A Hybrid Explicit-Implicit Scheme for Spectral-Element Time-Domain Analysis of Multiscale Simulation

摘要

The multiscale simulation usually leads to dense meshes discretization for fine structures, thus making time step size of the spectral-element time-domain (SETD) method extremely small to ensure stability for explicit scheme. In this paper, a hybrid explicit-implicit scheme for SETD is proposed to deal with the simulation of multiscale electromagnetic problems. The central-difference is applied for the coarse region with large cells and the Newmark-Beta scheme is for the fine region with small cells. Then a large size of time step can be selected in the whole domain instead of the one limited by the smallest cell. When solving the matrix equation formed by the implicit scheme, two approaches are employed. One uses the sparse matrix solver UMFPACK directly and the other involves an explicit and iterative scheme. Numerical results show that the hybrid method is an efficient alternative to conventional SETD method for multiscale simulation.