hp streamline-diffusion and discontinuous Galekin schemes with Nitsche correction for the three dimensional Vlasov-Maxwell system.

Preprint, 2017

We study stability and convergence of hp-streamline diffusion (SD) finite element, and Nitsche's schemes for the three dimensional, relativistic (3 spatial dimension and 3 velocities), time dependent Vlasov-Maxwell system and Maxwell's equations, respectively. For the hp scheme for the Vlasov-Maxwell system, assuming that the exact solution is in the Sobolev space of order s, we derive global {\sl a priori} error bound of order s+1/2 in h/p, where h is the mesh parameter and p is the spectral order. This estimate is based on the local version with hK= diam K being the diameter of the {\sl phase-space-time} element K and pK is the spectral order (the degree of approximating finite element polynomial) for K. As for the Nitsche's scheme, by a simple calculus of the field equations, first we convert the Maxwell's system to an {\sl elliptic type} equation. Then, combining the Nitsche's method for the spatial discretization with a second order time scheme, we obtain optimal convergence of (h2+k2), where h is the spatial mesh size and k is the time step. Here, as in the classical literature, the second order time scheme requires higher order regularity assumptions. Numerical justification of the results, in lower dimensions, is presented and is also the subject of a forthcoming computational work [20].