WHAT IS THE SPATIAL RELATIONSHIP BETWEEN HARD X-RAY FOOTPOINTS AND VERTICAL ELECTRIC CURRENTS IN SOLAR-FLARES

We examine the spatial relationship between solar hard X-ray sources o bserved with the Hard X-Ray Telescope aboard Yohkoh and photospheric e lectric currents observed at Mees Solar Observatory. In 1993, Canfield et al. concluded that energetic electron precipitation tends to occur at the edge of sites of high vertical current. They did not, however, have a direct diagnostic of particle precipitation; they used Ha Star k-wing emission as a proxy. In this paper, we analyze hard X-ray image s and vector magnetograms of six flares of M/X X-ray class to reach tw o basic conclusions. First, we confirm that electron precipitation avo ids sites of high vertical current density at photospheric levels, pre ferentially occurring adjacent to these current channels. Hence, we co nclude that our observations rule out flare models in which nonthermal electrons are accelerated within the large-scale active-region curren t systems that are observed by present vector magnetographs. Second, a t conjugate magnetic footpoints the stronger hard X-ray emission is as sociated with smaller vertical current density and weaker magnetic fie ld. This result is consistent with a ''cornucopia''-shaped magnetic mo rphology in which precipitating electrons are preferentially deflected away from the narrower footpoint by magnetic mirroring.