HR: 14:40h
AN: SA43B-05    [Abstracts]
TI: Critical Temperature for the Onset of Spacecraft Charging at Geosynchronous Altitudes in a `Cut-Off' Maxwellian Space Plasma
AU: * Lai, S T
EM: Shu.Lai@hanscom.af.mil
AF: Air Force Research Laboratory, Mail Stop: VSBXT 29 Randolph Road, Hanscom AFB., MA 01731-301 United States
AB: Spacecraft charging at geosynchronous altitudes occurs more likely on the dawn side than on the dusk side of midnight. The conventional wisdom says that hot electrons drift to the morning side because of convection and the Earth's magnetic field curvature and gradient. We point out that there is a supplementary reason: the cutoff energy of the electron distribution is lower on the dusk side than on the dawn side of midnight. We have derived a critical temperature formula for a `cutoff' Maxwellian distribution and obtained the critical temperature values for various surface materials at normal and isotropic incidence of ambient electrons with the cutoff energy as a variable parameter. Lowering the cutoff energy raises the critical temperature.
DE: 7800 SPACE PLASMA PHYSICS
DE: 7853 Spacecraft/atmosphere interactions
DE: 7855 Spacecraft sheaths, wakes, charging
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting