It is commonly believed that the observed solar activity is driven by the dissipation of free (nonpotential) magnetic energy injected into the corona by dynamic processes in the photosphere. The enormous range of scales involved in the solar activity makes it difficult to track down the photospheric origin of each coronal dissipation event, especially in the presence of complex magnetic topologies. In this paper, we propose a new statistical-physical approach for testing the photosphere-corona coupling as manifested in a quiet solar region. We investigate large ensembles of photospheric and coronal events detected in co-aligned sets of images provided respectively by SOHO MDI and STEREO EUVI instruments. We show that for properly adjusted detection thresholds corresponding to the same degree of intermittency in the photosphere and corona, the detected events are described by similar occurrence probability distributions of timeintegrated quantities but significantly different geometric properties. We derive a set of scaling relations reconciling these empirical results and enabling statistical forecast of coronal dynamics based on photospheric measurements. The perform analysis suggests that multiscale energy dissipation in the corona is directly controlled by the turbulent photospheric convection so that probabilistic properties of energy release events in the photosphere are imprinted in the corona. The nonlocal nature of the photospheric network makes this coupling essentially nonlocal and non-deterministic. Our results are in agreement with the Parker's coupling scenario in which random photospheric shuffling generates marginally stable magnetic discontinuities at the coronal level, and are also consistent with an impulsive wave heating involving multiscale Alfvénic wave packets. More research is needed to tell the two mechanisms apart.
Authors: Vadim M. Uritsky, Joseph M. Davila, Leon Ofman, and Aaron J. Coyner
Publication Status: under review
Last Modified: 2012-12-28 09:17