HR: 0830h
AN: SM51C-0535    [PDF]
TI: Pitch-Angle Scattering of Relativistic Electrons by Electromagnetic Ion Cyclotron Waves in the Magnetosphere
AU: * Loto'aniu, T M
EM: lotoaniu@ucla.edu
AF: Department of Atmospheric Sciences University of California Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90095 United States
AU: Thorne, R M
EM: rmt@atmos.ucla.edu
AF: Department of Atmospheric Sciences University of California Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90095 United States
AU: Fraser, B J
EM: brian.fraser@newcastle.edu.au
AF: Department of Physics University of Newcastle, University Drive, Callaghan, NSW 2308 Australia
AU: Horne, R
EM: r.horne@bas.ac.uk
AF: British Anartic Survey National Environment Research Council, High Cross, Madingley Road, United Kingdom, Cambridge, CB3 0ET United Kingdom
AB: Electromagnetic ion cyclotron (EMIC) waves which propagate at frequencies near the proton gyrofrequency can interact with relativistic electrons in the outer radiation belt, through cyclotron resonance, and cause pitch-angle scattering. During magnetic storms EMIC wave amplitudes can exceed the level required for strong diffusion scattering and significant electron losses to the atmosphere can occur over many drift orbits. The Combined Release and Radiation Effects Satellite (CRRES) was ideally situated to observe EMIC waves in the middle magnetosphere. In this study observations from CRRES are used to obtain spectral properties of EMIC waves (1-10 nT), and thus determine typical pitch-angle diffusion coefficients, $D\alpha \alpha$, during different phases of a storm. These diffusion rates are then compared to theoretical calculations assuming a simple functional form for $D\alpha \alpha$ based on quasi-linear theory that is valid for parallel propagating electromagnetic waves.
DE: 2716 Energetic particles, precipitating
DE: 2730 Magnetosphere--inner
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2772 Plasma waves and instabilities
DE: 2778 Ring current
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting