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.

E.E. Antonova et al. with evolution of partial ring current leading to symmetric ring current during storm recovery phase. Pressure disbalance at the flank magnetopause is also appeared. CRC is closed inside the magnetosphere and its development does not lead to problems with magnetopause pressure balance and partial ring current evolution. Isolated magnetospheric substorm onset The introduction of CRC removes some problems of magnetospheric substorm. Multiple results of observations demonstrate the position of substorm injection boundary not very far from the geostationary orbit (see Lopez et al. [1990]). It is well known that substorm injections lead to the effect of drift echo. Substorm injections are frequently considered as the source of the asymmetric ring current. Produced analysis show that substorm particle injections during magnetic storm are localized inside ring current or its high latitude continuation CRC. It is interesting to mention also that the introduction of CRC can lead also to definite changes of the analysis of the processes during isolated magnetospheric substorm. Isolated substorm onset in accordance with Akasofu [1964] is localized at the equatorial boundary of the auroral oval, which is ordinarily identified as the inner plasma sheet boundary. This boundary in accordance with the results of multiple observations (see, for example, [Parks, 1991]) is localized at ~1RE. It is greatly shifted to the Earth during magnetic storms. Isolated substorm onset in accordance with (see, Lui [20111 and references therein, Yahnin et al. [2002], Dubyagin et al. [2003]) is localized at geocentric distances smaller than 10Л£. This means that it is localized in the CRC region, which can be important for the analysis of the process of current disruption and field line dipolarization during substorm. Discussion and conclusions We summarize the data of observations demonstrating the existence of plasma ring at geocentric distances from ~1RE till ~\0Rr t t R E with the same as in the plasma sheet plasma characteristics. The discussed region is the region of quasitrapping for energetic particles. The nighttime part of the ring is ordinarily selected as the near Earth plasma sheet. The distribution of plasma pressure in the ring is obtained using data of THEMIS mission. It is shown, that quite time averaged plasma pressure profile is near to azimuthally symmetric and plasma pressure is near to isotropic. Radial gradient of plasma pressure has the earthward direction. Earthward direction of plasma pressure gradients in the conditions of magnetostatic equilibrium means the existence of transverse westward current. The value of dayside part of these current was previously underestimated, as it was not taken into account the compression of daytime field lines and the shifts of 14 minima of the magnetic field at the field line at high latitudes. Estimations of daytime transverse currents taking into account that these currents are not concentrated at the equatorial plane leads to comparatively high values of daytime transverse currents comparable with nighttime transverse currents at the same geocentric distances. Such feature gives the possibility to analyze the region of surrounding the Earth plasma ring as the high latitude continuation of the ordinary ring current. The existence of the high latitude continuation of the ordinary ring current requires the analysis of role of this current in the Dst formation during geomagnetic storm. We try to show that it is necessary to include the contribution of this current in the azimuthally symmetric part of the near Earth disturbance of magnetic field producing decrease of Dst during magnetic storms. Taking into account the existence of CRC it is possible to overcome problems of the hypothesis of comparatively large role of tail current in the Dst formation and location of isolated substorm onset. The produced simple analysis can be considered only as one of the first steps in the analysis of the role of the surrounding the Earth plasma ring in the magnetospheric dynamics. We hope that future studies will reveal this role more clearly. Acknowledgements . We are grateful to the THEMIS team for the mission data. The work was partially supported by the Russian Foundation for Basic Research by grants 10-05-00247, 12-05-01030, 12-02- 00217, and FONDECYT grant 1110729. References Akasofu, S.-I. (1964). The development of the auroral substorm, Planet. Space Sci., 12(4), 273-282. Angelopoulos, V. (2008), The THEMIS mission. Space Science Rev., 141, 5-34, doi: 10.1007/sl 1214-008- 9336-1. Antonova, E.E. (2001), Radial plasma pressure gradients in the earth's magnetosphere and the Dst variation, Geomagnetizm and aeronomia, 41(2), 142- 149. Antonova, E.E., E.Yu. Budnik, V.N. Lutsenko, and N.F. Pissarenko (2001), Interball/Tail observations of high latitude pressure distribution. Adv. Space Res., 30(10), 2289-2293. Antonova, E.E. (2003), Investigation of the hot plasma pressure gradients and the configuration of magnetospheric currents from INTERBALL, Adv. Space Res., 31(5), 1157-1166. Antonova, E.E., E.Yu. Budnik, I.P. Kirpichev, V.N. V.N. Lutsenko, and N.F. Pissarenko (2003), Magnetospheric plasma pressure and space weather. Adv. Space Res., 31(4), 1093-1098. Antonova, E.E. (2004), Magnetostatic equilibrium and current systems in the Earth’s magnetosphere. Adv. Space Res., 33, 752-760.