Difference between Spatial Distributions of the Hα Kernels and Hard X-Ray Sources in a Solar Flare

We present the relation of the spatial distribution of H-alpha kernels withthe distribution of hard X-ray (HXR) sources seen during the 2001 April 10solar flare. This flare was observed in H-alpha with the (Sartorius) telescopeat Kwasan Observatory, Kyoto University, and in hard X-rays (HXRs) with theHard X-ray Telescope (HXT) onboard Yohkoh. We compared the spatial distributionof the HXR sources with that of the H-alpha kernels. While many H-alpha kernelsare found to brighten successively during the evolution of the flare ribbons,only a few radiation sources are seen in the HXR images. We measured thephotospheric magnetic field strengths at each radiation source in the H-alphaimages, and found that the H-alpha kernels accompanied by HXR radiation havemagnetic strengths about 3 times larger than those without HXR radiation. Wealso estimated the energy release rates based on the magnetic reconnectionmodel. The release rates at the H-alpha kernels with accompanying HXR sourcesare 16-27 times larger than those without HXR sources. These values aresufficiently larger than the dynamic range of HXT, which is about 10, so thatthe difference between the spatial distributions of the H$\alpha$ kernels andthe HXR sources can be explained.Comment: 10 pages, 3 figure