Organized by:  











   ABSTRACTS:

Dr  A.S. Ulyanov, Lebedev Physical Institute

25-09-2012

The statistical analysis of small flare-like events in the quiet solar corona

Our work is dedicated to statistical analysis of high-speed coronal dynamics (5- second cadence) registered by TESIS instrument onboard CORONAS-PHOTON in 171 Å in November, 2009. We found a big number (above 2000) of small flare-like events outside active regions with thermal energies ~ 10^23 ÷ 10^26 erg. According to modern classification flare-like events with such energies are usually referred to as nanoflares. The main goal of our work was to obtain the energy distribution of these events in a given energy range N(E). The shape of nanoflare energy distribution, particularly in a range of low energies, is a matter of great importance. In fact, it may occur that the number of low-energy flares is high enough to exceed the quiet corona energy losses. Therefore the nanoflaring activity could actually account for the coronal heating. It was found that at least in a narrow range of energies the nanoflare energy distribution fits a single power law slope: N ( E )dE ∝ E dE . The derived value of power law index is α ≈ 2.2 − 2.4 . As it was shown in various works the value of α > 2 indicates the possibility of nanoflare heating scenario. The estimated upper limit of total energetic input of the given events of about 4 ⋅ 10^5 erg ⋅ cm^(-2) ⋅ s^(-1) is well above net losses in quiet corona (≈ 3 ⋅ 10^5 erg ⋅ cm^(−2) ⋅ s^(−1) ).


Dr A.S. Kirichenko, Lebedev Physical Institute

25-09-2012

Diagnostics of high-temperature plasma in extremely weak solar microflares during solar minimum of 2009.

In our study we consider so-called solar microflares which are relatively weak events with a total energy release of about 1027-1030 erg. Due to the low emission and short duration of impulse phase, the registration of such phenomena can be a difficult problem. The good conditions for observation of the solar microflares appear in the solar minimum when the X-ray emission of the Sun reduces to a very low level. For our study we selected three months near the deepest point of the recent solar minimum, from March to May, 2009, and performed a careful search and investigation of solar microflares during this period. In this work, we used data of two solar instruments operated on board the Russian spacecraft CORONAS-Photon: the imaging spectroheliometer TESIS/MISH (MgXII 8.42 Å; Tmax ~ 8 MK; spatial resolution of about 5'') and X-ray spectrophotometer SPHINX (energy range 0.8 – 15 keV). The fact of microflare and its location and spatial characteristics were determined by MgXII images. After that we used SPHINX data in order to provide a simple spectral diagnostic of the event (to find the temperature and density of the plasma). First of all we were interested in extremely weak events which were accompanied by the apparent plasma heating to the temperature of about 5-10 MK. Our main purpose was to find a clear evidence that even the weakest Sun's flares (of A1.0 class and lower) can efficiently heat the surrounding coronal plasma up to 5 MK and higher. We report here the results of this study and discuss their significance in terms of the flare physics and the corona heating problem.


Dr A.A. Reva, Lebedev Physical Institute

25-09-2012

Genetic Algorithm for DEM Reconstruction Using Simultaneous Images of XRT, EIT and TESIS.

Registration and diagnostics of hot coronal plasma is important and difficult problem in the solar physics. Spectral responses of modern “wide-band” telescopes do not allow to reliably measure properties of hot plasma (its average temperature or relative amount). In order to obtain reasonable DEM solution we need preliminary regularization or artificial limitation of temperature band. Spectroheliograph Mg XII was a part of TESIS complex onboard of CORONAS- PHOTON satellite. This device was building monochromatic images (λ = 8.42 Å – resonance line of Mg XII) of coronal plasma with temperature greater than 5 MK. Spectroheliograph Mg XII is a convenient tool for searching and diagnostics of hot plasma. The aim of this work is to develop a DEM diagnostics method which uses spectroheliograph Mg XII data. We use simultaneous images obtained by EIT, XRT and spectroheliograph Mg XII. This set of channels covers the wide temperature range: cool (EIT), warm (XRT) and hot (spectrohelograph Mg XII). We implemented genetic algorithm for DEM reconstruction. We analyzed two active regions for which simultaneous images where available: one with strong signal on Mg XII image and one with no signal on Mg XII image. For the first AR we obtained DEM with hot component (T = 10 MK) which was the same orders as the cool component (T = 1.5 MK). For the second AR the DEM doesn’t have hot component. The use of monochromatic images of spectroheliograph Mg XII allows us to obtain reasonable DEM solutions without unphysical “high-temperature tails”, preliminary regularization or artificial limitation of temperature band.


Prof. Kenneth Phillips, UCL Mullard Space Science Laboratory

02-10-2012

Flare Element Abundances and consequences for coronal modelling

While solar element abundances in coronal plasmas have been discussed for several years, there has been only a very slow convergence on their values and the nature of the 'FIP' (first ionization potential) effect, whereby the coronal abundance of an element differs from its photospheric abundance according to whether the FIP is less than or more than 10 eV. The situation has also been changed somewhat by alterations in the photospheric abundances of C, N, and O by Asplund and others. Work since 2010 using results from the RESIK instrument on Coronas-F spacecraft has indicated a much more involved picture than the ones previously given in papers up till the early 1990s. These indicate that coronal abundance enhancements F vary considerably: potassium (FIP = 4eV) has F of nearly 7; S (FIP = 10 eV) and Ar (FIP = 16 eV) have nearly equal photospheric and coronal abundances (F=1); and Si (FIP = 8 eV) has F = 2. RHESSI broad-band spectra indicate that Fe (FIP = 8 eV) has F = 2.6. In my contribution I will discuss the latest observational results and attempt to relate them to the theory of Martin Laming which holds that the coronal abundance enhancements are related to the ponderomotive force associated with Alfven waves accelerated into the solar corona.


Prof. Janusz Sylwester, Space Research Centre PAS, Solar Physics Division

J. Bąkała, S. Płocieniak, M. Siarkowski, S. Kuzin, K.J.H. Phillips, M. Kowaliński, P. Podgórski, Z. Szaforz, S. Shestov

04-10-2012

SolPEX: Bragg-crystal rotating spectro-polarimeter for the Russian module of the ISS

We will present the science rationale, instrument design, and operation modes of the new Polish-designed solar soft X-ray spectro-polarimeter, SolPEX. SolPEX is planned to be mounted atop the solar-pointed platform attached to the Russian section of the ISS. The instrument will contain a number of bent and flat rotating crystals that will observe X-ray emission from solar flares and active regions. It will be a predecessor of the planned advanced solar spectro-polarimeter and the ChemiX high-resolution spectrometer presently under development for the Interhelioprobe Russian interplanetary mission to the Sun.


Dr Szymon Gburek, Space Research Centre PAS, Solar Physics Division

T. Mrozek, M. Siarkowski, J. Sylwester, B. Sylwester, M. Gryciuk, A. Kępa

04-10-2012

Comparison of SphinX and GOES solar X-ray observations

We compare solar soft X-ray flux measurements from Solar Photometer in X-rays (SphinX) and Geostationary Operational Environmental Satellites (GOES) X-ray sensors. The SphinX operated from 20 February until 29 November 2009 onboard Russian CORONAS-PHOTON satellite on low earth orbit. The instrument observed the solar X-rays in the energy range ≈ 1.0 keV – 15.0 keV with resolution ≈ 0.4 keV. GOES satellites operate on geostationary orbits and measure solar soft X-ray flux nearly continuously since 1976 providing lightcurves in 0.5 – 4.0 Å (3.1 - 24.8) and 1 – 8 Å (1.5 – 12.4 keV) wavelength ranges. We compare SphinX and GOES lightcurves in the 1 – 8 Å range. Differences and similarities seen in SphinX and GOES calibrated data are shown. Possibilities of cross-calibrations of datasets obtained from both instruments are discussed.


Prof. Barbara Sylwester, Space Research Centre, PAS, Solar Physics Division

A. Kepa, K.J.H.Phillips, J. Sylwester

05-10-2012

Multitemperature solar plasma diagnostics from RESIK spectra

Data from the Polish-built RESIK Bragg crystal spectrometer on the CORONAS-F spacecraft, operational in 2001-2003, are well suited for studying the differential emission measure distributions (DEM) in coronal plasmas. We will present results of our recent DEM studies for a number of solar flare and active region sources with good spectral coverage. Results of these studies indicate a strong dependence of the inversion results on the assumed plasma composition. We will discuss the reliability of the inversion technique used, methods of selecting the optimum inversion parameters, and criteria for selecting reliable inversion results. Illustrations will be given of the use of the inversion technique as applied to real data collected by the RESIK instrument for numerous flares and active regions. Recommendations will be given on how to take advantage of the derived DEM distributions for analyzing the thermodynamic characteristics of the emitting source.


Dr. Fabio Reale, University of Palermo

05-10-2012

High temperature plasma as diagnostics of coronal heating

The presence of plasma at temperature higher than coronal average is an indicator of intermittent heating processes. Thus its detection is very important as diagnostics of coronal heating mechanisms. Data from recent solar missions, i.e. Hinode, Solar Dynamics Observatory, Coronas-Photon, have shown evidence for small amounts of very hot plasma. We review and discuss such evidence, and related hints from coronal loop modeling.


Prof. Barbara Sylwester, Space Research Centre, PAS, Solar Physics Division

J. Sylwester, M. Siarkowski, S. Gburek, K.J.H.Phillips

07-10-2012

Multitemperature analysis of solar quiet emission based on SphinX data

SphinX (Solar Photometer in X-rays) on the CORONAS-PHOTON spacecraft, an X-ray spectro-photometer observing in the 1--15 keV range with resolution (FWHM) of 464 eV, was operational during a nine-month period of the deep solar minimum in 2009. Over this period, there were many intervals when the solar X-ray activity was exceptionally low and the Sun's visible hemisphere was free from any active region. Spectra from SphinX enable the thermal characteristics of the solar corona in its low-activity state to be examined. We have adopted the Withbroe-Sylwester inversion algorithm to derive differential emission measure (DEM) from SphinX spectra during low-activity periods. We will discuss the reality of the presence of any hot component (temperature greater than about ~10MK), widely discussed recently in the context of nano-flare heating of the corona, based on these inversion results.


Prof. Janusz Sylwester, Space Research Centre PAS, Solar Physics Division

J. Sylwester, M. Kowalinski, M. Siarkowski, A. Kępa, Z. Kordylewski, J. Bąkała, B. Sylwester, S. Gburek

07-10-2012

RESIK entire database content and examples of some serendipitous measurements

Only recently, thanks to eHeroes 7FP, it has been possible to gather all RESIK measurements into a single data file accessible for the interpretation. All ~2 mln of PHA spectral measurements and 1.3 mln of X-ray spectra recorded have been assigned the time and supported with respective altitude and attitude of the CORONAS-F spacecraft. Concurrent GOES XRM 3 sec data have also been incorporated into this ~30 GB database. For the first time, we may directly subtract from the data full information recorded during S/C nights, passages through auroral regions, and over various locations of Earth on its travel along solar orbit. We will show examples how to extract the useful information from this database and will present some results potentially interesting in the solar, aeronomy and magnetosphere physics context. This is to encourage scientists to work with yet very much underused RESIK measurements.


Dr Marek Stęślicki, Space Research Centre, PAS, Solar Physics Division

09-10-2012

Is the Sun a typical solar-like star?

One of the significant question of modern astronomy is: Is the Sun an perfectly normal example of a G-type dwarf of the Milky Way's metal-rich Pop I? We summarize recent efforts to place the activity of the Sun in the context of the stars. The Kepler mission provides an exciting opportunity to study the lightcurves of stars with unprecedented precision. Asteroseismic analysis of Kepler data can clarify the evolutionary states of large numbers of stars. The evolution of magnetism in stellar samples will be set more quantitatively than is possible at present time.


Mrs Żaneta Szaforz, Space Research Centre, PAS, Solar Physics Division

M. Siarkowski, S. Płocieniak, J. Sylwester

17-10-2012

Design of crystal-detector assemblies for ChemiX spectrometer aboard Interhelioprobe

ChemiX will be X-ray Bragg crystal spectrometer for studies of solar coronal plasma chemical composition. The experiment will be sent into space onboard Interhelioprobe Interplanetary Mission (IHPM). The instrument design assumes two crystal-detector assemblies. Each of those assemblies will contain two wide mono-crystal wafers, bent to a desired radius of curvature for spectroscopic measurements, three dedicated bent crystals for the Dopplerometer and two detectors. Four wider crystals will allow for measuring in the energy range from approximately 1.3 A to 9 Å. Mathematical methods developed in order to design geometry of crystal-detector assemblies for ChemiX are presented. Results of calculations are shown and discussed.


Prof Alexandr Solov'ev, Central (Pulkovo) observatory

22-10-2012

Dissipative contraction of solar magnetic structures with force-free internal field: applications to solar flares and coronal heating

The twisted magnetic flux tube (magnetic rope) is a typical and most important element of solar activity. Normally, the magnetic flux ropes in solar atmosphere are surrounded by a quasi-potential magnetic field which provides the pressure balance in cross-section. We have found a new exact MHD-solution for the dissipative evolution of thin magnetic flux rope in passive resistive plasma, with the growing gas density in the rope. The magnetic field inside the flux rope is assumed to be of force-free: it is a set of concentric cylindrical shells (envelops) filled with twisted magnetic field (Lunquist,1951). There is no dissipation in a potential ambient field outside of the rope, but inside the rope, where the current density can be high enough, the magnetic energy is continuously converted into heat. The Joule dissipation decreases the magnetic pressure inside flux rope, which is balanced by the pressure of the ambient field, it results in radial and longitudinal contraction of magnetic rope with the speed defined by conductivity of plasma and characteristic spatial scale of magnetic field inside the flux rope. Formally, the structure shrinks to zero within a finite time interval (dissipative magnetic collapse). The compression time can be relatively small, within a few hours, for a flux rope with a radius of about 300 km, if the magnetic helicity trapped initially in the flux rope (the helicity is proportional to the number of magnetic shells in the rope) is quite large. This magnetic system is open along its axis of symmetry and along the separatrix surfaces, where the azimuthal field is zero. On the rope’s axis and on these surfaces, the magnetic field is longitudinal, so the plasma will be ejected from the compressing tube along the axis and separatrix surfaces outwards in both directions (jets!) at a rate much higher than the diffusion one. The similar exact MHD-solution has been derived for the magnetic force-free sphere mantained in equilibrium by the external potential magnetic field (Chandrasekhar,1956). The solutions obtained can be applied to the mechanisms of coronal heating and flare energy release.


Mr. Šimon Mackovjak, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia

Elena Dzifčáková, Jaroslav Dudík

26-10-2012

On the possibility to diagnose the κ-distributions from the HINODE/EIS spectra

We developed diagnostic methods for revealing the presence of κ-distributions in the coronal EUV spectra observed by Hinode/EIS. The type of distribution function influences the ionization, recombination and excitation rates and thus the relative intensities of spectral lines. The intensities are also dependent on temperature and electron density. We investigate the observed Ca, O, Ni, S, and Fe line ratios for the diagnostics of plasma parameters. The suitable line ratios have been selected and tested on observed data (Brown et al., 2008, ApJ, 176, 511). The density diagnostics for κ-distribution with κ = 2 and for Maxwellian distribution are performed. The evidence of the presence of non-Maxwellian type of distributions are discussed in relation to data errors and possible plasma multithermality. The DEM analysis could be used for estimate of blending line intensities.


Prof. Marek Siarkowski, Space Research Centre, PAS, Solar Physics Division

M. Gryciuk, B. Sylwester, J. Sylwester, S. Gburek

26-10-2012

Small flares during the 2009 solar minimum

We will present the examples of observations of small flares observed with the SphinX spectro-photometer during the last, deep solar minimum. SphinX measured solar X-ray spectra in the energy range 1.0 – 15.0 keV from 20 February until 29 November 2009 aboard Russian CORONAS–PHOTON satellite. A sensitivity of SphinX was much greater than GOES one which in spite of the exceptionally low activity level allowed to observe the tiny flares (microflares below GOES detection threshold). SphinX spectra have been used to study the temperature and emission measure changes for these small events. Images from Hinode/XRT and/or STEREO/SECCHI were used to illustrate the evolution of the morphology of these micro-events.


Prof. Konstantin Zioutas, University of Patras / Greece

29-10-2012

Axion - chameleon signatures in solar observations.

Axions or other similar exotica from the dark sector can be created inside the sun, and not only in the early universe. Once they escape from the sun, they can convert to photons in the magnetised outer sun's layers / atmosphere via the Primakoff-effect. Massive exotica (with ~keV rest mass)can be gravitationally trapped giving rise to an x-ray afterglow due to the enhanced spontaneous radiative decay. A single or combined such as yet unexpected processes can explain conventionally as mysterious dubbed solar behaviour. Novel signatures for physics beyond the Standard (Solar) Model may be uncovered in existing and/or future data from (soft) x-ray observatories. This exciting perspective is suggestive for a synergism between astronomers and astroparticle physicists.


Dr Tomasz Mrozek, 1. Astronomical Institute, University of Wroclaw, 2. Solar Physics Division, Space Research Centre, Polish Academy of Sciences

Gburek, S., Siarkowski, M., Sylwester, B., Sylwester, J., Kępa, A., Gryciuk, M.

30-10-2012

RHESSI and SphinX common observations of solar flares

RHESSI and Polish spectrophotometer SphinX instruments carried out observations of solar soft X-ray flux in temporal interval covering the SphinX mission which lasted from 20 February until 29 November 2009. Thus the comparison of SphinX and RHESSI observations is possible. We focused investigations on a group of flares which were well observed by both instruments simultaneously. RHESSI sensitivity allows to observe solar X-rays starting from ~3 keV. Due to very low solar activity during the mission, SphinX did not provide measurements with good signal to noise ratio above 8 keV. Therefore we compared measurements in several energy bands within 3-8 keV range. Results of comparison are shown and consistency level of both data sets are discussed.


Mr Jaromir Barylak, Space Research Centre, PAS, Solar Physics Division

A. Barylak, P. Podgórski, S. Gburek

30-10-2012

Simulation of energetic particle interactions with SphinX PIN detectors using Geant4 platform

Solar Photometer in X-rays (SphinX) operated on CORONAS-Photon satellite from 20 February until 29 November 2009. The spacecraft orbit was nearly circular with inclination angle of 82.5˚ and initial height 550 km. SphinX measured the Sun soft X-ray flux in energy range from ~1 to 15 keV and energy resolution of ~400 eV. In addition to solar X-ray measurements SphinX also recorded background coming from interactions of energetic particles with the instrument detectors. This background was particularly strong during passages through radiation belts and South Atlantic Anomaly. The particle contribution needs to be determined and subtracted from SphinX observations before solar X-ray data analysis. We use Geant4 platform in order to perform SphinX detector response to the Earth radiation environment. We show a preliminary model of SphinX in Geant4 package and discuss the first simulation results.


Dr O.V.  Dudnik, V.N.Karazin Kharkiv National University

J. Sylwester, P. Podgórski, S. Gburek

30-10-2012

Radiation belts of the Earth: overview, methods of investigations, recent observations on the CORONAS-Photon spacecraft

The overview of spatial zones with enhanced high energy ionized particles fluxes in the Earth’ magnetosphere is presented. Chemical composition, energy spectra, particle flux dynamics are characterized during different periods of the solar activity, and magnetosphere manifestation of strong optic and X-ray flares as well as of high speed solar wind streams. Different technique of particle monitoring at low Earth orbits, at geostationary orbit and in the interplanetary space is presented for previous missions as well for planned mission. The analysis of electron flux variations under Earth’ radiation belts (RB) at heights ~550 km in May, 2009, is performed on the base of experimental data obtained from the satellite telescope of electrons and protons STEP-F and from the solar X-ray spectrophotometer SphinX as a part of scientific apparatus complex “PHOTON” on board the spacecraft “CORONAS-Photon”. Based on a joint analysis of the data it was found that PIN diodes of the spectrophotometer SphinX reliably recorded also electron fluxes of low and intermediate energies as well as bremsstrahlung from construction materials of the instrument and spacecraft. Changing electron fluxes in a wide range of energies are detected at any geographic latitude and longitude due to the large geometric factor of the STEP-F detectors (~21 cm2 sr), and associated with the dynamics of the solar wind parameters as well as with the growth of magnetospheric activity. Common data processing had allowed to postulate the presence of narrow directed electron beams in outer RB at the altitude of ~550 km during a weak geomagnetic storm on May 8, 2009. At the same time in the South Atlantic Anomaly (SAA) region it has been observed rather isotropic distribution of electrons with energies ~200-550 keV. It was also shown that particle energetic spectra in the outer RB are much softer than in SAA, therefore effective energy threshold of electron registration for SphinX detectors decreases from ~550 keV in SAA to ~50 keV in the outer RB. The feature of the appearance of enlarged electron fluxes in the inner belt followed by significant growth in the same energy ranges in the outer radiation belt at the initial phase of magnetic storm is underlined. It was repeated for both: weak magnetic storm of May,7-8 (Dst <30 nT) and sub-storm of May, 14-15. The empirical values of various energy electron lifetimes in the basic inner and outer radiation belts are defined. The electron lifetime at low Earth orbits (LEO) is τ ~1.5 days for inner belt, and τ ~4.5 days for the same energy ranges. At the same time there is the tendency of lifetime declining in the outer radiation belt with the increase of electron energy as well as dependence of lifetime values as a function of pitch-angle at fixed energy.


Dr Urszula Bąk-Stęślicka, Astronomical Institute, University of Wroclaw

S. Gibson, Y. Fan, L. Rachmeler, C. Bethge, B. Forland

31-10-2012

The Magnetic Structure of Solar Prominence Cavities: New Observable

Solar coronal cavities are regions of rarefied density, with a tunnel-like morphology and elliptical cross-section. The Coronal Multi-channel Polarimeter (CoMP) obtains daily full-Sun coronal observations in linear polarization, allowing a systematic analysis of the coronal magnetic field in polar-crown prominence cavities for the first time. We show that these cavities commonly possess a characteristic `rabbit-head' signature in linear polarization that may be explained by a magnetic flux-rope model, a topology with implications for solar eruptions. We consider the spatial relation between the EUV cavity, the CoMP line-of-sight velocity, and the CoMP linear polarization signature in the context of this physical interpretation.


Mrs Magdalena Gryciuk, Space Research Centre, PAS, Solar Physics Division

Marek Siarkowski, Piotr Podgórski, Szymon Gburek, Janusz Sylwester

31-10-2012

SphinX Events Catalogue: Progress report

Solar Photometer in X-rays (SphinX) was designed to measure soft X-ray emission from the Sun as a star in the energy range between 1.2 keV and 15 keV. The instrument operated aboard the CORONAS-Photon satellite from February to November 2009, during the phase of unprecedently low minimum of solar activity. SphinX as a high sensitive spectrophotometer was able to reliably measure solar X-ray emission at levels even much below GOES threshold. Thanks to this, SphinX observations provide a large database of weak flare and X-ray brightennings. Our goal is preparation of the catalogue of X-ray flare events based on interpretation of SphinX lightcurves. The catalogue will contain set of characteristics for every flare, micro-flare or brightenning which will be a subject of further statistical analysis. Important problems of background subtraction and deconvolution of complicated lightcurve into components will be described.


Dr Sylwester Kolomanski, Astronomical Institute of the University of Wroclaw

Tomasz Mrozek

31-10-2012

Coronal flare sources in SDO/AIA observations

RHESSI is a powerful tool to analyse solar flares for many years. Now this tool can be combined with razor sharp sight of SDO/AIA instrument. Such a combination allow us to study flares in more detail then ever before. In this work we present analysis of coronal sources of flares. The sources are known since the mid 70s but their nature is still not fully understood.


Prof. Paweł Rudawy, Astronomical Institute, University of Wroclaw

K. Radziszewski

01-11-2012

High time resolution observations of flating kernels in Hα line

We present results of high time resolution spectral observations of the Hα emission of solar flaring kernels correlated in time with X-ray fluxes recorded with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Using the Large Coronagraph (LC), Multi-Channel Subtractive Double Pass (MSDP) spectrograph and the Solar Eclipse Coronal Imaging System (SECIS) at the Białkow Observatory, we collected a total of 31 sets of high time resolution (0.04 – 0.075 s) observations of Hα bright flare kernels.We will show numerous examples of good time correlations between X-ray flux Hα emission variations observed in selected bright flaring kernels, where the Hα emission follows the X-ray emission by a few seconds, but with some flares showing longer (10-18 s) delays. The former are consistent with energy transfer along the flaring loop legs by non-thermal electron beams, the latter to the passage of conduction fronts. We also found that the areas of all kernels decrease systematically when observed in consecutive wavelengths toward the wings of the H-alpha line, but their areas and emission intensity vary in time. Our results are in agreement with the commonly accepted model of the glass-shaped lower parts of the magnetic flaring loops channelling high energy variable particle beams toward the chromospheric plasma.


Dr Anna Kępa, Space Research Centre PAS, Solar Physics Division

Barbara Sylwester, Janusz Sylwester, Tomasz Mrozek

02-11-2012

Comparison of the ultraviolet and X-ray emissions in selected solar flares

RESIK observations constitute a unique spectral database for analysis of soft X-ray radiation in wavelength range from 3.1 Å to 6.1 Å. The large database of RESIK spectra enclose various periods of solar activity as observed between April 2002 and March 2003. For many flares seen by RESIK there are available images obtained in the ultraviolet (UV) part of the spectrum, fi. from the EIT instrument on board the SoHO satellite. With these concurrent data, we can compare time behavior of event-integrated emission in X-ray and UV bands. For the present study we selected those events for which the lightcurves in X- and UV- emissions are disparate during the decay phases. I will present selected examples of such events and discuss results of a preliminary analysis of their derived physical characteristics.


Mr Miroslaw Kowalinski, SRC, PAS

Piotr Podgórski, Witold Trzebiński, Jarosław Bąkała

06-11-2012

The Solar Photometer in X-rays (SphinX). The instrument objectives, design, performance and operation principle.

This paper presents the construction of Solar Photometer in X-rays (SphinX). SphinX was an instrument developed to detect the soft X-rays from the Sun. It was flown on board the Russian CORONAS-Photon satellite from January 30, 2009 to the end of November, 2009. Here, the SphinX instrument objectives, design, performance and operation principle are described. Below results of mechanical and thermal – vacuum tests necessary to qualify the instrument to use in space environment are presented. Also the calibration results of the instrument are discussed. In particular detail it is described the Electrical Ground Support Equipment (EGSE) for SphinX. The EGSE was used for all tests of the instrument. At the end of the paper results obtained from the instrument during operation in orbit are discussed. It is suggested design changes in future versions of SphinX.


Dr Sergey Shestov, Lebedev Physical Institute

06-11-2012

Absolute calibration of spectral fluxes registered by the SPIRIT spectroheliograph using the data of EIT/SOHO wide-band telescope


Prof. Michal Tomczak, Astronomical Institute, University of Wroclaw

08-11-2012

Ballooning Instability in a Yohkoh Event

The ballooning instability is a disturbance of the equilibrium between outward and inward directed forces. The name refers to elongations formed in a balloon when it is squeezed. This class of interchange instabilities occurs at the interface between two layers, where the thermal plasma beta is low (<1) and high (>1). The ballooning instability is often recognized in tokamak fusion power reactors and in the Earth\'s magnetosphere but rather exceptionally in the solar corona. I will present the Yohkoh observations of an X-ray plasma ejection (XPE) that suddenly changed its appearance. I interpret this reconfiguration as a result of the thermal plasma beta increase above the unity at the apex of this magnetic structure. High-beta plasma confined in magnetic loops is directly responsible for the observed disruption. Quantitative analysis of X-ray images and spectra shows that the reported ballooning instability could be caused by the interplay of several factors: (1) decrease of the magnetic field strength due to its expansion, (2)increase of the thermal plasma pressure due to flare energy release and chromospheric evaporation, and (3) the presence of bulk flows along the curvature of the magnetic lines of force at the apex.


Dr Karol Seweryn, Space Research Centr PAS

K. Seweryn, A. Przepiórka, K. Grassmann, G. J. Hurford, Säm Krucker, P. Orleański, K. R. Skup

09-11-2012

Thermal simulations of the STIX instrument for ESA Solar Orbiter mission

ESA Solar Orbiter mission is going to work on elliptical orbit around the Sun with perihelion of 0.28AU and aphelion of 0.952AU. Its main goal is to determine how Sun creates and controls the heliosphere. The Solar Orbiter spacecraft consists of ten different instruments one of which is the STIX instrument – Spectrometer/Telescope for Imaging X-rays. The STIX instrument is divided into three subsystems: (i) feedthrough with two X-ray windows, (ii) imager with grids and aspect system and (iii) detector and electronic module (DEM). The subsystems operate in two different thermal environments. The imager and DEM are located inside the spacecraft, surrounded by constant temperature (50°C and -20°C in operational modes) with almost zero direct exposure to the Sun. Furthermore, the CdTe detectors located inside the DEM are kept around -20°C by a cold element provided by the spacecraft. The feedthrough together with the X-ray windows are situated in the heat shield with one of the X-ray windows directly exposed to the Sun (17.8 kW/m2 @ 0.28AU). The thermal design of the STIX instrument should fulfill the following requirements: (i) the X-ray windows should be at least partially transparent down to 4keV and at the same time stop the incoming flux in visible and infrared range, (ii) the temperature gradient on grids should be below 6°C between any point on the grids, (iii) the CdTe detectors should be at the temperature between -50°C and -20°C, (iv) all other parts of the instrument should not exceed the specified temperature limits. At the same time the heat exchange between the instrument and the spacecraft should be limited as required by the spacecraft. The paper presents the solution to limit radiative and conductive heat flow between STIX subsystem and in the same time to minimize the spatial temperature gradient on the grids. The design was successfully validated by set of simulations in the ESATAN-TMS software and prepared for dedicated tests in relevant environment.


Mr Iiro Virtanen, University of Oulu

14-11-2012

Distribution of solar activity in SWAP observations


Mr Stefan Płocieniak, CBK

14-11-2012

Rotating Spectrometer

A concept of new X-ray Spectrometer is presented. The main idea behind the instrument is to use rotating crystal assembly instead of scanning. Two possible designs of the rotating spectrometer are discussed. Basic functional blocks of the envisaged instrument are shown.


Mr Piotr Podgorski, Space Research Centre PAS, Solar Physics Division

S. Gburek, M. Kowalinski, J. Sylwester

16-11-2012

Comparison of the Earth radiation environment observation from RESIK and SphinX instruments

RESIK and SphinX spectrometers operated at LEO orbit onboard CORONAS-F and CORONAS-Photon spacecrafts respectively and provided large database of solar X-ray flux observations. On top of these intended measurements there are also signatures of particle registration which constitutes an interesting subject for dedicated analysis. In the presentation we show examples of these additional particle observations from both instruments. Since the instruments differ in construction and operated in different time periods of solar activity a brief comparison of particle related data sets from both instruments is also reported.