Memory-optimized shift operator alternating direction implicit finite difference time domain method for plasma

• Published in: Journal of computational physics 2017-11, Vol.349, p.122-136
• Main Authors: Song, Wanjun, Zhang, Hou
• Format: Article
• Language: English
• Subjects: Alternating direction implicit methods; Alternating direction implicit technique; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COLLISIONAL PLASMA; Collisional plasmas; Computational efficiency; Computational physics; Computer memory; Computer simulation; COMPUTERS; Computing time; Conductors; Convolution; Dispersion; ELECTRIC CONDUCTORS; ELECTRON COLLISIONS; Electrons; FDTD; Finite difference method; Finite difference time domain method; Finite element analysis; Gaussian elimination; Iterative methods; LANGMUIR FREQUENCY; Mathematical analysis; MATHEMATICAL OPERATORS; Multilayers; Numerical dispersion; Optimization; Plasma; Plasma frequencies; PLASMA SHEET; Recursive methods; Reflectance; Reflection; Shift operator; Time domain analysis; Z transforms
• ISSN: 0021-9991; 1090-2716
• DOI: 10.1016/j.jcp.2017.08.017

Through introducing the alternating direction implicit (ADI) technique and the memory-optimized algorithm to the shift operator (SO) finite difference time domain (FDTD) method, the memory-optimized SO-ADI FDTD for nonmagnetized collisional plasma is proposed and the corresponding formulae of the proposed method for programming are deduced. In order to further the computational efficiency, the iteration method rather than Gauss elimination method is employed to solve the equation set in the derivation of the formulae. Complicated transformations and convolutions are avoided in the proposed method compared with the Z transforms (ZT) ADI FDTD method and the piecewise linear JE recursive convolution (PLJERC) ADI FDTD method. The numerical dispersion of the SO-ADI FDTD method with different plasma frequencies and electron collision frequencies is analyzed and the appropriate ratio of grid size to the minimum wavelength is given. The accuracy of the proposed method is validated by the reflection coefficient test on a nonmagnetized collisional plasma sheet. The testing results show that the proposed method is advantageous for improving computational efficiency and saving computer memory. The reflection coefficient of a perfect electric conductor (PEC) sheet covered by multilayer plasma and the RCS of the objects coated by plasma are calculated by the proposed method and the simulation results are analyzed.