,
including halo CMEs, are mapped as they move outward to distances as
great as 1 AU.
Title: Corotational Tomography of Heliospheric Features Using Global
Thomson Scattering Data
Authors: Jackson, Bernard V.; Hick, P. Paul
Bibcode: 2002SoPh..211..345J
Altcode:
The Air Force/NASA Solar Mass Ejection Imager (SMEI) will provide
two-dimensional images of the sky in visible light with high (0.1%)
photometric precision, and unprecedented sky coverage and cadence. To
optimize the information available from these images they must
be interpreted in three dimensions. We have developed a Computer
Assisted Tomography (CAT) technique that fits a three-dimensional
kinematic heliospheric model to remotely-sensed Thomson scattering
observations. This technique is designed specifically to determine
the corotating background solar wind component from data provided by
instruments like SMEI. Here, we present results from this technique
applied to the Helios spacecraft photometer observations. The
tomography program iterates to a least-squares solution of observed
brightnesses using solar rotation, spacecraft motion and solar wind
outflow to provide perspective views of each point in space covered
by the observations. The corotational tomography described here
is essentially the same as used by Jackson et al. (1998) for the
analysis of interplanetary scintillation (IPS) observations. While
IPS observations are related indirectly to the solar wind density
through an assumed (and uncertain) relationship between small-scale
density fluctuations and density, Thomson scattering physics is more
straightforward, i.e., the observed brightness depends linearly on
the solar wind density everywhere in the heliosphere. Consequently,
Thomson scattering tomography can use a more direct density-convergence
criterion to match observed Helios photometer brightness to brightness
calculated from the model density. The general similarities between
results based on IPS and Thomson scattering tomography validate both
techniques and confirm that both observe the same type of solar wind
structures. We show results for Carrington rotation 1653 near solar
minimum. We find that longitudinally segmented dense structures corotate
with the Sun and emanate from near the solar equator. We discuss the
locations of these dense structures with respect to the heliospheric
current sheet and regions of activity on the solar surface.
Title: Remote-Sensing of the Solar Wind: A Space Weather Application
Authors: Hick, P. P.; Rappoport, S. A.; Jackson, B. V.; Dunn, T.;
Wang, C.
Bibcode: 2002AAS...20114102H
Altcode: 2003BAAS...35Q.567H
Remote sensing observations of the solar wind in the inner
heliosphere fill an observational gap between near-Sun remote
sensing and near-Earth in-situ data. We use heliospheric tomography
to follow solar disturbances from Sun to Earth as the basis for a
real-time space weather system. Over the past few years interplanetary
scintillation observations from the Solar-Terrestrial Laboratory at
Nagoya University, Japan, were the main source of data. In the near
future Thomson scattering observations from the recently launched Solar
Mass Ejection Imager (SMEI) will be added. Here we show some recent
developments in the visualization techniques used to process the volume
data sets produced by the tomographic analyis: solar wind density,
velocity and magnetic field. 3D visualization is based on an image
rendering engine written in the IDL programming language. In addition,
we use hardware-based volume rendering with the Volume Pro PCI board
from TeraRecon. This board renders 4D volume data (three spatial, plus
the time dimension) in real-time, allowing interactive manipulation
of evolving (time-dependent) data sets. This work was supported
through NASA grant NAG5-9423 and Air Force MURI grant F49620-01-0359.
Title: Visualization of Remotely-Sensed Heliospheric Plasmas
Authors: Bailey, M.; Hick, P. P.; Wang, C.; Jackson, B. V.;
Buffington, A.
Bibcode: 2002AGUFMSH21A0511B
Altcode:
We demonstrate a software application designed for the display and
real-time manipulation of 3D heliospheric volume data, such as solar
wind density, velocity and magnetic field. The software exploits
the capabilities of the Volume Pro 1000 (from TeraRecon, Inc.), a
low-cost 64-bit PCI board capable of rendering a 512-cubed array of
volume data in real time at up to 30 frames per second on a standard
PC. The application allows stereo and perspective views, and animations
of time-sequences. We show several examples of three-dimensional
heliospheric volume data derived from tomographic reconstructions based
on heliospheric remote sensing observations of the heliospheric density
and velocity structure (e.g. Thomson scattering and interplanetary
scintillation observations). This work was supported through NASA
grant NAG5-9423 and Air Force MURI grant F49620-01-0359.
Title: Halo CME's - Will They Hit or Miss Earth?
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.
Bibcode: 2002AGUFMSH21A0474J
Altcode:
To optimize the information from maps of the sky that cover large
elongations we have developed a Computer Assisted Tomography (CAT)
program that models these using a time-dependent three-dimensional
heliospheric model to fit Thomson scattering or STELab (Nagoya
University) interplanetary scintillation (IPS) observations. The
duration of a CME event (typically several days) imposes the restriction
that the reconstruction model primarily uses outward solar wind motion
to give perspective views of each point in space. The results to date
are commensurate with the observational coverage, temporal and spatial
resolution, and signal to noise available from the original data. We
provide remote observer views of IPS-based reconstructions of halo
CMEs also observed by the LASCO coronagraphs. We practice our modeling
techniques by making these views available in real time to forecast
halo CME Earth-arrival. Here we explore the locations and shapes of a
few select halo CMEs and their three-dimensional velocity structure in
order to determine whether they will hit or miss the Earth. This work
is supported by NASA grant NAG5-8504 and AFOSR grant F49620-01-1-0054.
Title: 3-D Tomography of Interplanetary Disturbances
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.
Bibcode: 2002AAS...200.4910J
Altcode: 2002BAAS...34..723J
We are developing tomographic techniques for analyzing remote sensing
observations of heliospheric density and velocity as observed in
Thomson scattering (e.g. by the Helios photometers) and interplanetary
scintillation (IPS) observations. We have refined the program to
enable us to analyze time-dependent phenomena, such as the evolution of
corotating heliospheric structures and rapidly evolving events such as
coronal mass ejections. We intend our analyses to be used with data from
the future Solar Mass Ejection Imager (SMEI) experiment. We currently
provide these analyses in real-time using IPS observations in order to
forecast the arrival of corotating structures and CMEs at Earth. This
work is supported by NASA grant NAG5-9423 and AFOSR grant F49620-01-0054
Title: Introduction of the CSSS Magnetic Field Model into the UCSD
Tomographic Solar Wind Model
Authors: Dunn, T.; Hick, P. P.; Jackson, B. V.; Buffington, A.
Bibcode: 2001AGUFMSH31A0701D
Altcode:
Our time-dependent tomographic technique developed over the last few
years provides a kinematic model of the solar wind. The model, which
has one-day time steps, allows us to determine the large-scale three
dimensional extent of solar disturbances and to forecast their arrival
at Earth in real-time. We introduce magnetic field calculations from
the Stanford Current-Sheet Source Surface model (Zhao and Hoeksema,
1995) at the source surface of our kinematic model and extrapolate
the magnetic field out beyond Earth. We show an animated version of
the convected magnetic field, and compare results with in situ data
near Earth. We wish to thank Dr. XuePu Zhao for providing software and
input data for the Stanford Current-Sheet Source Surface model. This
work is supported by AFOSR contract F49620-01-1-0360. References: Zhao,
X. and J.T. Hoeksema, Prediction of the interplanetary magnetic field
strength, J. Geophys. Res. 100, 19, 1995.
Title: Space Weather Using Remote Sensing Data
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.; Dunn, T.;
Rappoport, S.; Kojima, M.; Tokumaru, M.; Fujiki, K.; Yokobe, A.;
Ohmi, T.
Bibcode: 2001AGUFMSH31A0698J
Altcode:
We are developing tomographic techniques for analyzing remote
sensing observations of the coronal and heliospheric density and
velocity structure as observed in Thomson scattering and also using
interplanetary scintillation (IPS) observations. We have refined our
program to enable us to analyze time-dependent phenomena, such as the
evolution of co-rotating heliospheric structures and rapidly evolving
events such as coronal mass ejections, as observed e.g. with the future
Solar Mass Ejection Imager (SMEI) experiment. We currently provide
heliospheric three-dimensional reconstructions in real-time using IPS
observations from STELab, Nagoya University, Japan in order to forecast
the arrival at Earth of CMEs. We compare these reconstructions modeled
at Earth with ACE in-situ spacecraft data and show these analyses along
with a goodness-of-fit criterion designed to certify the reconstructions
and refine our technique. This work is supported by AFOSR contract
F49620-01-1-0054 and NASA contract NAG5-8504. index.html</a>
Title: A Study of Interacting Plasma Phenomena Using the Tomographic
3-Dimensional Reconstruction Techniques Developed for the Solar Mass
Ejection Imager (SMEI)
Authors: Jackson, B. V.; Hick, P. P.
Bibcode: 2001AGUFMSH11D..04J
Altcode:
We are developing tomographic techniques for analyzing remote sensing
observations of heliospheric density and velocity structure as
observed in Thomson scattering (e.g. using the Helios photometer
data) for eventual use with Solar Mass Ejection Imager (SMEI)
observations. We have refined the tomography program to enable
us to analyze time-dependent phenomena, such as the evolution of
corotating heliospheric structures and more discrete events such
as coronal mass ejections. Both types of phenomena are discerned
in our data, and are reconstructed in three dimensions. We use our
tomography technique to study the interaction of these phenomena
as they move outward from the Sun for several events that have
been studied by multiple spacecraft in-situ observations and other
techniques. This work is supported by NASA grant NAG5-8504 and AFOSR
grant F49620-01-1-0054. >http://casswww.ucsd.edu/solar/crew/bjackson
/index.html</a>
Title: Study of ICME Structure Using LASCO White Light and STE Lab
IPS Observations of Halo CMEs
Authors: Webb, D. F.; Tokumaru, M.; Jackson, B. V.; Hick, P. P.
Bibcode: 2001AGUFMSH31A0700W
Altcode:
As part of a long-term investigation of halo-like coronal mass ejections
(CMEs) well observed in white light by the SOHO LASCO coronagraphs,
we report on a study comparing our catalog of parameters and solar and
solar wind associations of halo CMEs with interplanetary disturbances
observed with the interplanetary scintillation (IPS) radio array of
STE Lab in Japan. We have cataloged over 100 full halo CMEs observed
by LASCO from 1996 through 2000. This period covers the first half
of solar cycle 23 from activity minimum to maximum. Although the STE
Lab observations are limited during each year, nearly all of these
CMEs occurring during STE Lab observations were associated with IPS
disturbances within a day or so following the halo CME onset time. We
will present a summary of these comparisons, and will discuss how the
combined data sets can be used to determine key parameters of the
3D shape, structure and propagation of ICMEs. At STE Lab a program
is used to find best-fit parameters automatically by matching model
calculations to the observed IPS g-value (proportional to plasma
density) data. At UCSD a tomographic program is used to reconstruct
3D views of ICMEs using the IPS data in a reconstruction technique
based on solar rotation and outward solar wind motion. This work is
also pertinent for observations that will be available from the Solar
Mass Ejection Imager (SMEI) experiment to be launched next year and,
later, from the NASA STEREO mission.
Title: Volume Rendering of Heliospheric Data
Authors: Hick, P. P.; Jackson, B. V.; Bailey, M. J.; Buffington, A.
Bibcode: 2001AGUFMSH31A0699H
Altcode:
We demonstrate some of the techniques we currently use for the
visualization of heliospheric volume data. Our 3D volume data usually
are derived from tomographic reconstructions of the solar wind density
and velocity from remote sensing observations (e.g., Thomson scattering
and interplanetary scintillation observations). We show examples of
hardware-based volume rendering using the Volume Pro PCI board (from
TeraRecon, Inc.). This board updates the display at a rate of up to 30
frames per second using a parallel projection algorithm, allowing the
manipulation of volume data in real-time. In addition, the manipulation
of 4D volume data (the 4th dimension usually representing time) enables
the visualization in real-time of an evolving (time-dependent) data
set. We also show examples of perspective projections using IDL. This
work was supported through NASA grant NAG5-9423.
Title: A heliospheric imager for Solar Orbiter
Authors: Jackson, B. V.; Buffington, A.; Hick, P. P.
Bibcode: 2001ESASP.493..251J
Altcode: 2001sefs.work..251J
No abstract at ADS
Title: Evidence for space weather at Mercury
Authors: Killen, R. M.; Potter, A. E.; Reiff, P.; Sarantos, M.;
Jackson, B. V.; Hick, P.; Giles, B.
Bibcode: 2001JGR...10620509K
Altcode:
Mercury's sodium atmosphere is known to be highly variable both
temporally and spatially. During a week-long period from November
13 to 20, 1997, the total sodium content of the Hermean atmosphere
increased by a factor of 3, and the distribution varied daily. We
demonstrate a mechanism whereby these rapid variations could be due to
solar wind-magnetosphere interactions. We assume that photon-stimulated
desorption and meteoritic vaporization are the active source processes
on the first (quietest) day of our observations. Increased ion
sputtering results whenever the magnetosphere opens in response to
a southward interplanetary magnetic field (IMF) or unusually large
solar wind dynamic pressure. The solar wind dynamic pressure at
Mercury as inferred by heliospheric radial tomography increased by a
factor of 20 during this week, while the solar EUV flux measured by
the scanning electron microscope (SEM) instrument on board the Solar
and Heliospheric Observatory (SOHO) increased by 20%. While impact
vaporization provides roughly 25% of the source, it is uniformly
distributed and varies very little during the week. The variations
seen in our data are not related to Caloris basin, which remained in
the field of view during the entire week of observations. We conclude
that increased ion sputtering resulting from ions entering the cusp
regions is the probable mechanism leading to large rapid increases
in the sodium content of the exosphere. While both the magnitude and
distribution of the observed sodium can be reproduced by our model,
in situ measurements of the solar wind density and velocity, the
magnitude and direction of the interplanetary magnetic field, and
Mercury's magnetic moments are required to confirm the results.
Title: Space Weather Using Remote Sensing Data
Authors: Jackson, B. V.; Hick, P.; Buffington, A.
Bibcode: 2001AGUSM..SH22C05J
Altcode:
We are developing tomographic techniques for analyzing remote sensing
observations of the coronal and heliospheric density and velocity
structure as observed in Thomson scattering (e.g. by the SOHO/LASCO
coronagraph and Helios photometers) and interplanetary scintillation
(IPS) observations. We have refined the program to enable us to
analyze time-dependent phenomena, such as the evolution of corotating
heliospheric structures and rapidly evolving events such as coronal mass
ejections, as observed e.g. with the future Solar Mass Ejection Imager
(SMEI) experiment. We currently provide the three-dimensional analyses
in real-time using IPS observations in order to forecast the arrival
of CMEs, and we intend to show these analyses at our display. This work
is supported by AFRL grant F49620-01-1-0054 and NSF grant ATM-9819947.
Title: Visualization of Remotely-Sensed Heliospheric Plasmas
Authors: Hick, P.; Jackson, B. V.; Buffington, A.; Bailey, M. J.
Bibcode: 2001AGUSM..SH22C04H
Altcode:
We are currently developing a tomographic approach for analyzing
remote sensing observations of the coronal and heliospheric density
and velocity structure (e.g. Thomson scattering and interplanetary
scintillation observations). Parallel to the tomographic techniques
we are developing the visualization tools required for displaying
and manipulating the three-dimensional tomographic results. We use a
common graphics interface language (OpenGL, supported through IDL),
standard visual interfaces (pop-up menus, sliders, point-and-click
methods) and standard hardware (PCs). The visualization should be
capable of simultaneously displaying the tomographic density and
velocity model and should allow the user to dynamically view the
heliospheric model using any predefined flight path through the
three-dimensional cube covered by the model. For real-time volume
rendering we use a Mitsubishi Volume Pro PCI board. We present our
current progress in this visualization effort. Further details can
be found on http://casswww.ucsd.edu/solar/index.html. This work was
supported through NASA grant NAG5-9423.
Title: Three-Dimensional Solar Wind Modeling Using Remote-Sensing Data
Authors: Hick, P. P.; Jackson, B. V.
Bibcode: 2001SSRv...97...35H
Altcode:
We have developed a computer-assisted tomography (CAT) technique that
iteratively modifies a kinematic solar wind model to least-squares fit
heliospheric remote sensing observations (interplanetary scintillation
and Thomson-scattering observations). These remote sensing data cover a
large range of solar elongations, and access high-latitude regions over
the solar poles. The technique can be applied to a time-independent
solar wind model, assuming strict co-rotation, or, when sufficient
remote sensing observations are available, to a time-dependent
model. For the time-dependent case the technique depends primarily
on outward motion of structures in the solar wind to provide the
perspective views required for a tomographic reconstruction. We show
results of corotating tomographic reconstructions primarily using IPS
velocity observations from the Solar-Terrestrial Environment Laboratory
(STELab, Nagoya, Japan), and include comparisons with in situ velocity
data out of the ecliptic (Ulysses) and in the ecliptic (ACE).
Title: Certifying Stray-Light Rejection and Photometric Performance
for "SMEI"
Authors: Buffington, A.; Jackson, B. V.; Hick, P.
Bibcode: 2001AGUSM..SH22C03B
Altcode:
The Solar Mass Ejection Imager (SMEI) is a collaborative project
between the Air Force, UCSD/CASS, and the University of Birmingham,
England. It will fly on the CORIOLIS spacecraft, scheduled for
launch in September 2002. The platform provides a zenith-pointing,
terminator orbit. SMEI's three CCD cameras, each viewing a 3 x 60
degree swath of sky, will provide a visible-light map of nearly
the entire sky each 100-minute orbit. The instrument is designed to
deliver 0.1% differential photometry, and 10-15 orders of magnitude
scattered-light reduction when viewing further than 20 degrees from the
Sun. We present the results of laboratory measurements which certify
that these specifications are met by the SMEI flight hardware. We will
also present night-sky data taken with the SMEI prototype optics, and
progress on normalizing, flat-field correcting, and registering the
SMEI data into a standard sky coordinate frame. This work is supported
by AFRL contract F19628-00-C-0029.
Title: Certifying Stray-Light Rejection and Photometric Performance
for SMEI
Authors: Buffington, A.; Jackson, B. V.; Hick, P. P.; Kuchar, T. A.
Bibcode: 2000AAS...197.5103B
Altcode: 2000BAAS...32.1488B
The Solar Mass Ejection Imager (SMEI) is a collaborative project
between the Air Force, UCSD/CASS, and the University of Birmingham,
England. It will fly on the CORIOLIS spacecraft, scheduled for launch
at the end of 2001. The platform provides a zenith-pointing, terminator
orbit. SMEI's three CCD cameras, each viewing a 3 x 60 degree swath
of sky, will provide a visible-light map of nearly the entire sky
each 100-minute orbit. The instrument is designed to deliver 0.1%
differential photometry, and 10-15 scattered-light
reduction when viewing further than 20 degrees from the Sun. We
present the results of laboratory measurements which certify that
these specifications are met by the SMEI flight hardware. We will also
present night-sky data taken with the SMEI prototype optics. This work
is supported by AFRL contract F19628-00-C-0029.
Title: Space Weather Using Remote Sensing Data
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.
Bibcode: 2000AAS...197.3108J
Altcode: 2000BAAS...32.1448J
We are developing tomographic techniques for analyzing remote sensing
observations of the coronal and heliospheric density and velocity
structure as observed in Thomson scattering (e.g. by the SOHO/LASCO
coronagraph and Helios photometers) and interplanetary scintillation
(IPS) observations. We have refined the program to enable us to
analyze time-dependent phenomena, such as the evolution of co-rotating
heliospheric structures and rapidly evolving events such as coronal
mass ejections, as observed e.g. by the Helios photometers, and with
the future Solar Mass Ejection Imager (SMEI) experiment. We currently
provide these analyses in real-time using IPS observations in order
to forecast the arrival of CMEs and other heliospheric structures at
Earth. This work is supported by NASA grant NAG5-9423 and NSF grant
ATM-9819947.
Title: Visualization of Remotely-Sensed Heliospheric Plasmas
Authors: Hick, P. P.; Jackson, B. V.; Buffington, A.
Bibcode: 2000AAS...197.5102H
Altcode: 2000BAAS...32.1488H
We are currently developing a tomographic approach for analyzing
remote sensing observations of the coronal and heliospheric density
and velocity structure (e.g. Thomson scattering and interplanetary
scintillation observations). Parallel to the development of the
tomographic techniques we are developing the visualization tools
required for displaying and manipulating the three-dimensional
tomographic results. We use a common graphics interface language
(OpenGL, supported through IDL), standard visual interfaces (pop-up
menus, sliders, point-and-click methods) and standard hardware
(PCs). The visualization will target a software system capable of
simultaneously displaying the tomographic density and velocity model
(and, when available, magnetic field) and will allow the user to
dynamically view the heliospheric model using any predefined flight
path through the three-dimensional cube covered by the model, possibly
using stereographics to get a better feel for the three-dimensionality
of the model. Results of this ongoing visualization project
will be demonstrated on a dedicated web site accessible through
http://casswww.ucsd.edu/solar/index.html. This work was supported
through NASA grant NAG5-9423.
Title: Astronomy with SMEI
Authors: Kuchar, T. A.; Price, S. D.; Buffington, A.; Hick, P. P.;
Jackson, B. V.
Bibcode: 2000AAS...197.5101K
Altcode: 2000BAAS...32.1488K
The Solar Mass Ejection Imager (SMEI) is comprised of three detectors
capable of imaging coronal mass ejections (CMEs) from the Sun. It will
orbit in an 830 km sun-synchronous orbit and provide a hemispherical
view about the sun approximately every 100 minutes. The bandpass of
the detectors is in the visual and near IR and ranges from 400 to
1100 nm. The processed images will have a resolution of 1 degree in
science data mode. The detection of CMEs will follow after the stellar
background and other known astronomical phenomena (e.g. planets,
asteroids, and zodiacal emission) have been registered and removed
from the SMEI data. Since CMEs evolve on timescales of hours to days,
data from a series of consecutive orbits can be compared to show their
presence. The SMEI mission is scheduled to last for 5 years and thus
has the potential to reveal variations on annual timescales. The data
are uniquely suited to provide analysis for zodiacal background models
over this wavelength range. In this poster we present the methodology
for removing the stellar contribution from the SMEI data and how this
can be used to track annual changes seen in the zodiacal cloud. We
show a test of concept in this presentation using data taken with a
prototype SMEI camera at the Table Mountain Observatory. SMEI is a
collaborative project between the US Air Force, UCSD/CASS, and the
University of Birmingham, England.
Title: The Solar Mass Ejection Imager Optics and Baffles: Design
and Construction
Authors: Jackson, Bernard V.; Buffington, Andrew; Hick, P. P.
Bibcode: 2000STIN...0226912J
Altcode:
The purpose of SMEI is a proof-of-concept of the ability to predict
geomagnetic disturbances for Air Force space operations and to
establish the feasibility of tracking interplanetary disturbances from
the Sun to the Earth and beyond. The major subsystems of SMEI are an
electronic Camera Assembly, a Data Handling Unit and interconnection
harnesses. Each electronic Camera component consists of a baffle,
radiator, bright object sensor, strongbox (CCD, mirrors and shutter) and
electronics box. The electronic Camera Assembly is used to observe in
visible light mass ejections from the Sun by sensing sunlight scattered
from clouds of solar-produced interplanetary electrons. Predictions
of arrival time at Earth of this disturbance can be made up to three
days in advance.
Title: Prediction of Solar Wind Conditions in the Inner Heliosphere
Using IPS Tomography
Authors: Hick, P. P.; Jackson, B. V.; Buffington, A.
Bibcode: 2000SPD....31.0241H
Altcode: 2000BAAS...32..818H
The ability to determine the 3D structure of the co-rotating component
of the inner heliosphere, and of the 3D extent and evolution of
solar disturbances superposed on this co-rotating background, are
of primary importance for effective 'space weather' forecasting. We
developed a tomographic technique that uses remote sensing data to
reconstruct a heliospheric solar wind density and velocity model. This
enables us to reconstruct the background solar wind as well as solar
disturbances as they move away from the Sun, and forecast their
subsequent arrival at Earth. Currently we are testing a real-time
forecasting system based on tomographic reconstructions of the
solar wind from interplanetary scintillation (IPS) data, available
on a daily basis from the Solar Terrestrial Environment Laboratory
(STE-Lab) near Nagoya, Japan. The IPS tomography is used to determine
velocities at 1 AU where they are compared with in situ observations
from Earth-orbiting spacecraft. The tomographic solar wind model is
also used to passively 'convect' Stanford magnetic field data from
the source outward to 1 AU for comparison with in situ magnetic field
data. We show current results from this IPS forecasting system. The
real-time forecasting data are available on a dedicated Web site at
http://casswww.ucsd.edu/personal/bjackson/weather.htm. This work was
supported by NSF grant INT-9815377 and AFOSR grant AF49620-97-1-0070.
Title: Time-Dependent Tomography Of Heliospheric Features Using
Global Thomson-Scattering Data From the Helios Spacecraft Photometers
Authors: Jackson, B. V.; Hick, P. P.
Bibcode: 2000SPD....3102103J
Altcode: 2000BAAS...32..829J
In the near future white-light, all-sky imagery of the heliosphere
will become available from instruments such as the Air Force/NASA Solar
Mass Ejection Imager (SMEI), and all-sky cameras as currently included
in the instrument complement of the NASA Solar Probe and Solar Polar
Sail missions and the ESA Solar Orbiter mission. To optimize the
information available from these instruments, their 2-dimensional
sky images need to be interpreted in three dimensions. We have
developed a Computer Assisted Tomography (CAT) program that modifies
a time-segmented three-dimensional kinematic heliospheric model to
fit Thomson scattering observations and is designed specifically with
observations from the above instrumentation in mind. Here we apply
this technique to the Helios spacecraft photometer observations. The
tomography program iteratively changes these models to least-squares
fit observed global brightness data. The short time intervals of the
kinematic modeling impose the restriction that the reconstructions
primarily use outward solar wind motion to give perspective views of
each point in space accessible to the observations. We plot these
models as density Carrington maps and remote observer views for
the Helios data sets. The results to date are commensurate with the
observational coverage, temporal and spatial resolution, and signal to
noise available from the original data. At solar maximum, the Helios
photometer data show significant CME activity in the form of dense
transient structures at all heliographic latitudes. We explore the
location of these dense structures with respect to the heliospheric
current sheet and regions of activity on the solar surface.
Title: Coronal Reconstruction using LASCO and UVCS Observations
Authors: Hick, P. P.
Bibcode: 2000STIN...0017923H
Altcode:
The main goal of the research described in the original proposal was
to develop methods to quantify coronal and inner-heliospheric velocity
fields of the 'quiet' solar wind. For this we planned to use several
sources of observations:(1) SOHO/UVCS velocity information in the
range 1.5-3 Solar Radii obtained from Doppler dimming observations; (2)
projected solar wind velocities (into the plane of the sky) obtained
from SOHO/ LASCO images (1.1-30 Solar Radii), primarily derived from
two-dimensional correlation tracking techniques; (3) Interplanetary
scintillation observations of the heliospheric (> 26 Solar Radii)
solar wind velocity from the Solar-Terrestrial Environment Laboratory
(STELab) in Nagoya, Japan; (4) Ecliptic in situ observations: data
for the ecliptic solar wind are available from the MIT and Los Alamos
plasma experiments on the Earth-orbiting IMP-8 spacecraft, from the
Cellas instrument on SOHO near the LI Lagrange point, and from the WIND
spacecraft; (5) Out-of-ecliptic in situ observations: these data are
available primarily from the Los Alamos SWOOPS instrument on Ulysses,
which passed over the solar north pole in August 1995, about one year
prior to the Whole Sun Month period. Where ever possible we planned to
use the first Whole Sun Month as the main time period for the analysis,
since we expected that for this period it would be easiest to obtain
adequate coverage over the extended period of time required to analyze
'quiet' solar wind patterns. Beyond the observations mentioned above
(primarily SOHO data) we extended our selection of data to several
events identified in the Yohkoh/SXT data base which directly promised
to provide us with clues about the connection between the slow solar
wind observed by IPS in the inner heliosphere and their sources in the
low corona, in particular active regions. We also obtained valuable
results using SWOOPS ill situ observations from the pole-to-pole passage
of Ulysses in a comparison with solar wind velocities derived from a
tomographic reconstruction of Nagoya IPS observations.
Title: Three Dimensional Tomography of Heliospheric Features Using
Global Thomson Scattering Data
Authors: Jackson, B. V.; Hick, P.
Bibcode: 2000AdSpR..25.1875J
Altcode:
Images of the heliosphere will become available from the Air Force/NASA
Solar Mass Ejection Imager (SMEI), and from the all-sky cameras proposed
for the NASA missions STEREO, Solar Probe and Solar Polar Sail. To
optimize the information available from these instruments, their
2-dimensional images need to be interpreted in three dimensions. We have
developed a Computer Assisted Tomography (CAT) program that modifies a
three-dimensional heliospheric model to fit Thomson scattering solar
minimum observations from the Helios spacecraft photometers. The
tomography program iterates to a least-squares solution fit of
observed brightness data using spacecraft and solar wind motion
to provide perspective views of each point in space accessible to
the observations. We plot the optimized models as Carrington maps in
density for the Helios data sets. The results to date are commensurate
with resolutions available from the original data. At solar minimum,
longitudinally segmented dense structures emanate from near the
solar equator. We explore the location of these dense structures with
respect to the heliospheric current sheet and regions of activity on
the solar surface
Title: Comparison of solar wind speed with coronagraph data analyzed
by tomography
Authors: Yokobe, Atsushi; Ohmi, Tomoaki; Hakamada, Kazuyuki; Kojima,
Masayoshi; Tokumaru, Munetoshi; Jackson, Bernard V.; Hick, Paul P.;
Zidowitz, Stephan
Bibcode: 1999AIPC..471..565Y
Altcode: 1999sowi.conf..565Y
We have analyzed the relation between solar wind speeds observed
by interplanetary scintillation (IPS) and coronal densities derived
from coronagraph observations during the ``Whole Sun Month'' period
in 1996. Since both IPS and coronagraph observations are biased by
the effect of line-of-sight integration, tomography techniques are
applied to both data sets. For this analysis we made a synoptic map
of the solar wind speed at the source surface (2.5 Rsolar)
from the IPS tomography. Each speed region on the source surface
was traced to the height of the coronagraph observations along the
magnetic field lines calculated from the source surface potential
field model. This analysis has obtained clear anti-correlation between
the solar wind speed in interplanetary space and electron density at
lower coronal regions. We have also obtained the radial profiles of
coronal densities for both slow and fast wind flows in the range of
1.3-2.0 Rsolar. We expect that these provide experimental
constraints on solar wind acceleration models.
Title: Quiet solar wind signatures above active regions observed
in X-rays
Authors: Hick, P.; Svestka, Z.; Jackson, B. V.; Farnik, F.; Hudson, H.
Bibcode: 1999AIPC..471..231H
Altcode: 1999sowi.conf..231H
X-ray images from the Yohkoh satellite, obtained following occurrences
of limb flares sometimes show coronal fan-like structures extending
above a growing post-flare loop system. We show one such event
observed in AR 7270 on the east limb of the Sun on 28/29 August
1992. We suggest that these rays are `ministreamers,' formed as a
result of the re-structuring of the corona following the occurrence
of a flare-associated CME. Synoptic maps of the solar wind density,
constructed from a tomographic analysis of interplanetary scintillation
(IPS) measurements, show enhanced scintillation matching the position
of AR 7270 if we assume a radial outflow at a reasonable slow solar
wind speed of 400 km s-1. From this agreement we argue that outflow
of mass occurs from the active region into interplanetary space.
Title: Visible-light All-sky Imagers in Deep Space
Authors: Buffington, A.; Hick, P. P.; Jackson, B. V.
Bibcode: 1999AAS...194.7615B
Altcode: 1999BAAS...31..959B
Emerging new techniques for very wide-angle optics and efficient
light-baffling systems permit visible-light imagers capable of
viewing half the sky or more starting within only a few degrees
of the Sun. These instruments provide the 0.1% photometry required
for studying low-contrast heliospheric features such as solar mass
ejections and co-rotating structures. The imagers view sunlight
Thomson-scattered from interplanetary electrons. A typical imager
design provides "all-sky" photometric maps with 1 degree sky bins and
a 1-hour cadence. Instrument weights of only several kilograms and
modest power requirements make these imagers particularly suitable
for deployment to deep space. Tomographic reconstructions of the
interplanetary mass density distribution are enabled by combining
data from one or more deep-space probes, with comparable instruments
near Earth. These deep-space images are also suitable for discovery
and study of comets and asteroids, and for detailed measurements of
brightness variations in the zodiacal dust cloud.
Title: Recent UCSD Advances in Tomography for Use with Heliospheric
Remote-Sensing Data
Authors: Jackson, B. V.; Hick, P. P.; Buffington, A.
Bibcode: 1999AAS...194.7614J
Altcode: 1999BAAS...31R.958J
Solar disturbances produce major effects in the corona, its
extension into the interplanetary medium, and ultimately, the Earth's
environment. The ability to determine the three dimensional extent of
these disturbances and to forecast their arrival at Earth is of primary
scientific and practical interest. We have developed a tomographic
technique for use in mapping these disturbances as they move away from
the Sun. Our technique uses a solar wind density and velocity model
and available remote sensing data and iterates to a least squares fit
solution of these data. This technique provides more contrast between
high and low speed winds and more or less dense solar wind structures
than has been possible with previous techniques. Existing observations
include those from the HELIOS photometers (Thomson scattering data)
and velocity and scintillation-level measurements (from interplanetary
scintillation or IPS data). The latter observations are currently
available on a daily basis from the Solar Terrestrial Environment
Laboratory situated near Nagoya, Japan. We are developing a way to
provide a tomographic reconstruction from IPS data in real time for use
in heliospheric space weather forecasting, and we show our most recent
results on this. We are also in the process of developing this technique
to provide the three dimensional extent of heliospheric features which
vary in shape over short periods of time (i.e., CMEs). The result using
this extension of the technique is commensurate with the quantity,
quality and perspective views present from the remote sensing data,
and with present data is used to explore the extent to which solar
corotating structures are time-variable. As other remote sensing
data become available with high angular and temporal resolution
from spacecraft instruments such as the Solar Mass Ejection Imager
(SMEI), now being developed and constructed for the Air Force, or as
proposed for the NASA STEREO or Solar Probe Missions, the technique
should provide far better heliospheric three dimensional and temporal
resolution (by several orders of magnitude) than now available.
Title: The Gradual Phase of Flares
Authors: Svestka, Z. F.; Poletto, G.; Fontenla, J.; Hick, P.; Kopp,
R. A.; Sylwester, B.; Sylwester, J.
Bibcode: 1999mfs..conf..409S
Altcode:
Heating and Cooling in the Gradual Phase Emission Measure-Temperature
Diagrams Flaring Arches Gradual Phase of Eruptive Flares Postflare
Giant Arches Giant Arches: Modeling and Interpretation
Title: Corrals, hubcaps, and crystal balls: some new designs for
very-wide-angle visible-light heliospheric imagers
Authors: Buffington, Andrew; Hick, P. P.; Jackson, Bernard V.;
Korendyke, Clarence M.
Bibcode: 1998SPIE.3442...77B
Altcode:
Emerging techniques allow instruments to view very large sky areas,
a hemisphere or more, in visible light. In space, such wide-angle
coverage enables observation of heliospheric features form close to
the Sun to well beyond Earth. Observations from deep-space missions
such as Solar Probe, Stereo, and Solar Polar Sail, coupled with
observations near Earth, permit 3D reconstruction of solar mass
ejections and co-rotating structures, discovery and study of new comets
and asteroids, and detailed measurements of brightness variations in
the zodiacal cloud. Typical heliospheric features have 1 percent or
less of ambient brightness, so visible-light cameras must deliver <
0.1 percent photometry and be well protected from stray background
light. When more than a hemisphere of viewing area is free of bright
background-light sources, we have shown that corral-like structures
with several vane-like walls reduces background light illuminating
to wide-angle optical system by up to ten orders of magnitude. The
optical system itself typically provides another five orders of
surface-brightness reduction. With CCDs as the light-detection device,
images of point-like sources must cover typically 100 pixels to average
down sub-pixel response gradients and provide the above 0.1 percent
photometry. With present-day CCDs this requires images of order 1 degree
in angular size. Tolerating such large images in turn enables wide-angle
sky coverage using simple reflecting and refracting optical systems
such as convex spherical reflectors, toroids and thick lenses. We show
that combining these with light- reducing corrals yields practical,
light-weight instruments suitable for inclusion on deep-space probes.
Title: Three-dimensional tomography of heliospheric features using
Thomson scattering data
Authors: Hick, P. P.; Jackson, Bernard V.
Bibcode: 1998SPIE.3442...87H
Altcode:
All-sky cameras for viewing the heliosphere in white light are included
in the design of several future spacecraft missions. The first of
these to ge put in Earth-orbit will be the solar mass ejection imager,
a joint project of the US Air FOrce, NASA, and the University of
Birmingham, UK. Other missions, including an all-sky imager in their
current design, are STEREO, Solar Probe and Solar Probe Sail. The
white-light signal includes Thomson-scattered light from heliospheric
electrons, which can be used to study the structure and evolution of
large-scale heliospheric features. These studies are the principal
reason for putting all-sky cameras in Earth-orbit or deep space. We
discuss a tomographic technique, which uses the 2D information in
the all-sky images provided by these cameras to reconstruct the
heliospheric density structure in 3D. We present preliminary results
of this tomographic technique applied to Thomson scattering data from
the photometers onboard the two HELIOS spacecraft.
Title: Large-Scale Active Coronal Phenomena in Yohkoh SXT Images
IV. Solar Wind Streams from Flaring Active Regions
Authors: Švestka, Zdeněk; Fárník, František; Hudson, Hugh S.;
Hick, Paul
Bibcode: 1998SoPh..182..179S
Altcode:
We demonstrate limb events on the Sun in which growing flare loop
systems are embedded in hot coronal structures looking in soft X-rays
like fans of coronal rays. These structures are formed during the flare
and extend high into the corona. We analyze one of these events, on
28-29 August 1992, which occurred in AR 7270 on the eastern limb, and
interpret these fans of rays either as temporary multiple ministreamers
or plume-like structures formed as a result of restructuring due to
a CME. We suggest that this configuration reflects mass flow from the
active region into interplanetary space. This suggestion is supported
by synoptic maps of solar wind sources constructed from scintillation
measurements which show a source of enhanced solar wind density at
the position of AR 7270, which disappears when 5 days following the
event are removed from the synoptic map data. We also check synoptic
maps for two other active regions in which existence of these fan-like
structures was indicated when the active regions crossed both the east
and west limbs of the Sun, and both these regions appear to be sources
of a density enhancement in the solar wind.
Title: Fan-Like coronal X-ray Structures as Sources of Solar Wind
Authors: Hick, P.; Svestka, Z.; Farnik, F.; Hudson, H. S.; Jackson,
B. V.
Bibcode: 1998AAS...192.1503H
Altcode: 1998BAAS...30..840H
We show coronal soft X-ray images from the Yohkoh satellite, obtained
following occurrences of limb flares. These images show rising
post-flare loops, which are embedded in hot coronal structures looking
like fans of coronal rays. We analyze the event on 28/29 August 1992,
which occurred in AR 7270 on the east limb of the Sun. We suggest that
these rays are multiple 'ministreamers', which apparently are formed as
a result of the restructuring of the corona following the occurrence
of a flare-associated CME. We argue that this configuration allows
outflow of mass from the active region into interplanetary space. This
is supported by synoptic maps of solar wind sources constructed from
scintillation measurements showing a source of enhanced scintillation
at the position of AR 7270.
Title: An All-Sky Coronal Camera on Solar Probe: A Global View of
our Nearest Star's Atmosphere
Authors: Buffington, A.; Jackson, B. V.; Hick, P.
Bibcode: 1998AAS...192.1502B
Altcode: 1998BAAS...30..840B
NASA's proposed Solar Probe mission will provide an opportunity
to directly view material in the atmosphere of our nearest star:
the Sun. The Probe is designed to transit both solar poles and
approach about as close as currently feasible: within about 4
solar radii. Onboard instruments will directly sample the particle
composition near the spacecraft and view the solar poles from its
nearby perspective. UCSD's newly developed lightweight light-baffling
and very wide-angle optical systems permit viewing Thompson-scattered
sunlight over nearly the whole sky around the spacecraft to within a
few degrees of the solar disk. The fly-by's varying perspective will
enable a 3-dimensional coronal reconstruction having unprecedented
detail. These observations from within the acceleration region should
greatly refine our understanding of coronal material propagation.
Title: Heliospheric modeling used to map global solar wind flows
Authors: Jackson, B. V.; Hick, P.; Leinert, Ch.; Yokobe, A.
Bibcode: 1998AAS...192.1904J
Altcode: 1998BAAS...30..846J
In a recent paper Leinert and Jackson (1998) analyzed brightness
observations from the Helios spacecraft photometers, in situ data and
interplanetary scintillation (IPS) velocities, and used these to model
global heliospheric plasma changes over solar cycle no. 21. Our analysis
shows changes in the solar wind flow in terms of mass and velocity
over one Carrington rotation. We model the available IPS velocity
observations using a tomographic least squares fit to determine solar
wind speeds. This technique, crucial to our analysis, provides more
contrast between high speed winds over the solar poles and low speed
winds near the equator than possible with previous techniques. Here,
we confirm the validity of this technique with recent Ulysses spacecraft
measurements and a comparison between Ulysses-measured solar wind speeds
and IPS velocities available from the STELab in Japan. The primary
result of the measurements over solar cycle 21 show the extent to which
the approximation of constant solar wind momentum flux is valid in more
detail than was previously possible. Under this assumption we find that
additional mass at about the 15% level is added to the solar wind at
solar activity maximum, and that this mass is most likely present in
the form of discrete events (Coronal Mass Ejections). This implies that
there are probably two different processes acting to remove solar wind
from the sun - one provided by a constant coronal energization, and one
that is associated with the strongest solar magnetic fields. Leinert,
Ch. and B.V. Jackson, Global Solar Wind Changes Over Solar Cycle 21:
a Combination of Helios Photometer, In-situ and IPS Data, Astrophys. J.,
(accepted), 1998.
Title: Large-Scale Active Coronal Phenomena in YOHKOH SXT
Images. III. Enhanced Post-Flare Streamer
Authors: Švestka, Zdeněk; Fárník, František; Hick, Paul; Hudson,
Hugh S.; Uchida, Yutaka
Bibcode: 1997SoPh..176..355S
Altcode:
We demonstrate several events where an eruptive flare close to the
limb gave rise to a transient coronal streamer visible in X-rays in
Yohkoh SXT images, and analyze one of these events, on 28-29 October
1992, in detail. A coronal helmet streamer began to appear 2 hours
after the flare, high above rising post-flare loops; the streamer
became progressively narrower, reaching its minimum width 7-12 hours
after the flare, and widened again thereafter, until it eventually
disappeared. Several other events behaved in a similar way. We suggest
that the minimum width indicates the time when the streamer became
fully developed. All the time the temperature in the helmet streamer
structure was decreasing, which can explain the subsequent fictitious
widening of the X-ray streamer. It is suggested that we may see here
two systems of reconnection on widely different altitudes, one giving
rise to the post-flare loops while the other creates (or re-forms)
the coronal helmet streamer. A similar interpretation was suggested in
1990 by Kopp and Polettofor post-flare giant arches observed on board
the SMM; indeed, there are some similarities between these post-flare
helmet streamers and giant arches and, with the low spatial resolution
of SMM instruments, it is possible that some helmet streamers could
have been considered to be a kind of a giant arch.
Title: Post-Flare Loops Embedded in a Hot Coronal Fan-Like Structure
Authors: Švestka, Z.; Fárnik; Hudson, H. S.; Hick, P.
Bibcode: 1997ESASP.415..139S
Altcode: 1997cpsh.conf..139S
No abstract at ADS
Title: Y. Uchida, T. Kosugi, and H.S. Hudson (eds.), Magnetodynamic
Phenomena in the Solar Atmosphere - ProtoTypes of Stellar Magnetic
Activity.
Authors: Hick, Paul
Bibcode: 1997SoPh..176..217H
Altcode: 1997SoPh..176..217U
No abstract at ADS
Title: The Three Dimensional Tomography of Heliospheric Features
Authors: Jackson, B.; Hick, P.; Kojima, M.
Bibcode: 1997IAUJD..19E...2J
Altcode:
We have produced a Computer Assisted Tomography (CAT) program that
optimizes a three-dimensional heliospheric model to fit observational
data. We have used this program with interplanetary scintillation data
from UCSD, California, Nagoya, Japan, Cambridge, England and Ooty,
India; and with Helios photometer Thomson scattering data. The program
iterates to a least-squares solution fit of observed data using solar
rotation and solar wind outward motion to provide perspective views
of each point in space accessible to the observations. We plot the
optimized model as Carrington maps in velocity and density for the data
sets with resolutions commensurate with the original data. For the data
sets with the greatest numbers of points, we are able to convolve to
the multiple heliospheric heights probed by the lines of sight in order
to explore the evolution of heliospheric features with solar distance.
Title: The Solar Mass Ejection Imager (SMEI)
Authors: Jackson, B.; Buffington, A.; Hick, P.; Keil, S.; Altrock,
R.; Kahler, S.; Simnett, G.; Eyles, C.; Webb, D.; Anderson, P.
Bibcode: 1997IAUJD..19E..27J
Altcode:
The Solar Mass Ejection Imager (SMEI) experiment is designed to
detect and measure transient plasma features in the heliosphere,
including coronal mass ejections (CMEs), shock waves, and structures
such as streamers which co-rotate with the Sun. SMEI will provide
measurements of the propagation of solar plasma clouds and high-speed
streams which can be used to forecast their arrival at Earth from
one to three days in advance. SMEI consists of three cameras, each
imaging a 60o times 3o field of view for a total
image size of 180o times 3o. As the satellite
orbits the earth, repeated images are used to build up a view of the
entire heliosphere at resolutions of better than one degree. Here,
we will show the most recent progress on this instrument, now under
prototype construction.
Title: Coronal Velocity Determination Using Two-Dimensional
Correlation Techniques
Authors: Jackson, B.; Hick, P.
Bibcode: 1997IAUJD..19E..26J
Altcode:
With the availability of stable CCD images from the LASCO coronagraphs,
successive coronagraph images differenced from a single base have
been displayed in sequence in order to view transient effects such
as CMEs. In these video sequences, CMEs appear as the most obvious
differences of outward-moving material over the east or west limb
of the Sun. Also observed in these differences on the limb of the
Sun opposite the CME and elsewhere are features which become more
pronounced as time progresses. These differences, too, appear to move
outward from the Sun. We show that these outward-moving features are
from small structures which on other previous coronagraph observations
were too small or too poorly discerned to be visible. We have mapped
samples of these differences using two-dimensional cross-correlation
techniques which show how well a small section of one coronagraph image
corresponds to the same section on the other, and how much shift is
required to align the sections of the image. We demonstrate that this
technique measures the outward-motion. We will show the latest results
from this study in different solar coronal regions including streamer
areas and over the poles of the Sun.
Title: Solar Mass Ejection Imager (SMEI)
Authors: Keil, Stephen L.; Altrock, Richard C.; Kahler, Stephen;
Jackson, Bernard V.; Buffington, Andrew; Hick, Paul; Simnett, George
M.; Eyles, Christopher J.; Webb, David; Anderson, Peter
Bibcode: 1996SPIE.2804...78K
Altcode:
The Solar Mass Ejection Imager (SMEI) experiment is designed to
detect and measure transient plasma features in the heliosphere,
including coronal mass ejections, shock waves, and structures such as
streamers which corotate with the Sun. SMEI will provide measurements
of the propagation of solar plasma clouds and high-speed streams
which can be used to forecast their arrival at Earth from one to
three days in advance. The white light photometers on the HELIOS
spacecraft demonstrated that visible sunlight scattered from the free
electrons of solar ejecta can be sensed in interplanetary space with
an electronic camera baffled to remove stray background light. SMEI
promises a hundred-fold improvement over the HELIOS data, making
possible quantitative studies of mass ejections. SMEI measurements
will help predict the rate of energy transfer into the Earth's
magnetospheric system. By combining SMEI data with solar, interplanetary
and terrestrial data from other space and ground-based instruments, it
will be possible to establish quantitative relationships between solar
drivers and terrestrial effects. SMEI consists of three cameras, each
imaging a 60 degree(s) X 3 degree(s) field of view for a total image
size of 180 degree(s) X 3 degree(s). As the satellite orbits the earth,
repeated images are used to build up a view of the entire heliosphere.
Title: Evidence of active region imprints on the solar wind structure
Authors: Hick, P.; Jackson, B. V.
Bibcode: 1996AIPC..382..461H
Altcode:
A common descriptive framework for discussing the solar wind
structure in the inner heliosphere uses the global magnetic field
as a reference: low density, high velocity solar wind emanates from
open magnetic fields, with high density, low speed solar wind flowing
outward near the current sheet. In this picture, active regions,
underlying closed magnetic field structures in the streamer belt,
leave little or no imprint on the solar wind. We present evidence from
interplanetary scintillation measurements of the `disturbance factor'
g that active regions play a role in modulating the solar wind and
possibly contribute to the solar wind mass output. Hence we find that
the traditional view of the solar wind, though useful in understanding
many features of solar wind structure, is oversimplified and neglects
important aspects of solar wind dynamics.
Title: Coronal synoptic temperature maps derived from the Fe XIV/Fe
X intensity ratio
Authors: Hick, P.; Jackson, B. V.; Altrock, R. C.
Bibcode: 1996AIPC..382..169H
Altcode:
The large-scale temperature structure of the low corona is investigated
using synoptic temperature maps, derived from the intensity ratio of
the green (Fe XIV) and red (Fe X) coronal lines as observed at the
National Solar Observatory/Sacramento Peak. This intensity ratio is
sensitive to coronal plasma with temperatures of 1-2 MK, a range of
temperatures usually associated with the quiet corona. The synoptic
maps indicate an association between high coronal temperature and the
large-scale magnetic field. A comparison with Stanford `source surface'
synoptic maps shows that, especially when the heliospheric current
sheet is stable over several rotations, the large-scale high-temperature
features follow the current sheet remarkably well. For recent Carrington
rotations, temperature maps are available for four heights between
1.15 and 1.45 Rsolar. For these maps the correspondence
with the current sheet (calculated at 2.5 Rsolar) improves
with height. Discrepancies between temperature structure and magnetic
structure appear to be largest when the magnetic structure changes
rapidly from rotation to rotation.
Title: The Solar Coronal Temperature Structure and the Heliospheric
Current Sheet
Authors: Altrock, R. C.; Hick, P.; Jackson, B. V.; Slater, G.; Henry,
T. W.
Bibcode: 1996AAS...188.8004A
Altcode: 1996BAAS...28..956A
We explore the large-scale temperature structure of the low corona
using synoptic temperature maps, derived from the intensity ratio
of the green (Fe XIV) and red (Fe X) coronal lines as observed at
the National Solar Observatory/Sacramento Peak, and temperature maps
derived from the Al0.1 and AlMgMn filter intensity ratio measured by
the Yohkoh/SXT instrument. The red/green intensity ratio is sensitive
to coronal plasma with temperatures in the range of 1--2 MK and is
therefore useful for studying the `quiet' corona. The Yohkoh/SXT filter
ratio covers a much wider range of coronal temperature (>= 1 MK)
and, in particular, is sensitive to the high temperatures (>= 3 MK)
commonly observed above active regions. We use the temperature maps to
study the evolution of the large-scale coronal temperature distribution,
in particular in relation to the large-scale magnetic field, as given
by the `source surface' maps derived from the Stanford potential field
model. We find that the large-scale high-temperature features follow
the heliospheric current sheet remarkably well, especially when the
current sheet is stable over several rotations.
Title: Solar coronal structure: a comparison of NSO/SP ground-based
coronal emission line intensities and temperatures with YOHKOH SXT
and WSO magnetic data
Authors: Altrock, R. C.; Hick, P.; Jackson, B. V.; Hoeksema, J. T.;
Zhao, X. P.; Slater, G.; Henry, T. W.
Bibcode: 1996AdSpR..17d.235A
Altcode: 1996AdSpR..17..235A
The large-scale structure of the solar corona is investigated using
synoptic maps produced from Fe XIV (530.3 nm), Fe X (637.4 nm) and
Ca XV (569.4 nm) data obtained at NSO/SP, Yohkoh/SXT X-ray data and
Wilcox Solar Observatory (WSO) `source surface' maps. We find that the
Fe XIV data are an excellent proxy for spatially-averaged Yohkoh/SXT
data. Isolated emission features and large-scale structures are nearly
identical in SXT and Fe XIV maps. In addition, coronal holes and other
low-emission regions are very similar. Synoptic temperature maps,
calculated from the Fe X/Fe XIV ratio, show a tendency for the highest
temperatures to occur where the large-scale magnetic fields change
polarity at high latitudes (cf. /1/), while lower-latitude features,
including active regions, have lower apparent temperatures. Regions
of enhanced temperature generally follow the heliospheric current
sheet (HCS) as defined by the WSO maps. Further, emission in Ca XV
(formed at T ~ 3 MK), generally occurs only over low-latitude regions
that are bright in both Fe X (T ~ 1 MK) and Fe XIV (T ~ 2 MK). Thus,
there is evidence for low (~1 MK), moderate (~2 MK) and high (~3 MK)
temperatures in close proximity in the low corona.
Title: IPS observations of heliospheric density structures associated
with active regions
Authors: Hick, P.; Jackson, B. V.; Altrock, R.; Woan, G.; Slater, G.
Bibcode: 1996AdSpR..17d.311H
Altcode: 1996AdSpR..17..311H
Interplanetary scintillation (IPS) measurements of the `disturbance
factor' g, obtained with the Cambridge (UK) array can be used to explore
the heliospheric density structure. We have used these data to construct
synoptic (Carrington) maps, representing the large-scale enhancements
of the g-factor in the inner heliosphere. These maps emphasize the
stable corotating, rather than the transient heliospheric density
enhancements. We have compared these maps with Carrington maps of Fe XIV
observations (NSO, Sacramento Peak) and maps based on Yohkoh/SXT X-ray
observations. Our results indicate that the regions of enhanced g tend
to map to active regions rather than the current sheet. The implication
is that active regions are the dominant source of the small-scale
(≈ 200 km) density variations present in the quiet solar wind.
Title: Book review
Authors: Hick, P.
Bibcode: 1996SoPh..163..405H
Altcode:
No abstract at ADS
Title: The Coronal Temperature Structure and the Current Sheet
Authors: Hick, Paul; Jackson, B. V.; Altrock, R. C.; Slater, G.;
Henry, T.
Bibcode: 1996ASPC...95..358H
Altcode: 1996sdit.conf..358H
No abstract at ADS
Title: Geomagnetic Storms and Heliospheric CMEs as Viewed From HELIOS
Authors: Webb, David F.; Jackson, Bernard V.; Hick, Paul
Bibcode: 1996ASPC...95..167W
Altcode: 1996sdit.conf..167W
No abstract at ADS
Title: The Influence of Active Regions on IPS measurements near 1 AU
Authors: Hick, Paul; Jackson, B. V.
Bibcode: 1996ASPC...95..470H
Altcode: 1996sdit.conf..470H
No abstract at ADS
Title: Large-Scale Active Coronal Phenomena in YOHKOH SXT Images
Authors: Svestka, Z.; Farnik, F.; Hudson, H. S.; Uchida, Y.; Hick, P.
Bibcode: 1996ASPC..111..388S
Altcode: 1997ASPC..111..388S
The authors have checked in Yohkoh SXT images the appearance of giant
post-flare arches which were discovered in hard X-ray images from
the HXIS and FCS instruments onboard the SMM. They have verified the
existence of both the rising and stationary arches. In addition to
these two kinds of giant post-flare arches, known before from SMM
observations, Yohkoh also reveals other large post-flare coronal
structures which might have been considered to be giant arches by the
low-resolution SMM instruments. These include coronal helmet streamers
above rising flare loops or fans of hot structures in which the rising
loops are embedded.
Title: Large-Scale Active Coronal Phenomena in YOHKOH SXT Images
Authors: Svestka, Z.; Farnik, F.; Hudson, H. S.; Uchida, Y.; Hick,
P.; Lemen, J. R.
Bibcode: 1996mpsa.conf..609S
Altcode: 1996IAUCo.153..609S
No abstract at ADS
Title: Large-Scale Active Coronal Phenomena in YOHKOH SXT Images, I
Authors: Švestka, Zdeněk; Fárník, František; Hudson, Hugh S.;
Uchida, Yutaka; Hick, Paul; Lemen, James R.
Bibcode: 1995SoPh..161..331S
Altcode:
We have found several occurrences of slowly rising giant arches inYohkoh
images. These are similar to the giant post-flare arches previously
discovered by SMM instruments in the 80s. However, we see them now
with 3-5 times better spatial resolution and can recognize well their
loop-like structure. As a rule, these arches followeruptive flares
with gradual soft X-ray bursts, and rise with speeds of 1.1-2.4 km
s−1 which keep constant for >5 to 24 hours, reaching
altitudes up to 250 000 km above the solar limb. These arches differ
from post-flare loop systems by their (much higher) altitudes, (much
longer) lifetimes, and (constant) speed of growth. One event appears
to be a rise of a transequatorial interconnecting loop.
Title: Evidence of active region imprints on the solar wind structure
Authors: Hick, P.; Jackson, B. V.
Bibcode: 1995sowi.conf...48H
Altcode:
A common descriptive framework for discussing the solar wind structure
in the inner heliosphere uses the global magnetic field as a reference:
low density, high velocity solar wind emanates from open magnetic
fields, with high density, low speed solar wind flowing outward near
the current sheet. In this picture, active regions, underlying closed
magnetic field structures in the streamer belt, leave little or no
imprint on the solar wind. We present evidence from interplanetary
scintillation measurements of the 'disturbance factor' g that active
regions play a role in modulating the solar wind and possibly contribute
to the solar wind mass output. Hence we find that the traditional view
of the solar wind, though useful in understanding many features of
solar wind structure, is oversimplified and possibly neglects important
aspects of solar wind dynamics
Title: Coronal synoptic temperature maps derived from the Fe XIV/Fe
X intensity ratio
Authors: Hick, P.; Jackson, B. V.; Altrock, R.
Bibcode: 1995sowi.confQ..69H
Altcode:
The large-scale temperature structure of the low corona is investigated
using synoptic temperature maps, derived from the intensity ratio of the
green (Fe XIV) and red (Fe X) coronal lines as observed at the National
Solar Observatory/Sacramento Peak. This intensity ratio is sensitive to
coronal plasma with temperatures in the range of 1-2 MK. The synoptic
maps indicate an association between high coronal temperature and the
large-scale magnetic field. A comparison with WSO 'source surface'
synoptic maps shows that especially when the heliospheric current sheet
is stable over several rotations, the large-scale high-temperature
features follow the current sheet remarkably well. For recent Carrington
rotations temperature maps have been constructed for various heights
between 1.15 and 1.45 solar radii. For these maps the correspondence
with the current sheet (calculated at 2.5 solar radii) improves with
height. Deviations between temperature structure and magnetic structure
appears to be largest when the magnetic structure changes rapidly from
rotation to rotation.
Title: Yohkoh/SXT x-ray synoptic maps of coronal brightness and
temperature
Authors: Slater, G. L.; Lemen, J. R.; Hick, P.; Jackson, B. V.
Bibcode: 1995sowi.conf...68S
Altcode:
The Yohkoh soft X-ray telescope (SXT) records on the order of 50
solar images per day in two different color filters. These provide
material for the generation of synoptic maps, which compress the
3-dimensional data cube into two dimensions. We are creating synoptic
maps from strips of data both at disk center and at different heights,
including limb maps that are analogous to those produced by ground-based
coronagraphs. The ratios of intensities in images taken in two filters
provide estimates of the electron temperature in the range 1 - 3 x
106 K. These are broad-band temperature maps; rather than
maps created with discrete sampling as in the case of the coronal
green and red lines. We discuss the properties of these maps and their
application to the study of energy release in the corona.
Title: Synoptic IPS and Yohkoh soft X-ray observations
Authors: Hick, P.; Jackson, B. V.; Rappoport, S.; Woan, G.; Slater,
G.; Strong, K.; Uchida, Y.
Bibcode: 1995GeoRL..22..643H
Altcode:
Interplanetary scintillation measurements of the disturbance factor,
g, from October 1991 to October 1992 are used to construct synoptic
Carrington maps. These maps, which show the structure of the quiet
solar wind, are compared with X-ray Carrington maps from the Yohkoh
SXT instrument. For the period studied the global structure outlined
by (weakly) enhanced g-values apparent in the IPS maps tends to match
the active regions (as shown in the X-ray maps) significantly better
than the heliospheric current sheet. Contrary to traditional opinion,
which views active regions as magnetically closed structures that do
not have any significant impact on the solar wind flow, our results
suggest that density fluctuations in the solar wind are significantly
enhanced over active regions. These results support the suggestion
by Uchida et al. (1992), based on Yohkoh observations of expanding
active regions, that active regions play a role in feeding mass into
the quiet solar wind.
Title: Association of Solar Coronal Temperature and Structure from
Ground-Based Emission-Line Data with Global Magnetic Field Models
and Yohkoh SXT Data (Abstract only)
Authors: Altrock, R. C.; Hick, P.; Jackson, B. V.; Hoeksema, J. T.;
Zhao, X. P.; Slater, G.; Henry, T. W.
Bibcode: 1995itsa.conf...45A
Altcode:
No abstract at ADS
Title: Three-dimensional reconstruction of coronal mass ejections
Authors: Jackson, B. V.; Hick, P.
Bibcode: 1994ESASP.373..199J
Altcode: 1994soho....3..199J
No abstract at ADS
Title: Solar wind mass and momentum flux variations at 0.3 AU
Authors: Hick, P.; Jackson, B. V.
Bibcode: 1994AdSpR..14d.135H
Altcode: 1994AdSpR..14..135H
In the past we have used electron Thomson scattering brightness
observations, obtained with the zodiacal-light photometers on board
the spacecraft Helios 1 and Helios 2, to study the global density
structure of the quiet corona and inner heliosphere (> 17 solar
radii). This was done by means of a comparison of synoptic maps based
on these Thomson scattering observations and synoptic maps based on
other solar/heliospheric data, such as IPS velocity, K-coronameter
brightness and magnetic source surface data. In this paper we continue
this approach by combining the Helios Thomson scattering maps (which
provide density information) with IPS solar wind velocity maps to
map out variations in mass and momentum flux of the solar wind as a
function of latitude and phase of the solar cycle. The method used
to construct the Helios and IPS synoptic maps emphasizes the global,
persistent (as opposed to transient) structures, and thus can be viewed
as approximating conditions in the quiet corona and inner heliosphere.
Title: Comparison of CMEs, magnetic clouds, and bidirectionally
streaming proton events in the heliosphere using helios data
Authors: Webb, D.; Jackson, B.; Hick, P.; Schwenn, R.; Bothmer, V.;
Reames, D.
Bibcode: 1993AdSpR..13i..71W
Altcode: 1993AdSpR..13...71W
Coronal Mass Ejections (CMEs) are large, energetic expulsions of mass
and magnetic fields from the Sun; they can significantly affect large
volumes of the heliosphere and appear to be a key cause of geomagnetic
storms. We have compiled a list of all significant CMEs detected by
the HELIOS white light photometers from 1975-1982. We are studying the
characteristics of these CMEs, and present preliminary results of their
associations with in-situ features, especially magnetic ``clouds'' and
periods of bidirectionally streaming ions, two classes of structures
considered indicative of interplanetary loops. Advantages of this data
set include reliable association in the interplanetary medium of the
white light CME plasma with the in-situ features, and observations of
a large number of events over a long time base.
Title: Co-rotating structures of the inner heliosphere from helios
photometer and in-situ data
Authors: Jackson, B.; Hick, P.; Webb, D.
Bibcode: 1993AdSpR..13i..43J
Altcode: 1993AdSpR..13...43J
We have compiled a list of all major co-rotating structures in the
inner heliosphere detected by the white light photometers of both HELIOS
spacecraft from 1975-1982. We compare the three-dimensional extents of
these remotely-sensed structures over their times of observation. We pay
particular attention to the spatial extent of these structures and their
variability. We can measure the in-situ characteristics of the subset of
structures as they envelop the spacecraft. The advantages of this data
set include the association of the three-dimensional extent of these
co-rotating structures with in-situ observations of the same features.
Title: Responses of large-scale coronal structures to chromospheric
activity
Authors: Farnik, Frantisek; Hick, Paul; Svestka, Zdenek
Bibcode: 1993SoPh..146..313F
Altcode:
We have followed the transit of two active regions across the western
solar limb during June 29 through July 2, 1980, as imaged in 3.5-16
keV X-rays by HXIS aboard the SMM. During frequent brightenings of
large-scale coronal structures, hard X-ray emission in the 11-16 keV
energy band was recorded up to altitudes of 76 000 km. Soft X-rays
could be seen in excess of 250 000 km altitude above the photospheric
active region. Many X-ray brightenings low in the corona in the
active regions were followed by enhancements high in the corona in
the large-scale coronal structures. Although subsequent enhancements
rarely appeared in the same position, similar portions of the corona
brightened intermittently, indicating that the general configuration
of the coronal structures above the active regions did not change much,
in spite of the frequent energy inputs. These inputs were of two kinds:
nonthermal, with very fast response at high coronal altitudes within
seconds or tens of seconds, and thermal, with a delay of several
minutes. The nonthermal response is short-lived, reflecting the time
profile of the primary source; the thermal response is more gradual
and longer lasting than the primary source. In some enhancements of
large-scale coronal structures both these kinds of response occur and
can be clearly recognized. There are also active-region hrightenings
without any response in the high corona and,vice versa, high-corona
brightenings without any obvious primary source; in the latter case,
it is likely that the source was hidden behind the limb.
Title: Synoptic maps of heliospheric Thomson scattering brightness
from 1974-1985 as observed by the HELIOS photometers
Authors: Hick, P.; Jackson, B. V.; Schwenn, R.
Bibcode: 1992sws..coll..187H
Altcode:
We display the electron Thomson scattering intensity of the inner
heliosphere as observed by the zodiacal light photometers on board
the Helios spacecraft in the form of synoptic maps. The technique
extrapolates the brightness information from each photometer sector
near the Sun and constructs a latitude/longitude map at a given solar
height. These data are unique in that they give a determination
of heliospheric structures out of the ecliptic above the primary
region of solar wind acceleration. The spatial extent of bright,
co-rotating heliospheric structures is readily observed in the data
north and south of the ecliptic plane where the Helios photometer
coverage is most complete. Because the technique has been used on the
complete Helios data set from 1974 to 1985, we observe the change in
our synoptic maps with solar cycle. Bright structures are concentrated
near the heliospheric equator at solar minimum, while at solar maximum
bright structures are found at far higher heliographic latitudes. A
comparison of these maps with other forms of synoptic data are shown
for two available intervals.
Title: Synoptic maps for the heliospheric Thomson scattering
brightness as observed by the HELIOS photometers
Authors: Hick, P.; Jackson, B. V.; Schwenn, R.
Bibcode: 1991A&A...244..242H
Altcode:
A method for displaying the electron Thomson scattering intensity in the
inner heliosphere as observed by the zodiacal light photometers on board
the Helios spacecraft in the form of synoptic maps is presented. The
method is based on the assumption that the bulk of the scattering
electrons along the line of sight is located near the point closest to
the sun. Inner-heliospheric structures will generally be represented
properly in these synoptic maps only if they are sufficiently long-lived
(that is, a significant fraction of a solar rotation period). The
examples of Helios synoptic maps discussed (from data in April 1976 and
November 1978), indicate that it is possible to identify large-scale,
long-lived density enhancements in the inner heliosphere. It is expected
that the Helios synoptic maps will be particularly useful in the study
of corotating structures (e.g., streamers), and the maps will be most
reliable during periods when few transient featurs are present in the
corona, i.e., during solar minimum.
Title: Synoptic maps constructed from brightness observations of
Thomson scattering by heliospheric electrons
Authors: Hick, P.; Jackson, B.; Schwenn, R.
Bibcode: 1991AdSpR..11a..61H
Altcode: 1991AdSpR..11Q..61H
Observations of the Thomson scattering brightness by electrons in the
inner heliosphere provide a means of probing the heliospheric electron
distribution. An extensive data base of Thomson scattering observations,
stretching over many years, is available from the zodiacal light
photometers on board the two Helios spacecraft. A survey of these
data is in progress, presenting these scattering intensities in the
form of synoptic maps for successive Carrington rotations. The Thomson
scattering maps reflect conditions at typically several tenths of an
astronomical unit from the Sun. We discuss some representative examples
from the survey in comparison with other solar/heliospheric data,
such as in situ observations from the Helios plasma experiment and
synoptic maps constructed from magnetic field, Hα and K-coronameter
data. The comparison will provide some information about the extension
of solar surface features into the inner heliosphere.
Title: On Representing the Large-scale Structure of the Inner
Heliosphere in Synoptic Maps
Authors: Hick, P.; Jackson, B. V.; Schwenn, R.
Bibcode: 1990BAAS...22..810H
Altcode:
No abstract at ADS
Title: Slow Shock Heating in POST Flare Arches
Authors: Hick, P.; Priest, E. R.
Bibcode: 1989SoPh..122..111H
Altcode:
The heating of a coronal arch, following the occurrence of a dynamic
(two-ribbon) flare, is discussed. We investigate whether slow-shock
heating, occurring during the reconnection process in the dynamic
flare and responsible for the heating of the post-flare loops, is also
a workable proposition for the heating of a coronal arch. Contrary
to the flare loops, the shock structure in the arch is generally
not modified greatly by thermal conduction effects. As a result
slow-shock heating may be investigated in terms of the familiar MHD
shock jump relations. The observed enhanced arch density with respect
to the surrounding corona is explained as a direct consequence of the
reconnection process. For a combination of high arch temperatures and
low values of coronal magnetic field and density thermal conduction may
become important and will lead to an extra density enhancement in the
arch. Our interpretation of the arch of 21-22 May, 1980 suggests that
the formation of the arch took approximately one hour, and that observed
temperature, density and maximum energy content can be consistently
explained by the slow-shock heating mechanism.
Title: Interpretations of energetic phenomena in the solar corona
Authors: Hick, Pierre Paul Leonard
Bibcode: 1988PhDT.......202H
Altcode:
No abstract at ADS
Title: Thermal Structures Associated with Post-Flare Coronal Arches
Authors: Hick, Paul; Svestka, Zdenek
Bibcode: 1987SoPh..108..315H
Altcode:
Shortly after the dynamic flare of 14 ∶ 44 UT on 6 November, 1980,
which initiated the second revival in the sequence of post-flare coronal
arches of 6-7 November, a moving thermal disturbance was observed in
the fine field of view of HXIS. From 15 ∶ 40 UT until about 18 UT,
when it left the field of view, the disturbance rose into the corona,
as indicated by a projected velocity of 7.4 km s-1 in the
south-east direction. The feature was located above the reconnection
region of the dynamic flare and was apparently related to the revived
coronal arch. Observations in the coarse field of view after 18 UT
revealed a temperature maximum in the revived arch, rising with a
velocity of 7.0 km s-1 directly in continuation of the
thermal disturbance. The rise velocity of the disturbance was initially
(at least until 17 ∶ 20 UT) very similar to the rise velocities
observed for the post-flare loop tops of the parent flare. This
suggests that the rise of the reconnection point, in the Kopp and
Pneuman (1976) mechanism responsible for the rise of the loop tops,
also dictates the rise of the disturbance. From energy requirements
it follows that in this phase the disturbed region is still a separate
magnetic `island', thermally isolated from the old arch structure and
the post-flare loops. After 18 UT the rise of the post-flare loop tops
slowed down to 2 km s-1, which is significantly slower than
the rise of the brightness and temperature maxima of the revived arch
in the coarse field of view. Thus in this phase the Kopp and Pneuman
mechanism is no longer directly responsible for the rise of the thermal
structure and the rise possibly reflects the merging of the old and
the new arch structures.
Title: Post-flare coronal arches observed with the SMM/XRP Flat
Crystal Spectrometer
Authors: Hick, Paul; Svestka, Zdenek; Smith, Kermit L.; Strong,
Keith T.
Bibcode: 1987SoPh..114..329H
Altcode:
The phenomenon of post-flare coronal arches, initially discovered with
the Hard X-Ray Imaging Spectrometer (HXIS), was investigated using
observations made with the SMM Flat Crystal Spectrometer (FCS) on 20
through 23 January, 1985. Since these observations were made with
a different type of instrument from HXIS, they provide independent
information on the physical characteristics of the arch phenomenon
and extend our knowledge to lower coronal temperatures.
Title: Book reviews
Authors: Hick, Paul; Jackson, B.; Švestka, Zdenek; Křivský, L.
Bibcode: 1987SoPh..108..201H
Altcode:
No abstract at ADS
Title: Book-Review - the Lower Atmosphere of Solar Flares,
Relationships Between Low Temperature Plasmas and High Energy
Emissions
Authors: Neidig, D. F.; Hick, P.
Bibcode: 1987SoPh..108..201N
Altcode:
No abstract at ADS
Title: Approximate solutions to the cosmic ray transport equation
The maximum entropy method
Authors: Hick, P.; Stevens, G.
Bibcode: 1987A&A...172..350H
Altcode:
A method is described for obtaining approximate solutions to a
differential equation involving a density function in accordance
with Jaynes' principle of maximum entropy. The method uses some known
moments of the real solution, obtained directly from the differential
equation. Jaynes' principle provides a criterion necessary to construct
from these moments an approximation to the real solution. After some
introductory examples, the maximum entropy method is applied to simple
forms of the cosmic ray transport equation. The resulting approximation,
as well as the familiar diffusion approximation, are compared with a
numerical solution. It is found that there is qualitative agreement
between the maximum entropy approximation and the numerical solution,
and that the method is a significant improvement on the diffusion
approximation, especially in its description of first order anisotropy.
Title: Images of Post-Flare Coronal Structures in X-Rays
Authors: Svestka, Z.; Hick, P.
Bibcode: 1986SoPh..104..187S
Altcode:
This is an extended abstract of several papers mentioned in the
references describing extensive coronal structures related to radio
continua and imaged in > 3.5 keV X-rays.
Title: The Maximum Entropy Principle in Cosmic Ray Transport Theory
Authors: Hick, P.; Stevens, G.; van Rooijen, J.
Bibcode: 1986ASSL..123..355H
Altcode: 1986shtd.symp..355H
A procedure to obtain an approximate solution to the cosmic
ray transport equation, which, contrary to the familiar diffusion
approximation, is valid also for large anisotropies is described. Using
some moments of the distribution function an approximation is
constructed, in accordance with Jaynes (1957) principle of maximum
entropy. The procedure is applied to the case of the one-dimensional
transport equation and the resulting Maximum Entropy approximation and
the diffusion approximation with the numerical solution are compared,
that there is a qualitative agreement between the maximum entropy
approximation and the numerical solution, particularly close to the
particle source where the diffusion approximation breaks down.
Title: An interruption of the cooling of the coronal arch of 6/7
November 1980
Authors: Hick, Paul
Bibcode: 1986AdSpR...6f.271H
Altcode: 1986AdSpR...6..271H
During the decay phase of the giant coronal arch, which appeared after
the dynamic flare of 14:44 UT on 6 November 1980, the cooling of the
arch was interrupted for a period of two hours from ~ 18 UT until ~ 20
UT. In the upper parts of the arch (above ~12×104 km) the
temperature rose again. At lower altitudes the decline in temperature
was only slowed down. The energy input was an increasing function
of altitude and for the whole arch amounted to ~7×1029
erg. A thermal disturbance, formed after the dynamic flare low in the
corona and subsequently rising upward, moves through the old arch in
the same period. The reconnection which accompanies the coalescence
of the magnetic field structures of the disturbance and the old arch
is probably responsible for the energy release.
Title: The stationary post-flare arch of May 21/22, 1980
Authors: Hick, P.; Svestka, Z.
Bibcode: 1985SoPh..102..147H
Altcode:
On May 21/22, 1980 the Hard X-Ray Imaging Spectrometer aboard the
SMM imaged an extensive coronal structure after the occurrence of a
two-ribbon flare on May 21, 20:50 UT. The structure was observed from
22:20 UT on May 21 until its disappearence at 09:00 UT on May 22.
Title: The time scales of the scattering of energetic protons in
interplanetary space
Authors: Hick, P.; Stevens, G.
Bibcode: 1984AdSpR...4b.323H
Altcode: 1984AdSpR...4..323H
Observations with the directional spectrometer DFH aboard ISEE3 have
been used to obtain results on the scattering time scales of energetic
protons. Depending on the duration of the scattering process the
particle distribution will be subjected to either phase scattering or
full scattering. Our analysis of some representative events shows that
full scattering is applicable to shock-associated events.