On the energy release in solar flares

TL;DR

This paper challenges traditional models of solar magnetic fields, emphasizing the importance of non-force-free elements and dynamic instabilities in triggering solar flares, proposing a new perspective on energy release mechanisms.

Contribution

It introduces a dynamic, non-stationary model of solar magnetic fields incorporating non-force-free elements and instability mechanisms, contrasting with traditional static models.

Findings

Traditional models neglect non-force-free elements.

Instabilities like ballooning and tearing influence flare initiation.

Energy release resembles current percolation in a resistor network.

Abstract

High-resolution observations show the fine structure of the global equilibrium magnetic field configuration in solar atmosphere to be essentially different from that assumed in the traditional 'potential + force-free' field scenarios. The interacting large-scale structures of fine field elements are separated by numerous non-force-free elements (tangential discontinuities) which are neglected in the traditional field picture. An incorporation of these elements into the model implies a dynamical rather than statical character of equilibrium of the field configuration. A transition of the system into flaring can be triggered by the ballooning mode of flute instability of prominences or/and coronal condensations. Tearing-mode and MHD instabilities as well as the effects of overheating of the turbulent current sheet prevent the field from stationary reconnection as it is adopted in the traditional scenario. We speculate around the assumption that the energy release in active regions is governed by the same scenario as dynamical current percolation through a random network of resistors in which the saltatory resistance is controlled by local current.