Hard X-rays from neutralized ion beams in solar flares

Under suitable conditions, hard X-rays (HXRs) may be emitted by a neutraliz ed proton beam due to the "heating" of the electrostatically dragged electr ons in collisions with a nearly neutral background atmosphere. A simple est imate is made generalizing this HXR emission mechanism to heavier ions drag ging a neutralizing electron current. Recent gamma-ray results on the energ y content of flare ions of greater than or equal to 1 MeV nucleon(-1) are u sed to estimate the total HXR yield above 20 keV or so which would be expec ted from these processes, and in 19 flares the results are compared with HX R data in the same events. It is Found that only in two flares are the neut ral beam HXRs clearly important and that in a few others they may be signif icant. In most events, however, the neutral beam HXR contribution is small, though the ion energy is comparable with that of electrons.