Nonthermal hard X-ray flux saturation in solar flares
Daou, Antoun Georges
Master of Science
We use the unprecedented spectral and spatial resolution of RHESSI to explore the behavior of electrons and their associated currents in solar flares. Spectral images are used to determine an estimate of the effective surface area for the different independent substructures within each event. The incident electron spectra at those flaring footpoints are derived from the RHESSI photon spectra. We find that, over a wide range of flare X-ray magnitudes, the integrated photon flux above 20 keV asymptotically approaches a limiting value, suggesting a saturation of the photon production in flares. The inferred particle fluxes in the beam, together with this saturation limit, are used to determine the energy loss mechanism dominating the energetic particle transport in solar flares.