Mechanisms on the Solar Wind-Magnetosphere Interactions: Importance of the Svalbard Radar.

Abstract

Questions about basic concept of the dayside field line merging process are raised. Alternative new mechanisms on the IMF control of the magnetosphere and for the magnetosheath plasma injection into the magnetosphere are proposed. Importance of the Svalbard radar to pursue mechanisms on the solar wind-magnetosphere interactions is discussed. It has been emphasized in the new mechanisms that magnetization currents arise from spatial non-uniformity in distribution of the magnetosheath plasma within the magnetopause boundary layer and that integration of the magnetization currents is highly dependent on the IMF condition. In the present paper, the IMF effects predicted from the control mechanism are compared quantitatively with observations of two IMF effects; the IMF Bz control of the stand-off distance of the subsolar magnetopause and the superposition of fractions of the IMF By and Bz upon the background magnetotail field. In the latter part of the present paper, a mechanism on the IMF control of injection of the magnetosheath plasma crossing the magnetopause is proposed. The injection is based on the effects of E × B plasma drift crossing the magnetopause due to an electric field transferred from the ionosphere polar cusp regions. It has been emphasized in the mechanism that a persistent dawn-to-dusk electric potential of about 10 kV across the ionosphere polar cusp is generated by the thermosphere dynamo arising from the solar EUV radiation and that the injection process is controlled by the magnetic fields at the tail flanks and hence by the IMF Bz following the mechanism proposed in the first part of this paper. It has been emphasized that the Svalbard radar is important to pursue details of characteristics of the ionosphere polar cusp in response to the IMF and the magnetosheath plasma injection.