34th Solar Physics Division Meeting, June 2003
Session 14 RHESSI Results I
Oral, Wednesday, June 18, 2003, 9:00am-12:00noon, Auditorium

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[14.09] First Gamma-Ray Images of a Solar Flare: 2002 July 23

G. J. Hurford (Space Sciences Lab, UC, Berkeley), R. A. Schwartz (NASA-GSFC / SSAI), S. Krucker (Space Sciences Lab, UC, Berkeley), R. P. Lin (Space Sciences Lab, Physics Dept, UC, Berkeley), D. M. Smith (Space Sciences Lab, UC, Berkeley), N. Vilmer (LESIA, U. Paris)

Imaging of gamma-ray lines, produced by nuclear collisions of energetic ions with the solar atmosphere, provides the only direct indication of the spatial properties of accelerated ions near the Sun. The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) was used to make the first gamma-ray line images of a solar flare. The X4.8 flare of 2002 July 23, was imaged in the 2218-2228 band containing the narrow neutron-capture deuteriom line at 2223 keV, and in the 3250-6500 keV band which includes the prompt de-excitation lines of C and O. These are compared with images at 300-500 and 700-1400 keV, which are dominated by electron-bremsstrahlung. The centroids of 35-arcsecond resolution images made at these two lower-energy bands were displaced by ~20 arcseconds from the 2223 keV image of the neutron capture line. Such an offset indicates a difference in acceleration and/or propagation between the accelerated electron and ion populations near the Sun.

This work was supported by NASA grant NAS5-98033-05/03.

The author(s) of this abstract have provided an email address for comments about the abstract: ghurford@ssl.berkeley.edu

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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.