HR: 1330h
AN: SM32B-1158    [PDF]
TI: High Energy Precipitation and Consequences During the April 2002 Storms
AU: * Fang, X
EM: xhfang@umich.edu
AF: University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109-2143 United States
AU: Kozyra, J
EM: jukozyra@engin.umich.edu
AF: University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109-2143 United States
AU: Liemohn, M
EM: liemohn@umich.edu
AF: University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109-2143 United States
AU: Evans, D
EM: david.s.evans@noaa.gov
AF: SEC/NOAA, 325 Broadway, Boulder, CO 80305 United States
AU: Solomon, S
EM: stans@ucar.edu
AF: National Center for Atmospheric Research, 3450 Mitchell Ln, Boulder, CO 80301 United States
AB: Hemispheric maps of high energy proton and electron precipitation were created to characterize more accurately the energy inputs to the ionosphere-atmosphere system by interpolating NOAA-POES observations over 3-hour intervals during the April 2002 geomagnetic storms. The 3-hour cadence needed to achieve the required coverage is assumed to provide useful information, because of the relatively longer growth and development time scales for the ring current and the slow variation in long-duration solar particle events. These two populations probably account for most of the precipitation in the energy range $>$30 keV covered by the maps. The maps reveal interesting changes in the precipitation pattern with solar wind conditions and also a more isotropic in local time input during the intervals of sawtooth oscillations. Ring current ion precipitation is thought to be mainly a result of ion scattering in stretched geomagnetic fields as their gyroradii and the scale length of the field curvature become comparable near the equatorial plane. During the sawtooth activity, GOES observed tail-like fields to extend into the geosynchronous orbit region from midnight to dayside local times. Numerical results of our 3D Monte Carlo model will be presented for representative locations in the global particle precipitation. The transverse particle beam spreading effect is considered to be the result of the charge exchange and electron stripping collisions with the Earth's atmosphere. Initial comparisons between our model calculations and data will be provided as well.
DE: 2407 Auroral ionosphere (2704)
DE: 2455 Particle precipitation
DE: 2704 Auroral phenomena (2407)
DE: 2736 Magnetosphere/ionosphere interactions
DE: 7843 Numerical simulation studies
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting