DIRECT OBSERVATIONS IN THE DUSK HOURS OF THE CHARACTERISTICS OF THE STORM-TIME RING CURRENT PARTICLES DURING THE BEGINNING OF MAGNETIC STORMS

摘要

The characteristic features of the initial enhancement of the storm-time ring current particles in the evening hours are consistent with flow patterns resulting from a combination of inward convection, gradient drift and corotation which carries plasma sheet protons into low L-values near midnight and the higher-energy proton component into the plasmasphere and through the evening hours. Data from four magnetic storms during the early life of S3-A (Explorer 45) when the local-time of apogee was in the afternoon and evening hours show that protons with lower-magnetic moments penetrate deeper into the magnetosphere until a lower limit, determined by the corotation and gradient drift forces, is reached. Such particle motions produce the stable energy-dependent inner boundary of the ring current protons inside the plasmapause in the dusk sector and also provide the mechanism for energy injection into the ring current region.