SUBSTORMS CAUSED BY LARGE-AMPLITUDE SOLAR WIND DYNAMIC PRESSURE PULSES: CASE STUDY ON 3 NOVEMBER 2021

Abstract

We studied the geomagnetic effects of abrupt and large-amplitude changes in the solar wind dynamic pressure (Psw) on 3 November 2021. when there were observed three large-amplitude Psw pulses (up to 20 nPa) under the strong (up to −18 nT) southward IMF Bz and significantly varying IMF By (from +20 to −15 nT). Basing on IMAGE magnetometer data, we found three substorms associated with these Psw impulses. These substorms followed one after another with a short interval and each subsequent substorm began developing during the unfinished recovery phase of the previous one under disturbed space weather conditions. Under strong negative IMF Bz there was significant input of energy into the magnetosphere that indicated by the increasing PC-index values. It was shown that the spatial-temporal features of the substorm subsequence development was complicated, differed from a typical isolated “normal” substorm and changed from one substorm to another. According to the AMPERE 66 ionospheric satellite data, the global distribution of the ionospheric and field-aligned currents (FAC) was established during the considered substorms. We found that during all these substorms, there were strong FACs and corresponding ionospheric electrojets in the morning sector indicating an enhanced magnetospheric convection which formed the DP2 current system. In addition, in the night sector, the DP1 current system was observed, the clearest in the second event.