Observations of the ionization states of energetic particles accelerated in solar flares

We report results of a survey of ten solar flare particle events in which we measured the ionization states and spectra of 0.3 to 2.4 MeV/nuc He, C, O and Fe. We find He+ to be present in all events (He+/He++ approximately 0.1 to 0.25), and the mean ionization states of C, O and Fe to be high. The distribution functions of He+, He++ and heavier elements are well represented by simple exponentials of the particle speed times its rigidity to a power n, where n is between 0 and 1, and equal e-folding values. Our results are consistent with a model whereby ions are accelerated in the corona by multi-dimensional shocks out of a population taken from both hot (Tsub(e)> or approximately or 2.106 K) and cold (Tsub(e)<or approximately 105K) coronal regions