Frequency-energy distributions of flares and active region transient brightenings

In 1988, Uchida and Shibata proposed a model for compact loop flares as due to the collision of two large amplitude torsional Alfven wave packets comi ng up along a coronal magnetic loop, leaking out from the subphotospheric c onvective layers of the solar atmosphere. We investigate the possibility th at active region transient brightenings occur when a single torsional Alfve n wave packet transits a coronal loop. Assuming this related origin for fla res and transient brightenings, the statistics of the two phenomena must al so be closely related. It is shown that the observed power-law frequency-en ergy distributions of flares and transient brightenings may be accounted fo r in a natural way if the energy distribution of the underlying torsional A lfven wave packets is itself a power law.