High-Energy Electron Flux Enhancement Pattern in the Outer Radiation Belt in Response to the Interplanetary Coronal Mass Ejections

The high-energy electron flux enhancement pattern in the outer radiation belt is observed under the influence of the Interplanetary Coronal Mass Ejections (ICMEs). Ten events were selected during the Van Allen Probes era, with the high-energy electron flux enhancement starting close to L* = 4. A schematic diagram of the main physical processes responsible for this kind of high-energy electron flux enhancement is presented, considering the energy deposited in the inner magnetosphere under the influence of ICMEs. Superposed Epoch Analysis is applied to the interplanetary medium parameters, the magnetopause standoff distance, the storm-time geomagnetic activity indices, the Ultra-Low Frequency (ULF) waves, and the whistler-mode chorus waves. A compressed magnetopause, B-z component preferentially southward and storm indices considerably high are observed at the beginning of the electron flux enhancements. The modeled parameters of the chorus waves at the dayside/nightside sectors show the high acceleration efficiency at the beginning of the electron flux enhancement pattern II. These results suggest that the local acceleration driven by chorus waves is essential to these electron flux enhancements at low L*. In contrast, although the ULF waves are detected at the beginning of the studied electron flux enhancements, their contribution is insignificant.