HR: 1340h
AN: SH33A-1074    [Abstracts]
TI: Energy Spectra and Composition of Low-Energy Ions during Solar Quiet Times
AU: * Mewaldt, R A
EM: RMewaldt@SRL.caltech.edu
AF: Caltech, 220-47 Downs, Pasadena, CA 91125, United States
AU: Mason, G M
EM: Glenn.Mason@jhuapl.edu
AF: Applied Physics Laboratory, Johns Hopkins University, Laurel, Md 20723, United States
AU: Cohen, C M
EM: Cohen@srl.caltech.edu
AF: Caltech, 220-47 Downs, Pasadena, CA 91125, United States
AU: Leske, R A
EM: ral@srl.caltech.edu
AF: Caltech, 220-47 Downs, Pasadena, CA 91125, United States
AU: Stone, E C
EM: ECS@srl.caltech.edu
AF: Caltech, 220-47 Downs, Pasadena, CA 91125, United States
AU: von Rosenvinge, T T
EM: tycho@milkyway.gsfc.nasa.gov
AF: NASA/Goddard Space Flight Center, Code 661, Greenbelt, Md 20771, United States
AU: Wiedenbeck, M E
EM: mark.e.wiedenbeck@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Dwyer, J R
EM: jdwyer@fit.edu
AF: Florida Institute of Technology, 150 W. University Blvd, Melbourne, FL 32901, United States
AU: Mazur, J E
EM: joseph.mazur@aero.org
AF: The Aerospace Corporation, 15049 Conference Center Drive, Chantilly, VA 20151, United States
AB: Although the Sun is never completely quiet, various studies over the last 40 years have reached the conclusion that there exist some minimum quiet-time intensities of low-energy ions <10 MeV/nucleon that may vary over the solar cycle, but are more or less reproducible. Recently, Fisk and Gloeckler have reported that quiet-time energy spectra of protons measured by Ulysses in the suprathermal energy range from 10 to 60 keV have a common spectral shape with a spectral index of –5 in velocity space (corresponding to a power law in energy with a spectral index of -1.5). We present the results of a survey that extends the work of Fisk and Gloeckler to somewhat higher energies, based on data from ACE and STEREO ranging from 0.1 to 30 MeV/nucleon. We find that the spectra of the H, He, O and Fe from 0.1 to 1 MeV/nucleon are typically somewhat steeper than reported by Fisk and Gloeckler. We compare the composition and spectral shapes of major species from H to Fe over the years from 1997 to 2007, and discuss the implications for the origin of the quiet-time intensities in the suprathermal energy range.
DE: 2114 Energetic particles (7514)
DE: 7514 Energetic particles (2114)
DE: 7807 Charged particle motion and acceleration
DE: 7845 Particle acceleration
DE: 7859 Transport processes
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting