A New Hybrid Method for High-Order EM-PIC Simulations

We propose to prototype and test a new 3-D hybrid technique that combines two efficient algorithms, (a) the discontinuous Galerkin pseudospectral time-domain (DG-PSTD) method and (b) the boundary conformal finite-difference time-domain (BC-FDTD) method, as a high-order solver for electromagnetic particle-in-cell (EM-PIC) simulations. This hybrid technique overcomes the well-known limitation of existing EM-PIC solvers due to their stair-stepping approximation. The proposed hybrid method uses domain decomposion to divide the problem into DG-PSTD regions with coarse structures and BC-FDTD regions with fine structures. As the DG-PSTD method has spectral accuracy and the BC-FDTD method has second-order accuracy, the overall convergence of this EM-PIC solver is better than second order. The team has already developed the most relevant techniques for the pure electromagnetics problem in an existing commercial prototype, Wavenology EM Pack, and has worked on plasma simulations. The proposed 3-D hybrid numerical EM-PIC solver will be integrated into this commercial prototype. It promises to effectively mitigate spurious effects caused by the stair-stepping approximation in the EM-PIC simulation.