Inner Magnetospheric Electric Field and its Influence on Plasmasphere Erosion and Plasma Sheet Access

The large-scale electric field in the inner magnetosphere is a key driver of many processes and the dynamics of magnetospheric plasmas. During geomagnetic storms, the enhanced convection electric field is responsible for eroding the plasmasphere and for moving the inner edge of the plasma sheet earthward. In this presentation, we show the preliminary results of an examination of the distribution and variations of the inner magnetospheric quasi-static electric field as measured by the Electric Field and Waves (EFW) instruments onboard the twin spacecraft of the Van Allen Probes mission. We investigate the role that the electric field plays in plasmasphere erosion and plasma sheet access to the inner magnetosphere by analyzing the electric field measurements in conjunction with cold plasma density and plasma sheet particle flux measurements. Since the coupling between plasma populations in the magnetosphere is inherently related to the electric field, we expect that the combined measurements of the electric field and plasmas will enhance our understanding of the physical processes that drive the magnetospheric dynamics.