HR: 1340h
AN: SM33A-1103    [Abstracts]
TI: Geosynchronous Orbit: Life near the boundary of stable trapping
AU: * Cayton, T E
EM: tcayton@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Christensen, R A
EM: rchristensen@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-3, Los Alamos, NM 87545, United States
AU: White, R R
EM: rwhite@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Cunningham, G S
EM: cunning@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Belian, R D
EM: rdbelian@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Ingraham, J C
EM: cingraham@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Kippen, R M
EM: mkippen@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Tuszewski, M G
EM: mgtu@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Chen, Y
EM: cheny@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Friedel, R H
EM: rfriedel@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Reeves, G D
EM: gdreeves@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AU: Varotsou, A
EM: athina@lanl.gov
AF: Los Alamos National Laboratory, Group ISR-1, Los Alamos, NM 87545, United States
AB: New numerical methods[1-3] enable us to model and classify electron spectra near the geostationary orbit in terms of both energy and pitch angle. Our analysis of pitch-angle-resolved SOPA data focuses special attention on small pitch angles that mirror at or above the latitude of GPS space vehicles traversing this region of Earth's magnetosphere. In addition to the stably-trapped relativistic electron population, characterized by a dearth of small-pitch-angle particles and remarkably exponential high-energy tails, we also observe regions of quasi- trapping, characterized by a dearth of high-energy particles and little, if any, pitch-angle variation at small pitch angles, i.e., a filled-up loss cone. At least two types of precipitation events occur regularly in the geostationary region, both characterized by extreme pancake distributions and a loss cone filled up with low-energy electrons, but empty of high-energy electrons; the two types are distinguished by the presence or absence of an energy- dependent critical pitch angle below which the population vanishes. When the feature just mentioned is absent, we observe a different energy-dependent feature in the near-perpendicular population. Perhaps these two features indicate scattering losses by field-line curvature on the one hand, and by wave-particle interactions on the other. Several illustrative examples will be shown from high-speed-stream driven events of 2007. 1. T. E. Cayton, "Application of a Maximum-Likelihood-Estimation-using-Expectation-Maximization Algorithm to the Deconvolution of CXD Electron Spectra II: Continuity and Smoothness," technical report LA-UR-07-3683. 2. R. R. White, "Space Weather Multi-tool," technical report LA-UR-07-2037. 3. T. E. Cayton and R. D. Belian, "Numerical Modeling of the Synchronous Orbit Particle Analyzer (SOPA, Version 2) that Flew on S/C 1990-095: Final Report," Los Alamos Report LA-14335.
DE: 2700 MAGNETOSPHERIC PHYSICS (6939)
DE: 2716 Energetic particles: precipitating
DE: 2720 Energetic particles: trapped
DE: 2753 Numerical modeling
DE: 2774 Radiation belts
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting