Ion Temperature Effects on Magnetotail Alfven Wave
 Propagation and Electron Energization

Authors:  P.A. Damiano, J.R. Johnson, and C.C. Chaston

Abstract:   A new 2D self-consistent hybrid gyrofluid-kinetic electron model in dipolar coordinates is presented and used to simulate dispersive scale Alfven 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 [Damiano et al., 2007] 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 Pi = 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.
_________________________________________________________________________________________________

Submitted to:  Journal of Geophysical Research - Space Physics
_________________________________________________________________________________________________

Download PPPL-5176  (pdf 2.8 MB 27 pp)
_________________________________________________________________________________________________