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. Fig. 1 Superposed epoch analysis for 25 low-shear magnetopause crossings (left column) and 49 high-shear magnetopause crossings (right column). Magnetosheath is before T0, magnetosphere — after. From top to bottom: magnetic pressure (nPa), Z-component of the magnetic field in GSM (nT), proton density (cm"3), temperature (keV), bulk velocity (km/sec), and plasma p. Results and discussion The result obtained by the superposed epoch events we could see signs o f the magnetic magnetopause, in the decrease of the density B m b ( n T ) ^ m b ^nisph y f $ / y \ S ' В mb 0 - 8 Bmsph / О О o ° ° / / J 0*> 0 u о °o ° • V ж +008* 0 . i i „ i _ i i ? i 5 ^ ( n T ) Fig. 2 The Figure shows the field magnitude in the magnetic barrier Bmb depending on the magnetic field inside the magnetosphere Bmph. The shaded area is bounded by two lines: Bmb = BmsPh — at the top and Bmh = 0.8 Bmsph — at the bottom. 60 analysis showed full compliance with the result of [1]. For low-shear barrier which were expressed in the magnetic flux piling up at the and plasma p. For high-shear events the magnetic barrier is absolutely absent. In this case there are a leap o f the magnetic pressure, a slight decrease in the plasma density and the growth o f the velocity fluctuations close to subsolar magnetopause. The features of high- shear magnetopause crossings (a sharp drop in the plasma density and a growth of the velocity fluctuations) indicated an effective process of the dayside reconnection because o f which the magnetic barrier had disappeared. We compared the magnetic field magnitude in the magnetosheath and in the magnetosphere (Fig. 2). The lines limiting the shaded area correspond to 80% of the magnetospheric magnetic field. This level is determined by the minimum plasma inflow velocity into the reconnection area while IMF was oriented to the south. If the inflow velocity is at least 0.1 of the А1^ёп speed (the minimum reconnection rate) the field magnitude in the magnetic barrier does not exceed 80% of the magnetospheric magnitude. Therefore, in cases when the magnetic field magnitude greater than 80% we could assume that there is no reconnection. Almost all low-shear events (crosses in Fig. 2) are in the shaded area. There are clear signs o f a magnetic barrier in these events. For the low-shear events the approximation line lies along the shaded area. It means the field magnitude inside the magnetic barrier is about magnetospheric magnitude. The events located near the diagonal line indicate the maximum of field magnitude in the magnetic barrier.