Numerical Simulation of ULF Electromagnetic Waves Based on the ADI-FDTD Method

The propagation characteristics of ultra-low frequency (ULF) electromagnetic (EM) waves in the ocean and within the ocean-ionosphere waveguide model have been studied. Numerical simulations were conducted using the alternate-direction implicit finite-difference time-domain (ADI-FDTD) method, and the results were compared with those obtained using the traditional finite-difference time-domain (FDTD) method. The accuracy and efficiency of the ADI-FDTD method were validated through this comparison.