AAS 204th Meeting, June 2004
Session 2 When the Sun Went Wild
SPD Topical Related Poster, Monday, May 31, 2004, 9:20am-6:30pm, Ballroom

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[2.03] Non-Relativistic Electron Beam Stability in Solar Flares

A.G. Daou, D. Alexander (Rice University), T.R. Metcalf (Lockheed Martin Solar and Astrophysics Lab)

The thick-target electron beam model has been used for decades as a viable description for the production of solar flare hard X-ray emission. The required very rapid transport of energy to the footpoints during solar flares is achieved in this model by fast electrons traversing the loop to deposit their energy in the dense chromosphere. For some of the largest flares the currents (up to 1017 Amps or 1036 electrons/sec) inferred can significantly exceed the Alfven-Lawson limit suggesting that the assumed electron beam is inherently unstable. In this paper, we use the spectral and spatial resolution of RHESSI to explore whether the conditions for a stable non-thermal electron beam exist in large solar flares. The incident electron spectra at flaring footpoints are derived from the RHESSI photon spectra while an upper limit to the footpoint area is detremined form the hard X-ray images. We determine the electron beam density needed to produce the hard X-ray emission for two large flares, July 17, 2002 (M8.5) and October 28, 2003 (X17.2) and determine whether such beams are viable in these cases.

We gratefully acknowledge support from NASA (NAS5-02048).

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

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