Bounce Resonance Between Energetic Electrons and Magnetosonic Waves: A Parametric Study

Abstract

AbstractMagnetosonic (MS) waves are electromagnetic emissions from a few to 100 Hz primarily confined near the magnetic equator both inside and outside the plasmasphere. Previous studies proved that MS waves can transport equatorially mirroring electrons from an equatorial pitch angle of 90° down to lower values by bounce resonance. However, the dependence of the bounce resonance effect on wave or background plasma parameters is still unclear. Here, we applied a test particle simulation to investigate electron transport coefficients, including diffusion and advection coefficients in energy and pitch angle, due to bounce resonance with MS waves. We investigate five wave field parameters, including wave frequency width, wave center frequency, latitudinal distribution width, wave normal angle root‐mean‐square of wave magnetic amplitude, and two background parameters, L‐shell value and plasma density. We find different transport coefficient peaks resulting from different bounce resonance harmonics. Higher‐order harmonic resonances exist, but the effect of fundamental resonance is much stronger. As the wave center frequency increases, higher‐order harmonics start to dominate. With wave frequency width increasing, the energy range of effective bounce resonance broadens, but the effect itself weakens. The bounce resonance effect will increase when we decrease the wave normal angle, or increase the wave amplitude, latitudinal distribution width, L‐shell value, and plasma density. The parametric study will advance our understanding of the favorable conditions of bounce resonance.