On a parallel, 3-dimensional, finite element solver for viscous, resistive, stationary magnetohydrodynamics equations: Velocity-current formulation

We describe a parallel implementation for the numerical approximation of solutions to the three-dimensional viscous, resistive magnetohydrodynamics (MHD) equations using a velocity-current formulation. In comparison to other formulations, the velocity-current formulation presented in this paper is an integro-differential system of equations that incorporates nonideal boundaries and nonlinearities due to induction. The solution to the equations is approximated using a Picard iteration, discretized with the finite element method, and solved iteratively with the Krylov subspace method GMRES. Effective preconditioning strategies are required to numerically solve the resulting equations with Krylov solvers [12]. For GMRES convergence, the system matrix resulting from the discretization of the velocity-current formulation is preconditioned using a simple, block-diagonal Schur-complement preconditioner based on [14]. The MHD solver is implemented using freely available, well-documented, open-source, libraries deal.II, p4est, Trilinos, and PETSc, capable of scaling to tens of thousands of processors on state-of-the-art HPC architectures.