HR: 1340h
AN: SM13A-1119    [Abstracts]
TI: Stationary diffusion process at the Earth magnetopause
AU: * smets, r
EM: rsm@cetp.ipsl.fr
AF: cetp/cnrs, 10-12 avenue de l'europe, velizy, fr 78140, France
AU: belmont, g
AF: cetp/cnrs, 10-12 avenue de l'europe, velizy, fr 78140, France
AU: rezeau, l
AF: cetp/cnrs, 10-12 avenue de l'europe, velizy, fr 78140, France
AB: Using hybrid simulations, we examine how particles can diffuse across the Earth's magnetopause because of finite Larmor radius effects. We focus on tangential discontinuities and consider a reversal of the magnetic field that closely models the magnetopause under southward interplanetary magnetic field. When the Larmor radius is on the order of the field reversal thickness, we show that particles can cross the discontinuity. We also show that with a realistic initial shear flow, a Kelvin-Helmholtz instability develops that increases the efficiency of the crossing process. We investigate the distribution functions of the transmitted ions and demonstrate that they are structured according to a D-shape. It accordingly appears that magnetic reconnection at the magnetopause is not the only process that leads to such specific distribution functions. A simple analytical model that describes the built-up of these functions is proposed.
DE: 7807 Charged particle motion and acceleration
DE: 7811 Discontinuities (2109)
DE: 7835 Magnetic reconnection (2723, 7526)
DE: 7859 Transport processes
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting