HR: 13:40h
AN: SH32B-01 INVITED     [PDF]
TI: The Importance of Electrostatic Instabilities in Magnetic Reconnection
AU: * Brackbill, J U
EM: brackbill@cybermesa.com
AF: University of New Mexico, Department of Mathematics and Statistics, Albuquerque, NM 87131 United States
AB: Recent simulation studies of kinetic instabilities in reconnecting plasmas suggests that investigation of electromagnetic waves, such as the drift-kink-instability (DKI) and the Kelvin Helmholtz instability (KHI), may yield a theory of reconnection. However, the combined results of linear theory, and explicit and implicit plasma simulations fail to support a direct link between kinking and reconnection. Instead, the surprise has been the unexpected importance of the lower-hybrid-drift instability (LHDI). This electrostatic instability, which simulations suggest saturates at a level that is too low to provide the anomalous resistivity necessary for reconnection, alters current sheets in several important ways. The LHDI causes velocity shear, current sheet thinning, and anisotropic heating of electrons. The velocity shear drives a KHI mode, which explains current sheet kinking at high mass ratios, and the current sheet thinning and anisotropic heating significantly enhance the growth rate of the tearing instability, which may explain onset. Clearly, there is strong motivation for studies of the LHDI under magnetotail conditions.
DE: 2764 Plasma sheet
DE: 2772 Plasma waves and instabilities
DE: 7835 Magnetic reconnection
DE: 7843 Numerical simulation studies
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting