A Low-Storage PML Implementation within a High-order Discontinuous Galerkin Time-Domain Method

The perfectly matched layer (PML) is one of the most popular domain truncation techniques used by wave equation solvers. PML implementations often use smooth-varying attenuation coefficients to achieve desired levels of accuracy and efficiency by reducing numerical reflection and PML thickness, respectively. For a discontinuous Galerkin time-domain (DGTD) scheme, this approach requires storing a different mass matrix for every mesh element, and therefore significantly increases the memory footprint. In this work, an efficient implementation of PML, which makes use of weight-adjusted approximation to account for smooth-varying attenuation coefficients, is developed. The proposed scheme results in a DGTD scheme with a small memory footprint while maintaining the high-order accuracy of the solution using a thin PML.