AAS 204th Meeting, June 2004
Session 47 When the Sun Went Wild
Topical Session, Tuesday, June 1, 2004, 2:30-4:00pm, 4:15-6:00pm, 702/704/706

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[47.14] Source Motions and Foot-point Asymmetries in the 2003 October-November X-class Flares Observed by RHESSI

W. Liu, Y. W. Jiang, S. Liu, V. Petrosian (Dept. of Physics, Stanford University)

Motions and flux asymmetries of foot-point (FP) sources and related motions of loop-top (LT) sources play essential roles in understanding the energy release, particle acceleration, and transport processes in solar flares. During the October-November 2003 storms, 12 X-class flares, occurring at different locations across the solar disk, were observed by the high resolution spectroscopic imager, RHESSI, with generally good coverage. This provides an excellent opportunity for a comprehensive investigation of these flare characteristics. For a selected sample of these flares, we study the motions of the LT and FP sources. We use the component maps of images obtained by the CLEAN algorithm to determine the brightness-weighted centroids of the HXR sources and compare them with the corresponding peak positions. The sources are well defined in these maps, where there is no residual which is usually added back to the resulting CLEAN images and makes it difficult to infer accurate source centroids. The FP motions are combined with the SOHO/MDI magnetograms to estimate the electric field along the reconnecting current sheet. We also study the flux asymmetries between the conjugate FPs, using the more computationally intensive PIXON algorithm. A comparison between the results obtained with CLEAN and PIXON will be presented, and implications for particle acceleration processes and other theoretical aspects of solar flares will be discussed as well. The work is supported by NASA grants NAG5-12111, NAG5 11918-1, and NSF grant ATM-0312344 at Stanford University.

The author(s) of this abstract have provided an email address for comments about the abstract: weiliu@quake.Stanford.EDU

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