Performance Analysis of the Moving Computational Domain Technique for the Calculation of Sferics

In this paper, we analyzed the performance of the moving computational domain technique (MCDT) for the calculation of lightning-generated electromagnetic fields in the Earth-ionosphere waveguide (EIWG) using the finite-difference time-domain (FDTD) method. In the FDTD method with MCDT, a spatial window moving along with the wavefront is defined and, at each time step, the field components are updated only in that window. The FDTD efficiency can be improved by at least a factor of two with respect to the conventional FDTD, while the accuracy remains unchanged. The improvement in computational efficiency is dependent on the size of the simulation domain, the cell size and the time window of interest.