Thomas Higham, University of Oxford
A key part of the nuclear fusion industry is numerically reconstructing the plasma equilibria from diagnostic information. There are many approaches to find fusion equilibria and one is magneto-frictional relaxation. When solving this system it is crucial to preserve an invariant called helicity to get physical results. It is also important that the magnetic field remains divergence-free throughout iterations of relaxation. We employ ideas from finite element exterior calculus and use an auxiliary variable to preserve the divergence-free condition and the helicity numerically. The scheme performs well but slow convergence means it is best suited for experiments as opposed to direct industrial application.