Simultaneous Evolutions of Inner Magnetospheric Plasmaspheric Hiss and EMIC Waves Under the Influence of a Heliospheric Plasma Sheet

Abstract

Plasmaspheric hiss and electromagnetic ion cyclotron (EMIC) waves are two of the most important magnetospheric plasma waves inside the Earth's high-density plasmasphere. In this work, utilizing observations from the WIND and Van Allen Probes missions, we investigate the simultaneous evolutions of inner magnetospheric plasmaspheric hiss and EMIC waves under the influence of a heliospheric plasma sheet (HPS). The long duration impingement of high-density solar wind HPS onto the magnetosphere produced hot anisotropy electrons and protons, and then caused excitations of plasmaspheric hiss and EMIC waves in the duskside plasmasphere (L ∼ 6.75, MLT ∼ 16.85). In contrast, the solar wind decompression associated with the subsequent cessation of the HPS led to decreases in hot electron and proton fluxes, triggering prompt disappearances of the compression-related plasmaspheric hiss and EMIC waves. The presented results highlight the importance of solar wind conditions for the Earth's space weather and provide new insights into the solar wind-magnetosphere coupling.