AAS 204th Meeting, June 2004
Session 39 Solar Magnetic Fields and Activity
SPD Poster, Tuesday, June 1, 2004, 10:00am-7:00pm, Ballroom

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[39.02] Local Changes in Longitudinal Magnetic Field during Solar Flare Events

J.J. Sudol, J.W. Harvey, R. Howe (National Solar Observatory, GONG Program)

We present preliminary results from an investigation of local changes in the longitudinal magnetic field during solar flare events using GONG+ magnetograms. The one-minute cadence, 5" resolution, and near continuous coverage of the GONG+ magnetograms make them well suited for this kind of investigation. We have reviewed all of the available GONG+ magnetograms for two or more hours on either side of the X-class solar flare events that occurred between April 2001 and December 2003. In most cases, we have observed a discrete shift in the apparent, longitudinal magnetic field during the flare event that persists for more than two hours after the event. The shifts in the magnetic field are consistent with one another to within their uncertainties and average 120 ± 20 gauss. Such consistency, though, could be a selection effect. In some cases, we have observed weaker shifts in the apparent magnetic field that occur at later times at increasing distance from the flare center. The rate of propagation of these shifts in the magnetic field from the flare center is ~30 km s-1. We discuss the observed phenomena and possible explanations for them.

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

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