MHD Regularization for Magnetohydrostatic Equilibrium Computation

The viability of regularized MHD as a computational tool for the generation of magnetohydrostatic (MHS) equilibria is explored. Two choices of regularization, Voigt regularized and Lagrangian averaged MHD, are numerically implemented in 2D and shown to provide computational speed-up in accessing MHS equilibria compared to an ideal simulation. Both models conserve a modified magnetic helicity which allows for magnetic topology to change, so islands may grow and saturate in the equilibrium state. The boundary layer theory of these tearing modes is explored and compared to simulations. The equilibrium state depends on the choice of regularization parameters if resistivity vanishes, but this dependence becomes much weaker when finite resistivity is included.