Measurements of Broad Gamma-Ray Lines from Heavy-Ion Interactions in
R. J. Murphy and G. H. Share
We present broad-line g-ray spectra derived from observations of the
intense June 1991 solar flares obtained with the OSSE instrument on
CGRO. Broad g-ray lines are produced by interactions of accelerated
ions heavier than He with ambient hydrogen and helium. The large widths of
these lines ( ~ 25% FWHM) are due to the recoil velocity of the heavy
excited nuclei that have lost little of their original velocity in the
interaction. In contrast, g-ray lines produced by accelerated
protons and alpha particles interacting with ambient nuclei produce narrow
lines ( ~ 2% FWHM). Implications on the accelerated-particle
composition are discussed and the results are compared with results from a
similar analysis of flare data obtained with the SMM/GRS. Such broad
g-ray line observations provide the only direct measurement of the
composition of particles accelerated at the Sun and can be compared with
measurements of energetic particles escaping from the Sun with instruments
on spacecraft such as ACE.
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On 16 Jul 1999, 09:19.