Bandpass signal formulation with hybrid implicit-explicit procedure in open regions for unmagnetized plasma

The finite-difference time-domain (FDTD) algorithm shows disadvantages in bandpass signal simulation with fine structures along a single direction. The reason is that FDTD algorithm exists the Courant–Friedrichs–Levy (CFL) condition and bases on the lowpass-sampling theorem. Based on the numerical implementation, hybrid implicit-explicit procedure and complex envelope method are introduced. As a full-wave simulation method, higher order concept is incorporated into perfectly matched layer (PML) formulation for improving absorption at boundaries of the lattice. For unmagnetized plasma simulation, piecewise linear recursive convolution method is modified according to the bandpass signal. Through numerical example, the proposed algorithm shows considerable performance during the entire simulation which can be concluded from several aspects: (1) It takes advantages of higher order concept which shows enhanced absorption. (2) The proposed algorithm can overcome the CFL condition and maintain stability with the increment of time steps. (3) It shows considerable efficiency and accuracy in simulating structures with fine details along a single direction. (4) It can alleviate time increment problem among implicit algorithms with lower CFL numbers.