Optimal damping profile ratios for stabilization of perfectly matched layers in general anisotropic media
Conventional perfectly matched layers (PMLs) can be unstable for certain kinds of anisotropic media. The multiaxial PML removes such instability using nonzero damping coefficients in the directions tangential with the PML interface. Although using nonzero damping profile ratios can stabilize PMLs, it is important to obtain the smallest possible damping profile ratios to minimize artificial reflections caused by these nonzero ratios, particularly for 3D general anisotropic media. Using the eigenvectors of the PML system matrix, we have developed a straightforward and efficient numerical algorithm to determine the optimal damping profile ratios to stabilize PMLs in 2D and 3D general anisotropic media. Numerical examples indicate that our algorithm provides optimal damping profile ratios to ensure the stability of PMLs and complex-frequency-shifted PMLs for elastic-wave modeling in 2D and 3D general anisotropic media.