Physics of auroral phenomena : proceedings of the 35th Annual seminar, Apatity, 28 Februaru – 02 March, 2012 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2012. - 187 с. : ил., табл.

determine the normal to the solar surface magnetic field component, the Laplace equation has been solved using the oblique derivative of the magnetic potential as the photospheric boundary conditions. This method is developed in [ 6 , 7]. The active region magneticfield association with solarflares Fig. 3. X-ray flux during the flare and the SOHO MDI magnetograms 10.28.2003, demonstrating the high stability o f NOAA 10486 during the flareX17 UT 28-Oct-2003 W* — '— ■— 1— >— .— .— .— i — .— *— .— i — i— i— .— i — ,— .— .— L_-— .— 00:00 04:00 08:00 12:00 16:00 20:00 UT 2003-10-28T07:59:03,228Z 2003-10-28T09:35:03.226Z 2003-10-28T11:11:03.2242 2003-10-28T12:47:03.222Z X 10'1 M т w С [ e io4f Q> 10 " * GOES 12 AR10720 | » : \ 1 n\ 1 1 \ш I ... — I, i i - m \liW ■1 L 4 ! Gj°«| | jy^ |P ыТЧГ] I I i i / 4 l i . * г p u I I ill !w F 1 w ’W FW \ L ! fi I H M i t M .... 110 10 11 12 13 14 15 16 17 18 20 21 x 2 Я о Discussion Analysis of magnetic fluxes in strong AR confirm the conclusions o f [ 8 , 11] that the condition for appearance of large (X-class) flares above such AR with the magnetic flux greater than 10 22 Mx is a necessary but not sufficient. An example of the AR with the magnetic flux exceeding 1022 Mx, which produces no powerful flare, is AR 11190-11192. Fig. 5 shows distributions of the normal magnetic field component of AR 11190-11192 and NOAA 10365. The results of X-ray GOES measurements are also show. The values of the north and south magnetic fluxes in these AR are almost the same ~ 1.6xl0 22 Mx. However, only AR 10365 with complicated field distribution has produced a series of X-class flares, although the flare activity of the simple AR 11190-11192 does not exceed the C3. In AR 10365 local sources with north and south polarities are distributed randomly and their location cannot be classified as a simple dipole group ((3-region), with simple preceding and following solar spots. The maxima of positive and negative polarities are distributed irregularly. At such situation the conditions for the formation of singular magnetic lines in the corona and, consequently, the possibility of flare production are appeared The demonstration in the numerical experiment the appearance of a current sheet with a large magnetic field should be a direct indication of the flare occurrence in the near future, but for the exact prediction of flare requires numerical simulation of the situation above AR in real time. AR 11190-11192 has another type of field distribution (P-region). Here there is a distinct interface between magnetic sources of different polarity. It is clearly revealed two separate parts of the region, each of which contains magnetic sources of one direction. Parts of the region with different direction of the field are separated by the only inversion-polarity line (line of zero normal component).. Such a bipolar-type distribution of field sources on the photosphere must match to the magnetic loops in the corona, without singular lines and zero magnetic points. Ф N о Ф 8 SB 0 ^ 4 t j r t 1 11 12 13 14 15 16 17 18 19 20.01.2005. Fig 4. Powerful X-ray pulses and time dependence of NOAA 10720 magnetic flux. 90