Coordinated observations of magnetospheric reconfiguration during an overshielding event

Abstract

During 1400-1800 UT on September 15, 2005, the solar wind exhibited large variations and caused a moderate magnetic storm. The Jicamarca incoherent scatter radar, located near the local noon, observed an overshielding event after the northward turning of interplanetary magnetic field. The overshielding event featured distinct increase and decrease phases. We have examined the magnetospheric configuration variation with the geosynchronous observations provided by GOES12 (dayside) and LANL 97A (nightside), as well as the tail magnetic field monitored by Double Star TC1. The results suggested that the time-dependent magnetospheric reconfiguration process is closely related to the development of equatorial electric field. We speculate that the magnetospheric reconfiguration may cause equatorial ionosphere electric field disturbances through affecting the Region 2 field aligned current. Copyright 2008 by the American Geophysical Union.