HR: 0800h
AN: SM41A-1168    [Abstracts]
TI: Comprehensive Flux Occurrence Statistics at Geosynchronous Orbit
AU: * Thomsen, M F
EM: mthomsen@lanl.gov
AF: Los Alamos National Laboratory, ISR-1 MS D466, Los Alamos, NM 87545 United States
AU: Denton, M H
EM: mhdenton@lanl.gov
AF: Los Alamos National Laboratory, ISR-1 MS D466, Los Alamos, NM 87545 United States
AU: Bodeau, M
EM: michael.bodeau@boeing.com
AF: Boeing Satellite Design Center, PO Box 92919 MC W-S24-D561, Los Angeles, CA 90009-2919 United States
AB: Geosynchronous orbit, the distance at which the orbital period around the Earth is 24 hours, is home to more than 200 satellites. From a space weather perspective, the environment in this orbit is highly variable and far from benign. Satellites exposed to these harsh conditions are subject to episodes of deep dielectric charging, surface charging, solar panel degradation, single event upsets, radiation degradation of optical coatings and paints, and other deleterious effects. Either suddenly or gradually over time, such effects can cause catastrophic or simply lifetime-shortening consequences for satellite systems. To protect against these environmental effects, spacecraft designers need to know quantitatively what the nature of the environment is likely to be over the design lifetime of their satellites. In recent years a number of such statistical analyses have been conducted, demonstrating the systematic dependence of geosynchronous plasma properties on orbital position, geomagnetic activity, and phase of the solar cycle. These studies have helped illuminate the physical processes that govern the nature of the plasma at geosynchronous orbit, but they do not provide a condensed description of the environment that is suitable for use by spacecraft designers. We report here a definitive statistical characterization of the geosynchronous environment that will be more useful for such purposes. The analysis is based on the LANL MPA geosynchronous plasma dataset, which now comprises more than 70 satellite-years of measurements extending well over a full solar cycle. We present the flux occurrence statistics of ions and electrons with energies in the range from ~1 eV to ~45 keV, covering the populations that are responsible for satellite surface charging and radiation damage to surface materials, and that provide the source for the higher-energy ring current and radiation belts. Significant differences have been found in long-term averages compared to the AE-8, AP-8, and ATS-6 models of the GEO plasma environment.
DE: 2720 Energetic particles: trapped
DE: 2730 Magnetosphere: inner
DE: 2764 Plasma sheet
DE: 7894 Instruments and techniques
DE: 7914 Engineering for hazard mitigation
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005