HR: 1340h
AN: SH54A-1520    [Abstracts]
TI: The Origin of Low Energy 3He
AU: * de Nolfo, G A
EM: georgia@milkyway.gsfc.nasa.gov
AF: CRESST/UMBC & NASA/GSFC, Code 661, Building 2, Greenbelt, MD 20771, United States
AU: Wiedenbeck, M E
EM: Mark.E.Wiedenbeck@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AU: Binns, W R
EM: wrb@wuphys.wustl.edu
AF: Department of Physics & McDonnell Center for Space Sci., Washington University, St. Louis, MO 63130, United States
AU: Cohen, C M
EM: cohen@srl.caltech.edu
AF: Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Cummings, A C
EM: ace@srl.caltech.edu
AF: Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Israel, M H
EM: mhi@wuphys.wustl.edu
AF: Department of Physics & McDonnell Center for Space Sci., Washington University, St. Louis, MO 63130, United States
AU: Leske, R A
EM: ral@srl.caltech.edu
AF: Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Mewaldt, R A
EM: rmewaldt@srl.caltech.edu
AF: Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Stone, E C
EM: ecs@srl.caltech.edu
AF: Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: von Rosenvinge, T T
EM: tycho@milkyway.gsfc.nasa.gov
AF: CRESST/UMBC & NASA/GSFC, Code 661, Building 2, Greenbelt, MD 20771, United States
AB: Energetic ³He in local interplanetary space is expected to originate predominantly from the Sun and the Galaxy. Using solar quiet-time observations of ³He over a wide energy range, it is possible to study the distinct spectral shapes of the two different populations. Preliminary results suggest that at low energies of ~5 Mev/nuc, the origin of ³He is dominated by impulsive solar energetic particle events. However, above a transition energy of ~15 MeV/nuc, the galactic component appears to dominate. We present quiet-time ³He and ⁴He observations over a solar cycle from the Cosmic Ray Isotope Spectrometer (CRIS) on ACE and compare these results with low energy observations from the Solar Isotope Spectrometer (SIS) in order to ascertain the origins of low energy (~5-100 MeV/nuc) ³He.
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting