Energetics of acoustically active white light flares
University of Hull
White-light flares are solar flares which show an enhancement of the visible continuum emission. It was thought that only large flares showed continuum enhancement, due to the difficulty in observing white-light emission against the bright photospheric background. Sunquakes are observed as outward propagating ripples on the surface of the Sun, caused by flare generated acoustic waves traveling into the Sun and being reflected back by changes in the speed of sound. The observed sunquakes are usually associated with white-light flares. In this work, we study a number of such flares which show seismic activity, comparing and the sunquake's acoustic energy with the energy of the flare’s white-light emission and the class of the flare. The time delay between the onset of the flare and the sunquake will also be investigated, and then the energy in white-light and the time delay will be compared. We use the data from the Solar Dynamics Observatory’s Helioseismic and Magnetic Imager to detect and measure the acoustic and white light emission, applying Kerr & Fletcher 2014 method for calculating the energy in white light based on conversion of the HMI continuum data to absolute specific intensity technique provided by R.Bush.