HR: 0800h
AN: SH32A-0769    [Abstracts]
TI: Multi-spacecraft Observations of ³He-rich Solar Energetic Particle Events
AU: * Wiedenbeck, M E
EM: mark.e.wiedenbeck@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, M.S. 169-327 4800 Oak Grove Dr., Pasadena, CA 91109, United States
AU: Cohen, C M
AF: California Institute of Technology, M.C. 220-47 1200 East California Blvd., Pasadena, CA 91125, United States
AU: Cummings, A C
AF: California Institute of Technology, M.C. 220-47 1200 East California Blvd., Pasadena, CA 91125, United States
AU: Labrador, A W
AF: California Institute of Technology, M.C. 220-47 1200 East California Blvd., Pasadena, CA 91125, United States
AU: Leske, R A
AF: California Institute of Technology, M.C. 220-47 1200 East California Blvd., Pasadena, CA 91125, United States
AU: Mewaldt, R A
AF: California Institute of Technology, M.C. 220-47 1200 East California Blvd., Pasadena, CA 91125, United States
AU: Stone, E C
AF: California Institute of Technology, M.C. 220-47 1200 East California Blvd., Pasadena, CA 91125, United States
AU: von Rosenvinge, T T
AF: NASA/Goddard Space Flight Center, Code 661, Greenbelt, MD 20771, United States
AB: Solar energetic particle events with large abundance enhancements of ³He relative to ⁴He have been extensively studied since the 1970s using in situ observations from near-Earth spacecraft. These events, in which the compositional fractionation is believed to be the result of resonant wave-particle interactions, are thought to occur at the site of a solar flare when magnetic reconnection leads to the dissipation of a large amount of energy in plasma waves and the release of some previously-trapped particles onto open field lines. The very localized acceleration implied in such a model should result in energetic particle events that extend over relatively narrow range of heliolongitudes when observed near 1 AU. Several studies supporting this view have reported longitude distributions covering several tens of degrees for solar flares associated with ³He-rich events observed with a single, near-Earth spacecraft. The twin STEREO spacecraft, launched in October 2006 and moving away from Earth at 22.5 degrees per year, allow observations of individual ³He-rich events from two separated vantage points. We report observations of He isotopes in the MeV energy range from the first year of operation of the Low Energy Telescope (LET) instruments on STEREO-A and -B and compare with data from the ACE/SIS instrument, situated midway between the two STEREO spacecraft. This work was supported by NASA under grants NAS5-12929 and NAS5-03131.
DE: 2114 Energetic particles (7514)
DE: 7514 Energetic particles (2114)
DE: 7845 Particle acceleration
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting