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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[14.01] The RHESSI Mission to Study Particle Acceleration and Explosive Energy Release in Solar Flares

R. P. Lin (Physics Dept. and Space Sciences Laboratory, University of California, Berkeley), RHESSI Team

Solar flares are the most energetic explosions in the solar system, releasing up to 1032-1033 ergs in 10-1000s. They are also the most powerful particle accelerators, producing ions up to tens of GeV and electrons up to tens of MeV. The accelerated ~10-100 keV electrons (and sometimes ~1 MeV ions) appear to contain ~10-50% of this energy, indicating that the particle acceleration and energy release processes are intimately linked. The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) is a NASA Small Explorer mission designed to provide imaging and spectroscopy of hard X-ray/gamma-ray continua emitted by energetic electrons, and of gamma-ray lines produced by energetic ions. The single instrument consists of an imager, made up of nine bi-grid rotating modulation collimators (RMCs), in front of a spectrometer with nine cryogenically-cooled germanium detectors, one behind each RMC. The spatial resolution is as fine as ~2.3 arcsec with a full-Sun (~1 deg) field of view, and the spectral resolution is ~1-10 keV FWHM over the energy range from soft X-rays (3 keV) to gamma-rays (17 MeV). RHESSI was launched on February 5, 2002, into a nearly circular, 38 deg inclination, 600-km altitude orbit and began continous observations a week later. Among the many new results are the first hard X-ray imaging spectroscopy of solar flares, and the first high resolution spectroscopy and imaging of flare gamma-ray lines. RHESSI is funded by NASA through contract NAG5-98033 to the University of California at Berkeley.


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