Dr Jack Reid

Project Title: A Model for Solar Flares and Coronal Heating based on Magnetohydrodynamic Avalanches

Our surprisingly active Sun emits huge amounts of energy stored in its coronal magnetic field in very short, intense bursts, called solar flares. Hot, dense plasma in the upper region of the Sun’s atmosphere is ejected into planetary space, and can intersect with Earth’s orbit.  My project investigates solar flares from a new perspective: avalanches. By analogy with earthbound avalanches, energy is released in one part of the Sun’s atmosphere, which then causes the release of further energy from neighbouring regions, as the stressed magnetic field relaxes. These models of cellular automata have been considered before, but are predicated on a set of simple rules, following which during a long run gives output approximately matching observations. Such rules lacking a physical basis at present, my project seeks to solve the MHD equations using numerical techniques in order to verify these rules.  This makes it possible to determine whether, on a small scale, these models can explain coronal heating, the unexpectedly great temperature above the surface of the Sun.  Numerical experiments are used in order to determine the parameters and conditions which allow for the formation of instabilities and the onset of avalanches.