Dynamic evolution of energetic outer zone electrons due to wave‐particle interactions during storms

Relativistic electrons in the outer radiation belt are subjected to pitch angle and energy diffusion by chorus, electromagnetic ion cyclotron (EMIC), and hiss waves. Using quasi‐linear diffusion coefficients for cyclotron resonance with field‐aligned waves, we examine whether the resonant interactions with chorus waves produce a net acceleration or loss of relativistic electrons. We also examine the effect of pitch angle scattering by EMIC and hiss waves during the main and recovery phases of a storm. The numerical simulations show that wave‐particle interactions with whistler mode chorus waves with realistic wave spectral properties result in a net acceleration of relativistic electrons, while EMIC waves, which provide very fast scattering near the edge of the loss cone, may be a dominant loss mechanism during the main phase of a storm. In addition, hiss waves are effective in scattering equatorially mirroring electrons and may be an important mechanism of transporting high pitch angle electrons toward the loss cone.