Understanding Earth’s Radiation Belt Electron Acceleration and Its Solar Wind Drivers

Abstract:

Understanding electron acceleration to multi MeV energies is one of the most important questions in radiation belt science, and it is critical to the determine solar wind conditions leading to such acceleration. In this study, we focus on analyzing several typical electron acceleration events observed by the Van Allen Probes. Using the UCLA 3D particle diffusion code, we simulate the evolution of the electron phase space density by including the most important physical processes, such as electron energy diffusion and pitch angle scattering caused by whistler-mode chorus waves and plasmaspheric hiss, radial diffusion driven by ultra low frequency waves, and pitch angle scattering due to electromagnetic ion cyclotron waves, to quantify the role of each physical process in multiple individual events. We further perform a superposed epoch analysis to determine the most important solar wind conditions that lead to the rapid electron acceleration up to multi MeV in the Earth’s outer radiation belt.