Characterisation of the Emission Spectra of High Energy Solar Flares

The hardening in the non-thermal electron bremsstrahlung emissions of high energy solar flares is well modelled by a double power law broken at ~300keV. However, the correlations between the parameters of these models are not fully understood. Data from the Gamma-Ray Burst Monitor (GBM) on the Fermi Gamma-Ray Space Telescope was used to compile a selection of solar flares with significant emission at energies greater than 150keV. These flares were then analysed and models were fitted to the spectra. The comparisons on these models, particularly with regards to the proficiency of broken power laws relative to single power laws, were used to determine the best fit for each flare. The analysed flares suggest possible correlations between the parameters of these fits. They also indicate that all flares with significant high energy emission demonstrate this characteristic hardening.