Physics of auroral phenomena : proceedings of the 38th annual seminar, Apatity, 2-6 march, 2015 / [ed. board: A. G. Yahnin, N. V. Semenova]. - Апатиты : Издательство Кольского научного центра РАН, 2015. - 189 с. : ил., табл.

The saturation effect o f the Poyntmgflux into the magnetosphere during superstorms index reached, respectively, ~ 2000, 1750 and 3000 nT, and the latitude of the polar cap boundary lowered to 60°. Fig. 1 shows an example o f maps of field-aligned currents (FAC) density distribution in the polar ionosphere, obtained by MIT for the 20 November 2003 superstorm. Thick solid lines show the boundaries of the Iijima-Potemra regions R0, Rl, R2. The polar cap R0 is inside the region R l. On the basis of such maps we obtained time series 'Fi(t), where 4^ = - *F0 - is the value of the total open magnetic flux 4* minus its value before the substorm *Р0 = const [Mishin et al., 2014]. The polar cap magnetic flux ¥ in MIT is calculated as a product *F= B S, where B=0.6 Gs is the average geomagnetic field in a polar ionosphere, and S is the polar cap area. Further, in MIT the Poynting flux is calculated as a function of the magnetic flux e' ~ 0Fi)2 through the area of the polar cap S obtained from the FAC maps [Mishin et al., 2014], rather than through the expected unmeasurable length of an reconnection line l0 at the magnetopause as in the method by Akasofu [Perreault and Akasofu, 1978]. 20 Nov 2003 03:50 UT Figure 1. Maps of field-aligned current (FAC) density in the northern high-latitude ionosphere in geomagnetic dipole coordinates (MLT- latitude) obtained by magnetogram inversion technique (MIT) with 1-min resolution. Downward (upward) FACs are shown by dashed (solid) lines), borders between FAC zones R„ R2, Ro-by thick lines. R0- polar cap. In the global PPMLR- MHD simulation model [Ни et al., 2009; Wang et al., 2014] the basic input data are the SW parameters. The energy flux from SW to the magnetosphere is determined through a normal component of the velocity and magnetic field vectors at the magnetopause and its area. The total energy flux QT includes in addition to the Poynting flux Qe|m also the thermal and kinetic energy fluxes. Unlike satellite statistical data averaged over intervals of about an hour, we use the original MIT methods for determining ¥ (with a sampling interval o f >1 min) [Mishin et al., 2014] and for identifying hidden dependencies of ‘P on the variables Esw, Pd, and AE- index [e.g. Mishin, 1990]. The method o f maximal contributions We use this method for a detection and separation in time of hidden dependencies of the open magnetic flux 'Fi (Esw, Pd) obtained from observations [e.g. Mishin, 1990]. We assumed that the values 4^ are controlled mainly by AE-index values and by the SW parameters Eswand Pd. This method provides solving systems of the linear algebraic equations, including those used in the present paper, having the form: HE'i = AfEj + А2-Р; + A3'AEi (1) where i =1, к is the number of each time instant in the time interval considered, к - the quantity o f these instants for this interval (their centers are shown by three different symbols in Fig. 3). The polar cap magnetic flux 'PI variation Fig. 2 shows the saturation of the open magnetic flux 'Fb calculated by MIT during the growth of the southward IMF and Pd for the 20 November 2003. superstorm. 20 Nov 2003 Figure 2. “New” polar magnetic flux 'P], Y- % as a function of (a) the SW dynamic pressure Pd and the IMF Bz (b). Here 'P0=0.35GWb-the prestorm *F value. Figure 3. Derivatives S'P/dP и d'P/SE as a functions of Pd and Eswfor the three superstorms. The dispersion is due to the fact that the flux VF1 is a function of many SW parameters. In order to separate two processes of saturation 'Pl (B2) and 'F, (Pd) in time we have 41