HR: 0800h
AN: SA51B-0524    [Abstracts]
TI: Enhanced Aurora and Thin, Dense, Heavy Ion Ionization Layers
AU: Okuda, H
AU: * Johnson, J R
EM: jrj@pppl.gov
AF: Princeton University, Plasma Physics Laboratory, Princeton, NJ 08543, United States
AU: Choueiri, E
EM: choueiri@princeton.edu
AF: Princeton University, Electric Propulsion and Plasma Dynamics Laboratory, Princeton, NJ 08544, United States
AB: Thin layers of enhanced luminosity are commonly observed during auroral displays. The enhanced luminosity occurs at altitudes where thin, dense, heavy ion layers are often observed in the E-region. Based on the spectral characteristics of the enhanced layers, it is believed that the enhanced emissions result when wave-particle interactions heat ambient electrons to energies at or above the 17 eV ionization energy of N₂. We investigate instabilities that could occur in dense, heavy ion layers in the presence of strong cross-field currents that accompany electron precipitation. We present analytical studies of the cross-field current driven instability including kinetic effects, ion-neutral, and electron-neutral collisions. Electrostatic simulations have shown that the instability heats ambient electrons into a suprathermal tail that could produce enhanced emissions. We discuss the nonlinear development of the instability and compare the expected electron energy flux with typical auroral observations.
UR: http://w3.pppl.gov/~jrj/ionization.html
DE: 2407 Auroral ionosphere (2704)
DE: 2439 Ionospheric irregularities
DE: 2455 Particle precipitation
DE: 2471 Plasma waves and instabilities (2772)
DE: 2483 Wave/particle interactions (7867)
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting