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Ion temperature effects on magnetotail Alfvén wave propagation and electron energization
Author(s) -
Damiano P. A.,
Johnson J. R.,
Chaston C. C.
Publication year - 2015
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2015ja021074
Subject(s) - gyroradius , physics , alfvén wave , electron , substorm , computational physics , magnetic field , electron temperature , electric field , lower hybrid oscillation , atomic physics , ion , field line , ionosphere , kinetic energy , wave propagation , magnetohydrodynamics , geophysics , electromagnetic electron wave , magnetosphere , optics , classical mechanics , quantum mechanics
Abstract A new 2‐D self‐consistent hybrid gyrofluid‐kinetic electron model in dipolar coordinates is presented and used to simulate dispersive‐scale Alfvén wave pulse propagation from the equator to the ionosphere along an L = 10 magnetic field line. The model is an extension of the hybrid MHD‐kinetic electron model that incorporates ion Larmor radius corrections via the kinetic fluid model of Cheng and Johnson (1999). It is found that consideration of a realistic ion to electron temperature ratio decreases the propagation time of the wave from the plasma sheet to the ionosphere by several seconds relative to a ρ i =0 case (which also implies shorter timing for a substorm onset signal) and leads to significant dispersion of wave energy perpendicular to the ambient magnetic field. Additionally, ion temperature effects reduce the parallel current and electron energization all along the field line for the same magnitude perpendicular electric field perturbation.