Dual-stage reconnection during solar flares observed in hard x-ray

Abstract

In this Letter, we present hard X-ray (HXR) observation by the Reuven Ramaty High Energy Solar Spectroscopic Imager of the 2003 October 29 X10 flare. Two pairs of HXR conjugate footpoints have been identified during the early impulsive phase. This geometric configuration is very much in the manner predicted by the "tether-cutting" scenario first proposed by Moore & Roumeliotis. The HXR light curves show that the outer pair of footpoints disappeared much faster than the other pair. This temporal behavior further confirms that this event is a good example of the "tether-cutting" model. In addition, we reconstructed a three-dimensional magnetic field based on the nonlinear force-free extrapolation and found that each pair of HXR footpoints were indeed linked by corresponding magnetic field lines. © 2010. The American Astronomical Society. All rights reserved.