Author name code: sylwester-janusz
ADS astronomy entries on 2022-09-14
author:"Sylwester, Janusz"
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Title: Detection of the third innermost radiation belt on LEO
CORONAS-Photon satellite around 2009 solar minimum
Authors: Dudnik, Oleksiy V.; Sylwester, Janusz; Kowaliński, Mirosław;
Podgórski, Piotr; Phillips, Kenneth J. H.
Bibcode: 2022AdSpR..70.1441D
Altcode: 2022arXiv220804154D
We analyze variations of high energy charged particle populations
filling various magnetospheric regions under, inside and outside of the
Van Allen inner and outer electron radiation belts in May 2009. The
study is based on the experimental data obtained from the STEP-F and
the SphinX instruments placed close to each other aboard the low-Earth
circular orbit CORONAS-Photon satellite. Data analysis of particle
fluencies collected from the highly sensitive STEP-F device indicates
the presence of a persistent electron belt at L ≈ 1.6, i.e., beneath
the well-known Van Allen electron inner radiation belt of the Earth's
magnetosphere. The electron energy spectrum in this "new" belt is much
steeper than that of the inner belt, so that the electrons with energies
Ee ≥ 400 keV were almost not recorded on L ≈ 1.6 outside
the South Atlantic Anomaly (SAA). We introduce the concept of effective
lowest threshold energies for X-ray detectors used in the solar soft
X-ray spectrophotometer SphinX and define their values for two regions:
the SAA and in the Van Allen outer belt. Different values of lowest
threshold energies are directly associated with different slopes
of particle energy spectra. Cross-analyses of data obtained from the
STEP-F and SphinX instruments initially built for various purposes made
it possible to detect the highly anisotropic character of the spatial
electron distribution in radiation belts in both Southern and Northern
hemispheres. We detected also the presence of low-energy electrons at
all latitudes during the main phase of a weak geomagnetic storm.
Title: From solar corona to radiation belts: an idea of joint
experiment on one CubeSat
Authors: Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw;
Bakala, Jaroslaw; Podgorski, Piotr; Chechotkin, Dmitro Leonidovych;
Adamenko, Volodymyr Olecsiiovych; Zajtsevskiy, Igora Lavrovich
Bibcode: 2022cosp...44.3233D
Altcode:
In this work we represent the concept of a unique scientific satellite
experiment aimed to study the effects due to the influence of the
burst component of the solar corona and magnetospheric soft X-ray
emission on the spatial and temporal distribution of the high-energy
charged particles filling the Earth's radiation belts. This aim is
to be fulfilled using a compact soft X-ray solar spectrophotometer
SphinX-NG and the miniaturized recording analyser of electrons and
protons MiRA\_ep. The main scientific tasks of the MiRA\_ep device
are the following: a) verification of the existence of the additional
inner electron radiation belt at L $\sim$ 1.6 for particles with
energies from tens of keV to E $\sim$ 0.5 MeV during geomagnetically
quiet conditions; b) determination of the particle energy spectra
in stationary radiation belts and in microbursts present outside of
the belts; c) determination of the degree of anisotropy for electron
velocity distribution at the midpoint of the radiation belts and in
micro splashes, at the edges of Van Allen belts and beyond belts during
increased solar, magnetospheric and ionospheric activity. A functional
diagram, a description of the structural modules, and selected technical
characteristics of the MiRA\_ep are shown. In design, the SphinX-NG
is a compact X-ray solar spectrophotometer equipped with three solid
state detectors and one CMOS matrix imager. The aim of detectors'
tirade is to observe solar flux for the soft (0.8 - 15 keV) and harder
(5 - 150 keV) energy domains over a very wide dynamic range, covering
the 8 decades range, from 5 x 10$ ^{-11}$ W/m$ ^{2}$ to 5 x 10$ ^{-3}$
W/m$ ^{2}$ in the spectral band 1 - 8 Å. It is from 50 times below
the lowest "quiet Sun" emission level measurable with the prototype
SphinX instrument up to levels corresponding to the strongest on record
X20-class solar flare. The two of detectors (one SDD and one CdTe)
will look towards the Sun, the third one (SDD looking antisolar) will
measure particle background and ambient soft X-ray emission arising
in situ within the Earth's ionosphere or upper atmosphere. The pinhole
detector will take soft X-ray images of the solar disc and surrounding
corona using 2048 x 2048 pixels CMOS camera. The SphinX-NG results
will be crucial for understanding the energy balance and physical
processes occurring in active solar corona (flares and active regions)
and their respective heating mechanisms. The data will be useful for
establishing the chemical composition of the plasma in solar corona,
especially during solar flares.
Title: On the Variability of Calcium Abundance during Flare Decays
Authors: Sylwester, Barbara; Sylwester, Janusz; Kepa, Anna; Phillips,
Kenneth
Bibcode: 2022cosp...44.2570S
Altcode:
The NASA Solar Maximum Mission (operational 1980—1989) carried
instruments designed to observe solar flares during an especially
high-activity period. Among the instruments was a bent crystal X-ray
spectrometer (BCS) viewing high-temperature lines of ionized calcium
and iron. The BCS channel including the Ca lines is of particular
interest as lines (due to He-like Ca or Ca XIX with satellite lines)
and continuum uncontaminated by instrumental background could be
observed, emitted by hot (T > 7 MK) parts of the flare plasma. The
line-to-continuum ratios directly give the abundance of Ca, A(Ca), which
can be examined for individual intervals during decays of the numerous
flares observed. A recent re-assessment of instrumental parameters shows
that non-uniformities in the curvature of the Ca channel crystal need
to be allowed for, which has been done in a new analysis of 194 flare
decays reported here. The ratio of the entire line spectrum (rather than
only the Ca XIX resonance line) to the continuum is measured. Updated
atomic data to describe the theoretical spectrum have been used. The
results confirm an earlier analysis in that flare-to-flare changes in
A(Ca) are taking place, the average for all flares included being A(Ca)
= 6.74 (log scale with A(H) =12) and standard deviation of 0.08, which
largely reflects real changes (the estimated uncertainty for individual
spectra is only about 0.03). There are indications that flares with
shorter durations and smaller GOES importance have slightly higher
A(Ca), with a range of about 7.2 down to 6.7. The photospheric A(Ca)
is 6.32, so our values strongly indicate a "FIP" effect which, as Ca
is a low-FIP element, has a coronal (flare) abundance about 2.6 times
larger than photospheric.
Title: Differential evolution method for simultaneous determination
of elemental abundances and DEM distribution based on X-ray spectra
Authors: Kepa, Anna; Sylwester, Janusz; Sylwester, Barbara; Siarkowski,
Marek
Bibcode: 2022cosp...44.2582K
Altcode:
The basic characteristics of astrophysical plasma are its chemical
composition and differential emission measure (DEM) distribution. Since
spectral lines and continuum intensities (which are inputs data
for DEM reconstruction) depend directly on the absolute elemental
abundance, the results of any DEM inversion strongly depend on
assumed chemical composition. In this contribution we propose a new
approach based on the differential evolution method for X-ray spectra
analysis in which DEM distribution and the abundances of elements
are calculated simultaneously. We will present the usefulness of this
approach based on the corresponding tests and show the results of its
application to the analysis of the RESIK/Coronas-F and the Solar X-ray
Monitor/Chandrayaan-2 spectra.
Title: Three-electron belt profile in the Earth quiet magnetosphere
as recorded by STEP-F and SphinX onboard instruments
Authors: Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw;
Podgorski, Piotr; Phillips, Kenneth; Vasiliovich Yakovlev, Oleksandr
Bibcode: 2022cosp...44.3323D
Altcode:
In this research, we discuss presence of spatial zones of enhanced
subrelativistic electron fluxes in the Earth magnetosphere at the
altitudes of low Earth orbit satellites based on measurements of
the two instruments aboard the CORONAS-Photon semi Sun-synchronous
satellite. The STEP-F detector and the SphinX solar X-ray
spectrophotometer installed next to each other collected data on
particle fluxes during 2009, around the deep solar activity minimum. The
STEP-F provided direct measurements of high-energy charged particles,
while the SphinX observed the soft X-rays of solar corona preferably. At
the same time, SphinX has been registering in the upper spectral
energy channels bremsstrahlung emission arising as a result of the
interaction of high energy electrons with the satellite's housings
and instrument's body. In order to search for and clarify presence
of the sustained spatial zones of enlarged fluxes outside the South
Atlantic Anomaly we analyzed 2-second data from STEP-F's D1e channel
recording electrons (E = 0.18-0.51 MeV), and SphinX's Det1 5-second
data of May 2009. A sustained three electron radiation belts structure
of the Earth's magnetosphere was found by analyzing the D1e/STEP-F
data. Two of them represent known Van Allen radiation belts; the
third "additional" permanent layer is formed around the drift shell
with average McIlwaine parameter of L$\sim$1.65. This third belt was
distinguished on every day in May 2009 over a wide range of geographic
longitudes, both on the ascending and descending portions of the
satellite orbit, in the Northern and Southern hemispheres, between
$\sim$ 150 degrees and $\sim$ 290 degrees longitude. Using the STEP-F's
measurements as a reference we examined SphinX's data for presence of
the third belt signatures. In this respect we performed advanced raw
data processing defining an upper envelope UE and the lower envelope
LE patterns. On the mean curve calculated as (UE+LE)/2, Det1/SphinX
exhibits in many cases three-belt structure seen by STEP-F although
the fine form of spatial-time structures are different. Clearly
pronounced is the anisotropic character of the SphinX reaction for
radiation belts electrons while crossing them in both hemispheres -
this effect caused by a narrow field of view of Det1. The presence of
preferential detection of all three belts profile in the dawn side of
the Earth orbits proves unambiguous recording of bremsstrahlung from
magnetospheric electrons in the uppermost amplitude channel of the Det1
SphinX X-ray spectrophotometer. Separately, outside the outer edge of
the Van Alen outer radiation belt, at L $>$ 7-8, we noticed presence
of enhanced particle flux density over a wide range of L-shells. These
shells correspond to the high-latitude region of quasi-trapped energetic
charged particles. Increased particle fluxes have been recorded up to
the bow shock wave border of the Earth's magnetosphere (L $\sim$ 10-12).
Title: New Solar Flare Calcium Abundances with No Surprises: Results
from the Solar Maximum Mission Bent Crystal Spectrometer
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kępa, A.
Bibcode: 2022ApJ...930...77S
Altcode: 2022arXiv220302257S
The calcium abundance in flare plasmas is estimated using X-ray spectra
from the Solar Maximum Mission Bent Crystal Spectrometer (BCS) during
the decays of 194 flares (Geostationary Operational Environmental
Satellite, GOES, classifications from B6.4 to X13) occurring between
1980 and 1989. Previous work by Sylwester et al. found that the
abundance varied from flare to flare. That analysis is improved on
here using updated instrument parameters and by including all calcium
lines viewed by the BCS instead of only the resonance line, so greatly
enhancing the photon count statistics. The abundance variations are
confirmed with the average abundance, A(Ca) (expressed logarithmically
with A(H) = 12), equal to 6.77 ± 0.20 for 194 flares (141 of which are
new in this study). This range corresponds to factors of between 1.7 and
7.2 larger than the photospheric abundance, and so our results are in
line with a "first ionization potential" (FIP) effect whereby low-FIP
elements like Ca (FIP = 6.11 eV) have enhanced coronal abundances. The
Ca flare abundance is uncorrelated with solar activity indices, but
weak correlations are suggested with GOES flare class and duration
(larger A(Ca) for smaller and shorter flares). The ponderomotive force
theory of Laming explaining the FIP effect gives a range of parameters
within which our estimates of A(Ca) agree with the theory. However, this
then gives rise to disagreements with previous estimates of the flare
silicon and sulfur abundances, although those of argon and iron are in
good agreement. Small adjustments of the theory may thus be necessary.
Title: On the Application of Differential Evolution to the Analysis
of X-Ray Spectra
Authors: Kępa, Anna; Sylwester, Barbara; Siarkowski, Marek; Sylwester,
Janusz
Bibcode: 2022ApJ...927...19K
Altcode: 2022arXiv220209302K
Using methods of differential evolution (DE), we determined the
coronal elemental abundances and the differential emission measure
(DEM) distributions for the plasma flaring on 2003 January 21. The
analyses have been made based on RESIK X-ray spectra. DE belongs to
the family of evolutionary algorithms. DE is conceptually simple and
easy to implement, so it has been applied to solve many problems in
science and engineering. In this study we apply this method in a new
context: simultaneous determination of plasma composition and DEM. In
order to increase the confidence of the results obtained using DE,
we tested the use of its algorithms by comparing the DE synthesized
with respective spectra observed by RESIK. Extensive discussion of the
DE method used and the obtained physical characteristics of flaring
plasma is presented. * Released on 2021 March 1.
Title: STIX X-ray microflare observations during the Solar Orbiter
commissioning phase
Authors: Battaglia, Andrea Francesco; Saqri, Jonas; Massa, Paolo;
Perracchione, Emma; Dickson, Ewan C. M.; Xiao, Hualin; Veronig,
Astrid M.; Warmuth, Alexander; Battaglia, Marina; Hurford, Gordon J.;
Meuris, Aline; Limousin, Olivier; Etesi, László; Maloney, Shane A.;
Schwartz, Richard A.; Kuhar, Matej; Schuller, Frederic; Senthamizh
Pavai, Valliappan; Musset, Sophie; Ryan, Daniel F.; Kleint, Lucia;
Piana, Michele; Massone, Anna Maria; Benvenuto, Federico; Sylwester,
Janusz; Litwicka, Michalina; Stȩślicki, Marek; Mrozek, Tomasz;
Vilmer, Nicole; Fárník, František; Kašparová, Jana; Mann,
Gottfried; Gallagher, Peter T.; Dennis, Brian R.; Csillaghy, André;
Benz, Arnold O.; Krucker, Säm
Bibcode: 2021A&A...656A...4B
Altcode: 2021arXiv210610058B
Context. The Spectrometer/Telescope for Imaging X-rays (STIX) is the
hard X-ray instrument onboard Solar Orbiter designed to observe solar
flares over a broad range of flare sizes.
Aims: We report
the first STIX observations of solar microflares recorded during
the instrument commissioning phase in order to investigate the STIX
performance at its detection limit.
Methods: STIX uses hard
X-ray imaging spectroscopy in the range between 4-150 keV to diagnose
the hottest flare plasma and related nonthermal electrons. This first
result paper focuses on the temporal and spectral evolution of STIX
microflares occuring in the Active Region (AR) AR12765 in June 2020,
and compares the STIX measurements with Earth-orbiting observatories
such as the X-ray Sensor of the Geostationary Operational Environmental
Satellite (GOES/XRS), the Atmospheric Imaging Assembly of the Solar
Dynamics Observatory, and the X-ray Telescope of the Hinode mission.
Results: For the observed microflares of the GOES A and B class, the
STIX peak time at lowest energies is located in the impulsive phase of
the flares, well before the GOES peak time. Such a behavior can either
be explained by the higher sensitivity of STIX to higher temperatures
compared to GOES, or due to the existence of a nonthermal component
reaching down to low energies. The interpretation is inconclusive
due to limited counting statistics for all but the largest flare
in our sample. For this largest flare, the low-energy peak time is
clearly due to thermal emission, and the nonthermal component seen at
higher energies occurs even earlier. This suggests that the classic
thermal explanation might also be favored for the majority of the
smaller flares. In combination with EUV and soft X-ray observations,
STIX corroborates earlier findings that an isothermal assumption
is of limited validity. Future diagnostic efforts should focus on
multi-wavelength studies to derive differential emission measure
distributions over a wide range of temperatures to accurately describe
the energetics of solar flares.
Conclusions: Commissioning
observations confirm that STIX is working as designed. As a rule of
thumb, STIX detects flares as small as the GOES A class. For flares
above the GOES B class, detailed spectral and imaging analyses can
be performed.
Title: The CubeSat Imaging X-ray Solar Spectrometer (CubIXSS)
Authors: Caspi, A.; Shih, A. Y.; Panchapakesan, S.; Warren, H. P.;
Woods, T. N.; Cheung, M.; DeForest, C. E.; Klimchuk, J. A.; Laurent,
G. T.; Mason, J. P.; Palo, S. E.; Seaton, D. B.; Steslicki, M.;
Gburek, S.; Sylwester, J.; Mrozek, T.; Kowaliński, M.; Schattenburg,
M.; The CubIXSS Team
Bibcode: 2021AAS...23821609C
Altcode:
The CubeSat Imaging X-ray Solar Spectrometer (CubIXSS) is a 6U
CubeSat proposed to NASA H-FORT. CubIXSS is motivated by a compelling
overarching science question: what are the origins of hot plasma in
solar flares and active regions? Elemental abundances are a unique
diagnostic of how mass and energy flow into and within the corona,
and CubIXSS addresses its science question through sensitive, precise
measurements of abundances of key trace ion species, whose spectral
signatures reveal the chromospheric or coronal origins of heated plasma
across the entire temperature range from ~1 to >30 MK. CubIXSS
measurements of the coronal temperature distribution and elemental
abundances directly address longstanding inconsistencies from prior
studies using instruments with limited, differing temperature and
composition sensitivities. CubIXSS comprises two co-optimized
and cross-calibrated instruments that fill a critical observational
gap: MOXSI, a novel diffractive spectral imager using a pinhole
camera and X-ray transmission diffraction grating for spectroscopy of
flares and active regions from 1 to 55 Å, with spectral and spatial
resolutions of 0.28-0.37 Å and 29-39 arcsec FWHM, respectively;
and SASS, a suite of four spatially-integrated off-the-shelf
spectrometers for high-cadence, high-sensitivity X-ray spectra from
0.5 to 50 keV, with spectral resolution of 0.06-0.5 keV FWHM across
that range. If selected for implementation, CubIXSS will launch
in late 2023 to mid-2024 to observe intense solar flares and active
regions during the rising phase and peak of the solar cycle. Its 1-year
prime mission is well timed with perihelia of Parker Solar Probe and
Solar Orbiter, and with the launches of complementary missions such
as the PUNCH Small Explorer. CubIXSS is a pathfinder for the next
generation of Explorer-class missions with improved capabilities for
SXR imaging spectroscopy. We present the CubIXSS motivating science
background, its suite of instruments and expected performances, and
other highlights from the completed Concept Study Report, including
novel analysis techniques to fully exploit the rich data set of CubIXSS
spectral observations.
Title: KORTES mission for solar activity monitoring onboard
International Space Station
Authors: Kirichenko, Alexey; Kuzin, Sergey; Shestov, Sergey; Ulyanov,
Artem; Pertsov, Andrey; Bogachev, Sergey; Reva, Anton; Loboda, Ivan;
Vishnyakov, Eugene; Dyatkov, Sergey; Erkhova, Nataliya; Stȩślicki,
Marek; Sylwester, Janusz; Płocieniak, Stefan; Podgórski, Piotr;
Kowaliński, Mirosław; Bakała, Jarosław; Szaforz, Żaneta;
Siarkowski, Marek; Ścisłowski, Daniel; Mrozek, Tomasz; Sylwester,
Barbara; Malyshev, Ilya; Pestov, Alexey; Polkovnikov, Vladimir;
Toropov, Mikhail; Salashchenko, Nikolay; Tsybin, Nikolay; Chkhalo,
Nikolay
Bibcode: 2021FrASS...8...66K
Altcode:
We present a description of the recent advances in the development
of the KORTES assembly -- the first solar oriented mission designed
for the Russian segment of International Space Station. The KORTES
consists of several imaging and spectroscopic instruments collectively
covering a wide spectral range extending from extreme ultraviolet (EUV)
wavelengths to X-rays. The EUV telescopes inside KORTES will trace the
origination and dynamics of various solar phenomena, e.g. flares,
CMEs, eruptions etc. EUV spectra provided by grazing-incidence
spectroheliographs will enable precise DEM-diagnostics during these
events. The monochromatic X-ray imager will observe the formation
of hot plasma in active regions and outside them. The SolpeX module
inside KORTES will offer an opportunity to measure fluxes, Doppler
shifts and polarization of soft X-ray emission both in lines and
continuum. SolpeX observations will contribute to studies of particle
beams and chromospheric evaporation. The instrumentation of KORTES
will employ a variety of novel multilayer and crystal optics to be
discussed. The deployment of KORTES is planned of 2024.
Title: The non-Fourier image reconstruction method for the STIX
instrument
Authors: Siarkowski, Marek; Mrozek, Tomasz; Sylwester, Janusz;
Litwicka, Michalina; Dąbek, Magdalena
Bibcode: 2020OAst...29..220S
Altcode:
In this work we aimed to develop the image reconstruction algorithm
without any analytical simplifications and restrictions. In our
method we abandon Fourier's approach to image reconstruction, and
instead use the number of counts recorded in each detector pixel,
and then reconstruct each image using a classical Richardson-Lucy
algorithm. Among similar works performed in the past, our approach
is based, for the first time, on the real geometry of STIX. We made
a preliminary analysis of expected differences in STIX imaging which
may occur due to usage of slightly different geometries. The other
difference is that we use single-pixel-response maps. Namely, knowing
the instrument geometry we are able to calculate the detector response
for point sources covering entire the solar disc. Next, we iteratively
combine them with varying weights until the best match between
reconstructed and observed detector responses is achieved. Preliminary
tests revealed that the developed algorithm reproduces high quality
images. The algorithm is moderately fast, but the result comparable to
CLEAN algorithm is obtained within 20-50 iteration steps which takes
less than 2 seconds on typical portable computer configuration. The
location, size and intensity of reconstructed sources are very close
to simulated ones. Therefore the algorithm is very well suited for the
detailed photometry of the solar HXR sources. Moreover, its simplicity
allows to improve photon transmission calculation in case of any grids
uncertainties measured after the launch.
Title: The CubeSat Imaging X-ray Solar Spectrometer (CubIXSS)
Authors: Caspi, A.; Shih, A. Y.; Warren, H.; Winebarger, A. R.; Woods,
T. N.; Cheung, C. M. M.; DeForest, C.; Klimchuk, J. A.; Laurent,
G. T.; Mason, J. P.; Palo, S. E.; Schwartz, R.; Seaton, D. B.;
Steslicki, M.; Gburek, S.; Sylwester, J.; Mrozek, T.; Kowaliński,
M.; Schattenburg, M.
Bibcode: 2020AGUFMSH0480007C
Altcode:
The CubeSat Imaging X-ray Solar Spectrometer (CubIXSS) is a 6U
CubeSat currently in a formulation phase under the 2019 NASA H-FORT
program. CubIXSS is motivated by a compelling overarching science
question: what are the origins of hot plasma in solar flares and active
regions? Elemental abundances are a unique diagnostic of how mass
and energy flow into and within the corona, and CubIXSS addresses
its science question through sensitive, precise measurements of
abundances of key trace ion species, whose spectral signatures reveal
the chromospheric or coronal origins of heated plasma across the
entire range of coronal temperatures, from ~1 to >30 MK. CubIXSS
measurements of the coronal temperature distribution and elemental
abundances directly address longstanding inconsistencies from prior
studies using instruments with limited, differing temperature and
composition sensitivities. CubIXSS comprises two co-optimized and
cross-calibrated instruments that fill a critical observational gap:
MOXSI, a novel diffractive spectral imager using a pinhole camera
and X-ray transmission diffraction grating to achieve spectroscopy of
flares and active regions from 1 to 55 Å, with spectral resolution of
0.24 Å FWHM and a spatial resolution of 25 arcsec FWHM; and SASS,
a suite of four spatially-integrated off-the-shelf spectrometers for
high-cadence, high-sensitivity measurements of soft and hard X-rays,
from 0.5 to 50 keV, with spectral resolution from 0.06 to 0.5 keV
FWHM. If selected for implementation, CubIXSS will launch in
mid-2023 to observe intense solar flares and active regions during
the rising phase of the solar cycle. Its nominal 1-year mission is
well timed with perihelia of Parker Solar Probe and Solar Orbiter,
and with the launches of complementary missions such as the PUNCH
Small Explorer. CubIXSS is also a pathfinder for the next generation
of Explorer-class missions with improved capabilities for SXR imaging
spectroscopy. We present the CubIXSS motivating science background, its
suite of instruments and expected performances, and other highlights
from the completed Concept Study Report, including novel analysis
techniques to fully exploit the rich data set of CubIXSS spectral
observations.
Title: The Spectrometer/Telescope for Imaging X-rays (STIX)
Authors: Krucker, Säm; Hurford, G. J.; Grimm, O.; Kögl, S.;
Gröbelbauer, H. -P.; Etesi, L.; Casadei, D.; Csillaghy, A.; Benz,
A. O.; Arnold, N. G.; Molendini, F.; Orleanski, P.; Schori, D.; Xiao,
H.; Kuhar, M.; Hochmuth, N.; Felix, S.; Schramka, F.; Marcin, S.;
Kobler, S.; Iseli, L.; Dreier, M.; Wiehl, H. J.; Kleint, L.; Battaglia,
M.; Lastufka, E.; Sathiapal, H.; Lapadula, K.; Bednarzik, M.; Birrer,
G.; Stutz, St.; Wild, Ch.; Marone, F.; Skup, K. R.; Cichocki, A.; Ber,
K.; Rutkowski, K.; Bujwan, W.; Juchnikowski, G.; Winkler, M.; Darmetko,
M.; Michalska, M.; Seweryn, K.; Białek, A.; Osica, P.; Sylwester, J.;
Kowalinski, M.; Ścisłowski, D.; Siarkowski, M.; Stęślicki, M.;
Mrozek, T.; Podgórski, P.; Meuris, A.; Limousin, O.; Gevin, O.; Le
Mer, I.; Brun, S.; Strugarek, A.; Vilmer, N.; Musset, S.; Maksimović,
M.; Fárník, F.; Kozáček, Z.; Kašparová, J.; Mann, G.; Önel,
H.; Warmuth, A.; Rendtel, J.; Anderson, J.; Bauer, S.; Dionies, F.;
Paschke, J.; Plüschke, D.; Woche, M.; Schuller, F.; Veronig, A. M.;
Dickson, E. C. M.; Gallagher, P. T.; Maloney, S. A.; Bloomfield, D. S.;
Piana, M.; Massone, A. M.; Benvenuto, F.; Massa, P.; Schwartz, R. A.;
Dennis, B. R.; van Beek, H. F.; Rodríguez-Pacheco, J.; Lin, R. P.
Bibcode: 2020A&A...642A..15K
Altcode:
Aims: The Spectrometer Telescope for Imaging X-rays (STIX)
on Solar Orbiter is a hard X-ray imaging spectrometer, which
covers the energy range from 4 to 150 keV. STIX observes hard X-ray
bremsstrahlung emissions from solar flares and therefore provides
diagnostics of the hottest (⪆10 MK) flare plasma while quantifying
the location, spectrum, and energy content of flare-accelerated
nonthermal electrons.
Methods: To accomplish this, STIX applies
an indirect bigrid Fourier imaging technique using a set of tungsten
grids (at pitches from 0.038 to 1 mm) in front of 32 coarsely pixelated
CdTe detectors to provide information on angular scales from 7 to 180
arcsec with 1 keV energy resolution (at 6 keV). The imaging concept of
STIX has intrinsically low telemetry and it is therefore well-suited
to the limited resources available to the Solar Orbiter payload. To
further reduce the downlinked data volume, STIX data are binned on
board into 32 selectable energy bins and dynamically-adjusted time
bins with a typical duration of 1 s during flares.
Results:
Through hard X-ray diagnostics, STIX provides critical information
for understanding the acceleration of electrons at the Sun and their
transport into interplanetary space and for determining the magnetic
connection of Solar Orbiter back to the Sun. In this way, STIX serves
to link Solar Orbiter's remote and in-situ measurements.
Title: A Unique Resource for Solar Flare Diagnostic Studies: The
SMM Bent Crystal Spectrometer
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kępa,
A.; Rapley, C. G.
Bibcode: 2020ApJ...894..137S
Altcode: 2020arXiv200403241S
The Bent Crystal Spectrometer (BCS) on the NASA Solar Maximum Mission
spacecraft observed the X-ray spectra of numerous solar flares during
the periods 1980 February-November and 1984-1989. The instrument,
the first of its kind to use curved crystal technology, observed the
resonance lines of He-like Ca (Ca XIX) and Fe (Fe XXV), and neighboring
satellite lines, allowing the study of the rapid evolution of flare
plasma temperature, turbulence, mass motions etc. To date there has
not been a solar X-ray spectrometer with comparable spectral and
time resolution, while subsequent solar cycles have delivered far
fewer and less intense flares. The BCS data archive thus offers an
unparalleled resource for flare studies. A recent reassessment of
the BCS calibration and its operations is extended here by using data
during a spacecraft scan in the course of a flare on 1980 November 6
that highlights small deformations in the crystal curvature of the
important channel 1 (viewing lines of Ca XIX and satellites). The
results explain long-standing anomalies in spectral line ratios which
have been widely discussed in the past. We also provide an in-flight
estimation of the BCS collimator field of view which improves the
absolute intensity calibration of the BCS. The BCS channel 1 background
is shown to be entirely due to solar continuum radiation, confirming
earlier analyses implying a time-variable flare abundance of Ca. We
suggest that BCS high-resolution Ca XIX and Fe XXV line spectra be
used as templates for the analysis of X-ray spectra of nonsolar sources.
Title: A Multiwavelength Analysis of the Long-duration Flare Observed
on 15 April 2002
Authors: Kepa, Anna; Sylwester, Barbara; Sylwester, Janusz; Mrozek,
Tomasz; Siarkowski, Marek
Bibcode: 2020SoPh..295...22K
Altcode: 2019arXiv191207984K
We present a multiwavelength analysis of the long-duration flare
observed on 15 April 2002 (soft X-ray peak time at 03:55 UT,
SOL2002-04-15T03:55). This flare occurred on the disk (S15W01) in NOAA
9906 and was observed by a number of space instruments including the
Extreme-Ultraviolet Imaging Telescope on the Solar and Heliospheric
Observatory (SOHO/EIT), the RESIK spectrometer onboard the Coronas-F
spacecraft, and the Ramaty High Energy Solar Spectroscopic Imager
(RHESSI). We have performed a complex analysis of these measurements
and studied the morphology and physical parameters characterizing
the conditions in flaring plasmas. The 195 Å SOHO/EIT images have
been used to study evolution of flaring loops. Analysis of RHESSI
data provided the opportunity for a detailed analysis of hard X-ray
emission with 1 keV energy resolution. We have used Geostationary
Operational Environmental Satellite (GOES) observations for isothermal
interpretation of the X-ray measurements. Temperature diagnostics of
the flaring plasma have been carried out by means of a differential
emission measure (DEM) analysis based on RESIK X-ray spectra. The DEM
distributions were calculated based on two methods: Withbroe-Sylwester
(WS) and differential evolution (DE). Both of the approaches provided
similar results. We obtained two-component DEM distributions independent
of the evolutionary flare phase. We found that the amount of energy
of thermal plasma for this flare is of the order of 1030
ergs. The values obtained by assuming an isothermal plasma model are
lower than those determined from the differential emission measure
distributions.
Title: Solar Soft X-ray Variations from the 2008-2019 Solar Cycle
inferred from CORONAS/SphinX, GOES/XRS, Hinode/XRT, MinXSS, NuSTAR,
and RHESSI Instruments
Authors: Moore, C.; Takeda, A.; Sylwester, B.; Sylwester, J.; Hannah,
I.; Dennis, B.; Reeves, K.; Woods, T.
Bibcode: 2020AAS...23535901M
Altcode:
The Solar spectral irradiance (SSI) is vital for understanding the
physics of all layers of the solar atmosphere from the photosphere to
the corona. While most of the contribution to the Total Solar Irradiance
(TSI) reside in visible and infrared light, the UV and X-rays have the
largest change in magnitude. Quantifying the UV and X-ray variations
over the solar cycle is critical for constraining the physics of solar
flares, active regions, the quiet Sun, as well as the atmospheres
of planets and moons in the heliosphere. The GOES/XRS spectrally
integrated 0.1 - 0.8 nm energy flux has been a longstanding diagnostic
of soft x-ray variations, but is limited by non-linearities in signal
response for low solar flux levels and an observed minimum detection
limit. The Hinode/XRT filter images provide a unique alternative proxy
for solar soft X-ray flux inferences with larger dynamic range and a
lower flux sensitivity. We compare the spectral irradiance estimate
from a Hinode/XRT filter-ratio technique results to the lowest spectra
measured-to-date between 1.25 - 3 keV by CORONAS/SPhinX in 2009,
and MinXSS CubeSat spectra in 2016 - 2019. We also highlight the
large variability in the soft X-ray spectra as directly measured by
CORONAS/SphinX, MinXSS, NuSTAR, and RHESSI intermittently between 2009
- 2019.
Title: SOLPEX Complex for Studies of Solar Radiation in the Soft
X-Ray Range
Authors: Kuzin, S. V.; Kirichenko, A. S.; StÈ©ślicki, M.; Sylwester,
J.; Siarkowski, M.; Szaforz, Ż.; Płocieniak, S.; Ba̧kała,
J.; Barylak, J.; Podgórski, P.; Ścisłowski, D.; Kowaliński, M.;
Bogachev, S. A.; Pertsov, A. A.
Bibcode: 2020JTePh..64.1738K
Altcode:
The SOLPEX complex consists of two instruments for recording soft X-ray
radiation from the Sun and is a part of the KORTES equipment, which
will be installed on board the International Space Station. The first
instrument is a fast-rotating multi-crystalagg spectrometer designed to
record solar spectra in the range of 0.4-23 Å with a time resolution
of no less than 0.1 s. The second instrument is a pinhole camera with
a focal length of 58 cm. The camera has a field of viewof 2° × 2°,
angular resolution of 2 arcmin, and time resolution up to 0.2 s. The
energy range is determined by the input filter and is 1-10 keV; the
energy resolution is 0.5 keV. The combination of these two instruments
makes it possible to locate hot solar sources in the corona, determine
their speed, and conduct spectral diagnostics.
Title: Analysis of Quiescent Corona X-ray Spectra from SphinX During
the 2009 Solar Minimum
Authors: Sylwester, B.; Sylwester, J.; Siarkowski, M.; Phillips,
K. J. H.; Podgorski, P.; Gryciuk, M.
Bibcode: 2019SoPh..294..176S
Altcode: 2019arXiv191203082S
The SphinX X-ray spectrophotometer on the CORONAS-PHOTON mission
observed the 1 - 15 keV X-ray spectrum of the spatially integrated
solar corona during the deep minimum of 2009, when solar activity was
exceptionally low. Its sensitivity for energies >1.2 keV was higher
than that of any other solar X-ray spectrometer in orbit at the time,
including the detectors on the Geostationary Operational Environmental
Satellites (GOES). Using much improved instrumental data than was
used previously, we analysed SphinX spectra in 576 intervals for which
there was no discernible activity (NA), 40 intervals when there were
X-ray brightenings (B), and 16 intervals when there were micro-flares
with peak emission less than GOES A1 (F). An instrumental background
spectrum, formed over 34 hours of spacecraft night-time periods and
including electronic noise and particle radiation, was subtracted from
the solar spectra. Theoretical spectra were used to deduce temperatures
on an isothermal assumption for the NA, B, and F intervals (1.69,
1.81, and 1.86 MK, respectively). Differential emission measure (DEM)
analysis for the same spectra revealed a "cooler" component (logT =6.2
or T ≈1.6 MK) in each case, but with a second hotter component having
a less well-defined peak temperature varying from ≈2.5 to ≈3.5 MK
(logT =6.4 and 6.55) and an emission measure between two and three
orders smaller than that of the cooler component. These results are
similar to those obtained at times just after solar minimum with the
EVE instrument. A very hot component that might indicate the signature
of nano-flare heating of the corona is not evident in SphinX data.
Title: The soft X-ray spectrometer polarimeter SolpeX
Authors: Sylwester, J.; Stȩślicki, M.; Bąkała, J.; Płocieniak,
S.; Szaforz, Ż.; Kowaliński, M.; Ścisłowski, D.; Podgórski, P.;
Mrozek, T.; Barylak, J.; Makowski, A.; Siarkowski, M.; Kordylewski,
Z.; Sylwester, B.; Kuzin, S.; Kirichenko, A.; Pertsov, A.; Bogachev, S.
Bibcode: 2019ExA....47..199S
Altcode: 2019ExA...tmp...10S; 2019arXiv190306163S
We present a novel X-ray assembly of functionally related instrument
blocks intended to measure solar flare and active region (AR) spectra
from within the Russian instrument complex KORTES, to be mounted
aboard the International Space Station ( ISS). SolpeX consists of
three blocks: fast-rotating multiple flat crystal Bragg spectrometer,
pin-hole X-ray spectral imager and Bragg polarimeter. This combination
of measuring blocks will offer an opportunity to detect/measure
possible X-ray polarization in soft X-ray emission lines/continuum and
record spectra of solar flares, in particular during their impulsive
phases. Polarized Bremsstrahlung and line emission may arise from
presence of directed particle beams colliding with denser regions of
flares. As a result of evaporation, the X-ray spectral-components are
expected to be Doppler shifted, which will also be measured. In this
paper, we present details of the construction of three SolpeX blocks
and discuss their functionality. Delivery of KORTES with SolpeX to
ISS is expected in 2020/2021.
Title: Analysis of the differential emission measure distributions
for solar flares observed by RESIK
Authors: Kepa, A.; Sylwester, B.; Sylwester, J.; Gryciuk, M.;
Siarkowski, M.
Bibcode: 2018JASTP.179..545K
Altcode:
The Polish X-ray spectrometer RESIK observed the spectra in four
wavelength bands from 3.3 Å to 6.1 Å. This spectral range contains
many emission lines of H- and He-like ions for Si, S, Ar and K formed
in the high temperature of solar coronal plasma. Analysis of measured
spectra gives a possibility to study the differential emission measure
distributions (DEM) in the temperature range between 1 MK and 30
MK. We present the analysis of DEM distributions of the multi-peaked
C9.8 flare observed by RESIK on 9 January 2003 adopting the model of
elementary flare profile (EFP). The model allows to distinguish the
individual flare components based on the observed light curves in
selected spectral bands.
Title: Highly Ionized Calcium and Argon X-Ray Spectra from a Large
Solar Flare
Authors: Phillips, K. J. H.; Sylwester, J.; Sylwester, B.; Kowaliński,
M.; Siarkowski, M.; Trzebiński, W.; Płocieniak, S.; Kordylewski, Z.
Bibcode: 2018ApJ...863...10P
Altcode: 2018arXiv180608584P
X-ray lines of helium-like calcium (Ca XIX) between 3.17 and 3.21 Å
and associated Ca XVIII dielectronic satellites have previously been
observed in solar flare spectra, and their excitation mechanisms are
well established. Dielectronic satellites of lower-ionization stages
(Ca XVII-Ca XV) are not as well characterized. Several spectra during
a large solar flare in 2001 by the DIOGENESS X-ray spectrometer on the
CORONAS-F spacecraft show the Ca XVII and Ca XVI satellites, as well
as lines of ionized argon (Ar XVII, Ar XVI), including dielectronic
satellites. The DIOGENESS spectra are compared with spectra from a
synthesis code developed here based on an isothermal assumption with
various atomic sources including dielectronic satellite data from the
Cowan Hartree-Fock code. Best-fit comparisons are made by varying the
temperature as the code’s input (Ar/Ca abundance ratio fixed at 0.33);
close agreement is achieved, although with adjustments to some ion
fractions. The derived temperature is close to that derived from the
two GOES X-ray channels, T GOES . Some lines are identified
for the first time. Similar spectra from the P78-1 spacecraft and the
Alcator C-Mod tokamak have also been analyzed and similar agreements
were obtained. The importance of blends of calcium and argon lines is
emphasized, affecting line ratios used for temperature diagnostics. This
analysis will be applied to the Solar Maximum Mission Bent Crystal
Spectrometer archive and to X-ray spectra expected from the ChemiX
instrument on the Sun-orbiting Interhelioprobe spacecraft, while the
relevance to X-ray spectra from non-solar sources is indicated.
Title: Splitting of the outer radiation belt during substorms at
solar activity minimum as seen by CORONAS-Photon satellite instruments
Authors: Dudnik, Oleksiy; Sylwester, Janusz; Podgorski, Piotr
Bibcode: 2018cosp...42E.914D
Altcode:
The satellite telescope of electrons and protons STEP-F and the solar
X-ray spectrophotometer SphinX, placed in close proximity to each other,
have collected data on particle fluxes aboard circular low Earth orbit
CORONAS-Photon satellite during deep minimum of solar activity, which
took place in 2009. Whilst STEP-F, comprising a set of silicon PIN
and scintillation sensors, served as detector for direct registration
for particles, the SphinX has detected not only soft X-rays of solar
corona but also bremsstrahlung and line emission in bandwidth of X-rays
arising as a result of interaction of high energy electrons with the
satellite's housings and instrument's frames. These emissions provide
a number of new information on the physics of radiation belts. In
this research we discuss phenomena of outer radiation belt splitting
during weak geomagnetic substorms of May and August 2009, detected
by both instruments. We make use of the data on particle fluxes
observed at L1 Lagrange point and geostationary GOES satellites for
context analysis. Double-peaked L-profile of the outer radiation belt
and increase of electron fluxes were recorded by STEP-F and SphinX
instruments during recovery phase of weak geomagnetic storm on May 8,
2009. STEP-F recorded also barely perceptible outer belt splitting
on August 5 2009, after arrival of interplanetary shock. As far as
instruments' fields of view were orthogonally oriented, this allowed to
record particle beam at onset of May's substorm by SphinX instrument
only that prompted to suggest different mechanisms of populating
enhanced electron fluxes during the onset and recovery phases of
substorm. At onset of substorm processes of rapid radial diffusion of
narrowly directed low-energy electron fluxes from the boundary layers
of the Earth's magnetosphere to the region of steady particle capture
prevailed. During the main phase of storm the pitch-angle scattering
caused the emptying of outer radiation belt, which was observed both
at low altitudes and at altitudes of geostationary satellites.
Title: New solar diagnostics enabled by novel soft x-ray imaging
spectroscopy, and future missions
Authors: Caspi, Amir; Sylwester, Janusz; Gburek, Szymon; Crowley,
Geoff; Woods, Thomas; Shih, Albert Y.; DeForest, Craig; Steslicki,
Marek; Warren, Harry; Mason, James
Bibcode: 2018cosp...42E.525C
Altcode:
Solar soft X-ray (SXR) observations provide unique diagnostics of
plasma heating, during solar flares and quiescent times. Spectrally-
and temporally-resolved measurements are crucial for understanding the
dynamics and evolution of these energetic processes; spatially-resolved
measurements are essential for understanding energy transport. A
critical observational gap exists from ∼0.2 to ∼3 keV (∼4-60
Å), where spectrally-resolved stellar observations are plentiful
but have not been routinely made for the Sun in many decades. This
energy range includes spectral lines from highly-ionized atoms with
both low and high first ionization potential (FIP), as well as thermal
free-free (bremsstrahlung) and free-bound (radiative recombination)
continua. These SXR emissions provide crucial diagnostics of plasma
temperature distributions, as well as elemental abundances that
probe plasma origins over a wide range of temperatures, that are
not available from observations at other wavelengths. A better
understanding of thermal plasma also informs our interpretation of
hard X-ray (HXR) observations of nonthermal particles, improving our
understanding of the relationships between particle acceleration,
plasma heating, and the underlying release of magnetic energy during
reconnection.We discuss a proposed small satellite pathfinder mission,
the CubeSat Imaging X-ray Solar Spectrometer (CubIXSS), to measure
spectrally- and spatially-resolved SXRs from the quiescent and
flaring Sun from a 6U CubeSat platform in low-Earth orbit during
a nominal 1-year mission. CubIXSS includes the Amptek X123-FastSDD
silicon drift detector, a low-noise, commercial off-the-shelf (COTS)
instrument enabling full-Sun SXR spectroscopy from ∼0.5 to ∼20
keV with ∼0.15 keV FWHM spectral resolution with low power, mass,
and volume requirements. Multiple detectors and tailored apertures
provide sensitivity to SXR emission from deep solar minimum to >X5
flares. An X123-CdTe cadmium-telluride detector is also included for
∼5-50 keV HXR spectroscopy with ∼0.5 keV FWHM resolution. The
precise spectra from these instruments will provide detailed
measurements of the coronal temperature distribution and elemental
abundances during flares and quiescent times, and, for large flares,
context information of flare-accelerated electrons.CubIXSS also
includes a novel spectro-spatial imager - the first ever solar imager
on a CubeSat - utilizing a custom pinhole camera and Chandra-heritage
X-ray transmission diffraction grating to provide spatially- resolved,
full-Sun imaging spectroscopy from ∼0.2 to ∼10 keV (∼1-60
Å), with ∼25 arcsec and ∼0.25 Å FWHM spatial and spectral
resolutions, respectively. Additional pinholes with tailored filters
provide non-dispersed images with coarse spectral information to seed
analysis of the dispersed spectro-spatial images and for improved
sensitivity to quiescent conditions. MOXSI's unique capabilities
enable SXR spectroscopy and corresponding temperature and elemental
abundance diagnostics of individual flares and active regions over a
spectral range never before accessed by any prior solar mission.CubIXSS
is a pathfinder for larger satellites with improved resolution and
sensitivity. Through these groundbreaking new measurements, CubIXSS
and future missions will improve our physical understanding of thermal
plasma processes and impulsive energy release in the solar corona,
from quiet Sun to solar flares.
Title: Solar Microflares Observed by SphinX and RHESSI
Authors: Mrozek, Tomasz; Gburek, Szymon; Siarkowski, Marek; Sylwester,
Barbara; Sylwester, Janusz; Kepa, Anna; Gryciuk, Magdalena
Bibcode: 2018SoPh..293..101M
Altcode:
In 2009, the Russian Complex Orbital Observations Near-Earth of Activity
of the Sun (CORONAS-Photon) spacecraft was launched, carrying the Polish
Solar PHotometer In X-rays (SphinX). The SphinX was most sensitive in
the spectral range 1.2 - 15 keV, thus an excellent opportunity appeared
for comparison with the low-energy end of Ramaty High Energy Solar
Spectroscopic Imager (RHESSI) spectra. Common spectral measurements
with these instruments cover the range where most of the flare energy
is accumulated. We have chosen four consecutive small solar events
observed on 4 July 2009 at 13:43 UT, 13:48 UT, 13:52 UT, and 13:55
UT (RHESSI flare peak times) and used them to compare the data and
results from the two instruments. Moreover, we included Geostationary
Operational Environmental Satellite (GOES) records in our analysis. In
practice, the range of comparison performed for SphinX and RHESSI
is limited roughly to 3 - 6 keV. RHESSI fluxes measured with a use
of one, four, and nine detectors in the 3 - 4 keV energy band agree
with SphinX measurements. However, we observed that SphinX spectral
irradiances are three times higher than those of RHESSI in the 4 -
6 keV energy band. This effect contributes to the difference in
obtained emission measures, but the derived temperatures of plasma
components are similar. RHESSI spectra were fitted using a model with
two thermal components. We have found that the RHESSI hot component
is in agreement with GOES, and the RHESSI hotter component fits the
SphinX flaring component well. Moreover, we calculated the so-called
thermodynamic measure and the total thermal energy content in the four
microflares that we studied. The results obtained show that SphinX is
a very sensitive complementary observatory for RHESSI and GOES.
Title: Highly Ionized ca X-Ray Spectra from Flares Seen with the
Diogeness Spectrometer
Authors: Sylwester, Janusz; Kowalinski, Miroslaw; Sylwester, Barbara;
Siarkowski, Marek; Kordylewski, Zbigniew; Plocieniak, Stefan;
Trzebinski, Witold; Phillips, Kenneth
Bibcode: 2018cosp...42E3313S
Altcode:
X-ray lines of helium-like calcium (Ca XIX) and nearby Ca XVIII
dielectronic satellites have been observed in solar flares with a
number of high-resolution spectrometers. The DIOGENESS instrument
on the CORONAS-F spacecraft, a scanning crystal spectrometer which
operated in 2001, observed these lines but in addition satellites
of lower ionization stages of Ca as well as ionized Ar lines in the
spectral range 3.05-3.35 Angstroms. In this work, spectra from flares
including the X5 flare on 2001 August 25 are analyzed and compared
with synthetic spectra. The latter were generated with a specially
written code based on various theoretical data including results from
the Cowan Hartree-Fock pseudo-relativistic code run for satellite
lines. Solar flare spectra taken with the P78-1 SOLFLEX instrument
in 1980-1981 are also analyzed. There is close agreement between the
solar flare and synthetic spectra for the Ca XIX lines and Ca XVIII
satellites (3.17-3.21 Angstroms) and also the Ca XVII satellites at
3.215-3.235 Angstroms clearly seen in DIOGENESS and some SOLFLEX
spectra. In addition, fainter line emission at longer wavelengths
(λ> 3.24 Angstroms) in DIOGENESS spectra is identified with Ca XVI
satellites and with the Ca XVIII "o" and "p" satellites as well as a
feature due to Ar XVI. These identifications are confirmed by recent
analysis of X-ray Ar and Ca spectra from the Alcator-C Mod tokamak
high-temperature plasmas. The synthetic code developed for this work
will be used for analysis of X-ray spectra, recently characterized
with new calibration data, from the Solar Maximum Mission Bent Crystal
Spectrometer, and spectra expected from the Polish high-resolution
ChemiX spectrometer/dopplerometer, due to fly on the [two] Russian
Interhelioprobe spacecraft in 2025/2026.
Title: Hydrodynamical 1D modelling of flaring loops during a B8.3
flare on July 04, 2009
Authors: Awasthi, Arun Kumar; Sylwester, Janusz; Sylwester, Barbara;
Reale, Fabio; Liu, Rui
Bibcode: 2018cosp...42E.147A
Altcode:
Hydrodynamical evolution of flaring plasma is crucial in understanding
the response of various layers of solar atmospheres and the role of
plasma energy transport and radiative loss processes. Although the
insights obtained from the analysis of multi-wavelength emission are
limited by the sensitivity of the observing instruments, numerical
modelling constrained by observable provides a comprehensive picture of
the underlying processes. In this regard, we investigate the evolution
of thermal characteristics of plasma during a B8.9 flare of July 04,
2009 using Palermo-Harvard (PH) 1D hydrodynamic (HD) model. The X-ray
spectra during the event, observed commonly by SphinX (1-15 keV), SOXS
(4-25 keV) and Fermi (≥6 keV) instruments, were analysed in order to
derive thermal characteristics of flaring plasma. EUV images available
from SOHO and STEREO-twin satellites were used to derive projection-free
geometrical characteristics of flaring loop(s) which are provided as an
input to the PH model along with a number of heating profiles varying
spatially across the loop and in time. Resulting temperature and density
profiles along the loop were convolved with the response matrix of GOES
X-ray monitors to derive respective fluxes and then compared with that
observed. The PH exercise which best-represented the GOES observations
during the flare was further used in mapping the spatial distribution
of emission along the flaring loop(s) as well as the evolution of
flaring plasma on the diagnostic diagram (DD; log T against log EM)
as determined from the EUV and X-ray channels. Moreover, a comparison
of differential emission measure distribution (DEM[T]) derived
from the PH model were compared with that obtained by applying the
Withbroe-Sylwester deconvolution algorithm on the combined observation
of STEREO, SphinX, SOXS and Fermi instruments. This investigation
provides an exhaustive comparison of spatial and temporal evolution
of thermal characteristics of flaring plasma as determined from the
HD modelling with that available from the EUV and X-ray measurements.
Title: Feasibility of a usage of small-sized p-terphenyl scintillators
with oriented crystalline axes in space measurements of high energy
charge radiation
Authors: Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw;
Siarkowski, Marek; Lazarev, Igor
Bibcode: 2018cosp...42E.915D
Altcode:
Detector head of the Background Particle Monitor (BPM) is a constituent
part of the solar soft X-ray spectrophotometer ChemiX for interplanetary
space mission "Interhelioprobe". The BPM measurements of particle fluxes
will assist to determine level of X-ray spectra contamination due to
high-energy ambient interplanetary particles. BPM's head comprises
organic scintillator, which is built on the base of p-terphenyl
single crystal, optically coupled with semiconductor multi pixel photon
counter - silicon photomultiplier (Si-PM). As far as lightweight organic
scintillators typically have moderate technical light yields as compared
with "massive" inorganic scintillators such as CsI(Tl), NaI(Tl), we have
studied the possibility obtaining highest luminescence intensity from
small-sized p-terphenyl single crystals for particle detection. In this
research we present results of laboratory measurements of dependence
of technical light yield for small-sized p-terphenyl detectors in
relation with the direction of their crystalline axes. The research
was performed for a crystal sample with dimensions that are very
close to geometric parameters of BPM's anti-coincidence detector. A
cubic sample of the scintillator with dimensions 6 x 6 x 6 mm ^{3}
has been manufactured with this purpose to match an active area
of Si-PM. We have measured its spectrometric characteristics in the
energy range from 482 __ 1048 keV along specific crystalline axes using
betha-particles from isotopes bismuth-207 and cesium-137. We demonstrate
that scintillation detector made from lightweight organic scintillator
and 57,600 pixel' Si-PM photomultiplier is capable to respond to low
energy gamma-quanta and electron fluxes in a wide energy range from
E = 32 keV up to E = 1048 keV on conditions when the temperature of
photodetector is constant. The greatest technical light yield of such
type scintillator is seen when light splashes propagates along axis
b of sample crystalline array. Taking into account small values of
effective charge and density of this type of organic single crystal
scintillator the probability for registration of bremsstrahlung in
space is almost negligible, that allow us to detect, to count and even
to register energy spectra of primary electrons, protons and other
nucleons in magnetosphere and interplanetary space with high efficiency.
Title: A Novel Soft X-ray Slitless Imaging Spectrograph for Unique
Diagnostics of Hot Coronal Plasma
Authors: Caspi, Amir; Shh, Albert Y.; Warren, Harry; Woods, Thomas
N.; Mason, James Paul; Steslicki, MArek; Gburek, Szymon; Sylwester,
Janusz; DeForest, Craig; Schwartz, Richard; Crowley, Geoff
Bibcode: 2018tess.conf41006C
Altcode:
Solar soft X-ray (SXR) observations from ∼0.2 to ∼3 keV
(∼4-60 Å), during both solar flares and quiescent times, provide
crucial diagnostics that are not available from observations at other
wavelengths. Specifically, SXRs reveal plasma temperature distributions,
as well as elemental abundances that probe plasma origins over a wide
range of temperatures. Spectrally- and temporally-resolved measurements
are essential for understanding the dynamics and evolution of these
energetic processes; spatially-resolved measurements are essential
for understanding energy transport. The NGSPM study calls out an X-ray
spectroscopic imager (T-10) as a high-priority instrument, in particular
with a spectral resolution of better than 100 eV for SXR emission
lines. We describe a novel approach for a spectro-spatial imager
- combining a pinhole camera with a X-ray transmission diffraction
grating - that can achieve the required combination of spectral and
angular resolutions at SXR energies. Such an instrument has already
been demonstrated as a protoype on a sounding-rocket flight and can be
proven thoroughly on a small satellite, specifically as part of the
instrument complement of the proposed CubeSat Imaging X-ray Solar
Spectrometer (CubIXSS) mission. CubIXSS will measure spectrally-
and spatially-resolved SXRs from ~1 to 60 Å (~0.2-10 keV) with ~0.25
Å and ~25 arcsec FWHM resolutions, respectively, from the quiescent
and flaring Sun from a 6U CubeSat platform in low-Earth orbit during
a nominal 1-year mission. Accordingly, CubIXSS is a pathfinder for
larger satellites with improved resolution (<0.1 Å, ~few arcsec)
and sensitivity, that could be integrated with focusing optics if
desired. Through these groundbreaking new measurements, CubIXSS and
future missions will improve our physical understanding of thermal
plasma processes and impulsive energy release in the solar corona,
from quiet Sun to solar flares.
Title: Nonequilibrium Processes in the Solar Corona, Transition
Region, Flares, and Solar Wind (Invited Review)
Authors: Dudík, Jaroslav; Dzifčáková, Elena; Meyer-Vernet, Nicole;
Del Zanna, Giulio; Young, Peter R.; Giunta, Alessandra; Sylwester,
Barbara; Sylwester, Janusz; Oka, Mitsuo; Mason, Helen E.; Vocks,
Christian; Matteini, Lorenzo; Krucker, Säm; Williams, David R.;
Mackovjak, Šimon
Bibcode: 2017SoPh..292..100D
Altcode: 2017arXiv170603396D
We review the presence and signatures of the non-equilibrium processes,
both non-Maxwellian distributions and non-equilibrium ionization, in
the solar transition region, corona, solar wind, and flares. Basic
properties of the non-Maxwellian distributions are described
together with their influence on the heat flux as well as on the
rates of individual collisional processes and the resulting optically
thin synthetic spectra. Constraints on the presence of high-energy
electrons from observations are reviewed, including positive detection
of non-Maxwellian distributions in the solar corona, transition
region, flares, and wind. Occurrence of non-equilibrium ionization
is reviewed as well, especially in connection to hydrodynamic and
generalized collisional-radiative modeling. Predicted spectroscopic
signatures of non-equilibrium ionization depending on the assumed
plasma conditions are summarized. Finally, we discuss the future
remote-sensing instrumentation that can be used for the detection of
these non-equilibrium phenomena in various spectral ranges.
Title: The CubeSat Imaging X-ray Solar Spectrometer (CubIXSS)
Mission Concept
Authors: Caspi, Amir; Shih, Albert Y.; Warren, Harry; DeForest,
Craig; Laurent, Glenn Thomas; Schwartz, Richard A.; Woods, Thomas
N.; Mason, James; Palo, Scott; Steslicki, Marek; Sylwester, Janusz;
Gburek, Szymon; Mrozek, Tomasz; Kowalinski, Miroslaw; Torre, Gabriele;
Crowley, Geoffrey; Schattenburg, Mark
Bibcode: 2017SPD....4830503C
Altcode:
Solar soft X-ray (SXR) observations provide important diagnostics of
plasma heating, during solar flares and quiescent times. Spectrally-
and temporally-resolved measurements are crucial for understanding
the dynamics, origins, and evolution of these energetic processes,
providing probes both into the temperature distributions and elemental
compositions of hot plasmas; spatially-resolved measurements are
critical for understanding energy transport and mass flow. A better
understanding of the thermal plasma improves our understanding of the
relationships between particle acceleration, plasma heating, and the
underlying release of magnetic energy during reconnection. We introduce
a new proposed small satellite mission, the CubeSat Imaging X-ray Solar
Spectrometer (CubIXSS), to measure spectrally- and spatially-resolved
SXRs from the quiescent and flaring Sun from a 6U CubeSat platform in
low-Earth orbit during a nominal 1-year mission. CubIXSS includes the
Amptek X123-FastSDD silicon drift detector, a low-noise, commercial
off-the-shelf (COTS) instrument enabling solar SXR spectroscopy from
~0.5 to ~30 keV with ~0.15 keV FWHM spectral resolution with low
power, mass, and volume requirements. Multiple detectors and tailored
apertures provide sensitivity to a wide range of solar conditions,
optimized for a launch during solar minimum. The precise spectra
from these instruments will provide detailed measurements of the
coronal temperature distribution and elemental abundances from the
quiet Sun to active regions and flares. CubIXSS also includes a
novel spectro-spatial imager -- the first ever solar imager on a
CubeSat -- utilizing a custom pinhole camera and Chandra-heritage
X-ray transmission diffraction grating to provide spatially- resolved,
full-Sun imaging spectroscopy from ~0.1 to ~10 keV, with ~25 arcsec and
~0.1 Å FWHM spatial and spectral resolutions, respectively. MOXSI’s
unique capabilities enable SXR spectroscopy and temperature diagnostics
of individual active regions and flares. Through its groundbreaking
new measurements, CubIXSS will improve our physical understanding of
thermal plasma processes and impulsive energy release in the solar
corona, from quiet Sun to solar flares.
Title: Flare Characteristics from X-ray Light Curves
Authors: Gryciuk, M.; Siarkowski, M.; Sylwester, J.; Gburek, S.;
Podgorski, P.; Kepa, A.; Sylwester, B.; Mrozek, T.
Bibcode: 2017SoPh..292...77G
Altcode:
A new methodology is given to determine basic parameters of flares from
their X-ray light curves. Algorithms are developed from the analysis
of small X-ray flares occurring during the deep solar minimum of 2009,
between Solar Cycles 23 and 24, observed by the Polish Solar Photometer
in X-rays (SphinX) on the Complex Orbital Observations Near-Earth
of Activity of the Sun-Photon (CORONAS-Photon) spacecraft. One is a
semi-automatic flare detection procedure that gives start, peak, and end
times for single ("elementary") flare events under the assumption that
the light curve is a simple convolution of a Gaussian and exponential
decay functions. More complex flares with multiple peaks can generally
be described by a sum of such elementary flares. Flare time profiles
in the two energy ranges of SphinX (1.16 - 1.51 keV, 1.51 - 15 keV)
are used to derive temperature and emission measure as a function
of time during each flare. The result is a comprehensive catalogue -
the SphinX Flare Catalogue - which contains 1600 flares or flare-like
events and is made available for general use. The methods described
here can be applied to observations made by Geosynchronous Operational
Environmental Satellites (GOES), the Reuven Ramaty High Energy Solar
Spectroscopic Imager (RHESSI) and other broad-band spectrometers.
Title: New Results from the Solar Maximum Mission/Bent Crystal
Spectrometer
Authors: Rapley, C. G.; Sylwester, J.; Phillips, K. J. H.
Bibcode: 2017SoPh..292...50R
Altcode: 2017arXiv170206893R
The Bent Crystal Spectrometer (BCS) onboard the NASA Solar Maximum
Mission was part of the X-ray Polychromator, which observed numerous
flares and bright active regions from February to November 1980, when
operation was suspended as a result of the failure of the spacecraft
fine-pointing system. Observations resumed following the Space Shuttle
SMM Repair Mission in April 1984 and continued until November 1989. BCS
spectra have been widely used in the past to obtain temperatures,
emission measures, and turbulent and bulk flows during flares, as well
as element abundances. Instrumental details including calibration
factors not previously published are given here, and the in-orbit
performance of the BCS is evaluated. Some significant changes during the
mission are described, and recommendations for future instrumentation
are made. Using improved estimates for the instrument parameters and
operational limits, it is now possible to obtain de-convolved calibrated
spectra that show finer detail than before, providing the means for
improved interpretation of the physics of the emitting plasmas. The
results indicate how historical archived data can be re-used to obtain
enhanced and new, scientifically valuable results.
Title: Diagnosing Coronal Heating Processes with Spectrally Resolved
Soft X-ray Measurements
Authors: Caspi, Amir; Shih, Albert Y.; Warren, Harry P.; Stęślicki,
Marek; Sylwester, Janusz
Bibcode: 2017arXiv170100619C
Altcode:
Decades of astrophysical observations have convincingly shown that
soft X-ray (SXR; ~0.1--10 keV) emission provides unique diagnostics
for the high temperature plasmas observed in solar flares and active
regions. SXR observations critical for constraining models of energy
release in these phenomena can be provided using instruments that
have already been flown on sounding rockets and CubeSats, including
miniaturized high-resolution photon-counting spectrometers and a
novel diffractive spectral imager. These instruments have relatively
low cost and high TRL, and would complement a wide range of mission
concepts. In this white paper, we detail the scientific background and
open questions motivating these instruments, the measurements required,
and the instruments themselves that will make groundbreaking progress
in answering these questions.
Title: The Sun and heliosphere explorer - the Interhelioprobe mission
Authors: Kuznetsov, V. D.; Zelenyi, L. M.; Zimovets, I. V.;
Anufreychik, K.; Bezrukikh, V.; Chulkov, I. V.; Konovalov, A. A.;
Kotova, G. A.; Kovrazhkin, R. A.; Moiseenko, D.; Petrukovich,
A. A.; Remizov, A.; Shestakov, A.; Skalsky, A.; Vaisberg, O. L.;
Verigin, M. I.; Zhuravlev, R. N.; Andreevskyi, S. E.; Dokukin, V. S.;
Fomichev, V. V.; Lebedev, N. I.; Obridko, V. N.; Polyanskyi, V. P.;
Styazhkin, V. A.; Rudenchik, E. A.; Sinelnikov, V. M.; Zhugzhda,
Yu. D.; Ryzhenko, A. P.; Ivanov, A. V.; Simonov, A. V.; Dobrovolskyi,
V. S.; Konstantinov, M. S.; Kuzin, S. V.; Bogachev, S. A.; Kholodilov,
A. A.; Kirichenko, A. S.; Lavrentiev, E. N.; Pertsov, A. A.; Reva,
A. A.; Shestov, S. V.; Ulyanov, A. S.; Panasyuk, M. I.; Iyudin,
A. F.; Svertilov, S. I.; Bogomolov, V. V.; Galkin, V. I.; Marjin,
B. V.; Morozov, O. V.; Osedlo, V. I.; Rubinshtein, I. A.; Scherbovsky,
B. Ya.; Tulupov, V. I.; Kotov, Yu. D.; Yurov, V. N.; Glyanenko, A. S.;
Kochemasov, A. V.; Lupar, E. E.; Rubtsov, I. V.; Trofimov, Yu. A.;
Tyshkevich, V. G.; Ulin, S. E.; Novikov, A. S.; Dmitrenko, V. V.;
Grachev, V. M.; Stekhanov, V. N.; Vlasik, K. F.; Uteshev, Z. M.;
Chernysheva, I. V.; Shustov, A. E.; Petrenko, D. V.; Aptekar, R. L.;
Dergachev, V. A.; Golenetskii, S. V.; Gribovskyi, K. S.; Frederiks,
D. D.; Kruglov, E. M.; Lazutkov, V. P.; Levedev, V. V.; Oleinik,
F. P.; Palshin, V. D.; Repin, A. I.; Savchenko, M. I.; Skorodumov,
D. V.; Svinkin, D. S.; Tsvetkova, A. S.; Ulanov, M. V.; Kozhevatov,
I. E.; Sylwester, J.; Siarkowski, M.; Bąkała, J.; Szaforz, Ż.;
Kowaliński, M.; Dudnik, O. V.; Lavraud, B.; Hruška, F.; Kolmasova,
I.; Santolik, O.; Šimůnek, J.; Truhlík, V.; Auster, H. -U.;
Hilchenbach, M.; Venedictov, Yu.; Berghofer, G.
Bibcode: 2016Ge&Ae..56..781K
Altcode:
The Interhelioprobe mission aims to investigate the inner heliosphere
and the Sun from close distances (up to 0.3 AU) and from out of the
ecliptic plane (up to 30°). In this paper we present the relevance of
the mission and its main scientific objectives, describe the scientific
payload, ballistic scenario and orbits of the spacecraft. Possibilities
of scientific cooperation with other solar and heliospheric space
missions are also mentioned.
Title: Design of the detector to observe the energetic charged
particles: a part of the solar X-ray spectrophotometer ChemiX onboard
Interhelio-Probe mission
Authors: Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw;
Bakala, Jaroslaw; Siarkowski, Marek; Evgen Kurbatov, mgr. .
Bibcode: 2016cosp...41E.506D
Altcode:
Cosmic particle radiation may damages payload's electronics, optics,
and sensors during of long-term scientific space mission especially the
interplanetary ones. That is why it's extremely important to prevent
failures of digital electronics, CCDs, semiconductor detectors at
the times of passing through regions of enhanced charged particle
fluxes. Well developed models of the Earth's radiation belts allow
to predict and to protect sensitive equipment against disastrous
influence of radiation due to energetic particle contained in the
Van Allen belts. In the contrary interplanetary probes flying far
away from our planet undergoes passages through clouds of plasma
and solar cosmic rays not predictable by present models. Especially
these concerns missions planned for non-ecliptic orbits. The practical
approach to protect sensitive modules may be to measure the in situ
particle fluxes with high time resolution and generation of alarm
flags, which will switch off sensitive units of particular scientific
equipment. The ChemiX (Chemical composition in X-rays) instrument is
being developed by the Solar Physics Division of Polish Space Research
Centre for the Interhelio-Probe interplanetary mission. Charged
particle bursts can badly affect the regular measurements of X-ray
spectra of solar origin. In order to detect presence of these enhanced
particle fluxes the Background Particle Monitor (BPM) was developed
constituting now a vital part of ChemiX. The BPM measurements of
particle fluxes will assist to determine level of X-ray spectra
contamination. Simultaneously BPM will measure the energy spectra of
ambient particles. We present overall structure, design, technical and a
scientific characteristic of BPM, particle sorts, and energy ranges to
be registered. We describe nearly autonomous modular structure of BPM
consisting of detector head, analogue and digital electronics modules,
and of module of secondary power supply [1-3]. Detector head consists
of three-layer detector stack: first two layers consist of silicon
detectors; the third one is based on the p-terphenyl scintillation
detector coupled with pixelated silicon photomultiplier. Coincidence
logic allows collecting systematic data on particle variety and their
energy with 1 and/or 10 s time resolutions. Digital processing unit is
constructed based on FPGA Actel ProAsic M1A3PE1500, and contains each
event processing logic, forms telemetry data and housekeeping frames,
communicates with ChemiX digital processing unit and executes received
telecommands. In order to increase the reliability and time resource
of the BPM its digital processing unit and secondary power supply
unit has backup sets. Switching between backup sets is commanded by
externally orders. The BPM is capable to sort out in situ abundances
of individual particle constituents from electrons up to oxygen
nuclei. 1. O.V.Dudnik, E.V.Kurbatov, V.O.Tarasov, L.A.Andryushenko,
I.L.Zajtsevsky, J.Sylwester, J.Bąkala, M.Kowaliński. Background
particle detector for the solar X-ray photometer ChemiX of space
mission "Interhelioprobe": an adjustment of breadboard model modules
(in Russian) / ISSN 1561-8889: Kosmichna Nauka I Tekhnologiya,
2015, Vol.21, No.2, P.3-14. 2. O.V.Dudnik, E.V.Kurbatov, J.Sylwester,
M.Siarkowski, P.Podgórski, M.Kowaliński. Background Particle Monitor
- a part of the solar X-ray spectrophotometer ChemiX: principles of
the operation and construction / in: Abstracts of 15th Ukrainian
conference on space research, Odesa, Ukraine, August 24-28, 2015,
P.80, doi:10.13140/RG.2.1.2284.2649. 3. O.V.Dudnik, E.V.Kurbatov,
M.Kowaliński, M.Siarkowski, P.Podgórski, J.Sylwester. Operational
features of Background Particle Monitor, a vital part of the solar
X-ray spectrophotometer ChemiX / in: Abstract book of the Conference
"Progress on EUV&X-ray spectroscopy and imaging II", Wroclaw,
Poland, November 17 19, 2015, P.9, doi:10.13140/RG.2.1.1184.3604.
Title: L-shell bifurcation of electron outer belt at the recovery
phase of geomagnetic storm as observed by STEP-F and SphinX
instruments onboard the CORONAS-Photon satellite
Authors: Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw;
Podgorski, Piotr
Bibcode: 2016cosp...41E.505D
Altcode:
Radiation belts and sporadically arising volumes comprising enhanced
charged particle fluxes in the Earth's magnetosphere are typically
studied by space-borne telescopes, semiconductor, scintillation,
gaseous and other types of detectors. Ambient and internal electron
bremsstrahlung in hard X-ray arises as a result of interaction of
precipitating particles with the atmosphere (balloon experiments)
and with the satellite's housings and instrument boxes (orbital
experiments). Theses emissions provide a number of new information
on the physics of radiation belts. The energies of primary electrons
and their spectra responsible for measured X-ray emissions remain
usually unknown. Combined measurements of particle fluxes, and their
bremsstrahlung by individual satellite instruments placed next to
each other provide insight to respective processes. The satellite
telescope of electrons and protons STEP-F and the solar X-ray
spectrophotometer SphinX were placed in close proximity to each other
aboard CORONAS-Photon, the low, circular and highly inclined orbit
satellite. Based on joint analysis of the data we detected new features
in the high energy particle distributions of the Earth's magnetosphere
during deep minimum of solar activity [1-3]. In this research the
bifurcation of Van Allen outer electron radiation belt during the
weak geomagnetic storm and during passage of interplanetary shock
are discussed. Outer belt bifurcation and growth of electron fluxes
in a wide energy range were recorded by both instruments during the
recovery phase of May 8, 2009 substorm. STEP-F recorded also barely
perceptible outer belt splitting on August 5, 2009, after arrival of
interplanetary shock to the Earth's magnetosphere bowshock. The STEP-F
and SphinX data are compared with the space weather indexes, and with
relativistic electron fluxes observed at geostationary orbit. We discuss
possible mechanism of the phenomena consisting in the splitting of
drift shells because of Earth's magnetic field asymmetry and/or fast
radial and pitch-angle particle diffusion from the outer edge of the
magnetosphere. 1. P.Podgórski, O.V.Dudnik, J.Sylwester, S.Gburek,
M.Kowaliński, M.Siarkowski, S.Plocieniak, J.Bąkala. Joint analysis
of SphinX and STEP-F instruments data on magnetospheric electron flux
dynamics at low Earth orbit / in: Abstracts of 39th Scientific Assembly
of COSPAR, Mysore, India, July 14-22, 2012, Panel PSW.3: "Space Weather
Data: Observations and Exploitation for Research and Applications",
STW-C-119 PSW.3-0028-12, P.112. 2. O.V.Dudnik, P.Podgórski,
J.Sylwester, S.Gburek, M.Kowalinski, M.Siarkowski, S.Plocieniak, and
J.Bakala. X-Ray Spectrophotometer SphinX and Particle Spectrometer
STEP-F of the Satellite Experiment CORONAS-PHOTON. Preliminary Results
of the Joint Data Analysis / Solar System Research, 2012, V.46, No.2,
P.160-169, doi:10.1134/S0038094612020025. 3. O.V.Dudnik, P.Podgórski,
J.Sylwester. New perspectives to study the splitting of drift shells at
the outer magnetosphere by using STEP-F and SphinX instruments on board
the CORONAS-Photon satellite / in: Abstract Book of the Conference
"Progress on EUV&X-ray spectroscopy and imaging II", Wroclaw,
Poland, November 17-19, 2015, P.8, doi:10.13140/RG.2.1.1872.4889.
Title: Thermal Characteristics and the Differential Emission Measure
Distribution During a B8.3 Flare on 2009 July 4
Authors: Awasthi, Arun Kumar; Sylwester, Barbara; Sylwester, Janusz;
Jain, Rajmal
Bibcode: 2016ApJ...823..126A
Altcode: 2016arXiv160401935A
We investigate the evolution of the differential emission measure
distribution (DEM[T]) in various phases of a B8.3 flare which occurred
on 2009 July 04. We analyze the soft X-ray (SXR) emission in the
1.6-8.0 keV range, recorded collectively by the Solar Photometer in
X-rays (SphinX; Polish) and the Solar X-ray Spectrometer (Indian)
instruments. We conduct a comparative investigation of the best-fit
DEM[T] distributions derived by employing various inversion schemes,
namely, single Gaussian, power-law functions and a Withbroe-Sylwester
(W-S) maximum likelihood algorithm. In addition, the SXR spectrum in
three different energy bands, that is, 1.6-5.0 keV (low), 5.0-8.0
keV (high), and 1.6-8.0 keV (combined), is analyzed to determine
the dependence of the best-fit DEM[T] distribution on the selection
of the energy interval. The evolution of the DEM[T] distribution,
derived using a W-S algorithm, reveals multi-thermal plasma during
the rise to the maximum phase of the flare, and isothermal plasma in
the post-maximum phase of the flare. The thermal energy content is
estimated by considering the flare plasma to be (1) isothermal and
(2) multi-thermal in nature. We find that the energy content during
the flare, estimated using the multi-thermal approach, is in good
agreement with that derived using the isothermal assumption, except
during the flare maximum. Furthermore, the (multi-) thermal energy
estimated while employing the low-energy band of the SXR spectrum
results in higher values than that derived from the combined energy
band. On the contrary, the analysis of the high-energy band of the
SXR spectrum leads to lower thermal energy than that estimated from
the combined energy band.
Title: ChemiX: a Bragg crystal spectrometer for the Interhelioprobe
interplanetary mission
Authors: Siarkowski, M.; Sylwester, J.; Bąkała, J.; Szaforz, Ż.;
Kowaliński, M.; Kordylewski, Z.; Płocieniak, S.; Podgórski, P.;
Sylwester, B.; Trzebiński, W.; Stȩślicki, M.; Phillips, K. J. H.;
Dudnik, O. V.; Kurbatov, E.; Kuznetsov, V. D.; Kuzin, S.; Zimovets,
I. V.
Bibcode: 2016ExA....41..327S
Altcode: 2016ExA...tmp....1S
Interhelioprobe (IHP), an analogue to the ESA Solar Orbiter, is the
prospective Russian space solar observatory intended for in-situ and
remote sensing investigations of the Sun and the inner heliosphere
from a heliocentric orbit with the perihelion of about 60 solar
radii. One of several instruments on board will be the Bragg crystal
spectrometer ChemiX which will measure X-ray spectra from solar corona
structures. Analysis of the spectra will allow the determination of
the elemental composition of plasma in hot coronal sources like flares
and active regions. ChemiX is under development at the Wrocław Solar
Physics Division of the Polish Academy of Sciences Space Research
Centre in collaboration with an international team (see the co-author
list). This paper gives an overview of the ChemiX scientific goals
and design preparatory to phase B of the instrument development.
Title: Solar X-rays from 0.3 a.u.: the ChemiX Bragg Spectrometer
on Interhelioprobe
Authors: Sylwester, Janusz; Siarkowski, Marek; Bąkała, Jarosław;
Szaforz, Żaneta; Kowaliński, Mirosław; Stęślicki, Marek;
Sylwester, Barbara; Kordylewski, Zbigniew; Dudnik, Oleksiy; Kuznetsov,
Vladimir D.; Polansky, Valery; Kuzin, Sergey; Phillips, Kenneth J. H.
Bibcode: 2016IAUS..320..442S
Altcode:
ChemiX is a Bragg crystal spectrometer that will fly on the two
Interhelioprobe spacecraft due for launch in 2025 and 2026. The
spacecraft perihelion will be only 0.3 a.u. and the orbit inclination
up to 30°, and so instruments on board will have a close view of
solar active regions and flares and regions near each solar pole. The
ChemiX X-ray spectrometer, built by a consortium of groups led by
the Space Research Centre, Polish Academy of Sciences, will fly
on each of the spacecraft, and observe X-ray spectra in the 1.5 -
9 Å range. Spectral lines in this range include resonance lines of
helium-like and hydrogen-like ions of elements such as Fe, Ca, Ar, S,
and Si, with less abundant elements such as K and Cl represented by
weaker lines which the high sensitivity of ChemiX should be able to
detect. The free-free and free-bound continua should also be detected
since instrumental background will be eliminated. Three of the seven
channels of ChemiX will be in a ``dopplerometer'' arrangement by
which spatial and spectral shifts present in flare impulsive stages
can be disentangled.
Title: High-temperature solar flare plasma behaviour from crystal
spectrometer observations
Authors: Sylwester, Barbara; Sylwester, Janusz; Phillips, Kenneth
J. H.; Kepa, Anna; Mrozek, Tomasz
Bibcode: 2016IAUS..320...80S
Altcode:
We present results of analysis of the spectra collected with Polish
instrument RESIK flown on CORONAS-F satellite. RESIK was the bent
crystal spectrometer, measuring spectra in the spectral range 3.3 -
6.1 Å with a high cadence during flares. The emission lines as well
as the continuum observed by RESIK are formed in hotter (T > 3 MK)
plasmas of active regions and flares. RESIK observed various types of
flares: from X-ray class B and C up to strongest flares of X-class,
for both, short and long duration events. The analysis of absolute and
relative spectral intensities of the lines and continuum observed for
33 events allowed for determining the plasma elemental composition with
subsequent detailed study of time changes of the temperature structure
of the sources described in terms of the differential emission measure
(DEM). As an example we present the typical DEM evolutionary patterns
for the C1.9 flare (SOL2002-12-26T08:35) and discuss its thermodynamics.
Title: Thermal characteristics of a B8.3 flare observed on July
04, 2009
Authors: Awasthi, Arun Kumar; Sylwester, Barbara; Sylwester, Janusz;
Jain, Rajmal
Bibcode: 2016IAUS..320..112A
Altcode: 2016arXiv160401926A
We explore the temporal evolution of flare plasma parameters including
temperature (T) - differential emission measure (DEM) relationship
by analyzing high spectral and temporal cadence of X-ray emission in
1.6-8.0 keV energy band, recorded by SphinX (Polish) and Solar X-ray
Spectrometer (SOXS; Indian) instruments, during a B8.3 flare which
occurred on July 04, 2009. SphinX records X-ray emission in 1.2-15.0
keV energy band with the temporal and spectral cadence as good as 6
μs and 0.4 keV, respectively. On the other hand, SOXS provides X-ray
observations in 4-25 keV energy band with the temporal and spectral
resolution of 3 s and 0.7 keV, respectively. We derive the thermal
plasma parameters during impulsive phase of the flare employing
well-established Withbroe-Sylwester DEM inversion algorithm.
Title: Soft X-ray polarimeter-spectrometer SOLPEX
Authors: Stȩślicki, Marek; Sylwester, Janusz; Płocieniak,
Stefan; Bakała, Jarosław; Szaforz, Żaneta; Ścisłowski, Daniel;
Kowaliński, Mirosław; Hernandez, Jose; Kuzin, Sergey; Shestov, Sergey
Bibcode: 2016IAUS..320..450S
Altcode:
We present an innovative soft X-ray polarimeter and spectrometer
SOLPEX. The instrument is to be mounted aboard the ISS within the
Russian science complex KORTES. The measurements to be made by SOLPEX
are expected to be of unprecedented quality in terms of sensitivity
to detect the soft-X-ray polarization of solar emission emanating from
active regions and flares in particular. Simultaneous measurements of
the polarization degree and the other characteristics (eg. evolution
of the spectra) constitute the last, rather unexplored area of solar
X-ray spectroscopy providing substantial diagnostic potential. Second
important science task to be addressed are the measurements of Doppler
shifts in selected X-ray spectral emission lines formed in hot flaring
sources. The novel-type Dopplerometer (flat Bragg crystal drum unit)
is planned to be a part of SOLPEX and will allow to measure line
Doppler shifts in absolute terms with unprecedented time resolution
(fraction of a second) during the impulsive flare phases. We shall
present some details of the SOLPEX instrument and discuss observing
sequences in a view of science objectives to be reached.
Title: Multitemperature analysis of solar flare observed on 2003
March 29
Authors: Kepa, Anna; Sylwester, Barbara; Sylwester, Janusz; Siarkowski,
Marek; Mrozek, Tomasz; Gryciuk, Magdalena
Bibcode: 2016IAUS..320...86K
Altcode:
We present results of multitemperature analysis of GOES C7.2 class
flare SOL2003-03-29T10:15. This event occurred close to the centre of
the solar disk and had two maxima in soft X-rays. We have performed
analysis of physical parameters characterizing evolution of conditions
in the flaring plasma. The temperature diagnostics have been carried
out using the differential emission measure (DEM) approach based on the
soft X-ray spectra collected by RESIK Bragg spectrometer. Analysis of
data obtained by RHESSI provided opportunity to estimate the volume
and thus calculating the density and thermal energy content of hot
flaring plasma.
Title: Solar flare soft X-ray spectra from Diogeness observations
Authors: Stȩślicki, Marek; Sylwester, Janusz; Sylwester, Barbara;
Szaforz, Żaneta; Kordylewski, Zbigniew; Płocieniak, Stefan;
Siarkowski, Marek; Phillips, Kenneth J. H.
Bibcode: 2016IAUS..320..109S
Altcode:
Diogeness was an uncollimated scanning flat crystal spectrometer
observing solar flare X-ray spectra in four narrow wavelength bands
in the vicinity of Ca xix, S xv and Si xiii He-like line `triplets'
around 3.18 Å, 5.04 Å and 6.65 Å. In two of the spectral channels,
emission lines around the Ca xix 3.178 Å resonance line were scanned
in opposite directions, being diffracted from precisely adjusted
identical Quartz crystals mounted on a common shaft in a so-called
Dopplerometer (tachometer) configuration. Observations of solar X-ray
spectra made by Diogeness provide a direct diagnostic information on
plasma characteristics during the impulsive flare energy release. We
present a sample of events which occurred during the Diogeness operation
time from August 16, 2001 to September 17, 2001.
Title: Model of flare lightcurve profile observed in soft X-rays
Authors: Gryciuk, Magdalena; Siarkowski, Marek; Gburek, Szymon;
Podgorski, Piotr; Sylwester, Janusz; Kepa, Anna; Mrozek, Tomasz
Bibcode: 2016IAUS..320...89G
Altcode:
We propose a new model for description of solar flare lightcurve profile
observed in soft X-rays. The method assumes that single-peaked `regular'
flares seen in lightcurves can be fitted with the elementary time
profile being a convolution of Gaussian and exponential functions. More
complex, multi-peaked flares can be decomposed as a sum of elementary
profiles. During flare lightcurve fitting process a linear background
is determined as well. In our study we allow the background shape
over the event to change linearly with time. Presented approach
originally was dedicated to the soft X-ray small flares recorded by
Polish spectrophotometer SphinX during the phase of very deep solar
minimum of activity, between 23 rd and 24 th
Solar Cycles. However, the method can and will be used to interpret the
lightcurves as obtained by the other soft X-ray broad-band spectrometers
at the time of both low and higher solar activity level. In the paper
we introduce the model and present examples of fits to SphinX and GOES
1-8 Å channel observations as well.
Title: X-ray Flare Spectra from the DIOGENESS Spectrometer and Its
Concept Applied to ChemiX on the Interhelioprobe Spacecraft
Authors: Sylwester, Janusz; Kordylewski, Zbigniew; Płocieniak,
Stefan; Siarkowski, Marek; Kowaliński, Mirosław; Nowak, Stanisław;
Trzebiński, Witold; Śtęślicki, Marek; Sylwester, Barbara;
Stańczyk, Eugeniusz; Zawerbny, Ryszard; Szaforz, Żaneta; Phillips,
Kenneth J. H.; Fárník, František; Stepanov, Anatolyi
Bibcode: 2015SoPh..290.3683S
Altcode: 2015SoPh..tmp....4S; 2014arXiv1411.0850S
The DIOGENESS X-ray crystal spectrometer on the CORONAS-F spacecraft
operated only for a single month (25 August to 17 September) in 2001,
but in its short lifetime obtained one hundred and forty high-resolution
spectra of eight solar flares with GOES importance ranging from C9 to
X5. The instrument included four scanning flat crystals with wavelength
ranges covering the regions of Si XIII (6.65 Å), S XV (5.04 Å), and Ca
XIX (3.18 Å) X-ray lines and associated dielectronic satellites. Two
crystals covering the Ca XIX lines were oriented in a "dopplerometer"
manner, i.e. such that spatial and spectral displacements, both of which
commonly occur in flares, can be separated. We describe the DIOGENESS
spectrometer and the spectra obtained during flares that include lines
not hitherto seen from spacecraft instruments. An instrument with
a very similar concept is currently being built for the two Russian
Interhelioprobe spacecraft that are scheduled for launch in 2020 and
2022 and will make a near-encounter (perihelion ∼ 0.3 AU) with the
Sun in its orbit. We outline the results that are likely to be obtained.
Title: SolpeX: the soft X-ray flare polarimeter-spectrometer for
the ISS
Authors: Sylwester, Janusz; Płocieniak, Stefan; Bakała,
Jarosław; Szaforz, Żaneta; Stȩślicki, Marek; Ścisłowski,
Daniel; Kowaliński, Mirosław; Podgórski, Piotr; Hernandez, Jose;
Shestov, Sergey
Bibcode: 2015IAUS..305..114S
Altcode:
We present the innovative soft X-ray spectro-polarimeter, SolpeX. This
instrument consists of three functionally independent blocks. They are
to be included into the Russian instrument KORTES, to be mounted onboard
the ISS. The three SolpeX units are: a simple pin-hole X-ray spectral
imager, a polarimeter, and a fast-rotating drum multiple-flat-crystal
Bragg spectrometer. Such a combination of measuring blocks will offer
a new opportunity to reliably measure possible X-ray polarization
and spectra of solar flares, in particular during the impulsive
phase. Polarized Bremsstrahlung and line emission due to the presence
of directed particle beams will be detected, and measurements of
the velocities of evaporated hot plasma will be made. In this paper
we discuss the details of the construction of the SolpeX units. The
delivery of KORTES with SolpeX to the ISS is expected to happen in
2017/2018.
Title: The Bragg solar x-ray spectrometer SolpeX
Authors: Ścisłowski, D.; Sylwester, J.; Steślicki, M.; Płocieniak,
S.; Bąkała, J.; Szaforz, Ż.; Kowaliński, M.; Podgórski, P.;
Trzebiński, W.; Hernandez, J.; Barylak, J.; Barylak, A.; Kuzin, Sergey
Bibcode: 2015SPIE.9604E..0SS
Altcode:
Detection of polarization and spectra measurement of X-ray solar
flare emission are indispensable in improving our understanding of
the processes releasing energy of these most energetic phenomena in
the solar system. We shall present some details of the construction
of SolpeX - an innovative Bragg soft X-ray flare polarimeter and
spectrometer. The instrument is a part of KORTES - Russian instrument
complex to be mounted aboard the science module to be attached to the
International Space Station (2017/2018). The SolpeX will be composed
of three individual measuring units: the soft X-ray polarimeter with
1-2% linear polarization detection threshold, a fast-rotating flat
crystal X-ray spectrometer with a very high time resolution (0.1 s)
and a simple pinhole soft X-ray imager-spectrometer with a moderate
spatial (~20 arcsec), spectral (0.5 keV) and high time resolution (0.1
s). Having a fast rotating unit to be served with power, telemetry and
"intelligence" poses a challenge for the designer. Some of the solutions
to this will be provided and described.
Title: The Bpd Energetic Particle Detector as Part of the Solar X-Ray
Photometer ChemiX for the "interhelioprobe" Interplanetary Mission
Authors: Dudnik, O. V.; Kurbatov, E. V.; Zajtsevsky, I. L.; Sylwester,
J.; Siarkowski, M.; Kowaliński, M.; Podgórski, P.
Bibcode: 2015RRPRA..20..247D
Altcode:
The Background Particle Detector (BPD) is an important block of the
Polish-Ukrainian X-ray spectrophotometer ChemiX under development for
the “Interhelioprobe” interplanetary mission. The BPD primary
objective is to detect incoming charged particle fluxes, measure
particle energy spectra and safeguard the instrument in case of
emergency. The present work describes the BPD laboratory prototype
and current results of adjustment and measurements of its important
characteristics, in particular the analog signal processing unit and the
source of secondary power supply unit. Laboratory benches designed for
controlling the parameters of analog module and for characterization
of small-sized organic and inorganic scintillation detectors of high
energy charged particles are presented. The functional block diagram
of the experimental model of digital signal processing line and
information data streaming line designed using ProASIC3E M1A3PE1500
FPGA are introduced and explained. The results of respective digital
modules’ tests performed by using experimental ModelISim Microsemi
ME 10.2c program simulator are also presented.
Title: Multitemperature analysis of solar flare observed on 2003
March 29
Authors: Kepa, Anna; Sylwester, Barbara; Sylwester, Janusz; Siarkowski,
Marek; Mrozek, Tomasz; Gryciuk, Magdalena
Bibcode: 2015IAUGA..2254863K
Altcode:
We present results of multitemperature analysis of GOES C7.2 class flare
observed on 2003 March 29. This event occurred close to the centre of
the solar disk (S12W14) at 10:11 UT and had two maxima in X-rays. We
have performed analysis of physical parameters characterizing evolution
of conditions in the flaring plasma. The temperature diagnostics
have been carried out using the differential emission measure (DEM)
approach based on the soft X-ray spectra collected by RESIK Bragg
spectrometer. Analysis of data obtained by RHESSI provided opportunity
for a detailed analysis of HXR emission with good energy and spatial
resolutions.
Title: Analysis of selected solar flares soft X-ray spectra from
Diogeness observations
Authors: Steslicki, Marek; Sylwester, Janusz; Sylwester, Barbara;
Szaforz, Zaneta Anna; Kordylewski, Zbigniew; Plocieniak, Stefan;
Siarkowski, Marek; Phillips, Kenneth J. H.
Bibcode: 2015IAUGA..2254871S
Altcode:
Diogeness was the uncollimated scanning flat crystal spectrometer
observing flare X-ray spectra in four narrow wavelength bands in
vicinity of Ca XIX, S xv and Si XIII He-like line 'triplets' around
3.18 Å, 5.04 Å and 6.65 Å. In the two spectral channels, the
same emission lines around Ca XIX 3.178 Å resonance are scanned in
opposite directions, being diffracted from precisely adjusted identical
Quartz crystals mounted on the common shaft in so-called Dopplerometer
(tachometer) configuration. The observations of the solar X-ray spectrum
made by Diogeness provides a direct diagnostic information on plasma
characteristics during the impulsive flare energy release. We present
results of analysis for selected events which occurred during the
Diogeness operation time from August 16, 2001 to September 17, 2001.
Title: The X-Ray Line Feature at 3.5 KeV in Galaxy Cluster Spectra
Authors: Phillips, K. J. H.; Sylwester, B.; Sylwester, J.
Bibcode: 2015ApJ...809...50P
Altcode: 2015arXiv150704619P
Recent work by Bulbul et al. and Boyarsky et al. has suggested that
a line feature at ∼3.5 keV in the X-ray spectra of galaxy clusters
and individual galaxies seen with XMM-Newton is due to the decay of
sterile neutrinos, a dark matter candidate. This identification has
been criticized by Jeltema & Profumo on the grounds that model
spectra suggest that atomic transitions in helium-like potassium (K
xviii) and chlorine (Cl xvi) are more likely to be the emitters. Here
it is pointed out that the K xviii lines have been observed in numerous
solar flare spectra at high spectral resolution with the RESIK crystal
spectrometer and also appear in Chandra HETG spectra of the coronally
active star σ Gem. In addition, the solar flare spectra at least
indicate a mean coronal potassium abundance, which is a factor between
9 and 11 higher than the solar photospheric abundance. This fact,
together with the low statistical quality of the XMM-Newton spectra,
completely account for the ∼3.5 keV feature and there is therefore
no need to invoke a sterile neutrino interpretation of the observed
line feature at ∼3.5 keV.
Title: High-temperature solar flare plasma behaviour from crystal
spectrometer observations
Authors: Sylwester, Barbara; Sylwester, Janusz; Phillips, Kenneth
J. H.; Kepa, Anna; Mrozek, Tomasz
Bibcode: 2015IAUGA..2254762S
Altcode:
We discuss an analysis of spectra obtained from the Polish RESIK
instrument flown on the CORONAS-F satellite. RESIK was a bent crystal
spectrometer operating in the 3.3—6.1 Å range at high spectral and
time resolution during flares over the 2002—2003 period, at the
peak of the last solar cycle. Unlike many previous spectrometers,
RESIK was accurately (20%) calibrated and crystal fluorescence was
either eliminated or reduced to a minimum. The emission lines and
continuum observed are formed at high temperatures (T > 3 MK) that
are commonly present in active regions and flares. The spectra were
observed during flares ranging in GOES importance from B and C up to
multiples of X and with durations that were short and impulsive up
to several hours. An analysis of absolute and relative intensities of
lines and continuum that we performed for 33 flare events allowed the
determination of the plasma composition (abundances of Si, S, Ar, K, and
even the low-abundance element Cl) as well as a detailed study of the
time evolution of the flare temperature structure from the differential
emission measure (DEM). We will present the typical DEM evolutionary
patterns of the flares seen and discuss their thermodynamics which
helps our understanding of flares.
Title: Statistical analysis of tiny SXR flares observed by SphinX
Authors: Gryciuk, Magdalena; Siarkowski, Marek; Sylwester, Janusz;
Kepa, Anna; Gburek, Szymon; Mrozek, Tomasz; Podgórski, Piotr
Bibcode: 2015IAUGA..2252465G
Altcode:
The Solar Photometer in X-rays (SphinX) was designed to observe soft
X-ray solar emission in the energy range between ~1 keV and 15 keV
with the resolution better than 0.5 keV. The instrument operated from
February until November 2009 aboard CORONAS-Photon satellite, during
the phase of exceptionally low minimum of solar activity. Here we use
SphinX data for analysis of micro-flares and brightenings. Despite a
very low activity more than a thousand small X-ray events have been
recognized by semi-automatic inspection of SphinX light curves. A
catalogue of temporal and physical characteristics of these events
is shown and discussed and results of the statistical analysis of the
catalogue data are presented.
Title: Soft X-ray polarimeter-spectrometer SOLPEX
Authors: Steslicki, Marek; Sylwester, Janusz; Plocieniak, Stefan;
Bakala, Jaroslaw; Szaforz, Zaneta Anna; Scislowski, Daniel; Kowalinski,
Miroslaw; Hernandez, Jose; Vadimovich Kuzin, Sergey; Shestov, Sergey
Bibcode: 2015IAUGA..2254896S
Altcode:
We present an innovative soft X-ray polarimeter and spectrometer
SOLPEX. The instrument will be mounted aboard the ISS within the
Russian science complex KORTES. The measurements to be made by SOLPEX
are expected to be of unprecedented quality in terms of sensitivity to
detect the soft-X- ray polarization of solar emission emanating from
active regions and flares in particular. Simultaneous measurements of
the polarization degree and the other characteristics (eg. evolution
of the spectra) constitute the last, rather unexplored area of solar
X-ray spectroscopy providing substantial diagnostic potential. Second
important science task to be addressed are the measurements of Doppler
shifts in selected X-ray spectral emission lines formed in hot flaring
sources. The novel-type Dopplerometer (flat Bragg crystal drum unit)
is planned to be a part of SOLPEX and will allow to measure line
Doppler shifts in absolute terms with unprecedented time resolution
(fraction of a second) during the impulsive flare phases. We shall
present some details of the SolpeX instrument and discuss observing
sequences in a view of science objectives to be reached.
Title: X-ray spectra and analysis tools to be used in interpretation
of ChemiX Bragg spectrometer under construction for the
Interhelioprobe
Authors: Sylwester, Janusz; Siarkowski, Marek; Bakala, Jaroslaw;
Szaforz, Zaneta Anna; Kowalinski, Miroslaw; Steslicki, Marek;
Sylwester, Barbara; Volodymyrovich Dudnik, Oleksiy; Dmitrievich
Kuznetsov, Vladimir; Vadimovich Kuzin, Sergey; Phillips, Kenneth J. H.
Bibcode: 2015IAUGA..2254649S
Altcode:
ChemiX (CHEMical composition In X-rays) is a next-generation bent
crystal spectrometer designed for detailed fast-cadence measurements of
the soft X-ray spectra of solar sources in the spectral range 1.3 -
9 Angstroms instantaneously at all wavelengths. The instrument will
be placed on each of the two Russian interplanetary Interhelioprobe
missions (Solar Orbiter orbit), to be launched in 2020 and
2022. Phase B of the instrument construction is to be completed
soon.I shall describe the instrument in some detail (pin-hole
imager, background particle detector, four spectral atlas channels,
three ``Dopplerometer'' sections) focusing on the spectra to be
measured (and synthesized) for various types of solar X-ray sources
(flares with various characteristics, non-flaring active regions,
and the quiet corona). The likely observing modes to be used will
be discussed, covering various phases of the mission. Some example
spectral analysis tools will also be illustrated, allowing the study
of source characteristics including plasma composition, differential
emission measure, turbulent and directed bulk plasma motions, thermal
energy content etc. The sensitivity of the spectrometer to plasma
non-equilibrium effects will also be indicated.
Title: Thermal characteristics of multi-wavelength emission during
a B8.3 flare occurred on July 04, 2009
Authors: Awasthi, Arun Kumar; Sylwester, Barbara; Sylwester, Janusz;
Jain, Rajmal
Bibcode: 2015IAUGA..2254894A
Altcode:
We explore the temporal evolution of flare plasma parameters including
temperature (T) - differential emission measure (DEM) relationship
by analyzing high spectral and temporal cadence X-ray emission in
1.2-20 keV energy band, recorded by SphinX (Polish) and Solar X-ray
Spectrometer (SOXS; Indian) instruments, during a B8.3 flare which
occurred on July 04, 2009. SphinX records X-ray emission in 1.2-15 keV
energy band with the temporal and spectral cadence as good as 6µs
and 0.4 keV, respectively. On the other hand, SOXS provides X-ray
observations in 4-25 keV energy band with the temporal and spectral
resolution of 3s and 0.7 keV, respectively. In addition, we integrate
co-temporal EUV line emission in 171, 194 and 284 angstrom obtained
from STEREO mission in order to explore low-temperature response to the
flare emission. In order to fit observed evolution of multi-wavelength
emission during the flare, we incorporate multi-Gaussian and
well-established Withbroe - Sylwester maximum likelihood DEM inversion
algorithms. Thermal energetics are also estimated using geometrically
corrected flaring loop structure obtained through EUV images of the
active region from STEREO twin satellites. In addition, we also study
the trigger and energy release scenario of this low-intensity class
flare in terms of magnetic field as well as multi-wavelength emission.
Title: Resik Solar X-Ray Flare Element Abundances on a Non-isothermal
Assumption
Authors: Sylwester, B.; Phillips, K. J. H.; Sylwester, J.; Kępa, A.
Bibcode: 2015ApJ...805...49S
Altcode: 2015arXiv150300979S
Solar X-ray spectra from the REntgenovsky Spektrometr s Izognutymi
Kristalami (RESIK) crystal spectrometer on the CORONAS-F spacecraft
(spectral range 3.3-6.1 Å) are analyzed for 33 flares using a
method to derive abundances of Si, S, Ar, and K, emission lines
of which feature prominently in the spectra. For each spectrum,
the method first optimizes element abundances and then derives the
differential emission measure as a function of temperature based on
a procedure given by Sylwester et al. and Withbroe. This contrasts
with our previous analyses of RESIK spectra in which an isothermal
assumption was used. The revised abundances (on a logarithmic scale with
A(H)=12) averaged for all the flares in the analysis are A(Si)=7.53+/-
0.08 (previously 7.89 ± 0.13), A(S)=6.91+/- 0.07 (7.16 ± 0.17),
A(Ar)=6.47+/- 0.08 (6.45 ± 0.07), and A(K)=5.73+/- 0.19 (5.86 ±
0.20), with little evidence for time variations of abundances within
the evolution of each flare. Our previous estimates of the Ar and K
flare abundances are thus confirmed by this analysis, but those for
Si and S are reduced. This suggests that the flare abundances of Si
and Ar are very close to the photospheric abundance or solar proxies,
while S is significantly less than photospheric and the K abundance is
much higher than photospheric. These estimates differ to some extent
from those in which a single enhancement factor applies to elements
with first ionization potential less than 10 eV.
Title: Solar activity during the deep minimum of 2009
Authors: Sylwester, Janusz; Siarkowski, Marek; Gburek, Szymon; Gryciuk,
Magdalena; Kepa, Anna; Kowaliński, Mirosław; Mrozek, Tomek; Phillips,
Kenneth J. H.; Podgórski, Piotr; Sylwester, Barbara
Bibcode: 2014pas..conf...82S
Altcode:
We discuss the character of the unusually deep solar activity minimum
of 2009 between Solar Cycles 23 and 24. Levels of solar activity in
various parts of the solar atmosphere -- photosphere, chromosphere,
transition region, and corona -- were observed to be at their lowest
for a century. The soft X-ray emission from the corona (hot outer part
of the Sun's atmosphere) was measured throughout most of 2009 with the
Polish-built SphinX spectrophotometer. Unlike other X-ray monitoring
spacecraft, this sensitive spacecraft-borne instrument was able to
continue measurements throughout this extended period of low activity.
Title: Solar Orbiter spacecraft instrument interface simulator and
its applications for the STIX telescope tests
Authors: Ścisłowski, D.; Kowaliński, M.; Podgórski, P.; Sylwester,
J.; Orleański, P.; Mrozek, T.; Steślicki, M.; Barylak, J.; Barylak,
A.; Skup, K. R.; Cichocki, A.; Ber, K.; Juchnikowski, G.
Bibcode: 2014SPIE.9290E..38S
Altcode:
Solar Orbiter mission of European Space Agency, scheduled for launch
in 2017, is designed to explore the Sun and the inner heliosphere. Its
close, never achieved before by any other spacecraft, approach to the
Sun as well as ten remote-sensing and in-situ on board instruments will
allow obtaining unique solar science data. The Spectrometer Telescope
for Imaging X-rays (STIX) is one of them. Its measurements of solar
thermal and non-thermal hard X-ray emissions from ~4 to 150 keV will
play an important role to achieve mission's major science goals. The
Spacecraft Instrument Interface Simulator (SIIS) is specified as a
part of Electrical Ground Support Equipment with the aim to provide a
tool for power interface and telemetry/telecommand electrical and data
protocol validation during the delivery phase of STIX instrument for
spacecraft integration. It is designed to be used during the instrument
development and test phases of onboard algorithms, too. Brief overview
of SIIS use and performance for these purposes is given in this work.
Title: Geant4 simulations of detector response matrix for Caliste-SO
Authors: Barylak, J.; Podgórski, P.; Mrozek, T.; Barylak, A.;
Steślicki, M.; Sylwester, J.; Ścisłowski, D.
Bibcode: 2014SPIE.9290E..37B
Altcode:
The paper presents a method for determining the Detector Response Matrix
(DRM) using Monte Carlo simulations. For this purpose Geant4 package
was used which enables simulations of the interaction of particles
with matter. The DRM has been calculated for cadmium telluride sensor
of Caliste-SO detector, which will be used in the Solar Orbiter/STIX
instrument. Solar Orbiter is the M-class mission of the new ESA's
program Cosmic Vision 2015-2025. It is to be launched in July 2017. STIX
will provide imaging spectroscopy of solar hard X-ray emissions from
4 keV to 150 keV using a Fourier-imaging technique. Long operation
of detectors under space condition raises a need for development
of dedicated tools for analysis of behaviour of the detectors in
changing/harsh radiation environment and its impact on detector
quantum efficiency due to aging effects. Obtained results exhibit a
high usefulness of Geant4 package in this kind of analysis.
Title: Solar Flare Composition and Thermodynamics from RESIK X-Ray
Spectra
Authors: Sylwester, B.; Sylwester, J.; Phillips, K. J. H.; Kępa,
A.; Mrozek, T.
Bibcode: 2014ApJ...787..122S
Altcode: 2014arXiv1404.5775S
Previous estimates of the solar flare abundances of Si, S, Cl, Ar,
and K from the RESIK X-ray crystal spectrometer on board the CORONAS-F
spacecraft were made on the assumption of isothermal X-ray emission. We
investigate the effect on these estimates by relaxing this assumption
and instead determining the differential emission measure (DEM) or
thermal structure of the emitting plasma by re-analyzing RESIK data
for a GOES class M1.0 flare on 2002 November 14 (SOL2002-11-14T22:26)
for which there was good data coverage. The analysis method uses a
maximum-likelihood (Withbroe-Sylwester) routine for evaluating the
DEM. In a first step, called here AbuOpt, an optimized set of abundances
of Si, S, Ar, and K is found that is consistent with the observed
spectra. With these abundances, the DEM evolution during the flare
is found. The abundance optimization leads to revised abundances of
silicon and sulfur in the flare plasma: A(S) = 6.94 ± 0.06 and A(Si)
= 7.56 ± 0.08 (on a logarithmic scale with A(H) = 12). Previously
determined abundances of Ar, K, and Cl from an isothermal assumption
are still the preferred values. During the flare's maximum phase,
the X-ray-emitting plasma has a basically two-temperature structure,
with the cooler plasma with approximately constant temperature (3-6 MK)
and a hotter plasma with temperature 16-21 MK. Using imaging data from
the RHESSI hard X-ray spacecraft, the emission volume of the hot plasma
is deduced from which lower limits of the electron density Ne
and the thermal content of the plasma are given.
Title: Soft X-ray spectra of strong flares seen by Bragg flat crystal
spectrometer aboard Coronas-F
Authors: Sylwester, Barbara; Sylwester, Janusz; Farnik, Frantisek;
Siarkowski, Marek; Kordylewski, Zbigniew; Plocieniak, Stefan; Phillips,
Kenneth; Steslicki, Marek
Bibcode: 2014cosp...40E3257S
Altcode:
The uncollimated flat crystal spectrometer Diogeness was one of the
instruments observing the high-temperature plasma in 2001, around
the time of the maximum of Solar Cycle 23, from the payload of the
CORONAS-F satellite. This Polish-built scanning spectrometer measured
spectra with very high spectral resolution in three selected bands in
the vicinity of He-like triplets of Ca XIX, S XV and Si XIII, around
3.18 Å, 5.04 Å and 6.65 Å respectively. During its operation, a few
thousand spectral scans were performed and unique spectral sequences
obtained for a number of strong flares. Tens of lines are seen on the
spectra, some of them for Mg, Ar and Ca ions identified for the first
time. The time-evolution of spectral line profiles and intensities
will be presented and discussed for selected events. Reduced line
intensities will be interpreted in terms of differential emission
measure distributions.
Title: Analysis of selected microflares observed by SphinX over the
last minimum of solar activity
Authors: Siarkowski, Marek; Sylwester, Janusz; Sylwester, Barbara;
Gryciuk, Magdalena
Bibcode: 2014cosp...40E3068S
Altcode:
The Solar Photometer in X-rays (SphinX) was designed to observe
soft X-ray solar emission in the energy range between 1 keV and 15
keV with the resolution better than 0.5 keV. The instrument operated
from February until November 2009 aboard CORONAS-Photon satellite,
during the phase of exceptionally low minimum of solar activity. Here
we use SphinX data for analysis of selected microflare-class events. We
selected events of unusual lightcurves or location. Our study involves
determination of temporal characteristics (times of start, maximum
and end of flares) and analysis of physical conditions in flaring
plasma (temperature, emission measure). Dedicated method has been
used in order to remove emission not related to flare. Supplementary
information about morphology and evolution of investigated events has
been derived from the analysis of XRT/Hinode and SECCHI /STEREO images.
Title: ChemiX: a new generation bent crystal spectrometer for
Interhelioprobe mission to the Sun
Authors: Sylwester, Janusz; Zimovets, Ivan; Kowalinski, Miroslaw;
Bakala, Jaroslaw; Siarkowski, Marek; Trzebinski, Witold; Kuznetsov,
Vladimir; Szaforz, Zaneta
Bibcode: 2014cosp...40E3258S
Altcode:
Interhelioprobe (IHP) is the Russian interplanetary mission aimed
at multi-wavelength observations of solar plasmas at short distances
(up to 60RS) an analog to Solar Orbiter. The two IHP probes will each
carry several instruments for remote and in-situ observations. Among
the instruments, an advanced Bragg spectrometer CHEMIX is to be placed
for determinations of plasma composition of flaring and AR plasmas. I
shall describe the instrument concept and present its characteristics
and capabilities as they stand at present, close to the end of phase
B design.
Title: Chromospheric dynamics from RHESSI and RESIK data.
Authors: Mrozek, Tomasz; Sylwester, Janusz; Sylwester, Barbara;
Gburek, Szymon; Siarkowski, Marek; Kolomanski, Sylwester; Gryciuk,
Magdalena; Kepa, Anna; Szaforz, Zaneta; Steslicki, Marek
Bibcode: 2014cosp...40E2191M
Altcode:
We used RHESSI and RESIK observations of solar flares with clearly
seen double foot points morphology. RESIK spectra were obtained for
individual flare phases and used for estimation of the time evolution
of thermodynamical characteristics of flare loop-top source. The
analysis of HXR foot point sources, seen by RHESSI in narrow energy
bands, enabled us to trace changes of their altitude. The changes
are connected with the energy carried by non-thermal electrons which
penetrate deeper into solar atmosphere when of higher energies. Study
of time-dependent pattern of locations allowed us to trace changes of
the plasma density within very small volumes where the non-thermal
electrons deposit their energy. The relation between energy and
altitude of the HXR foot point sources provides unique opportunity to
study real plasma dynamics (the moving mass content may be estimated),
not only kinematics. It was found that the estimated mass that flows
during chromospheric evaporation is comparable to the additional mass
that supplies the loop top source. The analysis of plasma velocity
was used for calculation of full energy balance of analysed flares
and for the comparison with results of hydrodynamical flare modeling.
Title: SphinX catalogue of small flares and brightenings
Authors: Gryciuk, Magdalena; Sylwester, Janusz; Gburek, Szymon;
Siarkowski, Marek; Mrozek, Tomasz; Kepa, Anna
Bibcode: 2014cosp...40E1086G
Altcode:
The Solar Photometer in X-rays (SphinX) was designed to measure
soft X-ray solar emission in the energy range between 1 keV and 15
keV. The instrument operated from February until November 2009 aboard
CORONAS-Photon satellite, during the phase of extraordinary low minimum
of solar activity. Thanks to its very high sensitivity SphinX was able
to record large number of tiny flares and brightenings. A catalogue
of events observed by SphinX will be presented. Results of statistical
analysis of events’ characteristics will be discussed.
Title: Observations of Doppler Shifts of X-Ray Lines in Solar Flare
Spectra Based on DIOGENESS Spectrometer Data
Authors: Kordylewski, Z.; Sylwester, J.; Sylwester, B.; Siarkowski,
M.; Płocieniak, S.; Kȩpa, A.; Kowaliński, M.; Trzebiński, W.;
Farnik, F.
Bibcode: 2014ASSL..400..149K
Altcode:
The idea of measurement of X-ray lines Doppler shifts in spectra of
the Sun, applied in DIOGENESS spectrometer, was previously developed
and verified in rocket experiment with RDR X-ray Dopplerometer
(Vertical-11 Rocket, 1981). Upon the obtained results two X-ray
DIOGENESS spectrometers have been manufactured; the first one was
operated aboard the CORONAS-I satellite (launch in 1994), while the
second was operated aboard the CORONAS-F.
Title: Investigations of Physical Processes in Solar Flare Plasma
on the Basis of RESIK Spectrometer Observations
Authors: Kordylewski, Z.; Sylwester, J.; Sylwester, B.; Kȩpa, A.;
Kowaliński, M.; Trzebiński, W.
Bibcode: 2014ASSL..400..157K
Altcode:
Simultaneous registration of spectra of quickly varying sources may
be obtained through the use of curved fixed crystals instead of the
scanning flat crystals spectrometer. Illuminating such a curved crystal
with parallel X-ray beam allows to obtain, after the reflection, the
whole spectrum covering certain wavelengths range, as the incidence
angle at curved crystal surface represents a monotonous function of
incidence point position measured along the crystal. The RESIK bent
crystal spectrometer was developed in Poland with the help from experts
of Naval Research Laboratory (USA), Rutherford Appleton Laboratory (UK),
and Mullard Space Science Laboratory (MSSL, UK). The development work
was also supported by scientists of Pushkov Institute of Terrestrial
Magnetism, Ionosphere and Radio Waves Propagation of the Russian
Academy of Sciences. Unique RESIK spectra and the results obtained
are presented and discussed.
Title: Common observations of solar X-rays from SPHINX/CORONAS-PHOTON
and XRS/MESSENGER
Authors: Kepa, Anna; Sylwester, Janusz; Sylwester, Barbara; Siarkowski,
Marek; Mrozek, Tomasz; Gryciuk, Magdalena; Phillips, Kenneth
Bibcode: 2014cosp...40E1451K
Altcode:
SphinX was a soft X-ray spectrophotometer constructed in the Space
Research Centre of Polish Academy of Sciences. The instrument was
launched on 30 January 2009 aboard CORONAS-PHOTON satellite as a
part of TESIS instrument package. SphinX measured total solar X-ray
flux in the energy range from 1 to 15 keV during the period of very
low solar activity from 20 February to 29 November 2009. For these
times the solar detector (X-ray Spectrometer - XRS) onboard MESSENGER
also observed the solar X-rays from a different vantage point. XRS
measured the radiation in similar energy range. We present results
of the comparison of observations from both instruments and show the
preliminary results of physical analysis of spectra for selected flares.
Title: Anomalous intensities of lines observed in RESIK soft X-ray
flare spectra
Authors: Sylwester, Barbara; Sylwester, Janusz; Mrozek, Tomasz; Kepa,
Anna; Phillips, Kenneth
Bibcode: 2014cosp...40E3256S
Altcode:
RESIK was a high-resolution solar X-ray Bragg spectrometer, the most
recent ever to be launched, being operational from 2001 to 2003. Its
nominal wavelength coverage, 3.3 Å - 6.1 Å, has considerable
diagnostic potential. RESIK observed numerous flares as well as
non-flaring active regions. During flares, the data gathering intervals
were as short as 2 s. Analysis of the data continues to the present
time; at the time of writing, data for more than 50 flares have been
reduced to science grade (level 2). The spectra include spectral
lines formed by H- and He-like ions of various elements as well as
continuum. The lines and continua are formed by hot coronal plasma
corresponding to temperatures T>2 MK if interpreted thermally. This
makes RESIK spectra uniquely suitable for investigations of the
physical conditions of the hotter plasma component of flares and active
regions. Many spectra were taken during the rise phase of flares. For
some events, anomalous line intensity ratios are evident, possibly
reflecting the presence of non-equilibrium conditions in flaring
plasma -- the observed intensity ratios are not easily explained by
isothermal or multi-thermal assumptions. In our presentation, we will
show examples of such observations and give possible interpretations.
Title: Flat crystal Bragg observations of the X-ray spectra during
impulsive phases of solar flares
Authors: Steslicki, Marek; Sylwester, Janusz; Farnik, Frantisek;
Sylwester, Barbara; Gburek, Szymon; Mrozek, Tomasz; Kordylewski,
Zbigniew; Plocieniak, Stefan; Trzebinski, Witold; Szaforz, Zaneta
Bibcode: 2014cosp...40E3203S
Altcode:
Diogeness is the uncollimated scanning flat crystal spectrometer
observing high-resolution flare X-ray spectra in four narrow wavelength
bands in the vicinity of Ca XIX, S xv and Si XIII He-like line
'triplets' around 3.18 Å, 5.04 Å and 6.65 Å. For? two spectral
channels, the same emission lines around Ca XIX 3.178 Å triplet
are scanned in opposite directions, being diffracted from precisely
adjusted identical Quartz crystals mounted on the common shaft in
so-called Dopplerometer configuration. The observations of the solar
X-ray spectra made by Diogeness during rising phases provide a direct
diagnostic of the impulsive energy release of the flare. We present
results of analysis for of a several events occurred between August 16,
2001 and September 17, 2001.
Title: Erratum: "Stellar Coronae, Solar Flares: A Detailed Comparison
of σ Gem, HR 1099, and the Sun in High-resolution X-Rays" (2013, ApJ, 768, 135)
Authors: Huenemoerder, David P.; Phillips, Kenneth J. H.; Sylwester,
Janusz; Sylwester, Barbara
Bibcode: 2013ApJ...776..139H
Altcode:
No abstract at ADS
Title: Comparison of solar activity during last two minima on turn
of Activity Cycles 22/23 and 23/24
Authors: Gryciuk, Magdalena; Gburek, Szymon; Siarkowski, Marek;
Podgorski, Piotr; Sylwester, Janusz; Farnik, Frantisek
Bibcode: 2013IAUS..294...65G
Altcode:
The subject of our work is the review and comparison of solar
activity during the last two solar minima that occurred between
recent activity cycles. We use the soft X-ray global solar corona
observations covering the two nine-months long time intervals in
1997/98 and 2009. Data from RF15-I multichannel photometer are used
for the penultimate minimum. For the last unusually deep and prolonged
solar activity minimum in 2009 the data from SphinX spectrophotometer
are used. Comparison of measurements from both minima takes place in
the overlapping energy range 2-15 keV. We focus on the active region
formation, evolution and flaring productivity during respective minima.
Title: Solar flares observed simultaneously with SphinX, GOES
and RHESSI
Authors: Mrozek, Tomasz; Gburek, Szymon; Siarkowski, Marek; Sylwester,
Barbara; Sylwester, Janusz; Kępa, Anna; Gryciuk, Magdalena
Bibcode: 2013IAUS..294..571M
Altcode:
In February 2009, during recent deepest solar minimum, Polish Solar
Photometer in X-rays (SphinX) begun observations of the Sun in the
energy range of 1.2-15 keV. SphinX was almost 100 times more sensitive
than GOES X-ray Sensors. The silicon PIN diode detectors used in the
experiment were carefully calibrated on the ground using Synchrotron
Radiation Source BESSY II. The SphinX energy range overlaps with
the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) energy
range. The instrument provided us with observations of hundreds of
very small flares and X-ray brightenings. We have chosen a group of
solar flares observed simultaneously with GOES, SphinX and RHESSI and
performed spectroscopic analysis of observations wherever possible. The
analysis of thermal part of the spectra showed that SphinX is a very
sensitive complementary observatory for RHESSI and GOES.
Title: Stellar Coronae, Solar Flares: A Detailed Comparison of σ GEM,
HR 1099, and the Sun in High-resolution X-Rays
Authors: Huenemoerder, David P.; Phillips, Kenneth J. H.; Sylwester,
Janusz; Sylwester, Barbara
Bibcode: 2013ApJ...768..135H
Altcode: 2013arXiv1304.0408H
The Chandra High Energy Transmission Grating Spectrometer (HETG) spectra
of the coronally active binary stars σ Gem and HR 1099 are among the
highest fluence observations for such systems taken at high spectral
resolution in X-rays with this instrument. This allows us to compare
their properties in detail to solar flare spectra obtained with the
Russian CORONAS-F spacecraft's RESIK instrument at similar resolution in
an overlapping bandpass. Here we emphasize the detailed comparisons of
the 3.3-6.1\,{\mathring{\rm{A}}} region (including emission from highly
ionized S, Si, Ar, and K) from solar flare spectra to the corresponding
σ Gem and HR 1099 spectra. We also model the larger wavelength range
of the HETG, from 1.7 to 25\,{\mathring{\rm{A}}}—having emission
lines from Fe, Ca, Ar, Si, Al, Mg, Ne, O, and N—to determine coronal
temperatures and abundances. σ Gem is a single-lined coronally
active long-period binary which has a very hot corona. HR 1099 is a
similar, but shorter period, double-lined system. With very deep HETG
exposures we can even study emission from some of the weaker species,
such as K, Na, and Al, which are important since they have the lowest
first ionization potentials, a parameter well known to be correlated
with elemental fractionation in the solar corona. The solar flare
temperatures reach ≈20 MK, comparable to the σ Gem and HR 1099
coronae. During the Chandra exposures, σ Gem was slowly decaying from a
flare and its spectrum is well characterized by a collisional ionization
equilibrium plasma with a broad temperature distribution ranging from
2 to 60 MK, peaking near 25 MK, but with substantial emission from 50
MK plasma. We have detected K XVIII and Na XI emission which allow us
to set limits on their abundances. HR 1099 was also quite variable in
X-rays, also in a flare state, but had no detectable K XVIII. These
measurements provide new comparisons of solar and stellar coronal
abundances, especially at the lowest first ionization potential (FIP)
values. The low FIP elements do not show enhancement in the stellar
coronae as they do in the Sun, except perhaps for K in σ Gem. While
σ Gem and HR 1099 differ in their emission measure distributions,
they have very similar elemental abundances.
Title: SphinX: The Solar Photometer in X-Rays
Authors: Gburek, Szymon; Sylwester, Janusz; Kowalinski, Miroslaw;
Bakala, Jaroslaw; Kordylewski, Zbigniew; Podgorski, Piotr; Plocieniak,
Stefan; Siarkowski, Marek; Sylwester, Barbara; Trzebinski, Witold;
Kuzin, Sergey V.; Pertsov, Andrey A.; Kotov, Yurij D.; Farnik,
Frantisek; Reale, Fabio; Phillips, Kenneth J. H.
Bibcode: 2013SoPh..283..631G
Altcode: 2012SoPh..tmp..326G
Solar Photometer in X-rays (SphinX) was a spectrophotometer developed to
observe the Sun in soft X-rays. The instrument observed in the energy
range ≈ 1 - 15 keV with resolution ≈ 0.4 keV. SphinX was flown on
the Russian CORONAS-PHOTON satellite placed inside the TESIS EUV and X
telescope assembly. The spacecraft launch took place on 30 January 2009
at 13:30 UT at the Plesetsk Cosmodrome in Russia. The SphinX experiment
mission began a couple of weeks later on 20 February 2009 when the first
telemetry dumps were received. The mission ended nine months later on 29
November 2009 when data transmission was terminated. SphinX provided an
excellent set of observations during very low solar activity. This was
indeed the period in which solar activity dropped to the lowest level
observed in X-rays ever. The SphinX instrument design, construction,
and operation principle are described. Information on SphinX data
repositories, dissemination methods, format, and calibration is given
together with general recommendations for data users. Scientific
research areas in which SphinX data find application are reviewed.
Title: Silicon Abundance from RESIK Solar Flare Observations
Authors: Sylwester, B.; Phillips, K. J. H.; Sylwester, J.; Kȩpa, A.
Bibcode: 2013SoPh..283..453S
Altcode: 2012arXiv1212.2914S
The RESIK instrument on the CORONAS-F spacecraft obtained solar
flare and active-region X-ray spectra in four channels covering the
wavelength range 3.8 - 6.1 Å in its operational period between 2001
and 2003. Several highly ionized silicon lines were observed within
the range of the long-wavelength channel (5.00 - 6.05 Å). The fluxes
of the Si XIV Ly-β line (5.217 Å) and the Si XIII 1s2
- 1s3p line (5.688 Å) during 21 flares with optimized pulse-height
analyzer settings on RESIK have been analyzed to obtain the silicon
abundance relative to hydrogen in flare plasmas. As in previous work,
the emitting plasma for each spectrum is assumed to be characterized
by a single temperature and emission measure given by the ratio
of emission in the two channels of GOES. The silicon abundance is
determined to be A(Si)=7.93±.21 (Si XIV) and 7.89±.13 (Si XIII)
on a logarithmic scale with H=12. These values, which vary by only
very small amounts from flare to flare and times within flares, are
2.6±1.3 and 2.4±0.7 times the photospheric abundance, and are about
a factor of three higher than RESIK measurements during a period of
very low activity. There is a suggestion that the Si/S abundance ratio
increases from active regions to flares.
Title: Spectrometer Telescope for Imaging X-rays (STIX)
Authors: Benz, A. O.; Gallagher, P.; Veronig, A.; Grimm, O.; Sylwester,
J.; Orleanski, P.; Arnold, N.; Bednarzik, M.; Farnik, F.; Hurford,
G.; Krucker, S.; Limousin, O.; Mann, G.; Vilmer, N.
Bibcode: 2012IAUSS...6E.509B
Altcode:
The Solar Orbiter Mission has been confirmed within ESA's M-class
Cosmic Vision plan. Launch date is January 2017 into an orbit that
reaches nearly one quarter AU in the perihelion. STIX is one of
the 10 instruments selected for close cooperation. STIX applies
a Fourier-imaging technique using shading tungsten grids. A total
of 32 pixelized CdTe detectors will permit high resolution imaging
spectroscopy. The design has passed ESA's Preliminary Design Review
and will be finalized by the end of 2012. The instrument specification
will be presented and its scientific potential discussed.
Title: The spectrometer telescope for imaging x-rays on board the
Solar Orbiter mission
Authors: Benz, A. O.; Krucker, S.; Hurford, G. J.; Arnold, N. G.;
Orleanski, P.; Gröbelbauer, H. -P.; Klober, S.; Iseli, L.; Wiehl,
H. J.; Csillaghy, A.; Etesi, L.; Hochmuth, N.; Battaglia, M.;
Bednarzik, M.; Resanovic, R.; Grimm, O.; Viertel, G.; Commichau, V.;
Meuris, A.; Limousin, O.; Brun, S.; Vilmer, N.; Skup, K. R.; Graczyk,
R.; Stolarski, M.; Michalska, M.; Nowosielski, W.; Cichocki, A.;
Mosdorf, M.; Seweryn, K.; Przepiórka, A.; Sylwester, J.; Kowalinski,
M.; Mrozek, T.; Podgorski, P.; Mann, G.; Aurass, H.; Popow, E.;
Onel, H.; Dionies, F.; Bauer, S.; Rendtel, J.; Warmuth, A.; Woche,
M.; Plüschke, D.; Bittner, W.; Paschke, J.; Wolker, D.; Van Beek,
H. F.; Farnik, F.; Kasparova, J.; Veronig, A. M.; Kienreich, I. W.;
Gallagher, P. T.; Bloomfield, D. S.; Piana, M.; Massone, A. M.;
Dennis, B. R.; Schwarz, R. A.; Lin, R. P.
Bibcode: 2012SPIE.8443E..3LB
Altcode:
The Spectrometer Telescope for Imaging X-rays (STIX) is one of 10
instruments on board Solar Orbiter, a confirmed Mclass mission of the
European Space Agency (ESA) within the Cosmic Vision program scheduled
to be launched in 2017. STIX applies a Fourier-imaging technique
using a set of tungsten grids (at pitches from 0.038 to 1 mm) in
front of 32 pixelized CdTe detectors to provide imaging spectroscopy
of solar thermal and non-thermal hard X-ray emissions from 4 to 150
keV. The status of the instrument reviewed in this paper is based on
the design that passed the Preliminary Design Review (PDR) in early
2012. Particular emphasis is given to the first light of the detector
system called Caliste-SO.
Title: X-ray emitting hot plasma in solar active regions observed
by the SphinX spectrometer
Authors: Miceli, M.; Reale, F.; Gburek, S.; Terzo, S.; Barbera, M.;
Collura, A.; Sylwester, J.; Kowalinski, M.; Podgorski, P.; Gryciuk, M.
Bibcode: 2012A&A...544A.139M
Altcode: 2012arXiv1207.4665M
Aims: The detection of very hot plasma in the quiescent corona
is important for diagnosing heating mechanisms. The presence and the
amount of such hot plasma is currently debated. The SphinX instrument
on-board the CORONAS-PHOTON mission is sensitive to X-ray emission of
energies well above 1 keV and provides the opportunity to detect the
hot plasma component.
Methods: We analysed the X-ray spectra of
the solar corona collected by the SphinX spectrometer in May 2009 (when
two active regions were present). We modelled the spectrum extracted
from the whole Sun over a time window of 17 days in the 1.34-7 keV
energy band by adopting the latest release of the APED database.
Results: The SphinX broadband spectrum cannot be modelled by a single
isothermal component of optically thin plasma and two components are
necessary. In particular, the high statistical significance of the count
rates and the accurate calibration of the spectrometer allowed us to
detect a very hot component at ~7 million K with an emission measure of
~2.7 × 1044 cm-3. The X-ray emission from the
hot plasma dominates the solar X-ray spectrum above 4 keV. We checked
that this hot component is invariably present in both the high and
low emission regimes, i.e. even excluding resolvable microflares. We
also present and discuss the possibility of a non-thermal origin
(which would be compatible with a weak contribution from thick-target
bremsstrahlung) for this hard emission component.
Conclusions:
Our results support the nanoflare scenario and might confirm that
a minor flaring activity is ever-present in the quiescent corona,
as also inferred for the coronae of other stars.
Title: Diagnostics of Non-Thermal Distribution from RESIK and RHESSI
Flare Spectra
Authors: Kulinová, A.; Kašparová, J.; Dzifčáková, E.; Sylwester,
J.; Sylwester, B.
Bibcode: 2012ASPC..454..329K
Altcode:
Solar flare spectra observed by the X-ray spectrometers RESIK and
RHESSI with high energy resolution enabled us to analyse possible
non-thermality of plasma electron distribution in the keV range. For
RESIK diagnostics (in the 2-4 keV range) we assumed that the bulk
of the plasma is represented by the so-called n-distribution, which
describes the deviations from the Maxwellian distribution by two
parameters: n and T. Using thick-target approximation for RHESSI
spectral analysis, we obtained characteristics of injected electron
power-law distribution in the deka-keV range. The event presented here
shows a very good time correlation of non-thermality obtained from
the RESIK spectra with appearance of non-thermal component in RHESSI
and/or radio spectra. However, a thermal component was still present
in RHESSI. Both spectral and imaging information in RHESSI soft and
hard X-ray ranges were used for the estimation of the ratio of thermal
to non-thermal electron densities of the X-ray emitting plasma.
Title: Characteristics of elementary soft X-ray flare profiles based
on SphinX observations
Authors: Gryciuk, Magdalena; Sylwester, Janusz; Gburek, Szymon;
Siarkowski, Marek; Podgorski, Piotr
Bibcode: 2012cosp...39..672G
Altcode: 2012cosp.meet..672G
No abstract at ADS
Title: The Solar Flare Sulfur Abundance from RESIK Observations
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kuznetsov,
V. D.
Bibcode: 2012ApJ...751..103S
Altcode: 2012arXiv1203.5888S
The RESIK instrument on CORONAS-F spacecraft observed several sulfur
X-ray lines in three of its four channels covering the wavelength range
3.8-6.1 Å during solar flares. The fluxes are analyzed to give the
sulfur abundance. Data are chosen for when the instrument parameters
were optimized. The measured fluxes of the S XV 1s 2-1s4p
(w4) line at 4.089 Å gives A(S) = 7.16 ± 0.17 (abundances on a
logarithmic scale with A(H) = 12) which we consider to be the most
reliable. Estimates from other lines range from 7.13 to 7.24. The
preferred S abundance estimate is very close to recent photospheric
abundance estimates and to quiet-Sun solar wind and meteoritic
abundances. This implies no fractionation of sulfur by processes tending
to enhance the coronal abundance from the photospheric that depend on
the first ionization potential (FIP), or that sulfur, though its FIP
has an intermediate value of 10.36 eV, acts like a "high-FIP" element.
Title: SphinX Measurements of the 2009 Solar Minimum X-Ray Emission
Authors: Sylwester, J.; Kowalinski, M.; Gburek, S.; Siarkowski, M.;
Kuzin, S.; Farnik, F.; Reale, F.; Phillips, K. J. H.; Bakała, J.;
Gryciuk, M.; Podgorski, P.; Sylwester, B.
Bibcode: 2012ApJ...751..111S
Altcode: 2012arXiv1203.6809S
The SphinX X-ray spectrophotometer on the CORONAS-PHOTON spacecraft
measured soft X-ray emission in the 1-15 keV energy range during
the deep solar minimum of 2009 with a sensitivity much greater
than GOES. Several intervals are identified when the X-ray flux
was exceptionally low, and the flux and solar X-ray luminosity
are estimated. Spectral fits to the emission at these times
give temperatures of 1.7-1.9 MK and emission measures between
4 × 1047 cm-3 and 1.1 × 1048
cm-3. Comparing SphinX emission with that from the Hinode
X-ray Telescope, we deduce that most of the emission is from general
coronal structures rather than confined features like bright points. For
one of 27 intervals of exceptionally low activity identified in the
SphinX data, the Sun's X-ray luminosity in an energy range roughly
extrapolated to that of ROSAT (0.1-2.4 keV) was less than most nearby
K and M dwarfs.
Title: Instrument data processing unit for spectrometer/telescope
for imaging x-rays (STIX)
Authors: Skup, Konrad R.; Cichocki, A.; Graczyk, R.; Michalska,
M.; Mosdorf, M.; Nowosielski, W.; Orleański, P.; Przepiórka, A.;
Seweryn, K.; Stolarski, M.; Winkler, M.; Sylwester, J.; Kowalinski,
M.; Mrozek, T.; Podgorski, P.; Benz, A. O.; Krucker, S.; Hurford,
G. J.; Arnold, N. G.; Önel, H.; Meuris, A.; Limousin, O.; Grimm, O.
Bibcode: 2012SPIE.8454E..0KS
Altcode:
The Spectrometer/Telescope for Imaging X-rays (STIX) is one of 10
instruments on board Solar Orbiter, an M-class mission of the European
Space Agency (ESA) scheduled to be launch in 2017. STIX applies a
Fourier-imaging technique using a set of tungsten grids in front of
32 pixelized CdTe detectors to provide imaging spectroscopy of solar
thermal and non-thermal hard X-ray emissions from 4 to 150 keV. These
detectors are source of data collected and analyzed in real-time by
Instrument Data Processing Unit (IDPU). Besides the data processing
the IDPU controls and manages other STIX's subsystems: ASICs and ADCs
associated with detectors, Aspect System, Attenuator, PSU and HK. The
instrument reviewed in this paper is based on the design that passed the
Instrument Preliminary Design Review (IPDR) in early 2012 and Software
Preliminary Design Review (SW PDR) in middle of 2012. Particular
emphasis is given to the IDPU and low level software called Basic SW
(BSW).
Title: X-ray spectrophotometer SphinX and particle spectrometer STEP-F
of the satellite experiment CORONAS-PHOTON. Preliminary results of
the joint data analysis
Authors: Dudnik, O. V.; Podgorski, P.; Sylwester, J.; Gburek, S.;
Kowalinski, M.; Siarkowski, M.; Plocieniak, S.; Bakala, J.
Bibcode: 2012SoSyR..46..160D
Altcode:
A joint analysis is carried out of data obtained with the help of
the solar X-ray SphinX spectrophotometer and the electron and proton
satellite telescope STEP-F in May 2009 in the course of the scientific
space experiment CORONAS-PHOTON. In order to determine the energies
and particle types, in the analysis of spectrophotometer records data
are used on the intensities of electrons, protons, and secondary
γ-radiation, obtained by the STEP-F telescope, which was located
in close proximity to the SphinX spectrophotometer. The identical
reaction of both instruments is noted at the intersection of regions
of the Brazilian magnetic anomaly and the Earth's radiation belts. It
is shown that large area photodiodes, serving as sensors of the X-ray
spectrometer, reliably record electron fluxes of low and intermediate
energies, as well as fluxes of the secondary gamma radiation from
construction materials of detector modules, the TESIS instrument
complex, and the spacecraft itself. The dynamics of electron fluxes,
recorded by the SphinX spectrophotometer in the vicinity of a weak
geomagnetic storm, supplements the information about the processes
of radial diffusion of electrons, which was studied using the STEP-F
telescope.
Title: Common SphinX and RHESSI observations of solar flares
Authors: Mrozek, T.; Gburek, S.; Siarkowski, M.; Sylwester, B.;
Sylwester, J.; Gryciuk, M.
Bibcode: 2012CEAB...36...71M
Altcode:
The Polish X-ray spectrofotometer SphinX has observed a great number
of solar flares in the year 2009 - during the most quiet solar
minimum almost over the last 100 years. Hundreds of flares have been
recorded due to excellent sensitivity of SphinX's detectors. The Si-PIN
diodes are about 100 times more sensitive to X-rays than GOES X-ray
Monitors. SphinX detectors were absolutely calibrated on Earth with a
use of the BESSY synchrotron. In space observations were made in the
range 1.2-15~keV with 480~eV energy resolution. SphinX data overlap
with the low-energy end of the Ramaty High Energy Solar Spectroscopic
Imager (RHESSI) data. RHESSI detectors are quite old (7 years in 2009),
but still sensitive enough to provide us with observations of extremely
weak solar flares such as those which occurred in 2009. We have selected
a group of flares simultaneously observed by RHESSI and SphinX and
performed a spectroscopic analysis of the data. Moreover, we compared
the physical parameters of these flares plasma. Preliminary results
of the comparison show very good agreement between both instruments.
Title: The Solar Flare Chlorine Abundance from RESIK X-Ray Spectra
Authors: Sylwester, B.; Phillips, K. J. H.; Sylwester, J.; Kuznetsov,
V. D.
Bibcode: 2011ApJ...738...49S
Altcode: 2011arXiv1106.1387S
The abundance of chlorine is determined from X-ray spectra obtained
with the RESIK instrument on CORONAS-F during solar flares between 2002
and 2003. Using weak lines of He-like Cl, Cl XVI, between 4.44 and
4.50 Å, and with temperatures and emission measures from GOES on an
isothermal assumption, we obtained A(Cl) = 5.75 ± 0.26 on a scale A(H)
= 12. The uncertainty reflects an approximately a factor of two scatter
in measured line fluxes. Nevertheless, our value represents what is
probably the best solar determination yet obtained. It is higher by
factors of 1.8 and 2.7 than Cl abundance estimates from an infrared
sunspot spectrum and nearby H II regions. The constancy of the RESIK
abundance values over a large range of flares (GOES class from below
C1 to X1) argues for any fractionation that may be present in the low
solar atmosphere to be independent of the degree of solar activity.
Title: Diagnostics of non-thermal distributions in solar flare
spectra observed by RESIK and RHESSI
Authors: Kulinová, A.; Kašparová, J.; Dzifčáková, E.; Sylwester,
J.; Sylwester, B.; Karlický, M.
Bibcode: 2011A&A...533A..81K
Altcode: 2011arXiv1109.1011K
Context. During solar flares an enormous amount of energy is released,
and the charged particles, like electrons, are accelerated. These
non-thermal electrons interact with the plasma in various parts
of solar flares, where the distribution function of electrons can
therefore be non-Maxwellian.
Aims: We focus on the non-thermal
components of the electron distribution in the keV range and analyse
high-energy resolution X-ray spectra detected by RESIK and RHESSI for
three solar flares.
Methods: In the 2-4 keV range we assume that
the electron distribution can be modelled by an n-distribution. Using
a method of line-intensity ratios, we analyse allowed and satellite
lines of Si observed by RESIK and estimate the parameters of this
n-distribution. At higher energies we explore RHESSI bremsstrahlung
spectra. Adopting a forward-fitting approach and thick-target
approximation, we determine the characteristics of injected electron
beams.
Results: RHESSI non-thermal component associated with
the electron beam is correlated well with presence of the non-thermal
n-distribution obtained from the RESIK spectra. In addition, such an
n-distribution occurs during radio bursts observed in the 0.61-15.4
GHz range. Furthermore, we show that the n-distribution could also
explain RHESSI emission below ~5 keV. Therefore, two independent
diagnostics methods indicate the flare plasma being affected by
the electron beam can have a non-thermal component in the ~2-5 keV
range, which is described by the n-distribution well. Finally,
spectral line analysis reveals that the n-distribution does not
occupy the same location as the thermal component detected by RHESSI
at ~10 keV. Appendix A is available in electronic form at http://www.aanda.org
Title: SphinX soft X-ray spectrophotometer: Science objectives,
design and performance
Authors: Gburek, S.; Sylwester, J.; Kowalinski, M.; Bakala, J.;
Kordylewski, Z.; Podgorski, P.; Plocieniak, S.; Siarkowski, M.;
Sylwester, B.; Trzebinski, W.; Kuzin, S. V.; Pertsov, A. A.; Kotov,
Yu. D.; Farnik, F.; Reale, F.; Phillips, K. J. H.
Bibcode: 2011SoSyR..45..189G
Altcode:
The goals and construction details of a new design Polish-led X-ray
spectrophotometer are described. The instrument is aimed to observe
emission from entire solar corona and is placed as a separate block
within the Russian TESIS X- and EUV complex aboard the CORONAS-PHOTON
solar orbiting observatory. SphinX uses silicon PIN diode detectors
for high time resolution measurements of the solar spectra in the
range 0.8-15 keV. Its spectral resolution allows for discerning more
than hundred separate energy bands in this range. The instrument
dynamic range extends two orders of magnitude below and above these
representative for GOES. The relative and absolute accuracy of spectral
measurements is expected to be better than few percent, as follows
from extensive ground laboratory calibrations.
Title: Results of solar observations by the CORONAS-F payload
Authors: Kuznetsov, V. D.; Sobelman, I. I.; Zhitnik, I. A.; Kuzin,
S. V.; Kotov, Yu. D.; Charikov, Yu. E.; Kuznetsov, S. N.; Mazets,
E. P.; Nusinov, A. A.; Pankov, A. M.; Sylwester, J.
Bibcode: 2011AdSpR..47.1538K
Altcode:
The CORONAS-F mission experiments and results have been reviewed. The
observations with the DIFOS multi-channel photometer in a broad spectral
range from 350 to 1500 nm have revealed the dependence of the relative
amplitudes of p-modes of the global solar oscillations on the wavelength
that agrees perfectly well with the earlier data obtained in a narrower
spectral ranges. The SPIRIT EUV observations have enabled the study of
various manifestations of solar activity and high-temperature events on
the Sun. The data from the X-ray spectrometer RESIK, gamma spectrometer
HELICON, flare spectrometer IRIS, amplitude-temporal spectrometer
AVS-F, and X-ray spectrometer RPS-1 have been used to analyze the X-
and gamma-ray emission from solar flares and for diagnostics of the
flaring plasma. The absolute and relative content of various elements
(such as potassium, argon, and sulfur) of solar plasma in flares
has been determined for the first time with the X-ray spectrometer
RESIK. The Solar Cosmic Ray Complex monitored the solar flare effects
in the Earth's environment. The UV emission variations recorded during
solar flares in the vicinity of the 120-nm wavelength have been analyzed
and the amplitude of relative variations has been determined.
Title: Soft X-ray variability over the present minimum of solar
activity as observed by SphinX
Authors: Gburek, S.; Siarkowski, M.; Kepa, A.; Sylwester, J.;
Kowalinski, M.; Bakala, J.; Podgorski, P.; Kordylewski, Z.; Plocieniak,
S.; Sylwester, B.; Trzebinski, W.; Kuzin, S.
Bibcode: 2011SoSyR..45..182G
Altcode:
Solar Photometer in X-rays (SphinX) is an instrument designed to
observe the Sun in X-rays in the energy range 0.85-15.00 keV. SphinX
is incorporated within the Russian TESIS X and EUV telescope complex
aboard the CORONAS-Photon satellite which was launched on January 30,
2009 at 13:30 UT from the Plesetsk Cosmodrome, northern Russia. Since
February, 2009 SphinX has been measuring solar X-ray radiation nearly
continuously. The principle of SphinX operation and the content of the
instrument data archives is studied. Issues related to dissemination
of SphinX calibration, data, repository mirrors locations, types of
data and metadata are discussed. Variability of soft X-ray solar flux
is studied using data collected by SphinX over entire mission duration.
Title: Physical Characteristics of AR 11024 Plasma Based on SPHINX
and XRT Data
Authors: Sylwester, B.; Sylwester, J.; Siarkowski, M.; Engell, A. J.;
Kuzin, S. V.
Bibcode: 2011CEAB...35..171S
Altcode:
We have studied the evolution of basic physical properties of plasma
within the coronal part of the isolated, new cycle region (AR 11024)
during its crossing over the solar disc in July 2009. Our analysis
is based on the high temporal and spectral resolution measurements
performed by the Polish X-ray spectrometer SphinX onboard the
CORONAS-Photon satellite. Hinode XRT images provide information on
spatial extension of the emission within this active region. It is
found that the average temperature of the plasma within the analysed
region is the highest (∼6 MK) when the region is young and gradually
declines to ∼2 MK when the emission measure is the highest. An
average density during this first part of the evolution is estimated
to be ∼2 x 10^9 cm^{-3}.
Title: Flares and Their Underlying Magnetic Complexity
Authors: Engell, Alexander J.; Siarkowski, Marek; Gryciuk, Magda;
Sylwester, Janusz; Sylwester, Barbara; Golub, Leon; Korreck, Kelly;
Cirtain, Jonathan
Bibcode: 2011ApJ...726...12E
Altcode:
SphinX (Solar PHotometer IN X-rays), a full-disk-integrated
spectrometer, observed 137 flare-like/transient events with active
region (AR) 11024 being the only AR on disk. The Hinode X-Ray Telescope
(XRT) and Solar Optical Telescope observe 67 of these events and
identified their location from 12:00 UT on July 3 through 24:00 UT 2009
July 7. We find that the predominant mechanisms for flares observed
by XRT are (1) flux cancellation and (2) the shearing of underlying
magnetic elements. Point- and cusp-like flare morphologies seen by XRT
all occur in a magnetic environment where one polarity is impeded by
the opposite polarity and vice versa, forcing the flux cancellation
process. The shearing is either caused by flux emergence at the
center of the AR and separation of polarities along a neutral line
or by individual magnetic elements having a rotational motion. Both
mechanisms are observed to contribute to single- and multiple-loop
flares. We observe that most loop flares occur along a large portion
of a polarity inversion line. Point- and cusp-like flares become
more infrequent as the AR becomes organized with separation of the
positive and negative polarities. SphinX, which allows us to identify
when these flares occur, provides us with a statistically significant
temperature and emission scaling law for A and B class flares: EM =
6.1 × 1033 T 1.9±0.1.
Title: Science Objectives for an X-Ray Microcalorimeter Observing
the Sun
Authors: Laming, J. Martin; Adams, J.; Alexander, D.; Aschwanden, M;
Bailey, C.; Bandler, S.; Bookbinder, J.; Bradshaw, S.; Brickhouse,
N.; Chervenak, J.; Christe, S.; Cirtain, J.; Cranmer, S.; Deiker, S.;
DeLuca, E.; Del Zanna, G.; Dennis, B.; Doschek, G.; Eckart, M.; Fludra,
A.; Finkbeiner, F.; Grigis, P.; Harrison, R.; Ji, L.; Kankelborg,
C.; Kashyap, V.; Kelly, D.; Kelley, R.; Kilbourne, C.; Klimchuk, J.;
Ko, Y. -K.; Landi, E.; Linton, M.; Longcope, D.; Lukin, V.; Mariska,
J.; Martinez-Galarce, D.; Mason, H.; McKenzie, D.; Osten, R.; Peres,
G.; Pevtsov, A.; Porter, K. Phillips F. S.; Rabin, D.; Rakowski, C.;
Raymond, J.; Reale, F.; Reeves, K.; Sadleir, J.; Savin, D.; Schmelz,
J.; Smith, R. K.; Smith, S.; Stern, R.; Sylwester, J.; Tripathi, D.;
Ugarte-Urra, I.; Young, P.; Warren, H.; Wood, B.
Bibcode: 2010arXiv1011.4052L
Altcode:
We present the science case for a broadband X-ray imager with
high-resolution spectroscopy, including simulations of X-ray spectral
diagnostics of both active regions and solar flares. This is part of
a trilogy of white papers discussing science, instrument (Bandler et
al. 2010), and missions (Bookbinder et al. 2010) to exploit major
advances recently made in transition-edge sensor (TES) detector
technology that enable resolution better than 2 eV in an array that
can handle high count rates. Combined with a modest X-ray mirror, this
instrument would combine arcsecondscale imaging with high-resolution
spectra over a field of view sufficiently large for the study of
active regions and flares, enabling a wide range of studies such as
the detection of microheating in active regions, ion-resolved velocity
flows, and the presence of non-thermal electrons in hot plasmas. It
would also enable more direct comparisons between solar and stellar
soft X-ray spectra, a waveband in which (unusually) we currently have
much better stellar data than we do of the Sun.
Title: A Solar Spectroscopic Absolute Abundance of Argon from RESIK
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kuznetsov,
V. D.
Bibcode: 2010ApJ...720.1721S
Altcode: 2010arXiv1007.3574S
Observations of He-like and H-like Ar (Ar XVII and Ar XVIII) lines at
3.949 Å and 3.733 Å, respectively, with the RESIK X-ray spectrometer
on the CORONAS-F spacecraft, together with temperatures and emission
measures from the two channels of GOES, have been analyzed to obtain
the abundance of Ar in flare plasmas in the solar corona. The line
fluxes per unit emission measure show a temperature dependence like
that predicted from theory and lead to spectroscopically determined
values for the absolute Ar abundance, A(Ar) = 6.44 ± 0.07 (Ar
XVII) and 6.49 ± 0.16 (Ar XVIII), which are in agreement to within
uncertainties. The weighted mean is 6.45 ± 0.06, which is between
two recent compilations of the solar Ar abundance and suggests that
the photospheric and coronal abundances of Ar are very similar.
Title: Soft X-ray coronal spectra at low activity levels observed
by RESIK
Authors: Sylwester, B.; Sylwester, J.; Phillips, K. J. H.
Bibcode: 2010A&A...514A..82S
Altcode: 2010arXiv1003.2980S
Context. The quiet-Sun X-ray emission is important for deducing
coronal heating mechanisms, but it has not been studied in detail
since the Orbiting Solar Observatory (OSO) spacecraft era. Bragg
crystal spectrometer X-ray observations have generally concentrated
on flares and active regions. The high sensitivity of the RESIK
(REntgenovsky Spectrometer s Izognutymi Kristalami) instrument on the
CORONAS-F solar mission has enabled the X-ray emission from the quiet
corona to be studied in a systematic way for the first time.
Aims: Our aim is to deduce the physical conditions of the non-flaring
corona from RESIK line intensities in several spectral ranges using
both isothermal and multithermal assumptions.
Methods: We
selected and analyzed spectra in 312 quiet-Sun intervals in January
and February 2003, sorting them into 5 groups according to activity
level. For each group, the fluxes in selected spectral bands have been
used to calculate values of parameters for the best-fit that leads
to intensities characteristic of each group. We used both isothermal
and multitemperature assumptions, the latter described by differential
emission measure (DEM) distributions. RESIK spectra cover the wavelength
range (3.3-6.1 Å). This includes emission lines of highly ionized Si,
S, Cl, Ar, and K, which are suitable for evaluating temperature and
emission measure, were used.
Results: The RESIK spectra during
these intervals of very low solar activity for the first time provide
information on the temperature structure of the quiet corona. Although
most of the emission seems to arise from plasma with a temperature
between 2 MK and 3 MK, there is also evidence of a hotter plasma (T
~ 10 MK) with an emission measure 3 orders smaller than the cooler
component. Neither coronal nor photospheric element abundances appear
to describe the observed spectra satisfactorily.
Title: Xrt And Shinx Joint Flare Study: Ar 11024
Authors: Engell, Alexander; Sylwester, J.; Siarkowski, M.
Bibcode: 2010AAS...21640432E
Altcode: 2010BAAS...41..905E
From 12:00 UT on July 3 through July 7, 2009 SphinX (Solar Photometer
IN X-rays) observes 130 flares with active region (AR) 11024 being the
only AR on disk. XRT (X-Ray Telescope) is able to observe 64 of these
flare events. The combination of both instruments results in a flare
study revealing (1) a relationship between flux emergence and flare
rate, (2) that the presence of active region loops typically results
in different flare morphologies (single and multiple loop flares) then
when there is a lack of an active region loop environment where more
cusp and point-like flares are observed, (3) cusp and point-like flares
often originate from the same location, and (4) a distribution of flare
temperatures corresponding to the different flare morphologies. The
differences between the observed flare morphologies may occur as the
result of the heated plasma through the flaring process being confined
by the proximity of loop structures as for the single and multiple
loop flares, while for cusp and point-like flares they occur in an
early-phase environment that lack loop presence. The continuing flux
emergence of AR 11024 likely provides different magnetic interactions
and may be the source responsible for all of the flares.
Title: The Solar X-ray Continuum Measured by RESIK
Authors: Phillips, K. J. H.; Sylwester, J.; Sylwester, B.; Kuznetsov,
V. D.
Bibcode: 2010ApJ...711..179P
Altcode: 2010arXiv1001.2412P
The solar X-ray continuum emission at five wavelengths between 3.495
Å and 4.220 Å for 19 flares in a 7-month period in 2002-2003 was
observed by the RESIK (REntgenovsky Spektrometr s Izognutymi Kristalami)
crystal spectrometer on CORONAS-F. In this wavelength region, free-free
and free-bound emissions have comparable fluxes. With a pulse-height
analyzer having settings close to optimal, the fluorescence background
was removed so that RESIK measured true solar continuum in these
bands with an uncertainty in the absolute calibration of ±20%. With
an isothermal assumption, and temperature and emission measure derived
from the ratio of the two GOES channels, the observed continuum emission
normalized to an emission measure of 1048 cm-3
was compared with theoretical continua using the CHIANTI atomic
code. The accuracy of the RESIK measurements allows photospheric
and coronal abundance sets, important for the free-bound continuum,
to be discriminated. It is found that there is agreement to about 25%
of the measured continua with those calculated from CHIANTI assuming
coronal abundances in which Mg, Si, and Fe abundances are four times
photospheric.
Title: Highly Ionized Potassium Lines in Solar X-ray Spectra and
the Abundance of Potassium
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kuznetsov,
V. D.
Bibcode: 2010ApJ...710..804S
Altcode: 2010arXiv1001.1502S
The abundance of potassium is derived from X-ray lines observed during
flares by the RESIK instrument on the solar mission CORONAS-F between
3.53 Å and 3.57 Å. The lines include those emitted by He-like K and
Li-like K dielectronic satellites, which have been synthesized using
the CHIANTI atomic code and newly calculated atomic data. There is good
agreement between observed and synthesized spectra, and the theoretical
behavior of the spectra with varying temperature estimated from the
ratio of the two GOES channels is correctly predicted. The observed
fluxes of the He-like K resonance line per unit emission measure give
log A(K) = 5.86 (on a scale log A(H) = 12), with a total range of a
factor 2.9. This is higher than photospheric abundance estimates by
a factor 5.5, a slightly greater enhancement than for other elements
with first ionization potential (FIP) less than ~10 eV. There is, then,
the possibility that enrichment of low-FIP elements in coronal plasmas
depends weakly on the value of the FIP which for K is extremely low
(4.34 eV). Our work also suggests that fractionation of elements to
form the FIP effect occurs in the low chromosphere rather than higher
up, as in some models.
Title: The Sun's X-ray Emission During the Recent Solar Minimum
Authors: Sylwester, Janusz; Kowalinski, Mirek; Gburek, Szymon;
Siarkowski, Marek; Kuzin, Sergey; Farnik, Frantisek; Reale, Fabio;
Phillips, Kenneth J. H.
Bibcode: 2010EOSTr..91...73S
Altcode:
The Sun recently underwent a period of a remarkable lack of major
activity such as large flares and sunspots, without equal since the
advent of the space age a half century ago. A widely used measure of
solar activity is the amount of solar soft X-ray emission, but until
recently this has been below the threshold of the X-ray-monitoring
Geostationary Operational Environmental Satellites (GOES). There
is thus an urgent need for more sensitive instrumentation to record
solar X-ray emission in this range. Anticipating this need, a highly
sensitive spectrophotometer called Solar Photometer in X-rays (SphinX)
was included in the solar telescope/spectrometer TESIS instrument
package on the third spacecraft in Russia's Complex Orbital Observations
Near-Earth of Activity of the Sun (CORONAS-PHOTON) program, launched
30 January 2009 into a near-polar orbit. SphinX measures X-rays in a
band similar to the GOES longer-wavelength channel.
Title: A New High-sensitivity solar X-ray Spectrophotometer
SphinX:early operations and databases
Authors: Gburek, Szymon; Sylwester, Janusz; Kowalinski, Miroslaw;
Siarkowski, Marek; Bakala, Jaroslaw; Podgorski, Piotr; Trzebinski,
Witold; Plocieniak, Stefan; Kordylewski, Zbigniew; Kuzin, Sergey;
Farnik, Frantisek; Reale, Fabio
Bibcode: 2010cosp...38.2895G
Altcode: 2010cosp.meet.2895G
The Solar Photometer in X-rays (SphinX) is an instrument operating
aboard Russian CORONAS-Photon satellite. A short description of this
unique instrument will be presented and its unique capabilities
discussed. SphinX is presently the most sensitive solar X-ray
spectrophotometer measuring solar spectra in the energy range above
1 keV. A large archive of SphinX mea-surements has already been
collected. General access to these measurements is possible. The
SphinX data repositories contain lightcurves, spectra, and photon
arrival time measurements. The SphinX data cover nearly continuously
the period since the satellite launch on January 30, 2009 up to the
end-of November 2009. Present instrument status, data formats and
data access methods will be shown. An overview of possible new science
coming from SphinX data analysis will be discussed.
Title: Short time variability of solar corona during recent solar
cycle minimum
Authors: Siarkowski, Marek; Gryciuk, Magdalena; Gburek, Szymon;
Sylwester, Janusz; Sylwester, Barbara; Kepa, Anna; Buczkowska,
Agnieszka; Kowalinski, Miroslaw
Bibcode: 2010cosp...38.2905S
Altcode: 2010cosp.meet.2905S
Sphinx is the X-ray spectrophotometer designed to measure X-ray
emission from the Sun in the energy range between 0.8 keV and 15
keV. The instrument is placed onboard Russian KORONAS-PHOTON satellite
launched on January 30, 2009. In this paper we present the observations
of coronal emission obtained between March-April and August-September
2009, i.e. the times towards the end of the last, very prolonged and
deep minimum of solar activity. Prompt analysis of SphinX spectra reveal
the variability of the average coronal plasma charac-teristics like
the temperature and emission measure. These data are used to compare
SphinX and GOES measurements, for selected times. Examples of many
sub/microflare events with maxima of the X-ray flux, observed much
below the GOES sensitivity threshold level will be presented.
Title: Determination of Differential Emission Measure Distribution
of Coronal Structures Observed by SphinX During Recent Minimum of
Solar Activity
Authors: Kepa, Anna; Gburek, Szymon; Siarkowski, Marek; Sylwester,
Barbara; Sylwester, Janusz; Kowalinski, Miroslaw
Bibcode: 2010cosp...38.2907K
Altcode: 2010cosp.meet.2907K
SphinX is a high-sensitivity soft X-ray spectrophotometer which
measures soft X-ray spectra in the energy range between 0.8 keV and
15 keV. From February to November 2009 the instrument has observed
unusually quiet solar coronal emission as well as a number of weak
solar flares. Based on SphinX spectra it is possible to study the
differential emission measure distributions (DEM) in the temperature
range roughly between 1 MK and 10 MK. The aim of the present study is
to unveil DEM plasma distributions for selected activity conditions
and analyze their variability.
Title: Evolution of plasma characteristics for weak X-ray brightenings
seen by SphinX during recent deep minimum of solar activity
Authors: Sylwester, Barbara; Sylwester, Janusz; Siarkowski, Marek;
Gburek, Szymon; Phillips, Kenneth
Bibcode: 2010cosp...38.2896S
Altcode: 2010cosp.meet.2896S
Very high sensitivity of SphinX soft X-ray spectrophotometer
aboard Coronas-Photon allows to observe spectra of small X-ray
brightenings(microflares), many of them with maximum intensities well
below the GOES or RHESSI sensitivity thresholds. Hundreds of such small
flare-like events have been observed in the period between March and
November 2009 with energy resolution better than 0.5 keV. The spectra
have been measured in the energy range extending above 1 keV. In this
study we investigate the time variability of basic plasma parameters:
temperature T and emission measure EM for a number of these weak
flare-like events and discuss respective evolutionary patterns on the
EM-T diagnostic diagrams. For some of these events, unusual behavior
is observed, different from this characteristic for a "normal" flares
of higher maximum intensities. Physical scenarios providing possible
explanation of such unusual evolutionary patterns will be discussed.
Title: Non-thermal Diagnostics of a Flare Observed by RESIK
Authors: Kulinová, A.; Dzifčáková, E.; Sylwester, B.; Sylwester, J.
Bibcode: 2009CEAB...33..243K
Altcode:
The Polish soft X-ray spectrometer RESIK operated on Russian Coronas-F
spacecraft during the years 2001 - 2003. It has observed several flares
of different classes in a wavelength band of 3.35, 6.05 Å. We have
analysed two flares especially in a region of 5.0 - 6.05 Å which is
dominated by allowed lines of Si XIII, Si XIV ions, and satellite lines
of Si XII (Si XIId). The flare spectra showed unexpectedly high fluxes
of Si XIId satellite lines as compared with fluxes of allowed lines of
Si XIII ion which we attempted to explain under the assumption of a
non-thermal electron distribution. We have investigated the temporal
dependence of the deviation of the non-thermal distribution from the
Maxwell distribution during a flare. The maximal deviation from thermal
distribution correlates with times of observed radio bursts.
Title: Spectroscopic analysis of the solar flare event on 2002 August
3 with the use of RHESSI and RESIK data
Authors: Gburek, S.; Mrozek, T.; Siarkowski, M.; Sylwester, J.
Bibcode: 2008AdSpR..42..822G
Altcode:
We use simultaneous observations from RESIK and RHESSI instruments to
compare plasma properties of a major solar flare in its rise and gradual
phase. This event occurred on 2002 August 3 (peak time at 19:06 UT). The
flare had a very good coverage with RESIK data and well-resolved
soft and hard X-ray sources were seen in RHESSI images. Spectra of
X-ray radiation from RHESSI images are studied and compared with RESIK
measurements in different flare phases. Result shows large differences
in flare morphology and spectra between flare rise and gradual phase.
Title: Differential emission measure distributions in X-ray solar
flares
Authors: Kepa, A.; Sylwester, B.; Siarkowski, M.; Sylwester, J.
Bibcode: 2008AdSpR..42..828K
Altcode:
X-ray spectrometer RESIK has observed spectra in the four wavelength
bands from 3.3 Å to 6.1 Å. This spectral range contains many emission
lines of H- and He-like ions for Si, S, Ar and K. These lines are formed
in plasma of coronal temperatures (T > 3 MK). Analysis of their
intensities allows studying differential emission measure distributions
(DEM) in temperature range roughly between 3 MK and 30 MK. The aim
of present study was to check whether any relationship exists between
the character of DEM distribution, the event phase and the X-ray flare
class. To do this we have calculated and analyzed the DEM distributions
for a set of flares belonging to different GOES classes from the range
B5.6 X1. The DEM distributions have been calculated using “Withbroe
Sylwester” multiplicative, maximum likelihood iterative algorithm. As
the input data we have used absolute fluxes observed by RESIK in several
spectral bands (lines + continuum). Respective emission functions have
been calculated using the CHIANTI v. 5.2 atomic data package.
Title: He-like Ar XVII triplet observed by RESIK
Authors: Sylwester, B.; Sylwester, J.; Phillips, K. J. H.; Landi, E.
Bibcode: 2008AdSpR..42..833S
Altcode:
We present the observations of He-like Ar triplet lines obtained by
RESIK spectrometer aboard CORONAS-F. Interpretation of intensity ratios
between triplet lines of lower Z elements is known to provide useful
diagnostics of plasma conditions within the emitting source. Here, we
investigate whether triplet line ratios are useful for interpretation
of higher Z element spectra. A high sensitivity, low background and
precise absolute calibration of RESIK allow to consider in addition
also the continuum contribution. This provides a way to determine
the Ar absolute abundance from the observed triplet component
ratios. The method is presented and the results are shown for two
selected flares. Derived values of Ar absolute abundance for these
flares are found to be similar: 2.6 × 10 -6 and 2.9 × 10
-6. They fall in the range between presently accepted Ar
photospheric and coronal abundances.
Title: Determination of K, Ar, Cl, S, Si and Al flare abundances
from RESIK soft X-ray spectra
Authors: Sylwester, J.; Sylwester, B.; Landi, E.; Phillips, K. J. H.;
Kuznetsov, V. D.
Bibcode: 2008AdSpR..42..838S
Altcode:
The RESIK is a high sensitivity, uncollimated bent crystal spectrometer
which successfully operated aboard Russian CORONAS-F solar mission
between 2001 and 2003. It measured for the first time in a systematic
way solar soft X-ray spectra in the four wavelength channels from 3.3
Å to 6.1 Å. This range includes characteristic strong lines of H-
and He-like ions of K, Ar, Cl, Si, S and Al in the respective spectral
channels. A distinguishing feature of RESIK is its possibility
of making reliable measurements of the continuum radiation in
flares. Interpretation of line and the continuum intensities observed
in vicinity of respective strong lines provides diagnostics of plasma
temperature and absolute abundances of K, Ar, Cl, S, Si and Al in
several flares. We analyzed the observed intensities of spectral
lines and the nearby continuum using the CHIANTI v5.2 atomic data
package. A specific, so-called “locally isothermal” approach has
been used in this respect allowing us to make not only flare-averaged
abundance estimates, but also to look into a possible variability of
plasma composition during the course of flares.
Title: Nonthermal and thermal diagnostics of a solar flare observed
with RESIK and RHESSI
Authors: Dzifčáková, E.; Kulinová, A.; Chifor, C.; Mason, H. E.;
Del Zanna, G.; Sylwester, J.; Sylwester, B.
Bibcode: 2008A&A...488..311D
Altcode:
Aims: We aim to prove and diagnose the occurrence of nonthermal
electron distributions in solar flare plasma using X-ray spectral
observations.
Methods: An M4.9 flare on 2003 January 7/8 was
observed with the RESIK instrument in the 3-6 Å wavelength range (2-4
keV) and with RHESSI at energies above 6 keV. The temporal behavior
of RESIK flare spectra has been analyzed for two different types of
velocity distributions - a thermal (Maxwellian) distribution and a
nonthermal plasma distribution of free electrons. The Si XIV, Si XIII,
and Si XIId satellite lines observed with RESIK in the 5-6 Å range
were used to determine the degree of deviation from Maxwellian, and
the equivalent non-Maxwellian pseudo-temperature, τ. The diagnostics
presented are sensitive to the shape of the distribution in the energy
range where the maximum of the electron distribution occurs (where
the bulk of electrons reside) and does not include the influence
of the shape of the high-energy tail of the distribution. Under
the assumption of a Maxwellian distribution of electron velocities,
the plasma temperature was determined from an emission measure (EM)
loci analysis and a differential emission measure (DEM) analysis of
RESIK spectra. The high-energy end of the flare radiative emission
was investigated through RHESSI spectral analysis.
Results:
The nonthermal analysis of RESIK spectra has shown that the largest
deviations of the plasma electron distribution from Maxwellian appeared
during the impulsive phase of the flare. The decay phase spectra had
an almost isothermal character. The pseudo-temperature, τ, reached
its maximum around the peak time of the soft and hard X-ray fluxes. The
temporal behavior of the temperatures derived from the thermal analysis
was similar to the behavior of the nonthermal pseudo-temperature. The
values of the pseudo-temperature were consistent with the temperatures
obtained in both thermal analyses, but lower than the temperatures
derived from the slope of the RHESSI continua. In comparison with the
synthetic isothermal or multithermal spectra, the nonthermal synthetic
spectra fitted the observed Si XIId satellite lines much more closely
(the error is less than 10%). The fluxes in the Si XIId satellite lines
in isothermal or multithermal spectra have been underestimated by a
factor of three or more in comparison to the observed fluxes. The
value of this factor varies with time and it is different for the
different satellite lines.
Conclusions: Evidence was found for
considerable deviations of the distribution of free electrons from
Maxwellian in the plasma during a solar flare. These occurred mainly
during the flare impulsive phase and can be diagnosed using existing
X-ray spectral observations.
Title: Calibration of the SphinX experiment at the XACT facility
in Palermo
Authors: Collura, A.; Barbera, M.; Varisco, S.; Calderone, G.; Reale,
F.; Gburek, S.; Kowalinski, M.; Sylwester, J.; Siarkowski, M.; Bakala,
J.; Podgorski, P.; Trzebinski, W.; Plocieniak, S.; Kordylewski, Z.
Bibcode: 2008SPIE.7011E..2UC
Altcode: 2008SPIE.7011E..82C
Three of the four detectors of the SphinX experiment to be flown on
the Russian mission Coronas-Photon have been measured at the XACT
Facility of the Palermo Observatory at several wavelengths in the
soft X-ray band. We describe the instrumental set-up and report some
measurements. The analysis work to obtain the final calibration is
still in progress.
Title: RESIK Observations of Helium-like Argon X-Ray Line Emission
in Solar Flares
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.
Bibcode: 2008ApJ...681L.117S
Altcode: 2008arXiv0806.1462S
The Ar XVII X-ray line group principally due to transitions
1s2-1s2l (l = s, p) near 4 Å was observed in numerous flares
by the RESIK bent crystal spectrometer aboard CORONAS-F between 2001
and 2003. The three line features include Ar XVII w (resonance line),
a blend of x and y (intercombination lines), and z (forbidden line),
all of which are blended with Ar XVI dielectronic satellites. The
ratio G, equal to [ I(x) + I(y) + I(z) ]/I(w) , varies with electron
temperature Te mostly because of unresolved dielectronic
satellites. With temperatures estimated from GOES X-ray emission,
the observed G ratios agree fairly well with those calculated from
CHIANTI and other data. With a two-component emission measure,
better agreement is achieved. Some S XV and S XVI lines blend with
the Ar lines, the effect of which occurs at temperatures gsim8 MK,
allowing the S/Ar abundance ratio to be determined. This is found to
agree with coronal values. A nonthermal contribution is indicated for
some spectra in the repeating-pulse flare of 2003 February 6.
Title: SphinX: A fast solar Photometer in X-rays
Authors: Sylwester, J.; Kuzin, S.; Kotov, Yu. D.; Farnik, F.; Reale, F.
Bibcode: 2008JApA...29..339S
Altcode:
No abstract at ADS
Title: X-ray studies of flaring plasma
Authors: Sylwester, B.; Sylwester, J.; Phillips, K. J. H.
Bibcode: 2008JApA...29..147S
Altcode:
No abstract at ADS
Title: Cycle 23 flare temperatures and emission measures as derived
from GOES X-ray data
Authors: Gburek, S.; Sylwester, B.; Sylwester, J.
Bibcode: 2008JASTP..70..241G
Altcode:
Solar X-ray observations recorded by the series of geostationary
observational environmental satellites (GOES) are analyzed over a
time interval of the 23rd solar cycle. Statistical analysis of a
large database of GOES events is performed. Temperature and emission
measures derived based on GOES fluxes for all events are compared and
analyzed. A specific application of GOES X-ray measurements to space
weather forecasting is discussed. Namely, using an information about
maximum temperature and maximum emission measure of a given flare one
can assign a probability to this flare of being "non-SEP associated".
Title: The Soft X-ray Spectrophotometer SphinX for the CORONAS-Photon
Mission
Authors: Sylwester, Janusz; Kowalinski, Miroslaw; Szymon, Gburek;
Bakala, Jaroslaw; Kuzin, Sergey; Kotov, Yury; Farnik, Frantisek;
Reale, Fabio
Bibcode: 2008cosp...37.3111S
Altcode: 2008cosp.meet.3111S
The purpose, construction details and calibration results of the
new design, Polish-led solar X-ray spectrophotometer SphinX will be
presented. The instrument constitutes a part of the Russian TESIS X-ray
and EUV complex aboard the forthcoming CORONAS-Photon solar mission
to be launched later in 2008. SphinX uses Si-PIN detectors for high
time resolution (down to 0.01 s) measurements of solar spectra in
the energy range between 0.5 keV and 15 keV. The spectral resolution
allows separating 256 individual energy channels in this range with
particular groups of lines clearly distinguishable. Unprecedented
accuracy of the instrument calibration at the XACT (Palermo) and BESSY
(Berlin) synchrotron will allow for establishing the solar soft X-ray
photometric reference system. The cross-comparison between SphinX and
the other instruments presently in orbit like XRT on Hinode, RHESSI
and GOES X-ray monitor, will allow for a precise determination of
the coronal emission measure and temperature during both very low
and very high activity periods. Examples of the detectors' ground
calibration results as well as the calculated synthetic spectra will
be presented. The operation of the instrument while in orbit will
be discussed allowing for suggestions from other groups to be still
included in mission planning.
Title: Set of instruments for solar EUV and soft X-ray monitoring
onboard satellite Coronas-Photon
Authors: Kotov, Yury; Kochemasov, Alexey; Kuzin, Sergey; Kuznetsov,
Vladimir; Sylwester, Janusz; Yurov, Vitaly
Bibcode: 2008cosp...37.1596K
Altcode: 2008cosp.meet.1596K
Coronas-Photon mission is the third satellite of the Russian
Coronas program on solar activity observation. The main goal of the
"Coronas-Photon" is the study of solar hard electromagnetic radiation
in the wide energy range from UV up to high energy gamma-radiation
(2000MeV). Scientific payload for solar radiation observation consists
of three types of instruments: Monitors (Natalya-2M, Konus-RF, RT-2,
Penguin-M, BRM, PHOKA, Sphin-X, SOKOL spectral and timing measurements
of full solar disk radiation have timing in flare/burst mode up to
one msec. Instruments Natalya-2M, Konus-RF, RT-2 will cover the wide
energy range of hard X-rays and soft gamma-rays (15keV to 2000MeV)
and will together constitute the largest area detectors ever used
for solar observations. Detectors of gamma-ray monitors are based on
structured inorganic scintillators. For X-ray and EUV monitors the
scintillation phoswich detectors, gas proportional counter, CdZnTe
assembly and filter-covered Si-diodes are used. Telescope-spectrometer
TESIS for imaging solar spectroscopy in X-rays has angular resolution
up to 1arcsec in three spectral lines. Satellite platform and
scientific payload is under construction to be launched in autumn
2008. Satellite orbit is circular with initial height 550km and
inclination 82.5degrees. Accuracy of the spacecraft orientation to the
Sun is better 3arcmin. In the report the capability of PHOKA, SphinX,
SOKOL and TESIS as well as the observation program are described
and discussed.
Title: Detailed Calibration of SphinX instrument at the Palermo XACT
facility of INAF-OAPA
Authors: Szymon, Gburek; Collura, Alfonso; Barbera, Marco; Reale,
Fabio; Sylwester, Janusz; Kowalinski, Miroslaw; Bakala, Jaroslaw;
Kordylewski, Zbigniew; Plocieniak, Stefan; Podgorski, Piotr;
Trzebinski, Witold; Varisco, Salvatore
Bibcode: 2008cosp...37.3114S
Altcode: 2008cosp.meet.3114S
The Solar photometer in X-rays (SphinX) experiment is scheduled
for launch late summer 2008 on-board the Russian CORONAS-Photon
satellite. SphinX will use three silicon PIN diode detectors with
selected effective areas in order to record solar spectra in the
X-ray energy range 0.3-15 keV with unprecedented temporal and
medium energy resolution. High sensitivity and large dynamic range
of the SphinX instrument will give for the first time possibility
of observing solar soft X-ray variability from the weakest levels,
ten times below present thresholds, to the largest X20+ flares. We
present the results of the ground X-ray calibrations of the SphinX
instrument performed at the X-ray Astronomy Calibration and Testing
(XACT) facility of INAF-OAPA. The calibrations were essential for
determination of SphinX detector energy resolution and efficiency. We
describe the ground tests instrumental set-up, adopted measurement
techniques and present results of the calibration data analysis.
Title: Coronal plasma composition from RESIK soft X-ray spectra
Authors: Sylwester, Barbara; Sylwester, Janusz; Szymon, Gburek;
Kuznetsov, Vladimir
Bibcode: 2008cosp...37.3110S
Altcode: 2008cosp.meet.3110S
We investigated a number of solar flares' spectra obtained with
the high-sensitive Bragg spectrometer (RESIK) aboard the CORONAS-F
satellite. Using multi-temperature approach, we optimized the fits
of the synthetic and observed spectra in the spectral range from 3.2
˚ to 6 ˚ A A in respect with the adopted plasma composition. The
results indicate that even percent level plasma composition variations
noticeably influence the quality of the fit and therefore allow for a
precise determinations of actual plasma abundances in the investigated
flares. Example patterns of composition variability between flares
are presented.
Title: (im)Balance of Forces in the Corona
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 2007CEAB...31..229S
Altcode:
Observed pattern of variability of solar atmosphere plasma
structures, often accompanied by respective measured Doppler
shifts, provides a direct evidence of imbalanced forces acting in
this environment. Observed motions have been studied in various
energy bands, extending from radio to hard X-rays using ground and
space-borne instruments. Here, we present the results of a dedicated
study of present observational databases in selected energy ranges
with a special interest focused on TRACE movies. In our search we
included also recently released wavelet-processed EIT and LASCO movies
(from SOHO) as they provide additional support to the conclusions
of this study. The main outcome of the work performed is our
better understanding of a basic role played by plasma kernels in
every ``layer'' of the solar atmosphere. These kernels appear to
be present, and rapidly evolve at the locations of violent (intense)
energy release locations. Subsequent formation of a more stable coronal
magnetic structures seen in the form of ``spiders'' or ``scorpions''
is due to self-reorganization of plasma kernels. It comes out that the
spider structure represents a basic, quasi-equilibrium building block
of the solar atmosphere. When observed in a particular image, within
a limited energy band, i.e. optical, EUV, soft or hard X-rays, only a
part of this spider plasma structure can usually be seen, noticeably
resembling a loop-like structure with a brighter top, or an arcade
of loops connected along the ridge of summit kernels, or seemingly
isolated oval source. This energy-dependent visibility effects caused
a general confusion present in solar physics and led to proliferation
of simple fluxtube scenarios. In our study presented herewith, we used
the images obtained with the best available resolution, being enhanced
numerically where possible. For the first time we enhanced the TRACE
image data cube in a systematic way for a particular flare. Based on
the results of analysis of a large number of images, we push forward a
qualitative toy model of atmospheric connectivity pattern (Sylwester,
J. and Sylwester, B., 2004). This hierarchic model is able to handle
in a natural way observed complexity of atmospheric phenomena. Here, we
discuss to some extent verifiable predictions of the hierarchical model
outlining a number of new studies which might prove the concept. These
predictions arise concurrently with the first data coming down from new
missions being recently launched into orbit: the Hinode and the Stereo.
Title: X-Ray Study of Compact Flare Kernels
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 2007CEAB...31...77S
Altcode:
We have selected eight compact X-ray sources observed by Soft X-ray
Telescope (SXT) during the Yohkoh mission. Respective sequences of
images have been deconvolved in order to remove the instrumental
blur. In this way the spatial resolution on the images has been
increased to ∼ 1 arcsec. The analysis of deconvolved images allowed
us to study the dynamics and morphology of these compact plasma kernels
and infer their thermodynamic characteristics. Corresponding Hard X-ray
Telescope (HXT) observations were incorporated into the analysis where
possible. In addition the standard X-ray emission in the two channels
observed by GOES satellite has been incorporated into the analysis.
Title: A benchmark study for CHIANTI based on RESIK solar flare
spectra
Authors: Chifor, C.; Del Zanna, G.; Mason, H. E.; Sylwester, J.;
Sylwester, B.; Phillips, K. J. H.
Bibcode: 2007A&A...462..323C
Altcode:
Aims:To perform a benchmark analysis for the recent version of the
CHIANTI atomic database (v. 5.2) based on high-resolution solar
flare X-ray spectra in the range 3.4-6.1 Å from the RESIK crystal
spectrometer on the CORONAS-F spacecraft.
Methods: A C5.8 flare
occurring on 2003 February 22 was chosen for analysis. RESIK spectra
of this flare include emission lines of He-like and H-like K, Ar,
S, and Si, with some dielectronic lines. Initially, two independent
plasma diagnostic techniques are employed: an emission measure
(EM) loci analysis using the line flux and the line contribution
function G(T_e, N_e), and a new method based on continuum fluxes and
contribution functions. We further apply a differential emission measure
(DEM) analysis, from which CHIANTI synthetic spectra are derived. The
continuum from RESIK spectra is checked against simultaneous RHESSI and
GOES observations. Comparisons of CHIANTI synthetic spectra with those
from the MEKAL code in the 3.4-6.1 Å range are also presented.
Results: The emitting plasma appears multi-thermal, having one
dominant temperature component determined independently from the line
and continuum EM loci and DEM analyses. Consistency between line
and continuum emissions requires photospheric elemental abundances
(Asplund et al. 2005), with a depleted sulphur abundance. With the
exception of RESIK channel 4 (5.0-6.1 Å), we find overall very
good agreement between the calculated and observed intensities. From
comparisons with other instruments, RESIK's precision in the continuum
level is confirmed to be within the estimated 20% uncertainties in the
intensity calibration. We find general agreement between CHIANTI and
MEKAL isothermal spectra, but we note that the atomic data for the
Si xii and Si xiii ions contained in CHIANTI are more complete.
Conclusions: .RESIK observations of both lines and continua are
suitable for characterising the properties of the flaring plasma such
as temperature, emission measure and elemental abundance. These spectra
can be used to evaluate any atomic database.
Title: The Trace Telescope Point Spread Function for the 171 Å Filter
Authors: Gburek, S.; Sylwester, J.; Martens, P.
Bibcode: 2006SoPh..239..531G
Altcode: 2006SoPh..tmp...76G
We perform an analysis of the TRACE telescope blur from EUV
images. Theblur pattern is discussed in terms of the telescope
point-spread function (PSF) for the 171 Å filter. The analysis
performed consists of two steps. First, an initial shape for the
PSF core is determined directly from TRACE EUV images. Second,
the blind-deconvolution method is used for obtaining the final PSF
shape. The PSF core peak is fitted by analytical functions to determine
its parametric characteristics. The determined PSF includes the core
central peak and peaks caused by diffraction effects inherent in TRACE
EUV data. The diffraction portion of the PSF is studied theoretically
in the Fraunhofer diffraction limit. The temperature dependence of the
TRACE PSF shape is investigated for a selected temperature range. We
also discuss general properties of the obtained PSF and its possible
applications.
Title: Determination of differential emission measure from X-ray
solar spectra registered by RESIK aboard CORONAS-F
Authors: Kepa, A.; Sylwester, J.; Sylwester, B.; Siarkowski, M.;
Stepanov, A. I.
Bibcode: 2006SoSyR..40..294K
Altcode:
The differential emission measure (DEM) describes the temperature
distribution of the emitting plasma. The DEM distribution allows one
to study the physical conditions and the energy of flares in detail
(including the mean temperature and the total emission measure). In
this paper, we analyze the time changes of the DEM distributions
for a selected flare, which has been observed with the RESIK
instrument. To calculate the differential emission measure, we used
the Withbroe-Sylwester (W-S) iterative algorithm corresponding to
the maximum likelihood procedure. The required emission functions
were calculated with the CHIANTI package. We calculated the DEM for
four available estimates of the ionization equilibrium and coronal
composition of plasma.
Title: RESIK Flare X-ray Spectra: Benchmark Analysis And Plasma
Diagnostics Based On CHIANTI
Authors: Chifor, Cristina; Del Zanna, G.; Sylwester, J.; Sylwester,
B.; Phillips, K. J. H.
Bibcode: 2006SPD....37.1314C
Altcode: 2006BAAS...38..243C
We perform a benchmark analysis between the recent version 5.2 of the
CHIANTI atomic database and high-resolution solar flare X-ray spectra
obtained with the RESIK instrument in the wavelength range 3.4-6.1
Angstrom. The physical properties of emitting plasmas during a C-class
solar flare on 2003 February 22 are determined through two independent
plasma diagnostic techniques: an emission measure analysis applied to
strong, unblended atomic lines and a new method analyzing continuum
contributions. From these parameters, synthetic spectra are derived
using the CHIANTI database and software. The predicted spectra are then
benchmarked against observed RESIK lines and continuum. Comparisons
between CHIANTI and the MEKAL spectral code are also presented. In
order to evaluate the level of confidence in RESIK's calibration, RESIK
continuum levels are checked against simultaneous RHESSI observations
as well as GOES continua obtained from parameters derived from GOES
channel ratios.
Title: Thermodynamics of selected solar flares as determined from
the analysis of the spectra obtained with the RESIK instrument
Authors: Sylwester, B.; Sylwester, J.; Kepa, A.; Kordylewski, Z.;
Phillips, K. J. H.; Kuznetsov, V. D.
Bibcode: 2006SoSyR..40..125S
Altcode:
The RESIK instrument is an X-ray spectrometer with bent crystals
onboard the CORONAS-F satellite. It was used to observe the spectra
of solar flares, active regions, and quiet corona. During the period
of the instrument’s operation, many spectra were collected in four
energy channels covering the wavelength range from 3.2 to 6.1 Å. For
the present analysis, we selected solar flares of various X-ray classes
(B, C, and M in the GOES notation), which were observed during moderate
level of solar activity (from January to March 2003). The analysis
of the RESIK spectra fulfilled with different techniques allowed
us to determine the temperature, emission measure, and temperature
distribution of the differential emission measure, as well as to
examine their time variability.
Title: Si XII X-Ray Satellite Lines in Solar Flare Spectra
Authors: Phillips, K. J. H.; Dubau, J.; Sylwester, J.; Sylwester, B.
Bibcode: 2006ApJ...638.1154P
Altcode:
The temperature dependence of the Si XII n=3 and 4 dielectronic
satellite line features at 5.82 and 5.56 Å, respectively, near the
Si XIII 1s2-1s3p and 1s2-1s4p lines (5.681 and
5.405 Å), is calculated using atomic data presented here. The resulting
theoretical spectra are compared with solar flare spectra observed by
the RESIK spectrometer on the CORONAS-F spacecraft. The satellites, like
the more familiar n=2 satellites near the Si XIII 1s2-1s2p
lines, are formed mostly by dielectronic recombination, but unlike the
n=2 satellites, are unblended. The implications for similar satellite
lines in flare Fe spectra are discussed.
Title: Determination of flaring plasma characteristics from RESIK
X-ray spectra
Authors: Sylwester, B.; Sylwester, J.; Kepa, A.; Phillips, K. J. H.
Bibcode: 2006IAUS..233..165S
Altcode:
We present spectral analysis methods suitable for diagnostics of
flaring plasma from RESIK spectra. RESIK is the uncollimated bent
crystal spectrometer aboard the Russian CORONAS-F solar mission. It
collected many flare and active region spectra in the wavelength
range 3.3 Å-6.1 Å, where strong emission lines of Si, S, Ar, and K
are present. Based on a careful instrument calibration the absolute
fluxes in the individual spectral lines have been obtained. These
fluxes have been used for determination of a set of thermodynamic
parameters characterizing the emitting plasma and for studies their
time behavior during selected flares.
Title: He-like triplets observed by RESIK
Authors: Sylwester, B.; Sylwester, J.; Phillips, K. J. H.; Landi, E.
Bibcode: 2006cosp...36.2877S
Altcode: 2006cosp.meet.2877S
The RESIK is a high sensitivity uncollimated bent crystal spectrometer
which successfully operated aboard Russian CORONAS-F solar mission
between 2001 and 2003 It measured systematically for the first time
solar soft X-ray spectra in the four wavelength channels from 3 3 AA to
6 1 AA This range includes characteristic triplet lines of He-like ions
of K Ar Cl and S in the respective spectral channels Interpretation of
observed line ratios within each triplet provides diagnostics of plasma
conditions in the emitting source We reduced the observed spectra for
a number of flares using the absolute RESIK calibration software We
analyzed the observed intensities of spectral line components comprising
the triplets and investigated their time variability The evolution of
important plasma parameters like temperature and emission measure have
been studied for selected events Flaring plasma densities were measured
from these parameters using X-ray brightness maps as determined from
the RHESSI observations The CHIANTI v5 1 atomic data package was used
as a consistent tool for spectral data analysis
Title: Lines in the range 3.2 6.1 Å observed in RESIK spectra
Authors: Sylwester, B.; Sylwester, J.; Siarkowski, M.; Phillips,
K. J. H.; Culhane, J. L.; Lang, J.; Brown, C.; Kuznetsov, V. D.
Bibcode: 2006AdSpR..38.1534S
Altcode:
RESIK is a Bragg bent crystal X-ray spectrometer on board the CORONAS-F
satellite. Between 24 August 2002 and 22 May 2003 RESIK collected
a large number of solar X-ray spectra in four energy bands covering
the range 3.2 6.1 Å. A recent absolute calibration has allowed us to
make detailed identification of observed spectral features, and from
observed line and continuum fluxes to get temperature, emission measure,
etc. The lines were identified using spectra averaged over periods of
various solar activity levels. These averaged spectra contain a number
of strong lines with transitions in H- and He-like ions of K, Ar, S
and Si. Some of them are resonance parent lines and their satellites
which were observed with other spectrometers and have been described
elsewhere. Here, we report detection of several lines not previously
observed in solar spectra, including lines of H-like and He-like S
and Si ions with transitions 1s np and 1s2 1snp, n up to
10. In addition we provide identification of the He-like Cl (Cl XVI)
triplet in the range 4.43 4.45 Å. The feature at 4.182 Å, which is
the wavelength of the H-like Cl (Cl XVII) Lyα line, is probably a
blend of S XIV satellites from cooler plasma.
Title: Wrocław in Space: X-ray Diagnostics of Solar Corona
Authors: Siarkowski, M.; Kȩpa, A.; Sylwester, B.; Sylwester, J.
Bibcode: 2006AIPC..812..393S
Altcode:
X-ray observations of the solar corona have been undertaken in Solar
Physics Division (Space Research Centre of the Polish Academy of
Sciences, Wrocław) for more than 35 years. Short history of these
observations is presented. We focus mainly on the results from the
latest experiments. These are hard X-ray photometer onboard the
INTERBALL-Tail Probe and two Bragg crystal spectrometers recording
solar X-ray spectra from CORONAS-F satellite. Such observations provide
useful information on solar coronal plasma heated up to temperatures
of several 106 - 107 K.
Title: Determination of K, Ar, Cl, S and Si flare abundances from
RESIK soft X-ray spectra
Authors: Sylwester, J.; Sylwester, B.; Landi, E.; Phillips, K. J. H.;
Kuznetsov, V. D.
Bibcode: 2006cosp...36.2871S
Altcode: 2006cosp.meet.2871S
We investigate possible variability of coronal plasma composition
during flares based on the analysis of spectra measured by RESIK bent
crystal spectrometer aboard the CORONAS-F solar mission We fit the
measured spectra with synthesized theoretical ones in the vicinity of
the observed He-like ions The spectral synthesis is performed based on
CHIANTI v5 1 spectral code in so-called locally isothermal approximation
with the aim to reproduce observed line-to-continuum ratios Influence
of possible multitemperaure plasma structure is considered and discussed
based on respective differential emission measure calculations
Title: Differential emission measure distributions in X-ray
solarflares
Authors: Kepa, A.; Sylwester, B.; Siarkowski, M.; Sylwester, J.
Bibcode: 2006cosp...36.1295K
Altcode: 2006cosp.meet.1295K
X-ray spectrometer RESIK has observed spectra in the four wavelength
bands from 3 3 AA to 6 1 AA This spectral range contains many emission
lines of H- and He-like ions for Si S Ar and K These lines are formed
in plasma of coronal temperatures T 3 MK Analysis of their intensities
allows studying differential emission measure distributions DEM in
temperature range roughly between 3 MK and 30 MK The aim of present
study was to check whether any relationship exists between the
character of DEM distribution and the X-ray flare class To do this we
have calculated the DEM distributions for a set of flares belonging to
different GOES classes from the range B4 to X1 The DEM distributions
have been calculated using Withbroe - Sylwester multiplicative maximum
likelihood iterative algorithm As the input fluxes for DEM calculations
we have used absolute fluxes observed in several individual lines and
spectral bands observed by RESIK Respective emission functions have
been calculated using the CHIANTI v 5 1 atomic data package
Title: Temperature-sensitive line ratio diagnostics based on Si
satellite-to-resonance line ratios for 1s2 1snp transitions
Authors: Phillips, K. J. H.; Dubau, J.; Sylwester, J.; Sylwester,
B.; Culhane, J. L.; Doschek, G. A.; Lang, J.
Bibcode: 2006AdSpR..38.1543P
Altcode:
Dielectronic satellite lines due to 1s2n‧l‧ 1snpn‧l‧
(n = 3, 4) transitions in Li-like Si (Si XII) occur at 5.818 and
5.565 Å, on the long wavelength side of the He-like Si (Si XIII)
1s2 1s3p and 1s2 1s4p lines at 5.681 and 5.384 Å,
respectively. They have been extensively observed with the RESIK crystal
spectrometer on the Russian spacecraft CORONAS-F. As with corresponding
satellites 1s2nl 1s2pnl on the long-wavelength side of
the Si XIII 1s2 1s2p resonance line, there is an inverse
temperature dependence of the intensity ratio of the satellites to the
He-like ion lines (Isat/IHe). New atomic data
are used to calculate the Si XII satellite line intensities and thus
the Isat/IHe ratio. RESIK observations of the
ratio in solar flares, together with temperatures from the ratio of
the two GOES X-ray channels, are compared with theoretical variation
of the ratio with temperature. The good agreement indicates this to
be a valuable temperature diagnostic for solar flares and laboratory
plasmas such as tokamaks. There are implications for similar satellites
in Fe line spectra which are observed with broad-band resolution by
the RHESSI solar flare mission.
Title: Observations of 1s2 1s np and 1s np lines in RESIK
soft X-ray spectra
Authors: Kepa, A.; Sylwester, J.; Sylwester, B.; Siarkowski, M.;
Phillips, K. J. H.; Kuznetsov, V. D.
Bibcode: 2006AdSpR..38.1538K
Altcode:
RESIK is the X-ray bent crystal spectrometer on the CORONAS-F
satellite. Between 2002 and 2003, RESIK collected numerous spectra
of active regions and flares in the wavelength range from 3.37
to 6.09 Å. This range includes many strong emission lines due to
transitions 1s2 1s np and 1s np, in He-like and H-like ions,
respectively; the n = 2 and 3 lines are routinely observed for Si,
S and Ar ions. For some flares RESIK has observed enhanced emission
in spectral features coinciding with lines due to transitions for n up
to 9 or 10. Identifications of these features, not previously observed
in astrophysical spectra, are presented in this paper. Their observed
intensities are compared with those from theory.
Title: Analysis of potassium abundance in a large number of flares
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Culhane,
J. L.; Brown, C.; Lang, J.; Stepanov, A. I.
Bibcode: 2006AdSpR..38.1490S
Altcode:
An initial study of spectra observed in the shortest wavelength
channel (3.40-3.80 Å) of the RESIK X-ray spectrometer on CORONAS-F
indicates the presence of substantial flare-to-flare variations in
the line-to-continuum ratio of several lines, in particular He-like
potassium (K XVIII) lines, occurring in the range 3.53-3.57 Å. The
observed variations are larger than those expected from temperature
variations. This has motivated a study of possible variations in
the potassium abundance in the observed spectra. With a new RESIK
calibration available, we have obtained absolute fluxes of the K
XVIII resonance line as well as the continuum and lines observed in
other RESIK channels (3.40-6.05 Å) for some 1163 intervals observed
early in 2003. Analysis of these observations allowed us to determine
the average absolute potassium abundance for the period studied and
investigate the variability of abundance. The results obtained are
presented and discussed.
Title: Dem Distributions for Short and Long Duration Flares as
Determined from Resiksoft X-Ray Spectra
Authors: Kepa, A.; Sylwester, J.; Sylwester, B.; Siarkowski, M.;
Kuznetsov, V.
Bibcode: 2005ESASP.600E..87K
Altcode: 2005dysu.confE..87K; 2005ESPM...11...87K
No abstract at ADS
Title: Evolution of Flaring Plasma Components on Diagnostic Diagrams
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kepa, A.
Bibcode: 2005ESASP.600E.143S
Altcode: 2005ESPM...11..143S; 2005dysu.confE.143S
No abstract at ADS
Title: Plasma Kernels in Homologous (?) Flares
Authors: Sylwester, Barbara; Sylwester, J.; Kepa, A.
Bibcode: 2005ESASP.600E.169S
Altcode: 2005ESPM...11..169S; 2005dysu.confE.169S
No abstract at ADS
Title: Comparison of the solar corona and the coronae above accretion
disks surrounding black holes
Authors: Czerny, B.; Collin, S.; Dovciak, M.; Dumont, A. -M.; Falewicz,
R.; Goosmann, R.; Karas, V.; Ponti, G.; Pres, P.; Siarkowski, M.;
Sylwester, J.; Życki, P. T.
Bibcode: 2005AIPC..801..188C
Altcode:
We develope a model of an accretion disk corona motivated by the
observed solar corona. Such a model consists of many unresolved magnetic
loops coexisting above the disk surface. We compare the predicted
energy-dependent fractional variability amplitude with the observed
one, both for standard rms(E) and point-to-point rms(E). Finally, we
compare the parameters of a single large flare seen in the lightcurve
of MCG -6-15-30 with large solar flares.
Title: Observations of Solar X-ray Spectra by the DIOGENESS and
RESIK Spectrometers Onboard the CORONAS-F Satellite
Authors: Sylwester, J.; Sylwester, B.; Kordylewski, Z.; Phillips,
K. J. H.; Kuznetsov, V. D.; Boldyrev, S. I.
Bibcode: 2005SoSyR..39..479S
Altcode:
The first scientific results of the analysis of the X-ray spectra of
flares and active regions in the solar corona obtained by Polish-led
spectrometers RESIK and DIOGENESS onboard the CORONAS-F satellite
are presented. The instruments were designed and made in the Solar
Physics Division of the Space Research Center of the Polish Academy
of Sciences (SRC PAS, Wroclaw, Poland). The Institute of Terrestrial
Magnetism, Ionosphere, and Radio Wave Propagation (IZMIRAN, Russia)
and the Astronomical Institute of the Czech Academy of Sciences also
participated in designing the DIOGENESS spectrometer, while IZMIRAN
(Russia), Mullard Space Science Laboratory (MSSL, Great Britain),
Rutherford Appleton Laboratory (RAL, Great Britain), and Naval Research
Laboratory (NRL, United States) contributed to the development of the
RESIK spectrometer. In the paper, we give spectra obtained in a number
of previously unstudied spectral ranges and a preliminary identification
of new spectral lines. The results for the shifts of the X-ray spectral
lines observed with the use of a so-called dopplerometer configuration
are also presented. Methods for determining the abundances of the rare
elements in the solar corona, including chlorine, potassium, and argon,
are described.
Title: Dielectronic Satellites Near the 1s2 - 1snp (n >
2) Lines of He-like Ions in Solar X-ray Spectra
Authors: Landi, E.; Phillips, K. J. H.; Sylwester, J.; Sylwester,
B.; Dennis, B. R.; Dubau, J.
Bibcode: 2005AIPC..774..173L
Altcode:
We discuss the importance of dielectronic satellites with transitions
1s22l - 1s2l3p on the long-wavelength side of He-like ion
lines 1s2 - 1snp (n > 2). Their intensity ratios with
the He-like ion lines have an inverse temperature dependence, making
them useful as diagnostics. This is examined in the case of Si and
Fe satellites.
Title: Si XII X-ray Satellite Lines in Solar Flare Spectra
Authors: Phillips, K. J.; Sylwester, J.; Sylwester, B.; Dubau, J.
Bibcode: 2005AGUSMSP23B..08P
Altcode:
We demonstrate the temperature dependence of the intensity ratio of
dielectronic satellite lines due to Li-like Si (Si XII) to nearby
He-like Si (Si XIII) 1s2 - 1snp(n=3, 4, 5) lines emitted in solar
flare X-ray spectra. These lines, which occur in the wavelength
range 5.253~Å--5.818~Å, have been observed by the RESIK bent crystal
spectrometer on the Russian CORONAS-F solar mission. Line features made
up of several strong satellites with transitions 1s2 n'l' - 1s n'l'
nl lie near the `parent' Si XIII lines, transition 1s2 1S0 - 1snp 1P1;
thus, the feature at 5.818~Å is made up of several blended Si XII
satellites with `spectator' electrons n'l'=2s or 2p and nl=3p or 3d,
and lies on the long-wavelength side of the Si XIII 1s2 - 1s3p line
at 5.681~Å. A similar n=4 satellite feature at 5.565~Å is on the
long-wavelength side of the Si XIII 1s2 - 1s4p line at 5.384~Å. The
Si XII satellites are formed by dielectronic recombination and direct
(inner-shell) excitation. The ratio Is/IHe (Is = Si XII satellite
line flux, IHe = Si XIII line flux) depends on electron temperature
approximately as Te-1. The atomic data needed to calculate Is/IHe for
individual n=3 and n=4 Si XII satellite lines have been calculated
and will be presented in this paper; excitation mechanisms including
those by dielectronic recombination and inner-shell excitation were
included using the SUPERSTRUCTURE and Distorted Wave formalisms. With
these and theoretical fluxes of the Si XIII lines, synthetic spectra
were calculated and compared with RESIK solar flare spectra. Values
of Is/IHe measured from RESIK spectra during the decay of four
long-duration solar flares, together with temperatures estimated
both from the ratio of the GOES channels and from the ratio of total
fluxes in two of the four RESIK channels, enable a comparison to
be made with theoretical curves. The agreement with the theoretical
curve based on synthetic spectra is within expected uncertainties,
and the Te-1 dependence is confirmed. Satellites for other Li-like
ions are expected to have a similar temperature sensitivity, in
particular the Li-like Fe satellites near He-like Fe lines. Although
these lines have not been seen with high-resolution spectrometers,
the RHESSI mission observes the whole complex during solar flares
as the so-called Fe/Ni line feature; addition of these satellites to
theoretical spectra from the CHIANTI code have reduced a long-standing
discrepancy with intensities observed by RHESSI. KJHP acknowledges
an NRC Research Associateship, and JS and BS acknowledge support from
grants (2.P03D.002.22 and PBZ-KBN-054/P03/2001) of the Polish Committee
for Scientific Research. RESIK is a joint project between NRL (USA),
MSSL, and RAL (UK), IZMIRAN (Russia), and SRC (Poland). The CORONAS-F
mission is led by the IZMIRAN Institute.
Title: Small Scale Events Seen in SXT Observations
Authors: Gburek, S.; Sylwester, J.
Bibcode: 2005ASSL..320..255G
Altcode: 2005smp..conf..255G
No abstract at ADS
Title: The thermal X-ray spectrum of the 2003 April 26 solar flare
Authors: Dennis, B. R.; Phillips, K. J. H.; Sylwester, J.; Sylwester,
B.; Schwartz, R. A.; Tolbert, A. K.
Bibcode: 2005AdSpR..35.1723D
Altcode:
Observations and their analysis of the thermal X-ray spectrum of the
M2 flare on 2003 April 26 are described. The spectrum observed by the
RHESSI mission cover the energy range from ∼5 to ∼50 keV. With
its ∼1-keV spectral resolution, intensities and equivalent widths
of two line complexes, the Fe line group at 6.7 keV (mostly due to Fe
XXV lines and Fe XXIV satellites) and the Fe/Ni line group at 8 keV
(mostly due to higher-excitation Fe XXV lines and Ni XXVII lines)
were obtained as a function of time through a number of flares. The
abundance of Fe can also be determined from RHESSI spectra; it appears
to be consistent with a coronal value for at least some times during
the flare. Comparisons of RHESSI spectra with those from the RESIK
crystal spectrometer on CORONAS-F show very satisfactory agreement,
giving much confidence in the intensity calibration of both instruments.
Title: Multi-wavelength study of a strong impulsive solar limb flare
on 2002 August 3
Authors: Gburek, S.; Sylwester, J.; Sylwester, B.; Dennis, B. R.;
Phillips, K. J. H.
Bibcode: 2005AdSpR..35.1728G
Altcode:
We made a detailed study of the impulsive solar flare of GOES class
X1.0 which occurred near the west limb on 2002 August 3, peak time
19:07 UT. There is particularly good data coverage of this event, with
simultaneous observations in EUV, soft and hard X-rays available. We
used TRACE 171 Å images to study the morphology and evolution of this
event. Soft X-ray spectra in the wavelength range 3.34-6.05 Å measured
by the RESIK Bragg crystal spectrometer on CORONAS-F were used for
determination of the evolution of the flare plasma temperature. Data
from the RHESSI instrument were used to investigate properties of the
higher-temperature plasma during the flare.
Title: Resik: A Bent Crystal X-ray Spectrometer for Studies of Solar
Coronal Plasma Composition
Authors: Sylwester, J.; Gaicki, I.; Kordylewski, Z.; Kowaliński,
M.; Nowak, S.; Płocieniak, S.; Siarkowski, M.; Sylwester, B.;
Trzebiński, W.; Bakała, J.; Culhane, J. L.; Whyndham, M.; Bentley,
R. D.; Guttridge, P. R.; Phillips, K. J. H.; Lang, J.; Brown, C. M.;
Doschek, G. A.; Kuznetsov, V. D.; Oraevsky, V. N.; Stepanov, A. I.;
Lisin, D. V.
Bibcode: 2005SoPh..226...45S
Altcode:
We describe the RESIK (REntgenovsky Spektrometr s Izognutymi Kristalami)
instrument, consisting of two double-channel X-ray spectrometers,
designed to observe solar active region and flare plasmas. RESIK is
one of the instruments making up the scientific payload of the Russian
CORONAS-F solar mission. The uncollimated spectrometer uses two silicon
and two quartz bent crystals observing flare, active region and coronal
spectra in four wavelength bands with a resolving power (λ/Δ λ)
of ∼1000. The wavelength coverage, 3.3-6.1 Å, includes emission
lines of Si, S, Cl, Ar, and K and in the third diffraction order,
the wavelength range includes He-like Fe lines (1.85 Å) and Ni lines
(1.55 Å) with dielectronic satellites, emitted during intense, hot
flares. The instrument is believed to be the best calibrated space-borne
crystal spectrometer flown to date. The spectrometer dynamically adjusts
the data gathering intervals from 1 s to 5 minutes, depending on the
level of solar X-ray emission at the time of observation. The principal
aims of RESIK are the measurements of relative and absolute element
abundances in the emitting plasma and the temperature distribution of
plasma (differential emission measure) over the temperature interval 3
and 50 MK. This paper summarizes the scientific objectives of RESIK
and describes the design, characteristics, and performance of the
instrument.
Title: RHESSI, RESIK, and GOES Observations of the Solar Flare
Thermal Spectrum
Authors: Phillips, K. J. H.; Dennis, B. R.; Sylwester, J.; Sylwester,
B.
Bibcode: 2004AAS...204.8701P
Altcode: 2004BAAS...36..818P
The bulk of the thermal spectrum of solar X-ray flares extends from
very soft X-rays (<<1 keV) to beyond 10 keV. We present results
from three instruments detecting this spectrum: RHESSI, GOES, and
the Polish-led RESIK crystal spectrometer on the Russian Coronas-F
mission. RHESSI makes imaging and spectral observations at energies
above ∼ 5 keV; RESIK operates in a first-order diffraction mode
with energy range 2.0 to 3.7 keV and, for selected stronger flares,
in a third-order mode with energy range 6.1 to 8.6 keV; GOES makes
flux measurements in two wide energy bands between ∼ 1.5 and ∼
25 keV. Simultaneous observations by all three instruments were made
of an M2 flare on 2003 April 26, with RESIK in its first-order mode
at the beginning and decay portions of the flare and in third-order
during an 8-minute interval at the flare peak. Comparison of RHESSI
and both first-order and third-order RESIK spectra indicate agreement
to within the expected uncertainties of ∼ 25%. Both instruments
observe the continuum emission and the Fe line feature (mostly Fe XXV
lines and satellites) at 6.7 keV. The Fe/Ni line feature at 7.9 keV
(Fe XXV and Ni XXVII lines) is less certainly detected. The thermal
spectra derived from the GOES channel ratios agree closely with RESIK
and RHESSI spectra. Measurements of the equivalent width of the Fe
line feature and other lines in the RESIK first-order range allow
absolute element abundances to be determined during the flare for
comparison with standard photospheric values. KJHP acknowledges
an NRC Research Associateship, and JS and BS acknowledge support from
grants (2.P03D.002.22 and PBZ-KBN-054/P03/2001) of the Polish Committee
for Scientific Research. RESIK is a joint project between NRL (USA),
MSSL and RAL (UK), IZMIRAN (Russia), and SRC (Poland). The Coronas-F
mission is led by the IZMIRAN Institute.
Title: First Determinations of Differential Emission Measure
Distribution from RESIK X-ray Spectra
Authors: Kepa, A.; Sylwester, J.; Sylwester, B.; Siarkowski, M.
Bibcode: 2004IAUS..223..461K
Altcode: 2005IAUS..223..461K
RESIK Bragg spectrometer aboard CORONAS-F solar observatory collected
spectra of hundreds of solar flares in the unique spectral range between
3.3 Å and 6.1 Å. The instrument's absolute and relative calibrations
are now finished which allows for the first time to interpret the
observations in terms of the differential emission measure (DEM)
distribution. With known DEM shape it is possible to derive and study
in detail flaring plasma composition and energy balance. Here we report
results of using an improved Maximum Likelihood iterative algorithm
(Withbroe-Sylwester) for determination of the DEM distributions for
7 January 2003 flare at 23:30 UT. The study is based on the absolute
flux values observed in a number of strong H- and He-like transitions
of K xviii, Ar xviii, Ar xvii, S xvi, S xv, Si xiv and Si xiii ions. In
this respect, we use line and continuum X-ray emissivities as provided
by CHIANTI package from SolarSoft.
Title: Abundances of Potassium, Argon, and Sulphur in Solar Flares
Authors: Phillips, K. J. H.; Sylwester, J.; Sylwester, B.; Landi, E.
Bibcode: 2004IAUS..219..176P
Altcode:
No abstract at ADS
Title: Results of solar observations on-board the CORONAS-F satellite
Authors: Kuznetsov, V. D.; Sobelman, I. I.; Zitnik, I. A.; Kotov,
Yu. D.; Kocharov, G. E.; Kuznetsov, S. N.; Mazets, E. P.; Nusinov,
A. A.; Pankov, A. M.; Sylwester, J.
Bibcode: 2004cosp...35..812K
Altcode: 2004cosp.meet..812K
The CORONAS-F mission experiments and results have been reviewed. The
observations with the DIFOS multi-channel photometer in a broad
spectral range from 350 to 1500 nm have revealed that the relative
amplitudes of p-modes of the global solar oscillations depend on the
wavelength (This result agrees perfectly well with the earlier data
obtained in a narrower spectral range. The SPIRIT EUV observations
have enabled the study of various manifestations of solar activity and
high-temperature events on the Sun. The data from the gamma spectrometer
HELICON, flare spectrometer IRIS, amplitude-time spectrometer AVS-F,
and X-ray spectrometer RPS-1 have been used to analyze the X- and
gamma-ray emission from solar flares and to simulate the parameters
of solar plasma and supra-thermal electron beams in the generation
region. The absolute and relative content of various elements (such
as potassium, argon, and sulfur) in the flare-generated solar plasma
has been determined for the first time with the X-ray spectrometer
RESIK. The Solar Cosmic Ray Complex has been used to study the solar
flare effects in the Earth's environment. The UV emission variations
recorded during solar flares in the vicinity of the 120-nm wavelengh
been analyzed and the relative variation amplitude has been determined.
Title: Connectivity pattern in the corona
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 2004HvaOB..28...71S
Altcode:
We present images of the structures indicative for the existence
of hierarchical, self-similar organization of global connections
in the solar atmosphere. We discuss a geometrical model of the basic
building block, the atmosphere is envisaged to be made of. The important
elements of the proposed building block are the plasma kernels and the
connections between them. It appears that the concept of hierarchical
organization is generally applicable to the solar atmosphere from
the base of the photosphere towards the interplanetary space. If so,
we point out profound consequences of such a hierarchical system for
transport of energy and dynamics within the solar atmosphere. Possible
scenarios for the plasma dynamics and acceleration mechanisms are
also outlined.
Title: Identification of Lines in the Range 3.35 A - 6.1 A Observed
in RESIK Spectra
Authors: Sylwester, B.; Sylwester, J.; Siarkowski, M.; Phillips,
K. J. H.; Culhane, J. L.; Lang, J.; Brown, C.; Kuznetsov, V. D.
Bibcode: 2004cosp...35.2663S
Altcode: 2004cosp.meet.2663S
RESIK is the Bragg bent crystal X-ray spectrometer on board CORONAS-F
satellite. Between August 24, 2002 and May 22, 2003, the instrument
collected a large database of solar X-ray spectra in four energy bands
covering the range 3.35 Å - 6.1 Å. We have recently calibrated the
spectra in order to determine an absolute wavelength scale and absolute
photon fluxes. This has allowed us to make detailed indentifications
of observed spectral features, and to interpret the observed line
and continuum fluxes in terms of basic plasma characteristics
like temperature and emission measure. Our line identifications
have been made using spectra averaged over periods of various solar
activity levels, e.g. flare rise and decay phases, non-flaring active
regions and quiet Sun. The spectra contain a number of strong lines
corresponding to the transitions in H- and He-like ions of K, Ar, S
and Si. Some of these lines are resonance lines and their satellites
which have already been noted by previous authors using data from
other spectrometers, but several lines have never been observed in
solar spectra before. These include lines of H-like and He-like S and
Si corresponding to transitions 1s - np and 1s^2 -1s np with n up to
∼10. In addition we provide indentification of the H-like Cl (Cl
XVII) Ly-alpha lines at 4.182 Å, and He-like Cl (Cl XVI) triplet in
the range 4.43 Å,- 4.45 Å, never before observed simultaneously. We
will present detailed identifications of these lines in this paper.
Title: Detection of H- and He-like resonance lines of chlorine in
solar flare spectra
Authors: Sylwester, B.; Sylwester, J.; Siarkowski, M.; Phillips,
K. J. H.; Landi, E.
Bibcode: 2004IAUS..223..671S
Altcode: 2005IAUS..223..671S
Preliminary analysis of spectra collected with the RESIK Bragg bent
crystal X-ray spectrometer aboard CORONAS-F indicates the presence
of many spectral features which until recently were unidentified. We
present RESIK spectra in which the H-like Cl XVII Lyalpha line at 4.182
Å and He-like Cl XVI triplet components in the range 4.43 Å-4.45 Å
are identified.
Title: Bragg spectroscopy from CORONAS-F
Authors: Sylwester, J.
Bibcode: 2004IAUS..223..409S
Altcode: 2005IAUS..223..409S
There are dozen instruments successfully operating aboard the solar
satellite CORONAS-F, which was launched in the summer of 2001. Among
them are two (Polish-led) Bragg crystal spectrometers - RESIK and
Diogeness - recording solar flare and active region spectra. A short
description of the CORONAS-F satellite operation is presented together
with that of the two Polish spectrometers, stressing their unique
characteristics. The average spectra have been derived and shown here,
covering the wavelength range between 3 Å and 7 Å. Future steps in
the analysis of the large database collected are outlined.
Title: Analysis of Potassium Abundance Variability in Selected
Solar Flares
Authors: Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Culhane,
J. L.; Brown, C.; Lang, J.; Stepanov, A. I.
Bibcode: 2004cosp...35.2639S
Altcode: 2004cosp.meet.2639S
A quick-look inspection of spectra observed in the shortwavelength
channel (3.35 Å,- 3.8 Å) of the RESIK X-ray spectrometer on Coronas-F
indicates the presence of substantial flare-to-flare variations in
the line-to-continuum ratio of several lines, in particular He-like
potassium (K XVIII) lines, occurring at 3.53 Å,- 3.57 Å. The
observed variations are larger those expected from temperature
variations. This has motivated a detailed study of possible variations
in the flare-to-flare potassium abundance. With newly calibrated RESIK
spectra, we have obtained absolute fluxes of the K XVIII resonance,
intercombination and forbidden lines as well as the continuum and
lines observed in other RESIK channels (3.35 Å,- 6.1 Å). These
data have allowed us to determine the absolute potassium abundance
for a selection of flares, mostly short-lived with a range of X-ray
importance. The results obtained are presented and discussed.
Title: Observations of 1s^2-1s(np) and 1s-(np) Lines in RESIK Soft
X-ray Spectra
Authors: Kepa, A.; Sylwester, B.; Sylwester, J.; Phillips, K. J. H.;
Kuznetsov, V. D.
Bibcode: 2004cosp...35.2574K
Altcode: 2004cosp.meet.2574K
RESIK is the X-ray bent crystal spectrometer on the CORONAS-F satellite,
launched on 2001 July 31. Between 2002 and 2003, RESIK has collected
numerous spectra of active regions and flares in the wavelength range
3.37 Å to 6.09 Å. This range includes many strong emission lines
due to transitions 1s^2-1snp and 1s-np in He-like and H-like ions
respectively; the n = 2 and 3 lines are routinely observed for Si,
S and Ar ions. For some flares we have observed enhanced emission
in spectral features coinciding with these transitions for n up to
9 or 10. Identification of these features, not previously observed
in astrophysical spectra, are presented in this paper, as is their
diagnostic importance. Respective observed line series decrements are
determined and discussed in this paper.
Title: Analysis of physical plasma properties within flare kernels
from EUV/X-ray observations
Authors: Gburek, S.; Sylwester, J.; Sylwester, B.; Kowalinski, M.
Bibcode: 2004IAUS..223..455G
Altcode: 2005IAUS..223..455G
We performed the study of a solar flare of GOES class X1.0 which
occurred on 2002 August 21, peak time 05:34 UT. A new method was
applied for temperature determination of the plasma seen in TRACE
images. This method makes use of the detailed knowledge of the TRACE
point spread function (PSF) function. Substantial dependence of TRACE
PSF on wavelength allows for determination of temperature from a single
TRACE image even in these portions of the image which are saturated. We
also determined the average temperature of this flare from the soft
X-ray spectra measured by RESIK Bragg spectrometer aboard CORONAS-F
satellite. The results obtained from TARCE and RESIK data are compared.
Title: Solar forced variations of terrestrial high energy particle
environment as seen by RESIK PIN detectors on CORONAS-F
Authors: Kowalinski, M.; Kordylewski, Z.; Sylwester, J.; Trzebinski,
W.; Lisin, D.
Bibcode: 2004IAUS..223..551K
Altcode: 2005IAUS..223..551K
RESIK is the bent crystal spectrometer aboard the CORONAS-F
satellite. It is equipped with four PIN diode detectors. These detectors
were used in order to detect background counts due to energetic particle
contamination present within polar regions and SAA belts. At altitudes
above 300 km (Coronas-F altitude is about 500 km) the population of
charged particles trapped by the Earth's magnetic field consists of
protons (energies between 100 keV and several hundred MeV) and electrons
(energies between few tens of keV and 10 MeV). The construction of RESIK
PIN diode detectors allows to sense particles with the energy above
1 MeV. We present diagrams illustrating the coupling of the Coronas-F
particle environment and selected proxies of solar activity. The data
shown have been collected during initial phase of mission.
Title: Temperature-sensitive Line Ratios Diagnostics of the
non-flaring Corona based on Satellite-to-Resonance Line Ratios for
1s^2-1s(np) Transitions
Authors: Phillips, K. J. H.; Dubau, J.; Sylwester, J.; Sylwester,
B.; Kordylewski, Z.; Culhane, J. L.; Doschek, G. A.; Lang, J.
Bibcode: 2004cosp...35.2579P
Altcode: 2004cosp.meet.2579P
One of the most convenient electron temperature diagnostics of
hot astrophysical plasmas is the intensity ratio of dielectronic
satellite lines to resonance lines in the X-ray region. Until now,
this diagnostic has been applied to satellites near the 1s-2p lines of
H-like ions or the 1s^2 - 1s2p lines of He-like ions, these lines being
extensively observed with crystal spectrometers during flares. However,
satellites near the 1s^2 - 1snp (n>2) lines of He-like ions,
unlike those near the 1s^2 - 1s2p lines, have the important advantage
of being well separated from their parent lines and unblended with
other lines. Spectra from the RESIK spectrometer on Coronas-F,
covering the wavelength range 3.4 Å,- 6.1 Å, are highly suited
for observation of these satellites, due to transitions from the n =
3, 4 and 5 levels to the n = 1 level, near corresponding resonance
lines of H-like and He-like Si (Si XIII, Si XIV) and S (S XV, S XVI)
ions. New calculations of satellite intensity factors presented in
this paper enable temperatures to be calculated from observed ratios
of Li-like Si (Si XII) 1s^2 2p ^2P1/2,3/2 - 1s 2p (^3P) 3p
^2D3/2,5/2 satellite complex (5.816 Å) near He-like Si (Si
XIII) 1s^2 ^1S_0 - 1s 3p ^1P_1} resonance (5.681 Å) line. These lines
are well observed in recent quiet and non-flaring active region RESIK
X-ray spectra, and therefore provide the most sensitive temperature
diagnostic tool for physical conditions in weakly active corona.
Title: Thermal and nonthermal contributions to the solar flare
x-ray flux
Authors: Dennis, B.; Phillips, K.; Sylwester, J.; Sylwester, B.;
Schwartz, R.; Tolbert, K.
Bibcode: 2004cosp...35.1284D
Altcode: 2004cosp.meet.1284D
The relative thermal and nonthermal contributions to the total energy
budget of a solar flare are being determined through analysis of
RHESSI X-ray imaging and spectral observations in the energy range
from ∼ 5 to ∼ 50 keV. The classic ways of differentiating between
the thermal and nonthermal components -- exponential vs. power-law
spectra, impulsive vs. gradually varying flux, compact vs. extended
sources -- can now be combined for individual flares. In addition,
RHESSI's sensitivity down to ∼ 4 keV and energy resolution of
∼ 1 keV FWHM allow the intensities and equivalent widths of the
complex of highly ionized iron lines at ∼ 6.7 keV and the complex of
highly ionized iron and nickel lines at ∼ 8 keV to be measured as a
function of time. Using the spectral line and continuum intensities
from the Chianti (version 4.2) atomic code, the thermal component
of the total flare emission can be more reliably separated from the
nonthermal component in the measured X-ray spectrum (Phillips, ApJ
2004, in press). The abundance of iron can also be determined from
RHESSI line-to-continuum measurements as a function of time during
larger flares. Results will be shown of the intensity and equivalent
widths of these line complexes for several flares and the temperatures,
emission measures, and iron abundances derived from them. Comparisons
will be made with 6.7-keV Fe-line fluxes measured with the RESIK bent
crystal spectrometer on the Coronas-F spacecraft operating in third
order during the peak times of three flares (2002 May 31 at 00:12 UT,
2002 December 2 at 19:26 UT, and 2003 April 26 at 03:00 UT). During
the rise and decay of these flares, RESIK was operating in first order
allowing the continuum flux to be measured between 2.9 and 3.7 keV
for comparison with RHESSI fluxes at its low-energy end.
Title: Multi-Wavelength Study of a Strong Impulsive Solar Limb Flare
on 2002 August 3.
Authors: Gburek, S.; Sylwester, J.; Sylwester, B.; Dennis, B.;
Phillips, K. J. H.
Bibcode: 2004cosp...35.1080G
Altcode: 2004cosp.meet.1080G
We have made a detailed study of an impulsive solar flare with GOES
class X1.0 which occurred near the west limb on 2002 August 3, peak
time 19:07 UT. There is particularly good coverage of this event, with
simultaneous observations in EUV, soft and hard X-rays available. We
used TRACE 171 A images to study the morphology and evolution of the
event. Soft X-ray spectra between 2.0 and 3.7 keV (wavelengths 3.4 -
6.1 A) measured by the RESIK Bragg crystal spectrometer on Coronas-F
have been used for differential emission measure calculations of the
thermal plasma. Imaging and spectral data from RHESSI with energies
between ~3 and 100 keV have been used to derive characteristics of the
higher-temperature plasma and nonthermal electrons accelerated during
the flare. Comparison of these data sets enable valuable insight into
the heating and particle acceleration during this well observed event.
Title: A review of the solar results from CORONAS-F satellite
Authors: Kuznetsov, V. D.; Charikov, Yu. E.; Kotov, Yu. D.; Kuznetsov,
S. N.; Mazets, E. P.; Nusinov, A. A.; Pankov, V. M.; Sobelman, I. I.;
Sylwester, J.
Bibcode: 2004IAUS..223..357K
Altcode: 2005IAUS..223..357K
The solar results from CORONAS-F satellite have been reviewed. The
observations with the DIFOS multi-channel photometer in a broad
spectral range from 350 to 1500 nm have allowed to determine the
dependence of the relative amplitudes of p-modes of the global
solar oscillations on the wavelength. The EUV observations in SPIRIT
experiment have enabled the study of various manifestations of solar
activity and high-temperature events on the Sun. The data from the
flare instruments-gamma spectrometer HELICON, flare spectrometer
IRIS, amplitude-time spectrometer AVS-F, and X-ray spectrometer RPS-1
have been used to analyze the hard emission from solar flares and to
carry out the diagnostics of the solar flare plasma. The Solar Cosmic
Ray Complex has investigated the solar flare effects in the Earth's
environment. The UV emission variations during solar flares in the
vicinity of the 120-nm wavelengh have been recorded and the relative
variation amplitude has been determined.
Title: Analysis of Yohkoh-observed limb flares accompanying CME events
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 2003ESASP.535..483S
Altcode: 2003iscs.symp..483S
We have made the literature/web search in order to find well observed
limb flares seen by Yohkoh instruments. For the purpose of this study
we have looked for flares associated with CME counterparts. Only few
such events have been found and analysed (including compact and arcade
type flares as seen on SXT images). In this contribution we present
results illustrating several aspects of selected flare evolution. The
results shown concern the morphology (SXT deconvolved images, HXT
reconstructed images) and the flaring plasma dynamics as seen in
transversal (from image cadences) and radial directions (from BCS
spectral analysis). As the selected event has been observed over the
limb, detailed investigation of vertical motions of the hot plasma
is possible.
Title: Patterns of X-ray line emission variability as observed by
the RESIK Bragg spectrometer
Authors: Sylwester, J.; Sylwester, B.; Culhane, J. L.; Doschek, G. A.;
Oraevsky, V. N.; Phillips, K. J. H.
Bibcode: 2003ESASP.535..733S
Altcode: 2003iscs.symp..733S
RESIK is a unique Bragg bent crystal spectrometer operating continuously
since August 2001. By now, it has collected ~10 GB of solar flare and
active region spectra in a very much unexplored spectral region between
3.2 Å and 6.1 Å. In this paper we present a number of representative
observations covering periods of various solar activity: from the most
active level (M+ flares) to exceptionally quiet corona. We present also
a tentative list of the spectral features observed. In the wavelength
range observed by RESIK there are a number of strong emission lines
corresponding to H- and He-like resonance transitions of Si, S, Ar and K
ions. These lines are formed by thermal plasma of temperature between
5 and 50 MK, and therefore their analysis reveal the distribution
of hot plasma over this interval. RESIK sees lines from a number of
different elements, so it is possible to do abundance analyses. The
elements concerned have a wide range of first ionisation potentials
(FIPs) so it has been possible to examine the dependence of coronal or
flare abundances on FIP. We have observed substantial variations of
the K/Ar line ratio, and respective line/continuum ratios, which can
be best explained by allowing for changes in the chemical composition
of the coronal plasma
Title: Origins of strong solar geo-effective events as seen by
SXT telescope
Authors: Gburek, S.; Sylwester, J.
Bibcode: 2003ESASP.535..235G
Altcode: 2003iscs.symp..235G
We investigate patterns of solar activity preceding stronger solar
geo-effective events as seen in soft X-rays. The data from SXT
telescope on Yohkoh satellite are used to address this issue. The
investigation covers the period since September 1991 to December 2001 -
the Yohkoh mission duration. For selected events their coincidence and
relationship to flares, coronal mass ejection and/or solar energetic
particle emission is studied also.
Title: Solar Flare Abundances of Potassium, Argon, and Sulphur
Authors: Phillips, K. J. H.; Sylwester, J.; Sylwester, B.; Landi, E.
Bibcode: 2003ApJ...589L.113P
Altcode:
The absolute abundance of potassium has been determined for the first
time from X-ray solar flare line and continuum spectra. The absolute
and relative abundances of Ar and S have also been determined. Assuming
that the flare plasma is coronal, and since potassium has the lowest
first ionization potential (FIP) of any common element on the Sun,
this determination is of importance in the continuing debate concerning
the nature of the coronal/photospheric element abundance ratios, which
are widely considered to depend on the FIP. The measurements were made
with the RESIK crystal spectrometer on the Coronas-F spacecraft. A
differential emission measure DEM~exp(-βTe) was found to
be the most consistent with the data of three models considered. We
find that the K/H abundance ratio is (3.7+/-1.0)×10-7,
a factor of 3 times photospheric. Our measured values of the
Ar/H ratio, (2.8+/-0.2)×10-6, and of the S/H ratio,
(2.2+/-0.4)×10-5, are equal to previous coronal and
photospheric determinations to within uncertainties. These measurements
therefore fit a pattern in which low-FIP elements are enriched in
the corona by a factor 3 and in which high-FIP elements (including S)
have equal coronal and photospheric abundances.
Title: Solar Flare Abundances of Potassium, Argon, and Sulphur
Authors: Phillips, K. J. H.; Sylwester, J.; Sylwester, B.; Landi, E.
Bibcode: 2003SPD....34.1622P
Altcode: 2003BAAS...35..837P
The absolute coronal abundances of potassium, argon, and sulphur
are determined from X-ray solar flare spectra using the RESIK
bent crystal spectrometer on the Coronas-F space observatory. A
differential emission measure of the form exp(-α Te) was
found to be appropriate for describing the fluxes of the lines due
to K XVIII (λ 3.53Å), Ar XVIII (λ 3.73Å), Ar XVII (λ 3.95Å),
S XV (λ λ 4.09, 4.30Å), Si XIV (λ 5.22Å), and Si XIII (λ λ
5.40, 5.68Å) which are observed by RESIK over a period of several
hours in four long-duration flares. The continuum in two of the four
RESIK channels appears to be uncontaminated by crystal fluorescence
or other instrumental effects, allowing abundances relative to H to
be determined. We estimate the following abundances relative to H:
[K/H] = 4.7 X 10-7; [S/H] = 2.9 X 10-5; [Ar/H] =
2.0 X 10-6. These values agree with a pattern that depends
on the first ionization potential (FIP) of an element in which the
coronal abundances of low-FIP elements (like K) are enhanced over
their photospheric abundances by a factor 3 and high-FIP elements
(like Ar) are depleted by a factor 2. The coronal abundance of sulphur
(medium-FIP) is slightly enhanced (factor of 1.5) compared with its
photospheric abundance. The exponential temperature dependence of the
differential emission measure is applied to simultaneous X-ray data
from the RHESSI mission which sees a thermal spectrum (continuum plus
Fe lines at 6.7 keV) for some of these flares. Results of this will
be discussed. We acknowledge support for this research from the
National Research Council (KJHP), Polish Committee for Scientific
Research (JS, BS), and from the Office of Naval Research (EL).
Title: CORONAS-F Solar Observations
Authors: Oraevsky, V.; Sobelman, I.; Kuznetsov, V.; Zitnik, I.;
Sylwester, J.; Mazets, E.; Kocharov, G.
Bibcode: 2003EAEJA.....4848O
Altcode:
Observations of the Sun made within the CORONAS-F mission during
2001-2002 have been discussed. The broadband measurements obtained
with the multi-channel photometer DIFOS in six spectral channels
(350, 500, 650, 850, 1100, and 1500 nm) have been used to plot the
amplitude spectra of p-modes of the global solar oscillations and to
determine the relative oscillation amplitudes as a function of the
wavelength. The spectrophotometer DIOGENESS and X-ray spectrometer
RESIK recorded multiple spectral lines in the 3-7 Å X-ray range
from the most intensive solar flares, which could not be measured
earlier, because all previous instruments went off-scale, i.e. the
line profiles were cut-off in amplitude. High-resolution temporal
series of monochromatic full-Sun images in the L MgXII emission line
at 8.42 Å have been obtained by the SPIRIT spectroheliograph. The
images revealed plasma structures with the temperature in the range
3 20 MK characterized by specific shape and dynamics, differing
from that of relatively low temperature (1 2 MK) plasma. The main
remarkable features of the phenomena observed for the first time
in monochromatic images are as follows: high spatial variability in
brightness with the contrast of more than two orders of magnitude;
presence of some compact sources with high locations up to 0.3 solar
radius and well-pronounced ’spider’-like forms; substantially
different variability in the dynamic behaviour characterized by the
life-times from minutes to days. The gamma-ray spectrometer HELICON
and flare spectrometer IRIS provided high-resolution (10 milliseconds)
records of the flare-generated X-ray emission. These records were used
to identify the characteristic features of pre-flare situation in the
Sun and the flare process itself.
Title: The Solar Flare of November 4, 2001, and Its Manifestations
in Energetic Particles from Coronas-F Data
Authors: Kuznetsov, S. N.; Bogomolov, A. V.; Denisov, Yu. I.;
Kordylewski, Z.; Kudela, K.; Kurt, V. G.; Lisin, D. V.; Myagkova,
I. N.; Podorol'skii, A. N.; Podosenova, T. B.; Svertilov, S. I.;
Sylwester, J.; Stepanov, A. I.; Yushkov, B. Yu.
Bibcode: 2003SoSyR..37..121K
Altcode:
Based on X-ray, gamma-ray, and charged-particle measurements with
several instruments onboard the Coronas-F satellite and on ACE and
GOES experimental data presented on the Internet, we investigate
the parameters of the solar flare of November 4, 2001, and the
energetic-particle fluxes produced by it in circumterrestrial space. The
increase in relativistic-electron fluxes for about 1.5 days points to
a moving source (shock front). The structure of the energetic-particles
fluxes in the second half of November 5, 2001, can be explained by the
passage of the coronal mass ejection that was ejected on November 1,
2001, and that interacted with the shock wave from the flare of November
4, 2001.
Title: Multitemperature analysis of selected limb-occulted flares
lines in solar flares
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 2002ESASP.506..769S
Altcode: 2002ESPM...10..769S; 2002svco.conf..769S
The aim of this contribution was to compare the so-called "quasi"
differential emission measure distributions (qDEM) with "classical"
DEM distributions. The qDEM distributions for the flaring region have
been derived from the maps of "isothermal" temperatures and emission
measures for the flaring region. The temperature and emission measure
maps have been derived based on the deconvolved Yohkoh SXT images. The
deconvolution has been performed in order to increase the spatial
resolution. Next the images have been overlaid precisely using the
position of the occulting solar disc as a reference. The high accuracy
of coalignment allowed to derive the temperature maps with spatial
resolution down to ~1 arcsec. From the other side the DEM distributions
have been determined for a flare as a whole, based on integral flare
fluxes measured by SXT and GOES using maximum likelihood iterative
algorithm. In principle such a comparison of qDEM and DEM shapes should
allow to investigate which part of DEM is related to the bright kernels
observed on SXT images.
Title: Mission long analysis of distribution of compact X-ray sources
observed by SXT on Yohkoh
Authors: Gburek, S.; Sylwester, J.
Bibcode: 2002ESASP.506..517G
Altcode: 2002ESPM...10..517G; 2002svco.conf..517G
We analyse properties of X-ray sources from a large database of compact
source images that we have created last year. The database links to
over 105SXT A112 images with well localized X-ray emission
regions. This database includes compact events being observed over
entire Yohkoh mission. Except the link, each database record contains
coordinates of source location on CCD, exact image acquisition and
exposure times and estimates of the peak "width". We use this database
to study location of compact sources on the Sun over the period about
solar cycle long. We incorporated into the analysis both flaring and
non-flaring sources. We present also locations of limb and near limb
compact (candidate) source observations.
Title: Comparison of trace and deconvolved SXT images for solar flares
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 2002ESASP.506..773S
Altcode: 2002svco.conf..773S; 2002ESPM...10..773S
In this research we have studied the relationship between thermal
flaring plasma seen on TRACE and on Yohkoh SXT images. Before the
comparison we have performed the deconvolution (with oversampling) of
SXT images using ANDRIL algorithm. This effectively brought to scale
the spatial resolution on SXT and TRACE images. For the comparison
we selected events partly occulted by the limb in order to use its
apparent position for fine adjustment of images obtained in soft X-ray
and EUV ranges. Based on the performed comparison we have confirmed
that EUV and soft X-ray emissions do NOT exactly match. However, the
overall appearance of patterns suggests presence of correspondence
between plasma contributing to both emissions.
Title: Flare X-ray spectra observed by Diogenes scanning bragg
spectrometer
Authors: Siarkowski, M.; Sylwester, J.; Plocieniak, S.; Kordylewski, Z.
Bibcode: 2002ESASP.506..753S
Altcode: 2002svco.conf..753S; 2002ESPM...10..753S
Diogeness is the uncollimated scanning flat crystal spectrometer
observing flare X-ray spectra in four narrow wavelength bands
in vicinity of Ca XIX, S XV and Si XIII He-like line "triplets"
around 3.18 Å, 5.04 Å and 6.65 Å. In two spectral channels, the
same emission lines around Ca XIX 3.178 Å resonance are scanned in
opposite directions, being diffracted from precisely adjusted identical
Quartz crystals mounted on the common shaft in so-called Dopplerometer
configuration. During early phase of the CORONAS-F Mission, a number
of big flares have been observed by Diogeness. In particular, tens of
high resolution spectra have been measured during initial, maximum and
decay phase of 25 August 2001 X5.3 flare. We present examples of these
spectra, make prompt line identification, announcing observations
of spectral features corresponding to transitions in Si XIV (Lyβ)
He-like ion. Early interpretation of the spectra measured indicates
for substantial variations of average plasma temperature during the
observed flare. Our measurements will be further analysed in detail
together with the spectra obtained aboard Yohkoh using Bent Crystal
Spectrometer observations.
Title: RESIK observations of highly ionized argon and potassium
X-ray emission lines in solar flares
Authors: Sylwester, J.; Culhane, J. L.; Doschek, G. A.; Oraevsky,
V. N.; Phillips, K. J. H.; Sylwester, B.
Bibcode: 2002ESASP.506..765S
Altcode: 2002svco.conf..765S; 2002ESPM...10..765S
The first detailed solar X-ray spectra obtained by the RESIK bent
crystal spectrometer aboard the CORONAS-F obervatory are presented
and instrument performance discussed. RESIK is a bent crystal
spectrometer covering four soft X-ray spectral ranges (3.369-3.879 Å,
3.821-4.326 Å, 4.307-4.890 Å 4.960-6.086 Å), some of which have
not been well covered by previous instruments. RESIK forms spectra
in each of these ranges in 250 bins simultaneously in intervals
of 10 s or so. Many flares, including several of GOES X-class,
and bright active regions have now been observed in detail. (See
http://www.cbk.pan.wroc.pl/2002.htm for examples.) In this paper,
observations of spectral lines due to K XVIII, Ar XVIII, Ar XVII, S XV,
Si XIV and Si XIII ions will be shown and the time evolution of their
intensities will be discussed. These observations will eventually
allow for precise determination of differential emission measure
(DEM) and chemical composition of the hot flare plasma, and should,
alongside data from the RHESSI, TRACE, and SOHO spacecraft, enable
new and detailed insight into solar flare mechanisms.
Title: Determination of wavelengths and line shifts based on X-ray
spectra from Diogeness
Authors: Plocieniak, S.; Sylwester, J.; Kordylewski, Z.; Sylwester, B.
Bibcode: 2002ESASP.506..963P
Altcode: 2002svco.conf..963P; 2002ESPM...10..963P
Diogeness is the uncollimated scanning flat crystal spectrometer
observing flare X-ray spectra in four narrow wavelength bands in the
vicinity of Ca XIX, S XV and Si XIII He-like "triplets" around 3.18
Å, 5.04 Å and 6.65 Å. In two spectral channels, the same emission
lines (around Ca XIX w resonance line, λ = 3.177 Å) are scanned
in opposite directions. The X-rays are reflected from precisely
adjusted identical Quartz monocrystals mounted on the common shaft in
so-called Dopplerometer configuration. This novel spectrometer design
allows for highly accurate determinations of wavelengths and precise
determination of line Doppler shifts. We explain the concept of the
X-ray Dopplerometer and present results of analysis of the Doppler line
shifts for the spectra collected during 25 August 2001 X5.3 flare. We
compare derived line of sight plasma velocities with those measured
by Yohkoh BCS.
Title: The x-ray package for spectroscopic measurements of solar
plasma composition
Authors: Sylwester, J.; Kordylewski, Z.
Bibcode: 2002AdSpR..30...67S
Altcode:
We present the instrument package dedicated to spectroscopic studies of
coronal flaring plasma composition. The package consists of two Bragg
spectrometers, RESIK and DIOGENESS. These instruments will be launched
aboard the Coronas-F solar observatory mid-2001. The relative abundance
of certain elements (Ca) in flaring plasma heated to several million
Kelvins (MK) is known to vary up to the factor of around 4 from flare to
flare. Two spectrometers have capabilities of determining the absolute
abundances of several important elements including low and high first
ionization potential (FIP) ones. It will be possible to investigate
fast temporal (∼ 1 min) changes of the plasma composition in flares
and hotter active regions. This will lead to a better understanding
of the processes causing elemental differentiation within the coronal
plasma. The RESIK spectrometer was developed by a Consortium including
NRL (USA), MSSL (UK), RAL (UK), IZMIRAN (Russia) and the Space Research
Centre (SRC) of the Polish Academy of Sciences. DIOGENESS was developed
in Poland and in the Astronomical Institute of the Czech Republic.
Title: On a possible cause of discrepancy between Yohkoh and SMM
calcium abundance determinations in flares
Authors: Sylwester, J.; Kepa, A.; Bentley, R. D.
Bibcode: 2002AdSpR..30..105S
Altcode:
We have investigated problems concerning the discrepancy between
estimates of absolute calcium abundances (A Ca) in solar
flares as derived from soft X-ray high resolution spectra as obtained
from Yohkoh and Solar Maximum Mission ( SMM) Bragg spectrometers. The
analysis of these spectra allows for determination of absolute calcium
abundance since both Ca XIX resonance line and neighbouring continuum
are reliably measured in these experiments. The abundance determinations
are possible by means of fitting the synthetic spectra to the observed
ones. In previous work, we attributed part (around 50%) of the observed
disagreement to a possible instrumental problem in Yohkoh. In the
present research, we consider in more details possible causes of
the other part of the discrepancy. We first investigate whether the
estimates of (A Ca) depend substantially on the extension of
the observed short wavelength wing of the Ca XIX resonance line. This
problem is important in the case of the analysis of Yohkoh spectra,
since the extension of the spectrum towards the short wavelengths
depends on the position of the flare along North—South direction
on the Sun. After verifying the robustness of results of the spectral
fitting technique, we have considered possible physical scenario which
may cause the observed discrepancy. The hypothesis tested was that
the Ca abundance in flares is correlated with brightness in the source
— namely that it is a few times higher in the centre of the source
(flaring kernel) than outside. We have found that postulated model may
account for a part of the noted discrepancy as the SMM spectrometer
has been equipped with the 6 × 6 arcmin collimator and no collimator
has been used on Yohkoh.
Title: Search for Compact x-ray Sources in sxt Observations
Authors: Gburek, S.; Sylwester, J.
Bibcode: 2002SoPh..206..273G
Altcode:
We show the result of a search for compact sources in observations of
Soft X-ray Telescope (SXT) aboard the Yohkoh satellite. We focused the
search on the highest-resolution SXT images taken with the SXT thick
aluminum filter. Non-standard methods have been used in order to avoid
data corrupted by spikes or dark current saturation effects. Search
criteria and certain questions concerning the SXT database are addressed
and discussed in more detail. For the most compact structures found
we show also comparison of their brightness spatial distribution with
ground calibration data. The search was performed to identify regions
with well-localized X-ray emission in SXT images and to gather basic
information about them.
Title: Analysis of differential emission measure evolution for
selected SEP and non-SEP associated flares based on hard and soft
X-ray observations
Authors: Kepa, Anna; Sylwester, Janusz
Bibcode: 2002ESASP.477..131K
Altcode: 2002scsw.conf..131K
We present prompt results of analysis of differential emission
measure distributions (DEM) for solar flares. The DEM describes the
distribution of emitting plasma with temperature. For calculations of
the DEM shape we use Withbroe - Sylwester (WS) multiplicative iterative
algorithm. Our input data set consists of total flare fluxes as measured
by the Yohkoh Soft X-ray Telescope (SXT) in most of available filters,
the Hard X-ray Telescope data (HXT), the Bragg Crystal Spectrometer
(BCS) line fluxes and GOES X-ray fluency as measured in 0.5 - 4 Å
and 1 - 8 Å bands. Reconstruction of DEM shape from observed X-ray
fluxes constitute uneasy ill-defined inverse problem. Therefore, before
applying the algorithm to real data we performed numerous tests of
the inversion method using several synthetic DEM distributions. This
has been done in order to better understand how to interpret the DEM
as obtained from real measurements and understand limitations of the
inversion procedure. In our tests, we have used a number of typical DEM
distribution shapes. The overall stability of the WS reconstruction
procedure led us to investigate DEM shapes for particular flare
events selected. We have chosen to look for possible differences in
DEM shape and behavior for flare events which have been associated
and not associated with the (following) solar energetic particle
(SEP) occurrence.
Title: Early results from RESIK and Diogeness soft X-ray spectrometers
aboard Coronas-F satellite
Authors: Sylwester, Janusz; Gaicki, Ireneusz; Kordylewski, Zbigniew;
Kowalinski, Miroslaw; Nowak, Stanislaw; Plocieniak, Stefan; Trzebinski,
Witold; Bentley, Robert D.; Whyndham, Matt; Lang, Jim; Brown, Charles;
Farnik, Frantisek; Oraevsky, Victor N.; Stepanov, Anatolyi; Lisin,
Dimitry
Bibcode: 2002ESASP.477..597S
Altcode: 2002scsw.conf..597S
We present examples of early, unreduced results obtained from
the instrument package dedicated for spectroscopic studies of
coronal flaring plasma composition. The package consists of two
Bragg spectrometers, RESIK and Diogeness. These instruments have
been launched aboard the Russian Coronas-F solar observatory on 31
July 2001. The data being received from these two spectrometers allow
for determining the absolute abundances of several important elements
including that of low and high first ionization potential (FIP). Based
on the data which have been (and hopefully will be) obtained, we will
investigate fast temporal variations (~1 min) of the plasma composition
in flares and hotter active regions. The analysis of spectra obtained
will certainly allow for spectroscopic studies of several, so-called
"triplet" lines forming in He-like, highly ionized plasma since the
spectra received are apparently of unprecedented quality. The Coronas-F
Mission is expected to be supported for at least two years.
Title: Thermodynamics of partly occulted limb flares
Authors: Sylwester, Barbara; Sylwester, Janusz
Bibcode: 2002ESASP.477..171S
Altcode: 2002scsw.conf..171S
We have studied time variations of the thermodynamic parameters for
several flares which have been partly occulted by solar disc. The data
consist mainly of deconvolved Yohkoh Soft X-ray Telescope (SXT) images
coaligned to sub-arcsec accuracy using specially designed method. At
first in our analysis we have followed the maximum brightness location
for pronounced flare kernels emission seen on deconvolved images. The
analysis of the data reveals systematic variations of the brightest
kernel position. Spatial resolution achieved on the deconvolved images
allows to derive the maps of temperature and emission measure within
unocculated portion of the flaring structures (kernels) with the
resolution below ~1 arcsec. It is possible to estimate the electron
density of plasma confined within individual kernels based on their
spatial dimensions. Our analysis indicates that the hottest regions
within the flaring kernels are these with the smaller density. As
a rule the cooler regions are related with the denser plasma. It is
typical that some amount of plasma with temperatures T >= 20 MK
is present within the flaring region during the rise phase. Derived
patterns of maximum brightness location as observed on A101, A112
and Be119 filter images have been cross-compared with the location
of hard X-ray emission centers as seen on the MEM-reconstructed Hard
X-ray Telescope (HXT) images.
Title: Modeling of X-Ray Source Occultation by the Solar Disk
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 2002mwoc.conf..409S
Altcode:
It is known, that the application of filter ratio (Al12/Be119)
technique into the analysis of SXT images requires a precise image
coalignment. The coalignment problems are even more serious in the
case of analysis of deconvolved images with oversampling. In order to
achieve the necessary alignment accuracy in this case, we have used
the occulting solar limb position as a reference. The limb's position,
as seen on images taken using individual SXT filters, may depend on the
source temperature and the filter transmission. We have investigated
this dependence using VAL model of the photosphere/chromosphere
transition region. We have found a difference of 0.3 arcsec (200
km) of the limb location as seen on images taken with Be119 and the
other SXT filters. The difference is even larger for individual HXT
channels. Results of the analysis allow us to coalign the Al12 and
Be119 deconvolved images to the required accuracy. In parallel, we
also discuss implications of the occultation phenomenon on the shape
of X-ray lightcurves for kernels evanescent from behind the limb. By
applying filter ratio (Al12/Be119) technique to deconvolved images
we have studied the evolution of temperature and emission measure
of flaring kernels with 1 arcsec resolution for behind the limb
sources. Obtained high resolution temperature and emission measure
maps we have compared with the maps of hard X-ray brightness (HXT). We
discuss physical implications of the results obtained.
Title: Physical conditions within flare kernels
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 2002AdSpR..30..617S
Altcode:
We have investigated the distribution of temperature and emission
measure (T, EM) within flare coronal kernels. The data used consist of
the soft and hard X-ray images of flares obtained onboard the Yohkoh
using Soft and Hard X-ray Telescopes (SXT and HXT). The analysed maps
of temperature and emission measure have been obtained using a pair
of Al12 and Be119 images which signal ratio is the most sensitive to
temperature for the flaring plasma. The SXT images have been deconvolved
using the ANDRIL routine and the HXT images have been reconstructed
using standard maximum entropy method (MEM). The flares selected for
the analysis have been simple, behind the limb events for which we
can undoubtably identify the isolated kernels located in the corona,
partly occulted by the limb. We present the analysis of 5 th
October 1992 flare as an example. The importance of precise image
coalignment is emphasised and the method of making the adjustment for
limb occulted flares is presented.
Title: JOSO national report 2000-2001 - Poland
Authors: Rompolt, B.; Sylwester, J.
Bibcode: 2002joso.book...83R
Altcode:
In 2000-2001 investigations of the Sun in Poland were reported by:
The Astronomical Institute of Wroclaw University, The Solar Physics
Division of Space Research Centre of Polish Academy of Sciences,
The Astronomical Observatory of Jagiellonian University, Cracow.
Title: Blind Deconvolution of the SXT PSF Core Part
Authors: Gburek, S.; Sylwester, J.; Martens, P. C. H.
Bibcode: 2002mwoc.conf..417G
Altcode:
The performance and speed of blind deconvolution algorithms for
restoration of SXT images depend on good initial guess for PSF function
shape. From the analysis of several compact flare kernels we came
to conclusion that a good guess for PSF can be provided directly
from images of X-ray compact structures observed by SXT. Recently,
we conducted extensive mission-long searches for compact structures
through entire database of SXT full resolution frames. The searches
returned plenty compact structures which my serve to construct
initial approximation of the PSF for BID restoration method. We show a
selection of the most compact structures found and its location on SXT
CCD detector. Using observation for this selected set of structures
we construct constraints for Al12 PSF shrouds and compare them with
ground calibration data.
Title: Experience of Wroclaw team in construction of solar X-ray
instruments
Authors: Sylwester, J.
Bibcode: 2001ESASP.493..377S
Altcode: 2001sefs.work..377S
No abstract at ADS
Title: Solar Soft/Hard X-ray Photometer-Imager Aboard the
Interball-Tail Probe
Authors: Sylwester, J.; Fárník, F.; Likin, O.; Kordylewski, Z.;
Siarkowski, M.; Nowak, S.; Płocieniak, S.; Trzebiński, W.
Bibcode: 2000SoPh..197..337S
Altcode:
We describe the RF15-I instrument, comprising a solar photometer and
an imager, designed for multi-band high-time resolution measurements of
integral solar fluxes in the energy range between 2 keV and 240 keV as
well as for imaging of solar flares in the 2-8 keV energy range. The
instrument was launched in August 1995 aboard the INTERBALL-Tail
spacecraft. Description of the construction and operations is
presented. The overall performance and the high sensitivity of
the photometer are shown in examples. The X-ray tomograph-imager
contains a unique rotationally modulated collimator. It provides
sets of one-dimensional scans of flares taken at varying angles due
to spinning of the satellite. We present principles of the algorithm
for imaging from these data and show example of reconstructed flare
image taken in the 2-4 keV range.
Title: Evolution of White-Light Flares Observed by YOHKOH
Authors: Sylwester, Barbara; Sylwester, Janusz
Bibcode: 2000SoPh..194..305S
Altcode:
We consider in detail the evolutionary patterns of few white-light
flares observed by Yohkoh. The following data have been used in the
analysis: sequences of de-convolved SXT images in X-ray and optical
filters, MEM reconstructed HXT images and the other supporting data. The
resolution in the de-convolved images is below 1 arc sec. Working with
sequences of de-convolved images makes it also possible to investigate
the dynamics of these structures with high spatial accuracy. Comparison
of the morphology of flare brightenings as observed in hard, soft
and optical ranges reveals that these emissions are not co-spatial
and are most probably related to different plasma volumes at any
instant. These observations cannot be easily accommodated within
standard flare scenarios. Traditionally, the hard and optical flare
emissions are expected to be co-spatial and the soft X-ray emission
is presumed to fill the coronal portion of flaring loop(s) during rise
phase. Present observations do not easily fit to such scenario.
Title: Analysis of Three SEP Associated Flares
Authors: Sylwester, J.
Bibcode: 2000ESASP.463..431S
Altcode: 2000sctc.proc..431S
No abstract at ADS
Title: Search for Basic Building Block Composing Solar Atmospheric
Structures
Authors: Sylwester, J.
Bibcode: 1999ESASP.448..665S
Altcode: 1999mfsp.conf..665S; 1999ESPM....9..665S
No abstract at ADS
Title: The Properties of Flares Produced Within AR 6919
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 1999ESASP.448..895S
Altcode: 1999mfsp.conf..895S; 1999ESPM....9..895S
No abstract at ADS
Title: Review of RF 15-I X-ray Photometer Observations
Authors: Siarkowski, M.; Sylwester, J.; Gburek, S.; Kordylewski, Z.
Bibcode: 1999ESASP.448..877S
Altcode: 1999ESPM....9..877S; 1999mfsp.conf..877S
No abstract at ADS
Title: In-Flight Analysis of the Yohkoh PSF Function
Authors: Gburek, S.; Sylwester, J.
Bibcode: 1999ESASP.448..819G
Altcode: 1999mfsp.conf..819G; 1999ESPM....9..819G
No abstract at ADS
Title: Influence of Yohkoh BCS Instrumental Shape on Results of
Spectral Fitting in Vicinity of Ca XIX Lines
Authors: Kepa, A.; Sylwester, J.; Bentley, R. D.
Bibcode: 1999ESASP.448..835K
Altcode: 1999ESPM....9..835K; 1999mfsp.conf..835K
No abstract at ADS
Title: Transversal and Radial Motions of Flaring Kernels for 11
August 2992 Event
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 1999ESASP.446..639S
Altcode: 1999soho....8..639S
We have studied time variations of the maximum brightness location
for pronounced flare emission kernels as seen on deconvolved Yohkoh
Soft X-ray Telescope images. Spatial resolution achieved on the
deconvolved images was +- 0.5 arcsec. Derived patterns of spatial
displacements observed on Al01, Al12 and Be119 filter images have
been intercompared. This comparison revealed systematic pattern of
variations for kernels located within the footpoint and summit flare
regions. We have found that the time variations of maximum brightness
location are typical for all flare kernels investigated. We have related
this transversal position changes with soft X-ray line displacements
as determined from Yohkoh Bent Crystal Spectrometer for SXV, Ca XIX
and Fe XXV ion spectra (radial velocity component). We have noticed
definite time correspondence between transversal motions of kernels,
spectral line displacements and the details of flare hard X-ray
flux variability. This correspondence is especially well pronounced
during the initial phase for many disc and limb events. We discuss
the importance of the noticed pattern on possible flare scenarios.
Title: Reconstruction of Images with Poisson Noise
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 1999AcA....49..189S
Altcode:
This paper addresses quantitatively the problem of influence
of statistical uncertainties embedded in the recorded image on
uncertainties of the reconstructed image. In the analysis we use
iterative maximum likelihood algorithm ANDRIL (described by Sylwester
and Sylwester 1998) developed for massive deconvolution of flare images
obtained by the Soft X-ray Telescope (SXT) on Yohkoh. We illustrate
the "ill-conditioned" nature of the image reconstruction problem and
suggest the ways to reduce, at least partly, propagation of noise to
the reconstructed image.
Title: Flaring Structures Observed in Deconvolved SXT Images
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 1999AcA....49...85S
Altcode:
We present and discuss evolution of flaring structures morphology
as observed in deconvolved soft X-ray images. The X-ray images have
been obtained using the Soft X-ray Telescope (SXT) on Yohkoh. The
deconvolution has been made using the iterative maximum likelihood
algorithm Andril. In the reconstructed images it is possible to study
the position of individual fine structures for the first time with
the resolution superior to the SXT pixel size. We show example of
the analysis of deconvolved images for one disc flare on July 11,
1992 at 15:25 UT. Corresponding figures and animations for two other
flares are available at the address www.cbk.pan.wroc.pl and at the
Acta Astronomica Archive (see second cover page for details). These
flares occurred on November 19, 1991 and on January 13, 1992 and have
been located near/at the limb. We conclude about the differences of
physical conditions of the flaring plasma confined in compact bright
regions (kernels) located in the footpoint and summit areas.
Title: Dynamics of coronal flux tubes in flares.
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 1999joso.proc...93S
Altcode:
The authors address the problem of dynamics of the soft X-ray coronal
structures being excited during flares. The investigation of this
problem has been possible thanks to development of dedicated Yohkoh
SXT image deconvolution algorithm ANDRIL which allows to remove the
instrumental blurring and increase spatial resolution on the images
below ≡1 arcsec.
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: Reconstruction of coronal magnetic fields from deconvolved
SXT images.
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 1999joso.proc..105S
Altcode:
The authors reconstruct the coronal magnetic field topology based
on analysis of deconvolved SXT images. In the analysis they use
the deconvolved SXT images and their earlier findings regarding the
differences of thermodynamic parameters (temperature, emission measure)
for plasma confined within footpoint and summit kernels. Additionally
MEM reconstructed HXT L channel data have been used.
Title: Coronal Abundances
Authors: Fludra, A.; Saba, J. L. R.; Henoux, J. -C.; Murphy, R. J.;
Reames, D. V.; Lemen, J. R.; Strong, K. T.; Sylwester, J.; Widing,
K. G.
Bibcode: 1999mfs..conf...89F
Altcode:
Flare X-Ray Measurements from BCS Calcium Abundance Fe/H and Fe/Ca
Abundance Relative Abundances of Ar. Ca. and Fe in Flares Factors
Affecting Abundance Determinations from X-Ray Spectra FCS Abundances
FCS Active-Region Abundances Abundance Variability in Active Regions
Impact of Resonance Scattering Assessment of FCS Active-Region Abundance
Results FCS Flare Abundance Studies Coronal CI/S and Ar/S Measurements
Dem Studies of Flare Abuncances Determination of Solar Abundances
by Solar Flare γ-Ray Spectrometry γ-Ray Spectral Analysis γ-Ray
Results Solar Energetic Particles Major Proton Events CIR Events from
Coronal Holes Impulsive Flare Events Theory of Abundance Fractionation
Gravitational Settling Pressure Gradient and Stationary Diffusion
Ion-Neutral Separation Due to Currents Ion-Neutral Separation Due to
Electromagnetic Forces Discussion Summary
Title: Detection of SGR 1900+14 Pulse on August 27, 1998 by RF-15I
Soft/Hard Solar X-ray Photometer
Authors: Sylwester, J.; Kordylewski, Z.; Siarkowski, M.; Gburek, S.;
Farnik, F.; Likin, O.
Bibcode: 1998AcA....48..819S
Altcode:
We report detection of the supposed magnetar gamma pulse by the
common Czech-Polish solar Soft/Hard X-ray Photometer aboard the
INTERBALL-Tail satellite. Timing information presented may allow for
better triangulation of the position of the gamma source.
Title: ANDRIL - Maximum Likelihood Algorithm for Deconvolution of
SXT Images
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 1998AcA....48..519S
Altcode:
We present an iterative deconvolution algorithm called ANDRIL
devoted for advanced processing of images obtained by the Soft X-ray
Telescope (SXT) on Yohkoh. The algorithm is based on maximum likelihood
approach. We introduced several modifications to this algorithm in order
to optimize its properties. The goal of the algorithm is to remove
numerically the image blurring due to the instrument point spread
function (PSF) and increase the image resolution. The application
of the algorithm allows to resolve soft X-ray structures in the SXT
images on the angular scales down to 1arcsec. Presented algorithm has
been recently used for analysis of detailed morphology and physical
conditions in the plasma of flaring structures.
Title: Detailed Evidence for Flare-to-Flare Variations of the Coronal
Calcium Abundance
Authors: Sylwester, J.; Lemen, J. R.; Bentley, R. D.; Fludra, A.;
Zolcinski, M. -C.
Bibcode: 1998ApJ...501..397S
Altcode:
The analysis of X-ray solar flare spectra obtained by the Bent
Crystal Spectrometer on board the Solar Maximum Mission satellite is
presented. The ratio of the Ca XIX resonance line intensity to the
nearby continuum is used to measure the calcium abundance relative to
hydrogen (ACa). A description of the spectroscopic method
of determining the absolute calcium abundance is given. Possible
instrumental and solar effects that might influence the abundance
estimates are evaluated. Over 5000 spectra from more than 100 flares are
analyzed. We find a flare-to-flare variation for ACa that is
not correlated with flare size, Hα importance, or with several other
flare characteristics. For flares observed from two active regions, the
observed value of ACa increases as a function of time. The
average for all flares is <ACa> = (5.77 +/- 1.41) ×
10-6. A discussion of investigated correlations of derived
ACa values with several flare characteristics is presented.
Title: On-board photometer for obtaining two-dimensional image of
a solar flare with the use of soft X-rays.
Authors: Likin, O. B.; Pisarenko, N. F.; Farnik, F.; Ullrich, J.;
Sylwester, J.; Kordylewski, Z.
Bibcode: 1998KosIs..36..305L
Altcode:
An on-board photometer for measuring soft and hard X-rays (2 - 240 keV)
from solar flares with automatic inflight sensitivity calibration
and a special collimator to get the source image in soft X-rays is
described. The photometer is installed on board the INTERBALL-1 (Tail
Probe) spacecraft.
Title: On-Board Photometer for Obtaining a Two-Dimensional Image of
a Solar Flare with the Use of Soft X-rays
Authors: Likin, O. B.; Pissarenko, N. F.; Farnik, F.; Ullrich, J.;
Sylwester, J.; Kordylewski, Z.
Bibcode: 1998CosRe..36..287L
Altcode:
No abstract at ADS
Title: Evolution of Flaring Structures
Authors: Sylwester, Janusz; Sylwester, Barbara
Bibcode: 1998ASPC..155..381S
Altcode: 1998sasp.conf..381S
No abstract at ADS
Title: RESIK: High Sensitivity Soft X-ray Spectrometer for the Study
of Solar Flare Plasma
Authors: Sylwester, J.; Gaicki, I.; Kordylewski, Z.; Nowak, M.;
Kowalinski, S.; Sjarkowski, M.; Bentley, W.; Trzebinski, R. D.;
Whyndham, M. W.; Guttridge, P. R.; Culhane, J. L.; Lang, J.; Phillips,
K. J. H.; Brown, C. M.; Doschek, G. A.; Oraevsky, V. N.; Boldyrev,
S. I.; Kopaev, I. M.; Stepanov, A. I.; Klepikov, V. Yu.
Bibcode: 1998ESASP.417..313S
Altcode: 1998cesh.conf..313S
No abstract at ADS
Title: Iron and calcium abundances in solar flares from the
multitemperature analysis of X-ray spectra (abstract)
Authors: Fludra, A.; Bentley, R. D.; Culhane, J. L.; Lemen, J. R.;
Sylwester, J.
Bibcode: 1998PAICz..88...91F
Altcode:
No abstract at ADS
Title: Analysis of the flare evolution in the emission measure -
temperature diagrams for selected events observed by SMM (abstract)
Authors: Sylwester, B.; Sylwester, J.; Siarkowski, M.; Fludra, A.;
Serio, S.
Bibcode: 1998PAICz..88...94S
Altcode:
No abstract at ADS
Title: Physical conditions in flaring loops.
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 1998joso.proc..155S
Altcode:
The authors present results of the analysis of physical conditions in
flaring limb X-ray coronal structures as observed on deconvolved Yohkoh
Soft X-ray Telescope (SXT) images. The results obtained indicate that
bright foot-point areas are cooler by 2-3 MK relative to the kernels
observed higher in the corona. This property may allow to distinguish
between the location (foot-point/coronal) of bright flare kernels
observed on the disc flares.
Title: Footpoint Structures of Flare Loops
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 1997ESASP.404..697S
Altcode: 1997cswn.conf..697S
No abstract at ADS
Title: Calcium abundance measurements using the Yohkoh BCS
Authors: Bentley, R. D.; Sylwester, J.; Lemen, J. R.
Bibcode: 1997AdSpR..20.2275B
Altcode:
Soft X-ray observations by SMM and other spacecraft have shown
that the abundance of certain elements in solar corona varies from
flare to flare. In this study, observations made by the Yohkoh Bragg
Crystal Spectrometer (BCS) in helium-like Ca XIX have been analysed,
and Ca abundance determined for 177 flares observed during the first
four years of the mission (1991-1995). The average abundance of Ca
relative to H for all flares is < A_Ca > = (3.64 +/- 0.39) x
10^-6. As with an earlier study of SMM data, the abundance is found to
be enhanced compared to the photosphere ((2.24 +/- 0.10) x 10^-6), and
with only minor variation from flare to flare. However, the absolute
value and range of values determined by this study is smaller than in
the previous study; these differences are discussed.
Title: Structures in vicinity of sunspots as seen on deconvolved
SXT images.
Authors: Sylwester, B.; Sylwester, J.
Bibcode: 1997joso.proc...97S
Altcode:
No abstract at ADS
Title: High-resolution temperature maps of flares from deconvolved
SXT images.
Authors: Sylwester, J.
Bibcode: 1996joso.proc..131S
Altcode:
The shape of the SXT point spread function is narrow enough that the
deconvolution of images may allow to study the brightness distribution
on sub-pixel scales. Intensity ratios of images taken in individual
bands (through different filters) contain information on the plasma
temperature distribution provided that the images are very precisely
overlaid (aligned). It is shown, that the accuracy of the image
alignment should not be worse than 0″1 throughout the investigated
region to allow for realistic temperature estimates. An example of
the temperature maps is shown for the flare of 19 November 1991 as
obtained before and after the deconvolution and application of the
additional pointing corrections.
Title: ANDRIL Algorithm for Deconvolution of SXT Images
Authors: Sylwester, J.; Sylwester, B.; Siarkowski, M.
Bibcode: 1996ASPC..111..244S
Altcode: 1997ASPC..111..244S
The authors present an iterative SXT image deconvolution algorithm
based on the Richardson (1972), Lucy (1974) and Withbroe (1975) methods.
Title: Improvement of SXT Image Alignment in Order to Obtain
High-Resolution Temperature Maps
Authors: Siarkowski, M.; Sylwester, J.; Jakimiec, J.; Tomczak, M.
Bibcode: 1996AcA....46...15S
Altcode:
Examples are shown and discussed which indicate that published
temperature maps derived using SXT intensity ratio technique may
be substantially biased if standard image processing routines are
used to coalign the images. Methods are discussed which allow for
independent of the Yohkoh satellite pointing information, precise
(0.12 arcsec), alignment of images obtained in selected energy bands
(filters). Examples are presented illustrating the differences in
the temperature maps derived using standard and additional pointing
correction (APC).
Title: The Soft X-Ray Spectrometer-Photometer Diogenes Aboad the
Coronas-I Satellite
Authors: Kordylewski, Z.; Sylwester, J.
Bibcode: 1996pas..meet...88K
Altcode:
No abstract at ADS
Title: Thermodynamic signatures of proton flares.
Authors: Sylwester, B.; Sylwester, J.; Garcia, H. A.
Bibcode: 1996joso.proc..161S
Altcode:
No abstract at ADS
Title: Fine Structures Observed on Deconvolved SXT Images
Authors: Sylwester, B.; Sylwester, J.; Siarkowski, M.
Bibcode: 1996ASPC..111..249S
Altcode: 1997ASPC..111..249S
The authors present prompt results of SXT image deconvolution obtained
using the ANDRIL algorithm worked out in Wroclaw. Using this algorithm
it is possible to study the morphology of individual fine structures
with the resolution superior to the SXT pixel size. The authors show
examples of deconvolved images for two selected flares.
Title: Soft X-ray imaging of the TY Pyx binary system - II. Modelling
the interconnecting loop-like structure
Authors: Pres, Pawel; Siarkowski, Marek; Sylwester, Janusz
Bibcode: 1995MNRAS.275...43P
Altcode:
In this paper we present improved results of 3D deconvolution of the
TY Pyx LEIT light curve, taking into account the effect of `halo'
emission. The results obtained indicate that the bulk of plasma
is between the two stars. The spatial distribution of the emission
suggests the presence of the loop structure interconnecting the stars,
as was argued in the previous paper by Siarkowski, Sylwester &
Pres. We have modelled the physical conditions in this loop using the
hydrostatic coronal loop model presented by Vesecky, Antiochos &
Underwood. The brightness distribution along this interconnecting
structure can be interpreted by loop models with 12<T_max<48 MK
and Gamma>15.
Title: Quantitative interpretation of GOES soft X-ray
measurements. I. The isothermal approximation: application of various
atomic data.
Authors: Sylwester, J.; Garcia, H. A.; Sylwester, B.
Bibcode: 1995A&A...293..577S
Altcode:
The most temporally complete set of solar soft X-ray flux
measurements available at the present time is contained in the
archive record of 0.5-4A and 1-8A broad-band ion chamber observations
from the Geostationary Operational Environmental Satellite (GOES)
spacecraft. The archive contains a nearly continuous record of the soft
X-ray observations since 1974. Physical analyses of these measurements
are often carried out under the isothermal plasma approximation. In
this paper we present calculations of the ion chamber current ratio -
temperature relationship for soft X-ray detectors onboard four GOES
satellites whose data comprise the main historical X-ray record. The
present calculations update and extend results obtained by Thomas et
al. for the GOES-1 detectors. Our analysis has been performed using two
modern sets of theoretical X-ray spectra calculated by Mewe et al. and
by Raymond. Comparisons of the detector responses obtained for each of
the above theoretical spectra are performed. These analyses indicate
that both Mewe et al. and Raymond X-ray spectra provide mutually
consistent interpretations of measured GOES X-ray data. Deficiencies in
the physical interpretation of a mixture of low-temperature (active
region) and high-temperature (flare) plasmas resulting from the
isothermal approximation are pointed out and discussed. It is shown
that the so called flare "thermodynamic measure", defined here and
derived from GOES measurements, compares well with co-temporal values
obtained from the analysis of the Yohkoh BCS spectra. It is proposed
that the presented method of a thermodynamic measure analysis may be
useful in the interpretation of global flare thermodynamics.
Title: Diagnostics of the Coronal Plasma (Invited)
Authors: Sylwester, J.
Bibcode: 1994scs..conf..391S
Altcode: 1994IAUCo.144..391S
The author discusses selected aspects of the X and EUV diagnostics of
the corona. Especially, he stresses on the publications which indicate
that the assumptions commonly adopted in the interpretation of solar
soft X-ray (SXR) spectra are not necessarily adequate. Theoretical
considerations, reinterpretation of previous measurements and
interpretation of incoming data stream indicate that number of
assumptions characteristic for the "classical approach" have to be at
least questioned.
Title: Soft X-ray Imaging of TY Pyx Binary System
Authors: Siarkowski, M.; Sylwester, J.; Pres, P.
Bibcode: 1994scs..conf..207S
Altcode: 1994IAUCo.144..207S
Using a new 3D deconvolution technique the authors analyze the X-ray
light curve of TY Pyx eclipsing binary to model the corona around the
system. The result indicates the possible presence of an interstellar
loop connecting the stars.
Title: On the Use of GOES Soft X-Ray Database in Solar Research
Authors: Sylwester, J.; Garcia, H. A.
Bibcode: 1994emsp.conf..213S
Altcode:
No abstract at ADS
Title: Manifestation of Multiple Energy Release on the Evolution of
Flares in the Diagnostic Diagrams
Authors: Sylwester, B.; Sylwester, J.; Reale, F.; Serio, S.
Bibcode: 1994scs..conf..257S
Altcode: 1994IAUCo.144..257S
The authors advance the investigation of evolution of flares in the
emission measure-temperature diagrams. Models are considered in which
the flare heating consists of a pair of elementary heating episodes
taking place in separate loops within flaring region.
Title: Book reviews
Authors: Heintze, J. R. W.; van Genderen, A. M.; van Oss, R.; van
der Klis, M.; Fárník, F.; Schadee, A.; Sylwester, J.; Torii, S.;
Iwaniszewska, C.; Nieuwenhuijzen, H.; Kleczek, J.; Schwartz, S. J.
Bibcode: 1993SSRv...64..363H
Altcode:
No abstract at ADS
Title: Estimation of equivalent flaring loop geometry based on
broadband soft x-ray observations
Authors: Sylwester, J.; Sylwester, B.; Jakimiec, J.; Garcia, H. A.;
Serio, S.; Reale, F.
Bibcode: 1993AdSpR..13i.307S
Altcode: 1993AdSpR..13..307S
Hydrodynamic models of a simple flaring loop, obtained using the
Palermo-Harvard code have been used to consider the flare global energy
balance. During the heating phase the time variations of the total
thermal energy contained in the coronal portion of the loop is well
represented by a simple analytical formula with parameters depending
on the flaring loop geometry. The loop geometry parameters are the
loop semi-length and the cross-sectional area. A method is introduced
which allows to estimate values of these parameters from a fit to the
measurements. We have applied this method to the interpretation of
GOES soft X-ray data for the flare on 11 September 1989, for which
high-resolution XUV images were available from the NIXT experiment.
Title: Book-Review - Physical Processes in Solar Flares
Authors: Somov, B. V.; Sylwester, J.
Bibcode: 1993SSRv...64Q.368S
Altcode:
No abstract at ADS
Title: Book reviews
Authors: Rutten, R. J.; Mewe, R.; Houziaux, L.; Cheng, Chung-Chieh;
van der Klis, M.; Sylwester, Janusz; Tajima, T.; Kresák, Ľ.; Minarik,
S.; de Jager, Cornelis; van der Kruit, P. C.
Bibcode: 1993SSRv...65..181R
Altcode:
No abstract at ADS
Title: Properties of SMM Flares
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 1993ASSL..183..139S
Altcode: 1993pssc.symp..139S
No abstract at ADS
Title: Book-Review - Eruptive Solar Flares
Authors: Svestka, Z.; Jackson, B. V.; Machado, M. E.; Sylwester, J.
Bibcode: 1993SSRv...65..186S
Altcode:
No abstract at ADS
Title: Analysis of Flare Evolution in the Emission Measure-Temperature
Diagram for Three Events Observed by SMM
Authors: Sylwester, B.; Sylwester, J.; Siarkowski, M.; Serio, S.;
Reale, F.
Bibcode: 1993ASSL..183..147S
Altcode: 1993pssc.symp..147S
No abstract at ADS
Title: Dynamics of flaring loops. III - Interpretation of flare
evolution in the emission measure-temperature diagram
Authors: Sylwester, B.; Sylwester, J.; Serio, S.; Reale, F.; Bentley,
R. D.; Fludra, A.
Bibcode: 1993A&A...267..586S
Altcode:
The aim of the paper is to illustrate the application of the
density-temperature diagrams discussed by Jakimiec (1992) to
interpretation of soft X-ray measurements, namely, calcium spectra
recorded by the Solar Maximum Mission Bent Crystal Spectrometer. Using
the emission measure and the temperature values derived for a set
of hydrodynamic flare models discussed in previous papers, we have
obtained and analyzed the (sq rt epsilon-T) counterparts of the (N-T)
diagrams. Inspection of these diagrams reveals that they qualitatively
resemble the (N-T) diagrams. The inclinations of the decay trajectories
make the main difference. Next, we have performed a comparison of the
modeled and observed flare evolutionary trajectories. This comparison
allowed us to identify characteristic cases of evolution during the
decay phase. We have discussed time variations of the heating rate
for selected observed flares. The results of this paper illustrate
how to use the diagnostic diagrams in the interpretation of flare soft
X-ray measurements.
Title: Objectives of RESIK solar concave soft X-ray spectrometer
for CORONAS-F mission.
Authors: Sylwester, Janusz; Bentley, R. D.
Bibcode: 1992ESASP.348..357S
Altcode: 1992cscl.work..357S
Several institutes are involved in construction of the high sensitivity
soft X-ray spectrometer RESIK, to be flown aboard the Russian CORONAS-F
satellite in 1994/95. The scientific objectives of the instrument are
discussed, arising as a compromise between the scientific interests and
constrained by good quality large area crystals obtainable, detector
dimensions and the geometry of Bragg concave crystal reflection. Four
bands have been selected to perform measurements of the solar active
region and flare spectra: 2.97 - 3.24 Å, 3.15 - 3.25 Å, 4.95 - 5.15
Å, and 6.50 - 7.19 Å. Special "Dopplerometer" arrangement of the
crystals will allow to assign "absolute" wavelength scale and determine
the role of directed and turbulent flows in the source. Interpretation
of the line and continuum intensities will permit to derive the
differential emission measure for plasma temperatures T > 3MK, and
to determine the composition (relative to H) of the coronal plasma for
many elements including these with different first ionization potential.
Title: Dynamics of flaring loops. II - Flare evolution in the
density-temperature diagram
Authors: Jakimiec, J.; Sylwester, B.; Sylwester, J.; Serio, S.; Peres,
G.; Reale, F.
Bibcode: 1992A&A...253..269J
Altcode:
The evolution of basic thermodynamic parameters of a single flaring
solar loop has been investigated in terms of density-temperature (N-T)
diagram. A grid of hydrodynamic models has been calculated for this
purpose, using the Palermo-Harvard code. The calculated models differ
in their initial conditions and the form of the energy imput (i.e., the
heating rate value, the heating duration, the assumed time profile). The
consequences of variation of these model parameters on the evolutionary
paths in the density-temperature diagrams is considered; over a
substantial duration, the decay occurs along a T varies as N-squared
trajectory when the impulsive flare heating function is switched-off
abruptly. The results obtained can be very useful as diagnostics of
the flare heating process, based on soft X-ray observations.
Title: Thermodynamic decay scaling laws in solar loop flares
Authors: Serio, S.; Reale, F.; Peres, G.; Jakimiec, J.; Sylwester,
B.; Sylwester, J.
Bibcode: 1992MmSAI..63..763S
Altcode:
Results of numerical calculations are used, together with analytical
considerations, as a guide to set up diagnostic tools for the flare
decay phase in terms of the temperature-density (n-T) diagram. The
decaying loop was modeled as a hydrodynamic process in a rigid
semicircular tube. It is shown that the trajectory on the n-T plane
has a slope of about 2 for a wide set of peak model flare conditions.
Title: Flare Evolution in the Density - Temperature Diagram
Authors: Serio, S.; Reale, F.; Peres, G.; Jakimiec, J.; Sylwester,
B.; Sylwester, J.
Bibcode: 1992LNP...399..135S
Altcode: 1992esf..coll..135S; 1992IAUCo.133..135S
No abstract at ADS
Title: Iron and calcium abundances in solar flares from the
multi-temperature analysis of X-ray spectra
Authors: Fludra, A.; Bentley, R. D.; Culhane, J. L.; Lemen, J. R.;
Sylwester, J.
Bibcode: 1991AdSpR..11a.155F
Altcode: 1991AdSpR..11Q.155F
A generalized method of calculating the distribution of the emission
measure with temperature (DEM) for optically thin plasma has been
developed. The method simultaneously uses line flux ratios in addition
to line fluxes. When a ratio of lines from the same element is used,
the resulting DEM is independent of this element's abundance. The method
has been applied to derive the absolute abundances of iron in solar
flares from X-ray spectra recorded by the Bent Crystal Spectrometer on
SMM. The iron abundances have been found to vary between flares. The
calcium abundances have also been calculated using the same method and
are found to be in close agreement with the values derived from the
line-to-continuum technique (Lemen et al., 1990 and Sylwester et al.,
1990). The variation of iron and calcium abundances is compared. A
correction to the ionization balance for iron is proposed.
Title: Thermondynamic Evolution of Flares
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Serio, S.;
Reale, F.
Bibcode: 1991LNP...387..188S
Altcode: 1991fpsa.conf..188S
No abstract at ADS
Title: Dynamics of flaring loops. I - Thermodynamic decay scaling laws
Authors: Serio, S.; Reale, F.; Jakimiec, J.; Sylwester, B.;
Sylwester, J.
Bibcode: 1991A&A...241..197S
Altcode:
A simple analytical approximate solution for the hydrodynamic equations
describing the decay of a flaring loop is derived. It is found that,
independent of chemical composition of the plasma, the entropy per
particle at the top of the loop undergoes an initial phase of linear
decay, with a slope related to the initial loop conditions. The
characteristic decay time is shorter than conductive or radiative
times for typical solar flare conditions. The analytical solution
is compared with numerical solutions of the full set of hydrodynamic
equations for loop flares, and it is shown that its validity extends
over a large fraction of the decay. Also the decay times of temperature,
density and pressure are related to the entropy decay time.
Title: DIOGENESS: soft X-ray spectrometer-photometer for studies of
flare energy balance.
Authors: Sylwester, J.; Farnik, F.
Bibcode: 1990BAICz..41..149S
Altcode:
The authors describe the scientific objectives and the technical
characteristics of the DIOGENESS (Diagnostic of Energy Sources and Sinks
in flares) instrument which is under development for the CORONAS-I
solar observatory to be launched in the early 1990's as part of the
INTERCOSMOS programme.
Title: Investigation of non-uniform heating during the decay phase
of solar flares
Authors: Sylwester, B.; Sylwester, J.; Bentley, R. D.; Fludra, A.
Bibcode: 1990SoPh..126..177S
Altcode:
We have analysed X-ray spectra of 13 solar flares as obtained
by the Bent Crystal Spectrometer (BCS) on the Solar Maximum
Mission. In particular, we have examined the observed ratio of
TFe/TCa where TFe and TCa
are the temperatures obtained from the FeXXV and CaXIX spectra,
respectively. In order to simplify the investigation we have analysed
only flares which reach quasi-steady-state during the decay. It
turned out that the observed ratios cannot be explained by a model
consisting of a single, uniformly heated loop, with a constant or
variable cross-sectional area. We propose that this problem may be
solved by introducing some distribution of the heating function across
the flaring loop. This model has been tested by detailed calculations.
Title: The Decay Phase of Three Large Solar Flares
Authors: Fludra, A.; Bentley, R. D.; Culhane, J. L.; Jakimiec, J.;
Lemen, J. R.; Sylwester, J.; Moorthy, S. T.
Bibcode: 1990PDHO....7..266F
Altcode: 1990ESPM....6..266F; 1990dysu.conf..266F
No abstract at ADS
Title: Study of Non-Uniform Heating in Solar Flares
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Serio, S.; Reale,
F.; Bentley, R. D.; Fludra, A.
Bibcode: 1990PDHO....7..255S
Altcode: 1990ESPM....6..255S; 1990dysu.conf..255S
The authors have analyzed the ratios of the temperatures derived from Fe
and Ca spectra (TFe/TCa) for the rising phase of
11 solar flares. Corresponding hydrodynamic models have been calculated
and the obtained results are compared with the observational data for
selected flares.
Title: X-ray Spectroscopy of the Upper Solar Atmosphere
Authors: Sylwester, J.
Bibcode: 1990PDHO....7..212S
Altcode: 1990dysu.conf..212S; 1990ESPM....6..212S
The author restricts his review to the soft X-ray wavelength interval
1 - 25 Å. He discusses X-ray sources in the solar corona, tasks of the
SXR spectroscopy, narrow-band spectral analysis, differential emission
measure, composition of the coronal plasma, summary and future problems.
Title: Turbulent and Directed Plasma Motions in Solar Flares
Authors: Fludra, A.; Lemen, J. R.; Jakimiec, J.; Bentley, R. D.;
Sylwester, J.
Bibcode: 1989ApJ...344..991F
Altcode:
An improved method for fitting asymmetric soft X-ray line profiles
from solar flares is presented. A two-component model is used where one
component represents the total emission from directed upflow plasma and
the other the emission from the plasma at rest. Unlike previous methods,
the width of the moving component is independent from that of the
stationary component. Time variations of flare plasma characteristics
(i.e., temperature, emission measure of moving and stationary plasma,
upflow and turbulent velocities) are derived from the Ca XIX and Fe XXV
spectra recorded by the Bent Crystal Spectrometer on the Solar Maximum
Mission. The fitting technique provides a statistical estimation
for the uncertainties in the fitting parameters. The relationship
between the directed and turbulent motions has been studied, and
a correlation of the random and directed motions has been found in
some flares with intensive plasma upflows. Mean temperatures of the
upflowing and stationary plasmas are compared for the first time from
ratios of calcium to iron X-ray line intensities. Finally, evidence
for turbulent motions and the possibility of plasma upflow late into
the decay phase is presented and discussed.
Title: Comparison of the Microwave and Soft X-Ray Emission above
a Sunspot
Authors: Siarkowski, M.; Sylwester, J.; Jakimiec, J.; Bentley, R. D.
Bibcode: 1989SoPh..119...65S
Altcode:
The Westerbork Synthesis Radio Telescope (WSRT) 6 cm radio observations
of the active region HL 16864 large spot (Strong, Alissandrakis,
and Kundu, 1984) are compared with X-ray data obtained from the Flat
Crystal Spectrometer (FCS) onboard the Solar Maximum Mission satellite
on May 25, 1980. The X-ray data confirm the presence of a temperature
depression above the spot umbra in agreement with suggestions obtained
from radio data analysis. Significant differences in the spatial
distribution of both kinds of emission observed in the corona above
this spot are attributed mainly to the strong resonant character of the
cyclotron radio radiation. Some differences are also caused by both
the relatively low efficiency and the low spatial resolution of the
FCS. Deconvolution of X-ray images allows to see the new structures
and enhances the mutual correlation between X-ray and radio pictures.
Title: Flare energetics.
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veck, N. J.
Bibcode: 1989epos.conf..377W
Altcode:
The authors have sought to establish a comprehensive and self-consistent
picture of the sources and transport of energy within a flare. To
achieve this goal, they chose five flares in 1980 that were well
observed with instruments on the Solar Maximum Mission, and with other
space-borne and ground-based instruments. The events were chosen to
represent various types of flares. Details of the observations available
for them and the corresponding physical parameters derived from these
data are presented. The flares were studied from two perspectives,
the impulsive and gradual phases, and then the results were compared
to obtain the overall picture of the energetics of these flares. The
authors also discuss the role that modeling can play in estimating the
total energy of a flare when the observationally determined parameters
are used as the input to a numerical model. Finally, a critique of
our current understanding of flare energetics and the methods used to
determine various energetics terms is outlined, and possible future
directions of research in this area are suggested.
Title: Results of the LEBAN diagnostic procedure applied to two
SMM-observedflares.
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.
Bibcode: 1988JPhys..49..309S
Altcode: 1988IAUCo.102..309S
In a previous paper (B. Sylwester et al., 1986) the authors proposed a
new procedure called LEBAN (Loop Energy Balance Analysis) for deriving
the basic geometrical parameters of flaring loops. In the present
paper they apply the LEBAN method to two well observed solar flares.
Title: Time variations of the calcium elemental abundance in flares
from NOAA active regions 2562 and 2779.
Authors: Sylwester, J.; Zolcinski-Couet, M. -C.; Bentley, R. D.;
Lemen, J. R.
Bibcode: 1988JPhys..49..189S
Altcode: 1988IAUCo.102..189S
Analysis of flare spectra obtained with the Bent Crystal Spectrometer
aboard the Solar Maximum Mission (SMM) satellite enables the
determination of the fluxes in the resonance (w) line of Ca XIX and
the near-by continuum. The line-to-continuum intensity ratio is a
sensitive measure of the calcium elemental abundance (ACa)
relative to hydrogen in the emitting plasma. The authors analyse
the variations of ACa for flares which occurred in two
active regions well observed by SMM. They conclude that it is not
possible to correlate the abundance variations with the time of the
flare occurrence as suggested in an earlier paper for flares produced
from a single active region. Further, the authors find no convincing
correlation of abundance variation with any other flare characteristics.
Title: Intercomparison of flare observations with two SMM
spectrometers: BCS and HXIS
Authors: Jakimiec, J.; Prés, P.; Fludra, A.; Bentley, R. D.; Lemen,
J. R.; Mewe, R.; Schrijver, J.; Sylwester, J.
Bibcode: 1988AdSpR...8k.231J
Altcode: 1988AdSpR...8..231J
The temperature diagnostics of hot flare plasma, obtained from two
Solar Maximum Mission instruments (HXIS and BCS), is compared. A good
general agreement between the HXIS and BCS-Fe temperature scales has
been found. However, for the growth phase of some flares a systematic
difference, THXIS>TFe, has been found,
which is not likely to be due to the typical non-thermal electron
beams. Possible explanation of this effect is briefly discussed.
Title: Coronal loops, X-ray diagnostics
Authors: Sylwester, J.
Bibcode: 1988AdSpR...8k..55S
Altcode: 1988AdSpR...8...55S
The study of physical conditions and the geometry of solar coronal
structures is a subject of substantial interest among the solar physics
community. In the present review the new methods are presented allowing
for identification of so called Non-Equilibrium and Quasi-Steady-State
phases during the evolution of the flare, based on the soft X-ray
observations. Identification of the Quasi-Steady-State phase in
the observed flares allows to relate the plasma parameters with the
effective geometrical characteristics of the flaring loops. Next, the
comparison with the observed flaring loop sizes allows to investigate
the heating rate of the plasma and the plasma density. Arguments
are presented showing validity of the heating rate diagnostics also
for the initial Non-Equilibrium flare phase. This, in turn, provides
an important diagnostic tool for studying the flare energy balance
during the initial phase. Results of the hydrodynamic flaring loop
model calculations confirm usefulness of the energy balance analysis
method for investigation of flares during the initial phase. Presented
methods have large potential possibilities of further improvement and
they should be used more efficiently in future studies.
Title: Influence of the energy calibration of broad-band X-ray
detectors on determination of the plasma parameters
Authors: Sylwester, B.; Farnik, F.; Sylwester, J.
Bibcode: 1988AdSpR...8k.267S
Altcode: 1988AdSpR...8..267S
Standard broad-band measurements of the solar soft X-ray spectra
are used to derive averaged values of parameters characterizing
flaring plasmas i.e. the temperature and emission measure. Derived
values of these parameters may be used as a basis for estimating the
thermal energy content, densities and other thermodynamic properties of
flares. These derived numerical values are subject to errors inherent in
the uncertainties of the energy calibration, filter transmission etc.,
of the measuring device. In this paper we investigate the influence of
the uncertainties of the detector's energy calibration on the accuracy
of the derived physical characteristics of solar flares. This analysis
is based on data obtained from the X-ray photometer flown aboard the
Prognoz-10 (Intershock) satellit
Title: Investigations of Turbulent and Direct Motions in Solar Flares
Authors: Bentley, R. D.; Fludra, A.; Lemen, J. R.; Jakimiec, J.;
Sylwester, J.
Bibcode: 1987BAAS...19R.750B
Altcode:
No abstract at ADS
Title: Variation in Calcium Abundance during Flares
Authors: Sylwester, J.; Lemen, J. R.; Mewe, R.; Bentley, R. D.;
Sylwester, B.
Bibcode: 1987sman.work..123S
Altcode:
The authors discuss the variation of the line-to-continuum ratio
throughout the entire flare including the temperature rise phase.
Title: LEBAN diagnostic for basic flaring loop parameters.
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Fludra, A.;
Peres, G.; Serio, S.
Bibcode: 1987PAICz..66..229S
Altcode: 1987eram....1..229S
The authors describe the diagnostic procedure called LEBAN which may
be helpful in deriving basic geometrical loop parameters. "Palermo
Code" hydrodynamic flare model calculations have been used to test
reliability of the procedure.
Title: High-Temperature Plasma Diagnostics of Solar Flares and
Comparison with Model Calculations
Authors: Jakimiec, J.; Sylwester, B.; Sylwester, J.; Lemen, J. R.;
Mewe, R.; Bentley, R. D.; Peres, G.; Serio, S.; Schrijver, J.
Bibcode: 1987sman.work...91J
Altcode:
The present state of flare diagnostics from X-ray spectra is briefly
outlined. The authors discuss how improved diagnostic results can be
used in flare heating process investigations.
Title: Characterization of the Total Flare Energy
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
Bibcode: 1986epos.conf.5.41W
Altcode: 1986epos.confE..41W
No abstract at ADS
Title: Energetics of the Impulsive Phase
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
Bibcode: 1986epos.conf..5.5W
Altcode: 1986epos.confE...5W
No abstract at ADS
Title: Energetics of the Gradual Phase
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
Bibcode: 1986epos.conf.5.20W
Altcode: 1986epos.confE..20W
No abstract at ADS
Title: Review of Impulsive Phase Phenomena
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
Bibcode: 1986epos.conf.5.60W
Altcode: 1986epos.confE..60W
No abstract at ADS
Title: Flares Chosen for Energetics Study
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
Bibcode: 1986epos.conf.5.47W
Altcode: 1986epos.confE..47W
No abstract at ADS
Title: Relationships among the Phases
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
Bibcode: 1986epos.conf.5.39W
Altcode: 1986epos.confE..39W
No abstract at ADS
Title: Erratum - Investigation of the Maxii 8.42A Doublet in Solar
Flare Spectra
Authors: Sylwester, B.; Faucher, P.; Jakimiec, J.; Korneev, V. V.;
Krutov, V. V.; McWhirter, R. W. P.; Sylwester, J.; Tomczak, M.;
Volonte, S.; Zhitnik, I. A.
Bibcode: 1986SoPh..105..429S
Altcode:
No abstract at ADS
Title: Comparison of Three Methods Used for Calculation of the
Differential Emission Measure
Authors: Fludra, A.; Sylwester, J.
Bibcode: 1986SoPh..105..323F
Altcode:
A comparison of three methods used for multi-temperature analysis of
solar X-ray spectra is presented. The modified method of conjugate
gradients appears to be very efficient for minimizing χ2
subject to regularizing (smoothing) constraints. The Withbroe-Sylwester
method also ensures good fits, particularly when computations are
carried out in wide temperature intervals. Both methods are much faster
than the Maximum Entropy method and yield models with an entropy close
to that of the Maximum Entropy models. The reliability of revealing
the shape of the differential emission measure is discussed. It is
shown that the total emission measure and the plasma thermal energy
content can be calculated to within a few percent.
Title: Density-temperature diagnostics of 31 August double flare
Authors: Sylwester, J.; Jakimiec, J.; Fludra, A.; Leman, J. R.
Bibcode: 1986CoSka..15..153S
Altcode:
No abstract at ADS
Title: Investigation of flare heating based on X-ray observations
Authors: Jakimiec, J.; Sylwester, B.; Sylwester, J.; Mewe, R.; Peres,
G.; Serio, S.; Schrijver, J.
Bibcode: 1986CoSka..15..123J
Altcode:
Using X-ray data recorded by the Solar Maximum Mission Hard X-ray
Imaging Spectrometer the authors have investigated flare evolution
in a (Tm, N)-diagram, where Tm is the maximum
temperature and N is the mean density in the flare volume. This
flare diagnostics allows one to show that most large flares achieve a
quasi-steady-state during their decay, which means that the cooling
is then so slow that a flare evolves along the line of steady-state
loops in the (Tm, N)-diagram. The diagnostics allows one
to determine the time evolution of the flare heating function, which
gives the rate of thermal energy release, per unit volume.
Title: Flare evolution from Prognos 9 data
Authors: Fárník, F.; Sylwester, B.; Sylwester, J.; Jakimiec, J.;
Valníček, B.
Bibcode: 1986CoSka..15..121F
Altcode:
No abstract at ADS
Title: Observational evidences for coronal temperature depression
above sunspot umbra
Authors: Siarkowski, M.; Bentley, R. D.; Jakimiec, J.; Sylwester, J.
Bibcode: 1986CoSka..15..677S
Altcode:
Three large spots observed by the X-ray Polychromator on the Solar
Maximum Mission satellite are analysed. The X-ray spectroheliograms were
used to derive the two-dimensonal electron temperature distribution. For
one of these spots, observed simultaneously by the Westerbork Synthesis
Radiotelescope at 6 cm, the temperature minimum corresponds to the
centre of a microwave ring structure. This confirms the existence of
a temperature depression above the spot umbra.
Title: Investigation of the Mg XII 8.42 Å doublet in solar flare
spectra
Authors: Sylwester, B.; Faucher, P.; Jakimiec, J.; Krutov, V. V.;
McWhirter, R. W. P.; Sylwester, J.; Tomczak, M.; Volonté, S.; Zhitnik,
I. A.
Bibcode: 1986SoPh..103...67S
Altcode:
The intensity ratio of the components of the Mg XII 8.42
Å (1s2S1/2 − 2p2P1/2,
3/2) doublet in solar flare spectra has been investigated using
observations recorded from the Intercosmos 7 satellite. The observed
values of the ratio fall within the interval 0.38-0.66 and have been
compared with recent theoretical predictions based on an optically
thin collisional-radiative model. It has been found that for the
flare plasma the low values of the ratio cannot be explained since
they fall below the smallest theoretical value. The highest values
on the other hand require that an unacceptably high electron density
be postulated. It is suggested that both high and low values may be
caused by the resonance line scattering of the Mg XII quanta in the
flare volume, provided that the volume is elongated and not spherical.
Title: Physical conditions in a large flare loop on Nov. 1980 derived
from SMM observations
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Fludra, A.;
Bentley, R. D.; Schrijver, J.
Bibcode: 1986CoSka..15..145S
Altcode:
The authors present the study of a large X-ray loop related to the
H-alpha 2N flare close to the center of the solar disc. Data from Solar
Maximum Mission have been used in the analysis. The authors have derived
the temperatures, densities and the geometrical parameters (length,
diameter) for a hot core and for a cooler envelope of the flaring loop.
Title: Investigations of turbulent motions and particle acceleration
in solar flares
Authors: Jakimiec, J.; Fludra, A.; Lemen, J. R.; Dennis, B. R.;
Sylwester, J.
Bibcode: 1986AdSpR...6f.191J
Altcode: 1986AdSpR...6..191J
Investigations of X-ray spectra of solar flares show that intense
random (turbulent) motions are present in hot flare plasma. Here we
argue that the turbulent motions are of great importance for flare
development. They can efficiently enhance flare energy release and
accelerate particles to high energies.
Title: Flare diagnostics based on Prognoz 9 X-ray data
Authors: Sylwester, B.; Fárník, F.; Sylwester, J.; Jakimiec, J.;
Valníček, B.
Bibcode: 1986AdSpR...6f.233S
Altcode: 1986AdSpR...6..233S
The X-ray fluxes measured aboard the Prognoz 9 satellite in the energy
range 2-160 keV have been analysed for several big flares which occurred
during 1983. A new method of analysis called LEBAN (Loop Energy Balance
Analysis) has been applied. The LEBAN method allows us to estimate the
effective length and volume of the flaring loop under the assumption
of single constant-cross-section geometry. Results of the analysis
provide the necessary information to investigate in detail the time
behaviour of individual terms comprising the energy balance equation
for the hot (T > 4MK) flaring plasma. The LEBAN method is described
and the flare parameters derived for eight flares are presented.
Title: Investigation of flare heating based on X-ray observations
Authors: Jakiemiec, J.; Sylwester, B.; Sylwester, J.; Mewe, R.; Peres,
G.; Serio, S.; Schrijver, J.
Bibcode: 1986AdSpR...6f.237J
Altcode: 1986AdSpR...6..237J
Using X-ray data recorded by the Solar Maximum Mission Hard X-ray
Imaging Spectrometer we have investigated flare evolution in a
(Tm, N)-diagram, where Tm is the maximum
temperature and N is the mean density in the flare volume. It is
important that the behaviour of a flare in such a diagram does not
depend significantly on details of the flare geometry and therefore
can be effectively compared with simplified model calculations of
flare loops. This flare diagnostics allows us to show that most large
flares achieve a quasi-steady-state during their decay, which means
that the cooling is then so slow that a flare evolves along the line of
steady-state loops in the (Tm, N)-diagram. The diagnostics
allows us to determine the time evolution of the flare heating function,
EH(t), which gives the rate of thermal energy release,
per unit volume. For the flares which achieve the quasi-steady-state
branch it gives a new valuable method of estimation of the electron
density in the flare loops.
Title: Flare energetics.
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veck, N. J.
Bibcode: 1986NASCP2439....5W
Altcode:
In this investigation of flare energetics, the authors establish a
comprehensive and self-consistent picture of the sources and transport
of energy within a flare. They chose five flares in 1980 that were
well observed with instruments on the SMM, and with other space-borne
and ground-based instruments. Details of the observations available
for them and the corresponding physical parameters derived from these
data are presented. The flares were studied from two perspectives,
the impulsive and gradual phases, and then the results were compared
to obtain the overall picture of the energetics of these flares. The
authors also discuss the role that modeling can play in estimating the
total energy of a flare when the observationally determined parameters
are used as the input to a numerical model.
Title: Determination of the calcium elemental abundance for 43 flares
from SMM-XRP solar X-ray spectra
Authors: Lemen, J. R.; Sylwester, J.; Bentley, R. D.
Bibcode: 1986AdSpR...6f.245L
Altcode: 1986AdSpR...6..245L
The helium and lithium-like X-ray transitions of Ca XVIII-XIX have been
used to make an absolute measurement of the coronal calcium elemental
abundance relative to hydrogen (ACa) in solar flares. Cooling
phase spectra of 43 flares obtained in channel 1 of the Bent Crystal
Spectrometer (BCS) on the Solar Maximum Mission have been analyzed. The
abundance is determined from the intensity ratio of the Ca XIX resonance
line (1S0 - 1P1) and
nearby continuum. A large variation is observed in the values of the
derived abundances, ranging up to a factor of 2.5 between the extreme
cases. This confirms the earlier results of Sylwester, Lemen, and Mewe
[1], who investigated a smaller sample of flares. In addition to the
variability of ACa observed between different flares, it
was suggested [1] that ACa varies during the heating phase
of some flares. We neglect this phenomenon in the present work, and
concentrate on the cooling phase during which ACa appears
to remain constant for any individual flare. Attempts to correlate
the ACa measurements with other observable features are
discussed.
Title: The Atmosphere of a Sunspot Based on Observations in the
X-Ray Extreme Ultraviolet Optical and Radio Ranges
Authors: Staude, J.; Furstenberg, F.; Hildebrandt, J.; Kruger,
A.; Jakimiec, J.; Obridko, V. N.; Siarkowski, M.; Sylwester, B.;
Sylwester, J.
Bibcode: 1984SvA....28..557S
Altcode:
No abstract at ADS
Title: The atmosphere of a sunspot based on observations in the X-ray,
extreme ultraviolet, optical, and radio ranges
Authors: Staude, J.; Furstenberg, F.; Hildebrandt, J.; Kruger,
A.; Jakimiec, J.; Obridko, V. N.; Siarkowski, M.; Sylwester, B.;
Sylwester, J.
Bibcode: 1984AZh....61..956S
Altcode:
A model of the solar atmosphere above a sunspot umbra is developed on
the basis of published X-ray, EUV, optical, and radio observations,
summarizing the findings of working conferences held at Wroclaw in
November-December 1979 (Bromboszcz et al. 1981) and at Ondrejov in
September-October 1981 (Bromboszcz et al., 1982). A lower-chromosphere
model like that of Teplitskaya et al. (1977 and 1978) is extended
upward by applying a strong temperature gradient, with T = 40,000 K
and n(e) = 4 x 10 to the 10th/cu cm at z = 2000 km above the umbral
chromosphere. At z = 3000-5000 km, cool loops with T = (1-100) x 10
to the 4th k are surrounded by hot (1.8 x 10 to the 6th K) coronal
matter with a narrow transition layer and n(e) = 5 x 10 to the 8th/cu
cm which occupies 0.8-0.9 of the total volume.
Title: Variation in observed coronal calcium abundance of X-ray
flare plasmas
Authors: Sylwester, J.; Lemen, J. R.; Mewe, R.
Bibcode: 1984Natur.310..665S
Altcode:
Variations in chemical composition during solar flares have been
inferred from elemental abundance changes in cosmic ray fluxes, but
have so far not been detected spectroscopically. We present here the
first spectroscopic evidence for the variation of the coronal calcium
abundance in high-temperature solar flare plasmas. The analysed data
consist of the high-resolution X-ray flare spectra (λ /Δλ ~ 4,000)
observed with the Bent Crystal Spectrometer (BCS) on board the Solar
Maximum Mission (SMM) satellite and described in detail by Acton
et al.1. The observed abundance variation has important
consequences for the analysis and interpretation of XUV and X-ray
spectra.
Title: Comparison of energy calibration of Prognoz 5, 6, 7 and 8,
and other hard X-ray solar photometers.
Authors: Farnik, F.; Valnicek, B.; Sylwester, B.; Sylwester, J.;
Jakimiec, J.
Bibcode: 1984BAICz..35..158F
Altcode:
The data obtained by the Prognoz 5, 6, 7, and 8 hard-X-ray photometers
are compared with the measurements carried out by similar instruments
aboard Solrad 11, ISEE 3, SMM, and Hinotori satellites. Using the
method of relative-amplitude analysis, the apparent disagreement in
the energy-discrimination-level calibration between the instruments
is pointed out. The results of the comparison and possible sources of
disagreement are given. An international effort to develop a system
of uniform prelaunch calibration of photometers based on a reference
calibration source is suggested.
Title: X-Ray Pictures of the Sun Taken from Vertical 8
Authors: Hudec, R.; Valnicek, B.; Hudcova, V.; Sylwester, J.;
Kordylewski, Z.
Bibcode: 1984BAICz..35..153H
Altcode:
Soft-X-ray images of the sun obtained in an experimental trial of
the f/45 RTF imaging telescope (using a 6-micron-thick Al filter for
0.8-2.2-nm wavelengths and a 20-micron-thick Be filter for 0.6-2.0 nm)
during the Vertical-8 high-altitude rocket flight of September 26, 1979,
are presented and analyzed using digital processing techniques. The two
images are found to be underexposed, so that only one active region,
corresponding in position to McMath 16,298, can be defined. The method
of filter ratios is used to calculate the temperature and emission
measure of the region as (1.3 + or 0.5) x 10 to the 6th K and 4 x 10
to the 29th/cm5, respectively.
Title: A Multiwavelength Study of a Double Impulsive Flare
Authors: Strong, K. T.; Benz, A. O.; Dennis, B. R.; Leibacher, J. W.;
Mewe, R.; Poland, A. I.; Schrijver, J.; Simnett, G.; Smith, J. B.,
Jr.; Sylwester, J.
Bibcode: 1984SoPh...91..325S
Altcode:
Extensive data from the Solar Maximum Mission (SMM) and ground-based
observatories are presented for two flares; the first occurred at
12:48 UT on 31 August, 1980 and the second just 3 min later. They were
both compact events located in the same part of the active region. The
first flare appeared as a typical X-ray flare: the CaXIX X-ray lines
were broadened (≡ 190±40 km s-1) and blue shifted (≡
60±20 km s-1) during the impulsive phase, and there was
a delay of about 30 s between the hard and soft X-ray maxima. The
relative brightness of the two flares was different depending on
the spectral region being used to observe them, the first being the
brighter at microwave and hard X-ray wavelengths but fainter in soft
X-rays. The second flare showed no significant mass motions, and the
impulsive and gradual phases were almost simultaneous. The physical
characteristics of the two flares are derived and compared. The main
difference between them was in the pre-flare state of the coronal plasma
at the flare site: before the first flare it was relatively cool (3 ×
106 K) and tenuous (4 × 109 cm-3),
but owing to the residual effects of the first flare the coronal plasma
was hotter (5 × 106 K) and more dense (3 × 1011
cm-3) at the onset of the second flare. We are led to believe
from these data that the plasma filling the flaring loops absorbed most
of the energy released during the impulsive phase of the second flare,
so that only a fraction of the energy could reach the chromosphere to
produce mass motions and turbulence.
Title: Variation in the Observed Coronal Calcium Abundance for
Various X-Ray Flare Plasmas
Authors: Lemen, J. R.; Sylwester, J.; Mewe, R.
Bibcode: 1984BAAS...16..545L
Altcode:
No abstract at ADS
Title: Differential emission measure analysis of hot-flare plasma
from solar-maximum mission X-ray data
Authors: Jakimiec, J.; Sylwester, J.; Lemen, J. R.; Mewe, R.; Bentley,
R. D.; Fludra, A.; Schrijver, J.; Sylwester, B.
Bibcode: 1984AdSpR...4g.203J
Altcode: 1984AdSpR...4..203J
We have investigated differential emission measure (DEM) distribution
of hot flare plasma (T>10 MK) using SMM X-ray data from Bent Crystal
Spectrometer (BCS) and Hard X-ray Imaging Spectrometer (HXIS). We have
found that the analysis provide a very sensitive test of consistency
of observational data coming from different instruments or different
channels of the same instrument. This has allowed to eliminate some
systematic differences contained in the analysed data. Typical
examples of the DEM distribution are discussed. It is stressed that
these improvements in the multitemperature flare diagnostics are very
important for the discussion of flare energetics.
Title: Analysis of Intensity Ratio for MG XII LY Components from
Intercosmos 7 Observations (short Abstract)
Authors: Sylwester, J.; Sylwester, B.; Jakimiec, J.; Tomczak, M.;
Mandelstam, S. L.; Zhitnik, I. A.; Korneev, V. V.
Bibcode: 1984uxsa.coll..154S
Altcode: 1984IAUCo..86..154S; 1984uxsa.conf..154S
No abstract at ADS
Title: Organisation of a unified system of energetic calibration of
X-ray experiments
Authors: Valnicek, B.; Farnik, F.; Sylwester, B.; Sylwester, J.
Bibcode: 1984AdSpR...4g.121V
Altcode: 1984AdSpR...4..121V
X-ray data obtained by the Prognoz 5,6,7 and 8 hard X-ray photometers
are compared with the measurements carried out by similar instruments
aboard the Solrad 11, ISEE 3, SMM and Hinotori satellites. Using the
method of relative amplitude analysis, the apparent disagreement in
the energy discrimination level calibration between the instruments
is pointed out. The results of the comparison and the possible sources
of disagreement are given. We suggest an international effort be made
to develop a system of uniform pre-launch calibration of photometers
based on a reference calibration source.
Title: Variation of the Observed Coronal Calcium Abundance for
Various X-Ray Flare Plasmas (short Abstract)
Authors: Sylwester, J.; Lemen, J. R.; Mewe, R.
Bibcode: 1984uxsa.coll...21S
Altcode: 1984uxsa.conf...21S; 1984IAUCo..86...21S
No abstract at ADS
Title: Analysis of the High Resolution Mgxi X-Ray Spectra - Part Four
- Derivation of the Plasma Densities Close to the Low-Density Limit
Authors: Bromboszcz, G.; Siarkowski, M.; Sylwester, J.; Korneev,
V. V.; Mandelshtam, S. L.; Oparin, S. N.; Urnov, A. M.; Zhitnik, I. A.
Bibcode: 1983SoPh...83..243B
Altcode:
In Part IV of the series of papers about the analysis of the INTERCOSMOS
16 ADP spectra a method is developed to evaluate plasma densities from
measured resonance, intercombination, and forbidden helium-like Mg XI
line intensities, using plots of the so-called G and R ratios. The
density is close to the low-density limit. For the active region
McMath 14352 a correlation between mean plasma density and electron
temperature has been found, in agreement with earlier results. In an
appendix systematic differences between measured and calculated line
fluxes in all bands A to F are discussed.
Title: A working model of sunspot structure in photosphere,
chromosphere and corona, derived from X-ray, EUV, optical and radio
observations
Authors: Staude, J.; Hildebrandt, J.; Fuerstenberg, F.; Krueger,
A.; Jakimiec, J.; Obridko, V. N.; Siarkowski, M.; Sylwester, B.;
Sylwester, J.
Bibcode: 1983AcA....33..441S
Altcode:
The presented sunspot model consists of several parts which have been
consistently put together: the umbral model describing the spatial
distribution of thermodynamic quantities up to the transition region as
derived from EUV and optical observations, the magnetic field model,
the model of X-ray emission, and the S-component emission model. The
model assumptions have been tested and corroborated by recently
published observations with high spatial resolution obtained in the
X-ray and EUV spectral range from Skylab, HRTS, and SMM, at centimeter
wavelengths from RATAN, VLA, and WSRT, and by ground-based magnetograms.
Title: Time variation of the differential emission measure of hot
flare plasma.
Authors: Jakimiec, J.; Mewe, R.; Schrijver, J.; Sylwester, J.;
Sylwester, B.
Bibcode: 1983PDHO....5..127J
Altcode: 1984PDHO....5..127J
The authors have investigated details of the time evolution of
the flare differential emission measure (DEM) distribution in the
temperature range 10 - 50 MK using high-resolution X-ray spectra
recorded by the Bent Crystal Spectrometer aboard the Solar Maximum
Mission satellite. It has been found that for big flares the local
maximum in the DEM distribution is systematically broader during the
phase of flare increase than during the phase of decay. It is shown
that this systematic effect is a result of development of a hot "wing"
of the DEM local maximum during flare increase and its disappearance
during flare decay.
Title: SMM flat crystal spectrometer data analysis of 7 April
1980 flare.
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Mewe, R.; Bentley,
R. D.
Bibcode: 1983PDHO....5...85S
Altcode: 1984PDHO....5...85S
The authors have analysed soft X-ray images of the 1B/M4 flare of 7
April 1980 recorded by Flat Crystal Spectrometer aboard Solar Maximum
Mission satellite. The X-ray flare consisted of two patches about 1
arcmin apart. A comparison with magnetograms and white light images
indicates that the two soft X-ray patches originate from two different
loops or systems of loops. For two selected resolution elements of
the X-ray pictures a detailed differential emission measure analysis
has been carried out and time evolution of the mean electron density
and thermal energy content has been investigated.
Title: Multi-temperature Analysis of Hard X-Ray Spectra Measured
aboard the Prognoz 5 Satellite
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Valnicek, B.;
Farnik, F.
Bibcode: 1983BAICz..34...40S
Altcode:
Following the method of multi-temperature analysis of hard X-ray
spectra presented by B. Sylwester et al. (1981), in the present
paper the authors analyse the hard X-ray radiation measured aboard
the Prognoz 5 satellite by means of a Czechoslovak photometer. The
analysis concerns the Feb. 11, 1977 flare event. Using the fluxes
measured in 4 energy bands they have calculated the differential
emission measure distributions for selected moments during the rise,
maximum and decay phases of the flare development. The results of the
analysis show that, in the case of the flare in question, the hard
X-ray radiation from 6 to 60 keV could have been produced by purely
thermal, multi-temperature plasma.
Title: Analysis of the High Resolution Mgxi X-Ray Spectra - Part
Three - Nonthermal Interpretation of Some Spectra
Authors: Siarkowski, M.; Sylwester, J.; Bromboszcs, G.; Korneev,
V. V.; Mandelshtam, S. L.; Oparin, S. N.; Urnov, A. M.; Zhitnik, I. A.
Bibcode: 1982SoPh...81...63S
Altcode:
In part III of the paper containing the analysis of the INTERCOSMOS
16 ADP spectra, it is shown that by assuming the existence of a small
admixture (1%) of non-thermal electrons in the active-region plasma it
is possible to improve the agreement between measured and calculated
fluxes for some spectra. The analysis follows the suggestion contained
in the paper by Karev et al. (1980).
Title: Analysis of the High Resolution Mg-Xi X-Ray Spectra - Part
Two - Physical Parameters of the Plasma in Active Region MCMATH14352
Authors: Siarkowski, M.; Sylwester, J.; Bromboszcz, G.; Korneev,
V. V.; Mandelshtam, S. L.; Oparin, S. N.; Urnov, A. M.; Zhitnik,
I. A.; Vasha, S.
Bibcode: 1982SoPh...77..183S
Altcode:
In this paper, the second in a series dealing with high-resolution
spectra (9.14-9.33 Å) measured on board the INTERCOSMOS-16 satellite,
the analysis of the physical conditions in the coronal part of the
McMath 14352 active region is performed. The temperature structure of
the emitting plasma is investigated on the basis of the photon fluxes
measured in six selected wavelength bands involving the resonance,
intercombination, and forbidden lines of the Mg XI ion and a number
of satellite lines. Relative line intensities are discussed in terms
of the active region plasma density.
Title: Transient Ionization Conditions in Solar Flares. Analysis of
High-Resolution X-Ray Spectra.
Authors: Schrijver, J.; Mewe, R.; Sylwester, J.; Strong, K. T.;
Bentley, R. D.
Bibcode: 1982uxsa.collQ...4S
Altcode: 1982IAUCo..73Q...4S
No abstract at ADS
Title: Analysis of the High Resolution X-Ray Spectra Obtained Aboard
the INTERCOSMOS-16 Satellite - Part One - Identification of the
Lines in the 9.14-9.33A Spectral Region
Authors: Krutov, V. V.; Korneev, V. V.; Karev, U. I.; Lomkova,
V. M.; Oparin, S. N.; Urnov, A. M.; Zhitnik, I. A.; Bromboszcz, G.;
Siarkowski, M.; Sylwester, J.; Vasha, S.
Bibcode: 1981SoPh...73..105K
Altcode:
The Bragg-type, flat ADP crystal spectrometer, launched on board
the INTERCOSMOS 16 satellite has been used for measurements of the
X-ray spectra emitted from solar active region plasmas. During the
period of the instrument operation (August-September, 1976) only
a few active regions were present on the Sun (minimum of the solar
activity). About 60 spectra have been registered. In the present paper
using a spectrum averaged over 20 scans, we measured the wavelengths
corresponding to the statistically significant spectral features seen
in this spectrum in the wavelength range 9.14-9.33 Å. By comparison
with the calculated line wavelengths and intensities predicted in
the framework of the thermal model of the `average' active region, we
performed the identification of these features. Besides rather prominent
resonance, intercombination, and forbidden lines of the He-like ion Mg
XI, it was possible to identify the satellite lines which correspond
to 1s2nl - 1s2p nl transitions from the states with n = 2,
3, and 4. The present paper is the first in a series dealing with the
INTERCOSMOS 16 Mg XI spectra.
Title: Analysis of the physical conditions in a strong X-ray flare
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Valnicek, B.
Bibcode: 1981AdSpR...1m.239S
Altcode: 1981AdSpR...1..239S
The temperature distribution of the hot plasma emission measure in
a large but slowly developing flare has been investigated using the
following data obtained from the INTERCOSMOS 4 satellite: (1) the X -
ray spectra in the range 1.7 - 1.9 Å, (2) the hard X - ray fluxes
in the range 10 - 40 keV. It has been found that all the data can be
explained by a consistent thermal model of the emitting region.
Title: Analysis of the physical conditions in a strong X-ray flare.
Authors: Sylwester, B.; Jakimiec, J.; Sylwester, J.; Valnícek, B.
Bibcode: 1981hea..conf..239S
Altcode:
No abstract at ADS
Title: Changes in the Characteristics of the Coronal Plasma During
Two Impulsive Flares
Authors: Strong, K. T.; Sylwester, J.; Parmar, A.; Dennis, B.;
Poland, A.
Bibcode: 1980BAAS...12R.911S
Altcode:
No abstract at ADS
Title: Analysis of X-ray spectra emitted by the 24 October 1970 flare.
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Korneev, V. V.;
Mandelstam, S. L.; Zhitnik, I. A.; Valnicek, B.
Bibcode: 1980PoAst..28..237S
Altcode:
In the present paper, high-resolution X-ray spectra obtained near 1.9
A with a quartz-crystal Bragg spectrometer, carried by the Intercosmos
4 satellite, are analyzed. The temperature dependence of the radiation
during the growth and main phases of the flare is determined.
Title: Multi-Temperature Analysis of Solar X-Ray Line Emission
Authors: Sylwester, J.; Schrijver, J.; Mewe, R.
Bibcode: 1980SoPh...67..285S
Altcode:
In this paper we propose and test a new method of multitemperature
analysis of solar X-ray spectra. The method, which is based on a
technique developed by Withbroe (1975), is designed to be used in the
interpretation of spectra, to be measured by the X-Ray Polychromator
on the Solar Maximum Mission. Various tests of the method on
simulated temperature models establish its usefulness, generality, and
stability. The possibilities of deriving the relative element abundances
are analysed. The results of the present paper extend the possibility
of the multitemperature analysis of X-ray spectra as compared with
the results of Craig and Brown (1976a, b) and Craig (1977).
Title: Heliumlike ion line intensities. IV - Z-dependence of
collision strengths for N = 2 - N = 1 transitions in helium- and
hydrogenlike ions
Authors: Mewe, R.; Schrijver, J.; Sylwester, J.
Bibcode: 1980A&A....87...55M
Altcode:
In earlier work a semi-empirical fit to the electron-excitation
collision strengths was obtained for the n = 1 to n = 2 transitions
in H- and He-like ions of nuclear charge Z ≳ 14. This work is here
extended to incorporate the effects of scaling with Z by a comparison
with more recent theoretical data for low Z.
Title: Analysis of X-ray line spectra from a transient plasma under
solar flare conditions. II - Rate coefficients. III - Diagnostics
for measuring electron temperature and density
Authors: Mewe, R.; Schrijver, J.; Sylwester, J.
Bibcode: 1980A&AS...40..323M
Altcode:
The rate coefficients for ionization, recombination, excitation, etc.,
needed for the calculations of high-resolution X-ray line spectra in
the wavelength range 1.7-3.2 Å from highly ionized iron and calcium
atoms have been presented.
Title: Analysis of X-Ray Line Spectra from a Transient Plasma Under
Solar Flare Conditions - Part Three - Diagnostics for Measuring
Electron Temperature and Density
Authors: Sylwester, J.; Mewe, R.; Schrijver, J.
Bibcode: 1980A&AS...40..335S
Altcode:
In this paper, the third in a series dealing with plasmas out
of equilibrium we present quantitative methods of analysis of
non-stationary flare plasma parameters. The method is designed to be
used for the interpretation of the SMM XRP Bent Crystal Spectrometer
spectra. Our analysis is based on measurements of 11 specific lines
in the 1.77-3.3 Å range. Using the proposed method we are able to
derive information about temperature, density, emission measure,
and other related parameters of the flare plasma. It is shown that
the measurements, to be made by XRP can give detailed information on
these parameters and their time evolution. The method is then tested
on some artificial flares, and proves to be useful and accurate.
Title: Analysis of the high-resolution X-ray spectra of an active
region
Authors: Bromboszcz, G.; Siarkowski, M.; Sylwester, J.
Bibcode: 1980PoAst..28..147B
Altcode:
High-resolution X-ray spectra (9.14-9.33 A) of the solar active region
McMath 14352 were obtained with the Intercosmos-16 satellite. Absolute
line fluxes for a number of lines were used to determine the physical
parameters of the plasma in this region.
Title: Solar flare X-ray spectra. I: Wavelengths of Fe XXIV - XXV
lines in the region lambda = 1.85 - 1.87 Å.
Authors: Korneev, V. V.; Krutov, V. V.; Mandelshtam, S. L.; Urnov,
A. M.; Zhitnik, I. A.; Kononov, A. Ia.; Golts, E. Ia.; Sidelnikov,
Iu. V.; Sylwester, B.; Sylwester, J.
Bibcode: 1979SoPh...63..319K
Altcode:
Results are presented of an investigation of solar flare X-ray spectra
in the region 1.70-1.95 Å, obtained aboard the `Intercosmos-4'
satellite during the maximum of solar activity (October-November,
1970). With the use of 6 high resolution spectra in the region 1.85-1.87
Å the identification of lines due to 18 transitions of 2p → 1s type,
consisting of the resonance, intercombination and forbidden Fe XXV ion
lines and the satellite Fe XXIV lines has been performed. With the use
of the recent laboratory data the averaged wavelengths of the lines were
obtained confirming the theoretically calculated ones with an accuracy
about ± 0.0004 Å. A variable Doppler shift of the Fe XXV resonance
lines was observed for the flare of November 16, 1970, which points
to hot plasma motions with velocities up to 400 km s-1.
Title: New satellite structure of the solar and laser plasma spectra
in vicinity of the Lα (mg xii) line
Authors: Aglizki, E. V.; Boiko, V. A.; Faenov, A. Ya.; Korneev, V. V.;
Krutov, V. V.; Mandel'Shtam, S. L.; Mandelstam, S. L.; Pikuz, S. A.;
Safronova, U. I.; Sylwester, J. A.; Urnov, A. M.; Vajnshtejn, L. A.;
Vainshtein, L. A.; Zhitnik, I. A.
Bibcode: 1978SoPh...56..375A
Altcode:
Spectra in the narrow vicinity of the Mg XII resonance line at λ =
8.42 Å were obtained aboard the satellites `Intercosmos-4, -7' and
the rocket `Vertical-2', as well as from laser-produced plasma. The
high resolution in solar and laboratory spectra made it possible to
reveal a new spectral structure close to the Lα (Mg XII) line from both
short and long wavelength sides. The main features were observed in all
the spectra and were interpreted as a single or group of dielectronic
satellite lines due to 2l3l' → 1s3l″ transitions in the He-like ions
according to theoretical calculations which were carried out by means
of relativistic Z-expansion technique. The derived electron temperature
of the emitting volumes seemed to be ≈ 3 × 106 K for laser
plasma and about 6 × 106 K for the solar flares studied. The
latter value is in good agreement with the temperature estimated with
the help of the resonance line-to-continuum intensity ratios.
Title: Discussion of the methods of determining the temperature
models of coronal active regions from the X-ray spectra.
Authors: Sylwester, J.; Sylwester, B.
Bibcode: 1977PDHO....3...75S
Altcode:
No abstract at ADS
Title: Analysis of behaviour of the Mg XII resonance line in solar
flares, from INTERCOSMOS-7 satellite observations.
Authors: Jakimiec, J.; Zhitnik, I. A.; Korneev, V. V.; Krutov, V. V.;
Sylwester, B.; Sylwester, J.
Bibcode: 1977PDHO....3...57J
Altcode:
No abstract at ADS
Title: Time variations of high-temperature plasma in solar flares.
Authors: Sylwester, B.; Zhitnik, I. A.; Korneev, V. V.; Krutov, V. V.;
Sylwester, J.; Jakimiec, J.
Bibcode: 1977PDHO....3...65S
Altcode:
No abstract at ADS
Title: Analysis of X radiation of coronal condensations observed
with broad-band filters.
Authors: Sylwester, J.
Bibcode: 1976str..book..139S
Altcode:
No abstract at ADS
Title: Observations of a soft X-ray flare on the solar limb.
Authors: Jakimiec, J.; Sylwester, B.; Sylwester, J.
Bibcode: 1976viao.conf...20J
Altcode:
No abstract at ADS
Title: X-ray spectrum of a coronal condensation and a flare.
Authors: Jakimiec, J.; Krutov, V. V.; Mandel'Shtam, S. L.; Mandelshtam,
S. L.; Sylwester, B.; Sylwester, J.; Zhitnik, I. A.
Bibcode: 1976str..book..151J
Altcode:
No abstract at ADS
Title: X-ray spectrum of a coronal condensation and a flare
Authors: Jakimiec, J.; Krutov, V. V.; Mandelshtam, S. L.; Sylwester,
B.; Sylwester, J.; Zhitnik, I. A.
Bibcode: 1976CoSka...6..151J
Altcode:
No abstract at ADS
Title: Influence of flux measurement errors in X-ray lines on the
accuracy of determination of temperature models of coronal active
regions.
Authors: Sylwester, J.
Bibcode: 1976viao.conf...24S
Altcode:
No abstract at ADS
Title: Physical conditions in a flare region.
Authors: Bejgman, I. L.; Vajnshtejn, L. A.; Korneev, V. V.; Krutov,
V. V.; Mandel'Shtam, S. L.; Sylwester, B.; Sylwester, J.; Urnov, A. M.
Bibcode: 1976viao.conf...16B
Altcode:
No abstract at ADS
Title: Analysis of the intensities and profiles of the spectral line
Mg XII 8.42 å in the solar X-ray spectrum
Authors: Jakimiec, J.; Korneev, V. V.; Krutov, V. V.; Zhitnik, I. A.;
Plocieniak, S.; Sylwester, B.; Sylwester, J.
Bibcode: 1975SoPh...44..391J
Altcode:
High resolution profiles of the Mg XII 8.42 å line in the solar
X-ray spectrum were recorded from the Intercosmos 7 satellite. The Mg
XII line intensity provides a sensitive indicator of the hot plasma
content (T ≳ 3 × 106 K) in coronal condensations and X-ray
flare volumes. The ratio of the line intensity to the intensity of the
adjacent continuum has been used to compute approximate thermal models
of the emitting regions. For all the investigated coronal condensations
the temperature distribution of plasma has been found to be a function
monotonically decreasing with temperature. But for some X-ray bursts
there occurred a distinct excess of the hot plasma of temperature
between 6-10 × 106K. FWHM values of the Mg XII line profiles
have been used to estimate ion temperature in the emitting regions.
Title: Analysis of the solar X-ray spectrum of 20 August 1971.
Authors: Jakimiec, J.; Krutov, V. V.; Mandel'Stam, S. L.; Sylwester,
B.; Sylwester, J.; Zhitnik, I. A.
Bibcode: 1974spre.conf..425J
Altcode:
No abstract at ADS
Title: Analysis of Broad-Band Observations of the X-ray Radiation
from a Coronal Condensation
Authors: Sylwester, J. A.
Bibcode: 1974AcA....24..299S
Altcode:
Analysis of the X-ray radiation from the central core of a coronal
condensation was carried out on the basis of the condensation model
of Landini and Monsignori Fossi. The maximum temperature and emission
measure in this model were treated as variable parameters, and their
values were estimated on the basis of observational data. Observations
made from the rocket 'Vertikal I' were used in the analysis. Moreover,
from the same observations, an estimation of the temperature
and emission measure of the condensation core was made assuming
an isothermal model for this region. A comparison of the results
obtained in the two approaches shows significant differences between
the non-isothermal and isothermal interpretation of the observations.
Title: Observations of the X-ray emission of solar active regions
on 28 November 1970 and 20 August 1971.
Authors: Kordylewski, Z.; Mergentaler, J.; Jakimiec, J.; Sylwester,
B.; Sylwester, J.
Bibcode: 1973spre.conf..787K
Altcode: 1973spre....2..787K
No abstract at ADS