Magnetospheric electric fields and plasma sheet injection to low L‐shells during the 4–5 June 1991 magnetic storm: Comparison between the Rice Convection Model and observations

Abstract

The major magnetic storm of 4–5 June 1991 was well observed with the Combined Release and Radiation Experiment (CRRES) satellite in the duskside inner magnetosphere and with three Defense Meteorological Satellite Program (DMSP) spacecraft in the polar ionosphere. These observations are compared to results from the Rice Convection Model (RCM), which calculates the inner magnetospheric electric field and particle distribution self‐consistently. This case study, which uses the most complete RCM runs to date, demonstrates two significant features of magnetospheric storms, the development of subauroral polarization streams (SAPS) and plasma‐sheet particle injection deep into the inner magnetosphere. In particular, the RCM predicts the electric field peak near L = 4 that is observed by the CRRES satellite during the second injection. The RCM calculations and DMSP data both show SAPS events with similar general characteristics, though there is no detailed point‐by‐point agreement. In the simulation, SAPS are generated by the deep penetration of plasma sheet protons to L < 4 and Earthward of the plasma sheet electrons. Similarly, the vast majority of the ions that make up the storm‐time ring current came from the plasma sheet; most of the particles that made up the prestorm quiet‐time ring current escaped through the dayside magnetopause during ring current injection. The RCM demonstrates the capability of plasma sheet ions to reach all ring current orbits and predicts the location of the injected particles (both ions and electrons) reasonably well. However, it overpredicts the ion flux in the inner magnetosphere.