Coronal energy release by MHD avalanches: continuous driving

¹ School of Mathematics and Statistics, University of St Andrews, St Andrews, Fife, KY16 9SS, UK
e-mail: jr93@st-andrews.ac.uk
² Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK
e-mail: awh@st-andrews.ac.uk
³ Space and Atmospheric Physics, The Blackett Laboratory, Imperial College, London, SW7 2BW, UK

Received: 1 December 2017
Accepted: 23 March 2018

Abstract

Previous work has confirmed the concept of a magnetohydrodynamic (MHD) avalanche in pre-stressed threads within a coronal loop. We undertook a series of full, three-dimensional MHD simulations in order to create three threads by twisting the magnetic field through boundary motions until an instability ensues. We find that, following the original instability, one unstable thread can disrupt its neighbours with continued driving. A “bursty” heating profile results, with a series of ongoing energy releases, but no evident steady state. For the first time using full MHD, we show that avalanches are a viable mechanism for the storing and release of magnetic energy in the solar corona, as a result of photospheric motions.