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Effects of magnetic drift shell splitting on electron diffusion in the radiation belts
Author(s) -
Zheng Liheng,
Chan A. A.,
O'Brien T. P.,
Tu W.,
Cunningham G. S.,
Albert J. M.,
Elkington S. R.
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023438
Subject(s) - diffusion , physics , adiabatic process , electron , fokker–planck equation , phase space , space (punctuation) , phase (matter) , tensor (intrinsic definition) , shell (structure) , computational physics , electron scattering , classical mechanics , quantum mechanics , geometry , differential equation , materials science , mathematics , philosophy , linguistics , composite material
Abstract Drift shell splitting in the presence of pitch angle scattering breaks all three adiabatic invariants of radiation belt electron motion and produces new diffusion terms that fully populate the diffusion tensor in the Fokker‐Planck equation. The Radbelt Electron Model (REM) solves such a Fokker‐Planck equation and is used to investigate the phase space density sources. Our simulation results and theoretical arguments suggest that drift shell splitting changes the phase space location of the source to smaller L shells, which typically reduces outer zone phase space density enhancements, and this reduction has a limit corresponding to two‐dimensional local diffusion on a curved surface in the phase space.