Flare Frequency‐Size Distributions for Individual Active Regions

Abstract

It is well known that the size (peak count rate of emission, or inferred energy) distribution of —ares observed on the Sun follows a power law. However, the distributions that are constructed include —ares from diUerent active regions that have a variety of physical properties. In this paper cumulative peak count rate distributions are constructed for individual active regions using events listed in the WATCH solar X-ray burst catalog. The individual distributions are found to be consistent with the distribution constructed from events in all active regions named in the catalog. This result suggests that the —are power-law size distribution re—ects an intrinsic property of the —are mechanism and is not a product of the distributions of physical parameters between active regions. The result is consistent with the ava- lanche model for —ares and more generally argues against macroscopic —are models. Subject headings: MHDSun: activitySun: coronaSun: —ares