Impulsive Solar X-Ray Bursts: Bremsstrahlung Radiation from a Beam of Electrons in the Solar Chromosphere and the Total Energy of Solar Flares

Analysis of various aspects of impulsive X-ray bursts (IXBs) has led us to consider a model in which the X-rays are produced by bremsstrahlung radiation from a beam of electrons directed toward the photosphere. We find that in general the X-ray spectrum from such a beam will fall off more rapidly than when the the beaming of radiation is neglected. Furthermore, the spectral index of the resulting X-rays appears to increase by about unity for X-ray energies greater than 100 keV, a fact which may explain the observed cutoff in the spectrum of the IXBs. It is also shown that in such a model there is sufficient energy in the form of nonthermal electrons to explain the total energy ( 1032 ergs) of a flare. Subject headings: chromosphere, solar - flares, solar - X-rays, solar