HR: 1340h
AN: SM33A-1109    [Abstracts]
TI: Temporal and spatial variation of outer radiation belt electron pitch angles: Cluster RAPID observations.
AU: * Taylor, M G
EM: mtaylor@rssd.esa.int
AF: ESA/ESTEC, Keplerlaan 1, Noordwijk, 2200AG, Netherlands
AU: Friedel, R H
EM: friedel@lanl.gov
AF: Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545, United States
AU: Reeves, G D
EM: reeves@lanl.gov
AF: Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545, United States
AU: Aasnes, A
EM: aasnes@rssd.esa.int
AF: ESA/ESTEC, Keplerlaan 1, Noordwijk, 2200AG, Netherlands
AU: Laakso, H
EM: hlaakso@rssd.esa.int
AF: ESA/ESTEC, Keplerlaan 1, Noordwijk, 2200AG, Netherlands
AU: Escoubet, C P
EM: pescoubet@esa.int
AF: ESA/ESTEC, Keplerlaan 1, Noordwijk, 2200AG, Netherlands
AU: Masson, A
EM: arnaud.masson@esa.int
AF: ESA/ESTEC, Keplerlaan 1, Noordwijk, 2200AG, Netherlands
AU: Opgenoorth, H J
EM: hopgenoo@rssd.esa.int
AF: ESA/ESTEC, Keplerlaan 1, Noordwijk, 2200AG, Netherlands
AB: The Earths radiation belts are the longest studied regions of the magnetosphere, in terms of in situ measurements, and are still the subject of intense study. Of particular interest are the source and dynamics of the relativistic particles in these regions. Previous studies have focused on two primary mechanisms of transport and acceleration: radial diffusion from the magnetosphere and wave-particle energization. Recent studies have firmly established that in-situ energization is more dominant [Chen et al., 2007], yet the source of the electrons that are locally accelerated must ultimately be the near-earth plasma sheet. Access of untrapped plasmasheet electrons into the quasi-stable trapping region just outside geosynchronous orbit may provide not only the seed population for relativistic electrons but also the source of free energy for gyroresonant wave fields such as whistler chorus. Additionally, once electrons are accelerated to relativistic electrons, outward radial diffusion/transport may be an important loss mechanism for the outer edge of the radiation belts. In this study we investigate energetic electron measurements at the edge of the radiation belt (L=8-9) made by the Cluster RAPID IES instrument. In particular we examine local spatial and temporal variance measurements of the electron pitch angle distribution, as the 4 spacecraft pass through a narrow range of local time during each orbit (every ~56 hours), in order to better constrain the source, transport, and losses in this region.
DE: 2730 Magnetosphere: inner
DE: 2774 Radiation belts
DE: 7984 Space radiation environment
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting