M.A.Livshits and M.M.Katsova
Test by observations for a new model of large CME/flare events on the Sun and late-type stars
New model for the CME/flare event that includes impulsive energy release and formation of post-eruptive arcade is proposed on the 1st RESIK-RHESSI-SPIRIT Workshop held in Wroclaw in 2005. It supposes that plasma is ejected after the pulse, but its part stays in the corona and then falls down. This down-flow provides additional income of plasma in a region where arches form at h ≈ 30000 km and then its heating that supports prolonged life of arcade. Subsequent consideration showed that this model can be realized when in given region the gas pressure approxomates to the magnetic one. Besides, the following point was suggested for – does it possible to observe hot plasma cloud tens of seconds after the pulse? We took attention also that data on particle acceleration can be interpreted otherwise than it was adopted earlier. These three problems were under our detailed investigation during past 3 years. We obtainted that the plasma beta becomes really close to 1 in the upper part of an arcade. For events on 25.January 2007 and some others where effective acceleration does not interfere to microwave observations of the thermal plasma, the thermal source was registered with the RATAN-600 and RHESSI. It is shown also that the spectrum of relativistic particles in 10 – 100 MeV does change insignificantly (if conditions of their escape from the corona and propagation in interplanetary space are close). It was associated with acceleration during the pulse, which occurs rather low in the corona in regions directly adjacent to spots. The only during a few events a large number of the soft particles (with E 10 keV or, in exceptional cases, under 60 keV) accelerates additionally during the post-eruptive phase in the coronal current sheet of at the shock front. So, this confirms two-stage of the CME/flare event and the CME is interlink between two phases of powerful non-stationary phenomena on the Sun. We discuss briefly data for the strong stellar flare on CN Leo, interpretation of which is the best application of the proposed model. Unfortunately, the root cause of the powerful impulsive energy release during solar and stellar flares is still uncleared.
A. Kulinova, E. Dzifčáková & J. Sylwester
The non-thermal diagnostics of flares observed by RESIK
The Polish soft X-ray spectrometer RESIK was operated on Russian Coronas-F spacecraft during the years 2001-2003. RESIK obtained X-ray spectra of more than hundred of flares in a wavelength range of 3.35-6.05 AA. We have analyzed the RESIK spectra of M and C class flares in a region of 5-6 A which is dominated by the allowed lines of Si XIII and Si XIV ions and by satellite lines of Si XII (Si XIId). The spectral ratios of satellite and allowed lines can provide us the information about the shape of electron distribution function. In this contribution we interpret the spectra under the assumption of non-thermal distribution.
E. Dzifcakova, A. Kulinova
Is it possible to diagnose the non-thermal distributions from EUV spectra?
It has been shown that non-thermal electron distributions with enhanced number of high energy particles (kappa-distributions) can origin in the solar corona. A set of synthetic spectra for different values of parameter kappa of non-thermal distributions, electron density and the mean energy of distribution has been computed in the spectral range corresponding to the EIS and SPIRIT detectors. The diagnostics of the basic parameters of plasma (electron density, the mean energy of distribution and the shape of the distribution function) is suggested. The suitability of lines which have been proposed for diagnostic is discussed.
Barbara Sylwester
Plasma temperature distribution & composition for low activity solar corona
The spectra observed by RESIK in the range 3.2-6.0 Å during the periods void of flaring activity have been used for the determination of plasma distribution with temperature (differential emission measure, DEM) as well as the absolute abundance of Ar, S and Si. The analysis has been done based on the RESIK fluxes measured in 15 selected energy bands. The Withbroe-Sylwester iterative procedure has been used in this context supported by extensive grid of spectra synthesized for selected plasma composition models. The RESIK spectral observations used covered the solar activity intervals related to GOES classes from A9 to B4. Performed analysis resulted in respective DEM distribution for each GOES subclass as well as respective best-fit abundance pattern.
V.Slemzin
EUV observations of the solar corona and transients at 1-5 Rsun with the SPIRIT telescope-coronagraph
The SPIRIT telescope aboard the CORONAS-F satellite for the first time observed the solar corona in the 175 and 304 Å EUV bands at the distance of 1-5 Rsun. This range fills the gap between fields of view of ordinary EUV telescopes (R=1-1.3 Rsun) and white-field coronagraphs (R>2 Rsun) being very important for acceleration of CME, forming the streamer belt and emergence of slow solar wind. Observations were made in special coronagraphic mode with inserted outer occulter and lasted from 1 day to several weeks with a cadence of 0.5-1 h. The images obtained in 2001-2003 show that at the high solar activity the solar EUV corona in the 175 and 304 A bands contained as structured and diffuse (unresolved) components depending on the latitude, radial distance and solar activity level. Some CMEs have been observed and analysed. The SPIRIT data are compared with corresponding EIT, LASCO and UVCS measurements. Observations of the EUV corona will be continued with the TESIS telescope aboard the CORONAS-Photon satellite.
B. Sylwester & J. Sylwester
SphinX spectral synthesis for low activity corona
Based on the DEM calculations performed using RESIK data for low activity levels (from A9 to B4) the respective SphinX spectra have been calculated and will be discussed. In the SphinX spectral synthesis routines we allowed for the dependence of line and continuum emission on specific, varying chemical composition of source plasma. The analysis has been made for individual levels of solar activity. Such spectra are expected to be observed preferentially early on, during the Coronas-Photon Mission. For the comparison a typical spectrum as would be obtained with SphinX calculated for the M class flare will be presented also. We envisage the possibility of establishing the absolute abundance of some elements based on the data to be obtained with SphinX. In the abundance determination we will use the method of fitting the synthetic spectra resulting from model calculations to the observed ones. The methodology will be similar to that which has been worked out based on RESIK data.
J. Sylwester, A. Kulinova & M. Kowalinski
Impact of local spacecraft environment on RESIK and SphinX measurements
Coronas-Photon will be put into semi Sun-synchronous 550 km orbit, inclined approximately 82.5 deg to the Equator. In such an orbit, spacecraft radiation and particle environment is changing rapidly with time, as the orbit crosses the polar oval regions due to Van Allen belts as well as the SAA anomaly from time to time. Based on the Coronas-F RESIK records obtained from the Si PIN particle detectors\' sensors as well as from the readouts of the main gas filled, large X-ray proportional detectors it was possible to identify several factors contributing to the orbital background. The analysis of RESIK PHA signals variability along the orbit allows us to discriminate between the contribution of particles as well as in situ emission due to X-ray auroral emission, fluorescence in the Earth atmosphere and other possible factors. Understanding the Coronas-F spacecraft environment variability is helpful in predicting the background for the SphinX detectors.
J. Sylwester & SphinX Team
Operation of SphinX during early phase of the CORONAS-Photon Mission
The presentation will show the construction of the final version of SphinX as is now mounted within TESIS on the Coronas-Photon flight payload. We will discuss the envisaged mode of the instrument operation during initial couple of months when the commissioning of the instrument will be performed. It is expected that solar activity will remain low for this period. Only few weak, class A or B flares are expected each week with the flux mostly at the quiet bottom level, below the threshold of present day instruments. Fortunately, the SphinX sensitivity is expected to be sufficient enough to measure spctra of such quiet coronal emission.
S. Gburek
SphinX data and software
SphinX software/hardware system consists of two independent data archives on servers in Wrocław – Poland and Ondřejov in Czech Republic. Both servers will be synchronized and their data content identical. Flexible data manipulation and visualization tools for SphinX observations in different instrument modes are now provided. Present version of IDL SphinX software is optimized for high performance and speed. Visualization tools are designed to be user friendly. They also support possible user modifications during the SphinX mission. The presentation will focus on the description of present SphinX system status. FITS format of SphinX data file, which is conformed now to OGIP standard of NASA Goddard Space Flight Center, will be discussed as well. Issues related to data access will also be addressed.
A. Kępa, B. Sylwester, J. Sylwester
Plans for further reduction, visualization and archiving of RESIK spectra
RESIK observations constitute a unique spectral database for analysis of soft X-ray lines in wavelength range from 3.1 Å to 6.1 Å. We have a large database of RESIK spectrometer covering various periods of solar activity from August 2001 to mid-May 2003. Understanding numerous instrumental and physical factors contributing to the measured signal was not easy. However, at present we are confident that all major instrumental corrections have been taken into account in the process of spectra reduction and calibration. I will present a short information about some instrumental effects which we revealed recently and about RESIK data catalogue. I will also discuss our plans for reduction of RESIK spectra.
A.Urnov
Determination of coronal plasma densities from Coronas observations
XUV spectroscopic methods of electron density disgnostics for various plasma structures are discussed in a view of recent calculations of line contribution functions. The data obtained in the SPIRIT experiment aboard the CORONAS-F spacecraft are used to estimate the density of plasma for quiet areas, active regions and flares of gifferent types. Future prospects for density diagnostics of solar corona structures by means of the TESIS experiment on the CORONAS-PHOTON are also considered.
P. Podgórski
SphinX dead times and throughput
The SphinX throughput curve depends on pulse width as well as on the other parameters like pulse height (photon energy), preamp reset dead time and even detector temperature. Based on the close-to-real numerical model of the SphinX shaping amplifier, throughput have been modelled using the Monte Carlo method for selected photons energies. Two SphinX detector channels with respective pulse widths of 8us and 25us have been simulated using Poisson-distributed sequences of photons. The evaluated throughput takes into account dead time due to preamp reset also. The obtained results compared with the SphinX BESSY calibration data will be shown and discussed.