Stable and convergent fully discrete interior–exterior coupling of Maxwell’s equations
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Maxwell’s equations are considered with transparent boundary conditions, for initial conditions and inhomogeneity having support in a bounded, not necessarily convex three-dimensional domain or in a collection of such domains. The numerical method only involves the interior domain and its boundary. The transparent boundary conditions are imposed via a time-dependent boundary integral operator that is shown to satisfy a coercivity property. The stability of the numerical method relies on this coercivity and on an anti-symmetric structure of the discretized equations that is inherited from a weak first-order formulation of the continuous equations. The method proposed here uses a discontinuous Galerkin method and the leapfrog scheme in the interior and is coupled to boundary elements and convolution quadrature on the boundary. The method is explicit in the interior and implicit on the boundary. Stability and convergence of the spatial semidiscretization are proven, and with a computationally simple stabilization term, this is also shown for the full discretization.
Mathematics Subject Classification35Q61 65M60 65M38 65M12 65R20
We thank two anonymous referees for their helpful comments. We are grateful for the helpful discussions on spatial discretizations with Ralf Hiptmair (ETH Zürich) during a BIRS Workshop (16w5071) in Banff. This work was supported by the Deutsche Forschungsgemeinschaft (DFG) through SFB 1173.
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