HR: 0830h
AN: SH11D-1132 [PDF]
TI: Temporal Variability of Gamma-Ray Lines from the X-Class Solar Flare of 2002 July 23
AU: * Shih, A Y
EM: ayshih@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA 94720 United States
AU: * Shih, A Y
EM: ayshih@ssl.berkeley.edu
AF: Department of Physics, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Smith, D M
EM: dsmith@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Smith, D M
EM: dsmith@ssl.berkeley.edu
AF: Department of Physics and Santa Cruz Institute for Particle Physics, University of California, Santa
Cruz, Santa Cruz, CA 95064 United States
AU: Lin, R P
EM: rlin@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Lin, R P
EM: rlin@ssl.berkeley.edu
AF: Department of Physics, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Hurford, G J
EM: ghurford@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Krucker, S
EM: krucker@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Schwartz, R A
EM: richard.schwartz@gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Greenbelt Rd., Greenbelt, MD 20771 United States
AU: Share, G H
EM: gerald.share@nrl.navy.mil
AF: E. O. Hulburt Center for Space Research, Naval Research Laboratory, Washington, DC 20375 United States
AU: Murphy, R J
EM: murphy@ssd5.nrl.navy.mil
AF: E. O. Hulburt Center for Space Research, Naval Research Laboratory, Washington, DC 20375 United States
AB:
On 2002 July 23, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) detected a GOES X4.8 solar flare, and
analysis of the data has produced the first spectrally resolved measurement of nuclear de-excitation gamma-ray lines in a
solar flare. These narrow lines result from accelerated ions colliding with the ambient medium (which includes Fe, Mg, Ne,
Si, C, and O nuclei), and thus their relative fluxes probe the composition of the solar atmosphere. We investigate the
temporal variability of the flux of these lines by analyzing the observed spectrum for two separate time intervals of the
flare (00:27:20-00:32:56 UT and 00:32:56-00:43:20 UT). The relative fluxes in the gamma-ray lines change dramatically
between these two intervals, suggesting that the circumstances of ion acceleration change as the flare progresses. We
consider the possibility of variations in the nuclear abundances, as well as other possible causes such as a varying
alpha/proton ratio or a varying energy spectrum for the accelerated ions. Finally, we compare these variations with the
source locations as determined by RHESSI's gamma-ray imaging.
The work at the University of California, Berkeley, was supported by NASA contract NAS 5-98033.
DE: 7514 Energetic particles (2114)
DE: 7519 Flares
DE: 7529 Photosphere
DE: 7554 X rays, gamma rays, and neutrinos
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting