The Radiation Belt Electron Scattering by Magnetosonic Wave: Dependence on Key Parameters




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Amer Geophysical Union


Magnetosonic (MS) waves have been found capable of creating radiation belt electron butterfly distributions in the inner magnetosphere. To investigate the physical nature of the interactions between radiation belt electrons and MS waves, and to explore a preferential condition for MS waves to scatter electrons efficiently, we performed a comprehensive parametric study of MS wave-electron interactions using test particle simulations. The diffusion coefficients simulated by varying the MS wave frequency show that the scattering effect of MS waves is frequency insensitive at low harmonics (f < 20 f(cp)), which has great implications on modeling the electron scattering caused by MS waves with harmonic structures. The electron scattering caused by MS waves is very sensitive to wave normal angles, and MS waves with off 90 degrees wave normal angles scatter electrons more efficiently. By simulating the diffusion coefficients and the electron phase space density evolution at different L shells under different plasma environment circumstances, we find that MS waves can readily produce electron butterfly distributions in the inner part of the plasmasphere where the ratio of electron plasma-to-gyrofequency (f(pe)/f(ce)) is large, while they may essentially form a two-peak distribution outside the plasmapause and in the inner radiation belt where f(pe)/f(ce) is small.



Magnetosphere, Magnetic fields, Radiation belts, Electrons, Electromagnetic waves, Plasmasphere

NSF grant AGS-1705079; AFOSR grant FA9550-16-1-0344; NSFC grants 41374166, 41674164, 41274167, 40831061, 41204120, 41474141, and 41674163; Chinese Key Research Project 2011CB811404; NSF Geospace Environment Modeling grant AGS- 1103064, AGS-1723342; AFOSR grant FA9550-15-1-0158


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