Response of Electric Field Pulse and Particle Dynamics in Earth's Magnetosphere to Enhanced Solar Wind Dynamic Pressure With Varied IMF Directions: A Statistical Study

Abstract

The electric field pulses caused by enhanced solar wind dynamic pressure are particularly effective in energization and inward transport of relativistic electrons in Earth's radiation belt. Utilizing electric field and particle measurements by Van Allen Probes and near-Earth solar wind measurements, we have conducted a statistical analysis to investigate the responses of electric field pulses and particle dynamics to enhanced solar wind dynamic pressure under varied interplanetary magnetic field (IMF) directions. On Earth's dayside, the generation of electric field pulses is independent of the IMF direction. In contrast, on the nightside, electric field pulses are more easily excited under northward IMF than under southward IMF. Interacted with the electric field pulses, the responses of electrons and protons show a day-night asymmetry under southward IMF. The statistical results also indicate that proton flux variations mostly cluster on the post-dawnside (MLT ∼ 6–12), while electron flux variations show a slight preference for the pre-duskside (MLT ∼ 12–18) under some conditions. Moreover, the occurrence rate of proton flux variation is lower than that of electrons, and a clear change in proton flux usually appears in lower energy channels. Our study provides new insights into understanding the interaction between solar winds and magnetospheres of the Earth and other magnetized planets.