GODDARD SPACE FLIGHT CENTER Greenbelt, Maryland SUPRATHERMAL PROTON X-RAY BREMSSTRAHLUNG

Copious x-ray production is shown to attend the collisions of suprathermal (?MeV) protons with ambient electrons,via a process of inverse bremsstrahlung. Such suprathermal protons have been detected in cosmic rays and in solar f lare events; the inverse bremsstrahlung of such cosmic ray protons is expected to make a significant contribution to the diffuse sky background of x-rays and suprathermal solar protons to the x-ray bursts associated with solar flares. The x-ray production in the supernova remnant Tau A (Crab Nebula) is too high to be readily accounted for by the inverse bremsstrahlung of suprathermal protons.