Roles of whistler-mode waves and magnetosonic waves in changing the outer radiation belt and the slot region

TitleRoles of whistler-mode waves and magnetosonic waves in changing the outer radiation belt and the slot region
Publication TypeJournal Article
Year of Publication2017
AuthorsLi, LY, Yu, J, Cao, JB, Yang, JY, Li, X, Baker, DN, Reeves, GD, Spence, H
JournalJournal of Geophysical Research: Space Physics
Date Published04/2017
Keywordsmagnetosonic waves; Plasmapause movement; Spatial variation of outer radiaton belt; Spatial variation of slot region; Temporal-spatial variations of chorus waves; Temporal-spatial variations of plasmaspheric hiss; Van Allen Probes
AbstractUsing the Van Allen Probe long-term (2013 – 2015) observations and quasi-linear simulations of wave-particle interactions, we examine the combined or competing effects of whistler-mode waves (chorus or hiss) and magnetosonic (MS) waves on energetic (<0.5 MeV) and relativistic (>0.5 MeV) electrons inside and outside the plasmasphere. Although whistler-mode chorus waves and MS waves can singly or jointly accelerate electrons from the hundreds of keV energy to the MeV energy in the low-density trough, most of the relativistic electron enhancement events are best correlated with the chorus wave emissions outside the plasmapause. Inside the plasmasphere, intense plasmaspheric hiss can cause the net loss of relativistic electrons via persistent pitch angle scattering, regardless of whether MS waves were present or not. The intense hiss waves not only create the energy-dependent electron slot region, but also remove a lot of the outer radiation belt electrons when the expanding dayside plasmasphere frequently covers the outer zone. Since whistler-mode waves (chorus or hiss) can resonate with more electrons than MS waves, they play dominant roles in changing the outer radiation belt and the slot region. However, MS waves can accelerate the energetic electrons below 400 keV and weaken their loss inside the plasmapause. Thus, MS waves and plasmaspheric hiss generate different competing effects on energetic and relativistic electrons in the high-density plasmasphere.
URLhttp://onlinelibrary.wiley.com/doi/10.1002/2016JA023634/full
DOI10.1002/2016JA023634
Short TitleJ. Geophys. Res. Space Physics


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