Simulation of Resonant Interaction between Energetic Electrons and Whistler-Mode Chorus in the Outer Radiation Belt

Abstract

We construct a realistic model to evaluate the chorus wave-particle interaction in the outer radiation belt L = 4.5. This model incorporates a plasmatrough number density model, a field-aligned density model and a realistic wave power and frequency model. We solve the 2D bounce-averaged momentum-pitch-angle Fokker–Planck equation and show that the Whistler-mode chorus can be effective in the acceleration of electrons, and enhance the phase space density for energies of ∼1 MeV by a factor from 10 to 103 in about two days, consistent with the observation. We also demonstrate that ignorance of the electron number density variation along field line and magnetic local time in the previous work yields an overestimate of energetic electron phase space density by a factor 5∼10 at large pitch-angle after two days, suggesting that a realistic plasma density model is very important to evaluate the evolution of energetic electrons in the outer radiation belt.