Combined Effects from Chorus Pitch Angle Scattering and Storm-time Transport on Ring Current Electrons

The high variability of energetic particle fluxes in the inner magnetosphere remains not adequately explained due to their complex dynamics including competing particle acceleration and loss processes. We study the combined effects from pitch angle scattering by chorus waves and transport in realistic inner magnetospheric fields on ring current electrons (from ~100 eV to ~300 keV energy). We use our ring current-atmosphere interactions model (RAM) that solves the kinetic equation for H+, O+, and He+ ions and electrons and is two-way coupled with a 3-D equilibrium code that calculates self-consistently the magnetic field in force balance with the anisotropic ring current plasma pressure. We simulate wave-particle interactions on a global scale as particles drift around the Earth using newly updated L and MLT-dependent diffusion coefficients for upper and lower band chorus based on multiple spacecraft data from CRRES, THEMIS, Double Star, Cluster and DE1. We find that the pitch angle distributions of ring current electrons become pancake or "head and shoulder" on the dawnside within regions of enhanced chorus scattering, while they are field-aligned or "butterfly" on the nightside due to drift-shell splitting. The effects on the electron precipitation as well as further chorus wave excitation are investigated.