HR: 1330h
AN: SM52B-0582    [PDF]
TI: 3D Hybrid Simulations of Finite Amplitude Alfven Wave Filamentation.
AU: * Alexandrova, O
EM: olga.alexandrova@obspm.fr
AF: LESIA, Observatoire de Paris, 5 place Jules Janssen, Meudon, 92195 France
AU: Travnicek, P
EM: trav@despace.obspm.fr
AF: Institute of Atmospheric Physics, Bocni II. cp. 1401, Prague, 14131 Czech Republic
AU: Mangeney, A
EM: mangeney@despace.obspm.fr
AF: LESIA, Observatoire de Paris, 5 place Jules Janssen, Meudon, 92195 France
AB: Recents observations of the Earth bowshock (Alexandrova et al., 2003, to be published in J. Geophys. Res.) suggest that the Alfven waves observed downstream of the shock may be unstable to a "filamentation" instability. The outcome of this instability, which occurs for wavelength larger but comparable to the ion inertial length and a large plasma beta, is the formation of field aligned magnetic tubes at the expanse of the initial Alfven wave energy. This instability and its nonlinear development have been extensively studied and simulated in the three dimensional Hall MHD regime (Laveder et al., 2002). In the present work we present the first 3D hybrid simulations (the protons are treated as particles and the electrons as a massless fluids) of this instability, with 400 cells in each direction, allowing to resolve the fine structure (of the order of a fraction of proton inertial length) of the final magnetic tubes, resulting from the instability of a parallel propagating Alfven wave, of wavelength of the order of 10-20 inertial length. We shall discuss the influence of kinetic effects on the instability and its development as well as the comparison with the space observations.
DE: 2752 MHD waves and instabilities
DE: 2772 Plasma waves and instabilities
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting