Hybrid ray-FDTD moving window approach to pulse propagation

A moving window finite difference time domain method is developed to simulate the propagation of electromagnetic pulses over large distances. Both Eulerian and Lagrangian approaches to solving Maxwell's equations in a moving window are obtained and contrasted. The Lagrangian approach is shown to be superior for electromagnetic pulse propagation; it is demonstrated that dispersion-free numerical propagation can be achieved with the Lagrangian approach. Examples of propagation in homogeneous and inhomogeneous media, and scattering from a interface between two media are considered. The scattering results are achieved with a window splitting approach in which the original incident pulse window is frozen at the interface and new windows are generated after the interface interactions occur that move with the reflected and transmitted pulses. The simulation results are shown to be accurate and physically appealing.