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D. M. Smith (U. C. Santa Cruz), A. Y. Shih (U. C. Berkeley), R. J. Murphy, G. H. Share (Naval Research Laboratory), R. A. Schwartz (NASA/Goddard), R. P. Lin (U. C. Berkeley)
During large flares, nuclei in the solar atmosphere which have experienced interactions with accelerated protons and other ions emit de-excitation gamma-rays characteristic of each element. The brightness and evolution of these lines constrains the spectrum and composition of the accelerated particles and the composition of the local atmosphere. Since the emission of these lines occurs promptly, they are emitted with a Doppler shift that records the recoil velocity of the ion, and thus also constrains the angular distribution of the accelerated ions.
We will present studies of the Doppler profiles of de-excitation lines from C, O, Ne, Mg, Si, and Fe using data from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), which made the first observations of solar de-excitation lines at high energy resolution in the X4.8 flare of 23 July, 2002. In addition to this flare, we will present data from the major X-class flares of 28 October, 29 October, and 2 November 2003, and interpret the results in terms of the magnetic field orientation and angular distribution of the accelerated ions in these flares.
This work is supported by NASA contract NAS5-98033.
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Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.