Frequency distributions of solar X-ray flare parameters

Abstract

We have determined frequency distributions of flare parameters from the over 12,000 solar flares that were recorded with the Hard X-ray Burst Spectrometer (HXRBS) on SMM. These parameters include the total flare duration, peak counting rate, the peak hard X-ray flux, the total energy in electrons, and the peak hard X-ray flux in electrons (the latter two computed assuming a thick-target model). The energies were computed above a threshold energy between 25 and 50 keV. All the distributions can be represented by power-laws over a range of several orders of magnitude, above the HXRBS sensitivity threshold. Power-laws can be taken as evidence for self-organized criticality in solar flares. Correlations among these parameters are determined from linear regression fits as well as from the slopes from the frequency distributions. Variations of the frequency distributions were also investigated with respect to the solar cycle.