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.

К. Yu. Slivka et al. In formulas Bm и Bs is magnetospheric field magnitude and field magnitude in a magnetic barrier correspondingly; the angle в is the deviation o f IMF vector from axis Z; n0, u0 и MA is correspondingly plasma density, bulk velocity and the Alfven Mach number in the solar wind; В и n is the dimensionless functions from £ parameter (they used in [5] for calculation of MGD parameters on a border of the reconnection area). Calculating £ for different values of reconnection rate g we determined field magnitudes and densities and compared them to experimentally received values. In each case, for comparison with the experimental Bs and ns we chose the similar of the three calculated values of В and n. Thus, we determined the reconnection rate corresponding to each event. As a result the histogram o f events distribution on reconnection rates g was built. It turned out that the most likely g = 0.3. Thus selected pairs of В and n values are compared in Fig. 4(b-l, c-1). A similar comparison for the condition g = 0.3 in all the events is shown in the Fig 4(b-2, c-2). (b-1) 20 15 10 (a) —'----1----.----[----Г- Number of events 0.8 0.6 0.4 0.2 ■1■1• 1' 1Ч ' 1Ч 11Ч 1 о ■В'тЬ д = 0 . 8 8 / ' L о * 1 0.8 . 1111 [К ,ь ! 1[ 1!1 ’ 11! 1! '■■' R = 0.68 . о ° ° . 1 1 г Г О о ч о <$ J—L-L..1 0.6 - ° о ' о*00 <$>/§> Г / ) “ - от оо 0.4 - ^о ■'"о ” оо Г ОО в ’тЬ- . 1 . 1 . 1 . 1 . 1 , 1 . 1 , 1 , 1 . 0.2 00 ' <1. 1 В'тЬ~ . 1, I . 1 , 1, 1, 1, 1. 0.2 0.4 0.6 0.8 1 (с-1) ■■гг* .-ii , ■ | 1111| Ч 1' 1' . R = 0.47 : ; о °о 0 Оо° ~ \ . . , 1 . .с* 1 N . : mb ■ . . . 1 . . . . 1 ' 2 3 4 5 6 0.2 0.4 0.6 0.8 3 0 0.1 0.2 0.3 0.4 Fig. 4 Statistics for 31 events with destroyed magnetic barrier. The histogram o f the events distribution with destroyed magnetic barrier by the magnetopause reconnection rate (a). In Figure theoretical (*) and experimental (') magnetic field (b) and plasma density (c) are presented in comparison with the solar wind parameters for rates of magnetopause reconnection g obtained by compare theoretical and experimental values (1) and for fixed g = 0.3 (2). Conclusions It was shown by the superposed epoch analysis that the features of the magnetic barrier (enhancement of the magnetic field and the decrease in the plasma density) were observed for northern IMF and not observed for the southern IMF. These are consistent with the results o f [1]. For southern IMF the features of the magnetic barrier (increase magnetic field by more than 80% of the magnetospheric magnitude) are observed in 5 of the 49 events. This ratio corresponds to the magnetic barrier accumulation time (~10 min) several times longer its destruction (1-2 min). Thus, the magnetic barrier is formed for all IMF directions, including southern, however, it is unlikely to detect accumulated magnetic barrier for southern IMF. It was found (Fig. 4(b-l, c-1, b-2, c-2)) that the correlation between the calculated and experimantal values is better at choosing reconnection rate for each event. It follows that reconnection rate can vary in different events. This is reflected in the large scatter o f points for the event (Fig. 2). References 1. Phan, T.-D, G. Paschmann, W. Baumjohann, N. Sckopke and H. Luhr, «The magnetosheath region adjacent to the dayside magnetopause: AMPTE/IRM observations», Journal of Geophysical Research, 99, p. 121-141, 1994. 2. themis.ssl.berkeley.edu/ 3. cdaweb.gsfc.nasa.gov/istp_public/ 4. Erkaev N.V., Farrugia C.J., and Biemat H.K., «The role of the magnetic barrier in the Solar wind-magnetosphere interaction», Planetary and Space Science, 51, p. 745-755, 2003. 5. Еркаев H.B., «Результаты исследования МГД-обтекания магнитосферы», Геомагнетизм и аэрономия, том 28, №4, с. 529-541, 1988. 62