Discontinuous Galerkin version of PERSEUS for Studying HED plasma

The Discontinuous Galerkin(DG) version of Cornell PERSEUS [1,2] code is developed in an effort to reduce the numerical diffusivity of the existing Finite Volume(FV) version of PERSEUS code. A Positivity- Preserving limiter [3] is used instead of TVD limiter to maintain a second order accuracy at smooth extrema. A Structure-Preserving limiter [4] is used when $\nabla\cdot B=0$ needs to be enforced. The code is tested on several MHD benchmark problems with both resistive MHD and extended-MHD models. The simulation results of compressible magnetic reconnection problem are presented here as an example. Since DG-PERSEUS is better for simulating shocks with less numerical diffusivity, we applied the code for studying the difference between the structures of a shock formed by a super-Alfvenic-supersonic flow and that formed by a sub-Alfvenic-supersonic flow, so that one can tell whether the outflow is super-Alfvenic in a magnetic reconnection experiment. The code is parallelized with MPI, we expect a higher parallel efficiency, since the only information needed to be passed between computation units is the flux through boundary, which is less than the passed information in the FV case.\\[4pt] [1] M.R. Martin, PhD. Thesis\\[0pt] [2] C.E. Seyler, M.R. Martin, 2011\\[0pt] [3] X. Zhang, PhD. Thesis\\[0pt] [4] F. Li, C. Shu, 2006