HR: 09:45h
AN: SM51B-06    [Abstracts]
TI: Modeling Ion Outflows Associated with Electromagnetic Ion Cyclotron Waves
AU: * Johnson, J R
EM: jrj@pppl.gov
AF: Princeton University, Plasma Physics Laboratory, PO Box 451, Princeton, NJ 08543 United States
AU: Cheng, C Z
EM: fcheng@pppl.gov
AF: Princeton University, Plasma Physics Laboratory, PO Box 451, Princeton, NJ 08543 United States
AB: Satellites in the auroral region often detect energetic heavy ion outflows together with electromagnetic ion cylotron wave activity (1-100Hz). Because the Poynting flux of the waves is into the ionosphere, the waves can energize the ions at lower altitude leading to ion outflow from the topside ionosphere. One difficulty with relating the ion outflows to the wave activity is the nonlocality of the heating process---much of the heating occurs between the ionosphere (where the ions originate) and the spacecraft. A common practice is to assume a heating rate based upon the spectrum observed by the satellite. However, nonlocal wave solutions suggest that propagation and dissipation of the wave spectrum depends sensitively on the heavy ion plasma profiles in the topside ionosphere as well as the collisional ionospheric model. Consequently, the heating rate is strongly dependent on the plasma density profile. Because the heating rate determines the plasma profiles and the plasma profiles determine the heating rate, it is necessary to account for the feedback in a self-consistent manner. We successively iterate (1) a wave propagation code based on background plasma profiles (which solves the full electromagnetic equations including a realistic ionospheric model) and (2) a Monte Carlo simulation code to obtain the ion profiles based on heating rates obtained from the results of the wave propagation code. The method converges rapidly to a stable state, and the results suggest that the temporal evolution of the plasma profiles may involve a two-step process where helium is first heated then oxygen.
UR: http://w3.pppl.gov/~jrj/icw.html
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2487 Wave propagation (6934)
DE: 2704 Auroral phenomena (2407)
DE: 7867 Wave/particle interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly