HR: 0830h
AN: SM41B-0562    [PDF]
TI: Determination of the Short- and Long-Range Parallel Potential in the Downward Auroral-Current Region From FAST Satellite Data and Theory
AU: * Jasperse, J R
EM: john.jasperse@hanscom.af.mil
AF: Air Force Research Laboratory, Hanscom AFB, Bedford, MA 01731 United States
AU: Lund, E J
AF: Space Science Center, University of New Hampshire, Durham, NH 03842 United States
AU: Lynch, K A
AF: Physics Department, Dartmouth, Hanover, NH 03842 United States
AU: Carlson, C W
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: Bonnell, J
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: Bouhram, M
AF: CETP-CNRS, 4 Avenue de Neptune, Saint-Maur Cedex, 94107 France
AB: Over the years, satellite observations have suggested the following characteristics of the downward auroral-current region: diverging electrostatic shocks and a downward pointing parallel E-field; upflowing low energy (less than a few kilovolts) field-aligned electrons; intense transverse ion heating; small-scale density cavities; intense ELF and VLF electric-field turbulence; and sometimes rapidly moving bipolar solitary structures. We give a multimoment fluid theory for the auroral return-current region that is based on the Vlasov-Maxwell equations for the particle dynamics and a Fokker-Planck model for the wave-particle interactions. Using FAST particle and wave data as a boundary condition, these equations may be integrated from the satellite altitude down to the shock- and transition-region altitude and up to several earth radii in order to determine both the short- and long-range, self-consistent parallel potential. For a particular winter satellite pass near local midnight, this model finds that typical voltage distributions are: a 240 volt increase from the bottom of the shock region to the top of the transition region (2800 km); a 30 volt increase from the top of the transition region to the satellite altitude (4130 km); and a 330 volt increase from the satellite altitude to 3 earth radii for a total potential increase from the topside ionosphere to 3 earth radii of about 600 volts.
DE: 2704 Auroral phenomena (2407)
DE: 2708 Current systems (2409)
DE: 2712 Electric fields (2411)
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting