An efficient integral approach for plane wave 3D electromagnetic modeling in complex anisotropic media

Abstract We have developed a novel integral approach for modeling plane wave electromagnetic (EM) fields in 3D anisotropic earth models. To handle complex models with arbitrary conductivity structures accurately and efficiently, we propose an optimized solver for integral equation-based 3D magnetotelluric modeling. The core innovation of our method lies in applying a horizontal 2D Fourier transform to reduce the 3D integration of secondary fields into a 1D integration in the space-wavenumber domain. To achieve high computational efficiency and precision, we implement the following numerical strategies. First, we employ the 2D Fast Fourier Transform (FFT) to compute electromagnetic fields rapidly, ensuring the overall computational efficiency of the method. Second, we develop an efficient algorithm for calculating layered Green’s tensor functions in the space-wavenumber domain and adopt a shape-function-based quadrature scheme to maintain the precision of the integrand. Third, we iteratively apply a compact operator to guarantee the convergence of the integral equation solver. Numerical experiments on synthetic anisotropic models validate the accuracy, convergence rate, and computational efficiency of the proposed method. The results demonstrate that the proposed algorithm significantly reduces computational time and memory requirements, making it particularly suitable for large-scale simulations of complex 3D anisotropic models.