AAS 200th meeting, Albuquerque, NM, June 2002
Session 68. Flares
Display, Thursday, June 6, 2002, 9:20am-4:00pm, SW Exhibit Hall

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[68.09] What Can We Learn about Magnetic Reconnection in the Solar Corona from Joint SOHO/MDI and TRACE Observations?

J.L.R. Saba (LMSAL at NASA/GSFC), T. Gaeng (L-3 Com Analytics Corp), T.D. Tarbell (LMSAL)

High-resolution, high-cadence images from the Transition Region and Coronal Explorer (TRACE) together with high quality line-of-sight magnetograms from the Michelson Doppler Imager (MDI) on SOHO let us examine signatures of magnetic reconnection and attempt to infer associated physical parameters.

Recently we analyzed joint TRACE UV and MDI magnetogram data for the rise phase of a two-ribbon, GOES M1 class flare from NOAA active region 9236 at 2000 Nov 23 23:28 UT. We estimated the magnetic reconnection rate from the change in the photospheric magnetic flux swept out by the evolving 1600 Å-band flare ribbons. For simple assumptions with standard coronal parameters, the reconnection appeared to be fast, with the inferred inflow velocity a significant fraction of the Alfvén velocity.

We extend our analysis to the peak and decay phases of that event, and consider other reconnection events observed jointly by TRACE and MDI, with guidance from coronal imaging of the reconnection region by the SOHO/EUV Imaging Telescope or the Yohkoh/Soft X-ray Telescope when not available from TRACE, and from extrapolation of the MDI magnetograms. We look for correlations of, e.g., the local reconnection rate with the instantaneous, peak, and integrated intensities and the time rate of change of intensity of the flare ribbons as a check on our analysis. The TRACE 1600 Å\ intensity includes contributions from both chromospheric and transition region (C IV) emission; it should be a proxy for the energy transmitted to the lower atmosphere and perhaps correlated with the total energy released by reconnection in the corona.

This work is supported by NASA contracts NAG5-10483 (MDI) and NAS5-38099 (TRACE).

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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.