Wavelets, Intermittency and Solar Flare Hard X-rays 1. Local Intermittency Measure in Cascade and Avalanche Scenarios

Abstract

We introduce the local intermittency measure (LIM) as a tool for the investigation of solar flare hard X-ray light curves. Constructed from wavelet amplitudes, the LIM allows us to investigate the extent to which rapid fluctuations reveal an underlying, scale-invariant process, and to identify those episodes during a flare which definitely represent ‘intermittent’ behaviour (e.g. involvement of new spatial structures). We carry out two sets of simple simulations intended to provide generic examples of ‘top-down’ and ‘bottom-up’ scenarios for the development of flares, and show how LIM may discriminate between them.