HR: 1330h
AN: SM43B-06    [Abstracts]
TI: RHESSI Observations of Relativistic Electron Precipitation at L=1.0-2.6 Following Large Solar Energetic Particle Events
AU: * Goodhue, A C
EM: agoodhue@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA 94720 United States
AU: Lin, R P
EM: rlin@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA 94720 United States
AU: Smith, D M
EM: dsmith@scipp.ucsc.edu
AF: Department of Physics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 United States
AU: Hudson, H S
EM: hhudson@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA 94720 United States
AB: The past eighteen months have produced the largest solar energetic particle events in the current solar cycle. We present a preliminary investigation of the effects of large solar storms on trapped electron populations in the magnetosphere using observations from the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) following the 28 October 2003, 27 July 2004, and 10 November 2004 storms. Although RHESSI's germanium detectors were designed to measure solar hard x-rays and gamma rays, they are large enough (7.1 cm diameter x 8.5 cm) to stop penetrating electrons and measure their energy up to 17 MeV, as well as detect bremsstrahlung radiation from the precipitating electrons. We first obtain raw counts spectra, which are a superposition of bremsstrahlung and direct electron detection signatures. We then apply a GEANT simulation model of the spacecraft and instrument in order to infer the original spectra of incoming electrons from the measured spectra. After the October 2003 storm, RHESSI detected electrons up to ~5 MeV that were transported into the slot region (below L=2.6), and subsequently began to diffuse away. In the month following the storm, the spectrum became softer as high-energy electrons receded from the L=1.0-2.6 region. By the end of November 2003, the highest-energy electrons detected dropped to ~2 MeV. At the beginning of June 2004, six months after the original storm, the relativistic electrons disappeared completely. A similar spectral analysis is done for the July 2004 and November 2004 storms.
DE: 2716 Energetic particles, precipitating
DE: 2788 Storms and substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly