电磁波场数值计算中时间域有限差分法与时间域伪谱法的对比研究

为提高电磁波场数值计算精度，对时间域有限差分法与时间域伪谱法进行了对比研究。时间域有限差分法是一种目前流行的电磁场时域数值计算方法，已被广泛应用于求解与时间有关的偏导数方程。对于大规模数值计算，时间域有限差分法需要较多的内存空间。时间域伪谱法基于时间域有限差分法，该方法使用快速傅里叶度换来计算麦克斯韦方程中的空间导数。由于傅里叶变换的准确性，时间域伪谱法使计算精度提高，数值计算时所需的格子数大大减少，这极大地节省了计算机内存空间，适合于大规模正反演问题的数值计算。

Study on the Differences Between Finite Difference Time Domain Method and Pseudo-spectral Time Domain Algorithm in Numerical Calculation of Electromagnetic Wave Fields

In order to improve the resolution of numerical calculation of electromagnetic wave fields,the differences between finite difference time domain(FDTD) method and psedo-spactral time domain(PSTD) algorithm were studied.The FDTD method is a common numerical calculation method of electromagnetic wave fields,and it is widely applied to the solution of the partial derivative equations related to time.More memory is needed using FDTD method in large-scale numerical calculation.The PSTD algorithm is based on FDTD method and employs fast Fourier transform(FFT) to calculate the spatial derivatives in Maxwell's equations.Due to accuracy by FFT,the calculation precision is improved and grid numbers needed is decreased greatly by using PSTD algorithm.The PSTD algorithm has the advantage of saving computational memory space and is suitable for large-scale numerical calculation of forward modeling and inversion.