Physics of auroral phenomena : proceedings of the 36th Annual seminar, Apatity, 26 February – 01 March, 2013 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2013. - 215 с. : ил., табл.

A. I. Podgomy and I. M. Podgorrry The results of 3D MHD simulation [3, 4] and comparison of with X-ray observations on spacecrafts Yohkoh and RHESSI permit to create the solar flare electrodynamical model [9, 10]. The model explains main flare manifestations. The flare occurs because of fast release of energy accumulated in the magnetic field of the current sheet, created in the preflare state above an active region. The plasma, heated by fast dissipation o f the magnetic field, emits X-ray radiation with thermal spectrum for the temperature, which equal to several keV. In this model the Hall electric field in the sheet generates field-aligned electric currents in the corona along the magnetic field lines that are crossing a current sheet. The hard X-ray emission is the bremsstrahlung emission in the chromospheres of electrons, which are accelerated in field-aligned currents. The positions o f sources o f X-ray radiation can be found, if the magnetic field configuration is known from results of MHD simulation. According to the solar flare electrodynamical model the position of thermal X-ray emission is situated in the current sheet, and positions of nonthermal hard X-rays are places of crossing of the photosphere with the magnetic lines, which are going out o f the current sheet. The aim of present work is investigation of the possibility o f finding o f the current sheet position in the numerical experiment and comparison this position with positions of the thermal X-ray radiation. Fig. 1 The lines o f the constant current density and plane current density maximums marked in the plains containing the point Max j | : Front View z=0.445, Top View >>=0.04, Side View x=0A6. The projections o f 3D current density maximums are marked by crosses. The maximums are marked only in the subregion 0.3389 <x< 0.5456, 0.02362 <y< 0.1919, 0.355 <z< 0.505, which boundaries are marked by dashed lines. The chosen points Max ji and Max j 2 are marked. The method of search current sheets positions The analysis of magnetic field configurations in the different planes, which was fulfilled for MHD simulation results in the active region 10365 [9,10], showed the formation of several current sheets above this active region. Each of them can case the flare. In this paper an attempt is made to find the position o f X-ray sources o f the flare, which occurred May 27, 2003 at 02:53 in the active region NOAA 10365, using the results o f the MHD simulations, and to compare with the X-ray observations. To find positions of sources of soft X-ray radiation in the corona the graphical system developed by authors is used. To find the position of the current sheet, its property is used, according to which the local maximum of the absolute value of the current density is located in the center of a current sheet. In any selected plane, which can be placed arbitrarily in the space in the computational domain, the lines of level o f absolute values of current density are constructed. Furthermore, in this plane all positions of local maxima of the current density in the plane and projections of all positions of the local maxima of the current density in the space on the plane are marked. Marked points are located at the intersection o f the current sheets with the plane, or they are corresponded to centers of current sheets. The program can easily obtain information about any marked point o f the maximum. It can be outputted coordinate value of that point in any chosen coordinate system and the all calculated variables (magnetic field vector, plasma density, and plasma temperature, etc.) in this point. In order to determine whether a given point of the current density maximum correspond the current sheet center or simply corresponds to an increase of the current density as a result of some disturbance, the program offers the possibility to build the configuration of the magnetic field in the vicinity of the selected point in any arbitrarily rotated coordinate system. Typically, in first turn it is expected to build the magnetic field configuration in a plane containing the selected point o f the maximum current density which is situated perpendicular to the magnetic field vector. [11]. For comparing of observed X-ray sources positions with the results of MHD simulations the strongly reduced time scale [9, 10] are used because even using a powerful personal computer, simulation in the real time scale 118 ,Y FRONT VIEW Z= 0.445 SIDE VIEW X=0.46 J 0<X<0.4 0<Y<0.3 X ~ J TOP VIEW V=0.04 0<Y<0.3 0<Z<0.4 Z TIME = 2.2 TOP VIEW * SIDE VIEW FRONT VIEW 0<X<0.4 0<Y<0.3 0<Z<0.4 s - POINT Max 8- POINT Max j 2 - PLANE MAXIMUMS J , - 3D MAXIMUMS J