HR: 0830h
AN: SA21B-0082    [PDF]
TI: Enhanced Auroras and Current Driven Instabilities in Thin Ionization Layers
AU: Okuda, H
EM: okuda@pppl.gov
AF: Princeton University, Princeton Plasma Physics Laboratory, PO Box 451, Princeton, NJ 08543 United States
AU: * Johnson, J R
EM: jrj@pppl.gov
AF: Princeton University, Princeton Plasma Physics Laboratory, PO Box 451, Princeton, NJ 08543 United States
AB: Natural auroras frequently exhibit enhanced intensity within relatively thin (1 km) horizontal layers [Hallinan, J. Geophys. Res., 8461, 1985]. These layers appear to be relatively stable atmospheric structures. Radar observations also show enhancements in the background electron density around the same altitude. The electron enhancement is related to an accumulation of heavy Fe and Mg into thin layers, which occurs for specific orientations of the ionospheric electric field. The similarity in altitude and duration of the enhanced aurora and heavy ion layers suggests a connection. We investigate instabilities that occur in dense, heavy ion layers in the presence of strong cross-field currents that accompany electron precipitation. The growth rate of the lower hybrid drift instability is increased in the dense, heavy ion layer, and ambient electrons may be heated into a suprathermal tail. Such electrons could produce enhanced emissions in the aurora. We present analytical full-wave solutions and full-particle electrostatic simulations of the nonlinear development of the instability.
DE: 2407 Auroral ionosphere (2704)
DE: 2439 Ionospheric irregularities
DE: 2455 Particle precipitation
DE: 2471 Plasma waves and instabilities
DE: 2483 Wave/particle interactions
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting