HR: 0800h
AN: SM41A-1116    [Abstracts]
TI: Characteristics of Ion Outflow Near the Auroral Zones
AU: * Peria, W J
EM: peria@ess.washington.edu
AF: University of Washington, Earth and Space Sciences Condon Hall Box 351310, Seattle, WA 98195
AU: Carlson, C W
EM: cwc@ssl.berkeley.edu
AF: Space Sciences Lab, Centennial Drive at Grizzly Peak, Berkeley, CA 94720
AU: Peterson, W K
EM: Bill.Peterson@lasp.colorado.edu
AF: LASP, 1234 Innovation Drive, Boulder, CO 80303
AB: We have performed a large statistical survey of the net upward flux of ions from the auroral ionosphere, using data from the electrostatic analyzer aboard the FAST mission. Measurements of ions from 0.05- 30 keV, at all pitch angles simultaneously and with redundancy, are integrated to give measurements of the net flux. The flux data are binned according to 3 ancillary and 3 intrinsic properties. The ancillary properties are (1) location relative to the auroral zone, (2) concurrent interplanetary magnetic field condition, (3) ionospheric illumination at the 100 km footpoint of the corresponding flux tube. The intrinsic properties are (1) distribution type, (2) intensity, and (3) the characteristic energy. We use a dynamic coordinate, based on the instantaneous latitudinal location and width of the auroral zone, as defined by precipitating electron flux. Doing so allows us to resolve spatial features (in synoptic averages) which would otherwise be obscured by the variation (with auroral activity) in the latitude of the auroral zone. Binning the data according to outflow intensity shows that most of the ions leaving the ionosphere do so as part of relatively rare and intense ($> 10^{8}$ cm$^{-2}$-sr$^{-1}$-s$^{-1}$) beam-like events. The relative significance of beam-like and conic distributions will be compared at different locations and under various geophysical conditions.
DE: 2407 Auroral ionosphere (2704)
DE: 2431 Ionosphere/magnetosphere interactions (2736)
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting