A residual perfectly matched layer for wave propagation in elastic media

Absorbing boundary conditions are often utilized to eliminate spurious reflections that arise at the model's truncation boundaries. The perfectly matched layer (PML) is widely considered to be very efficient artificial boundary condition. A new alternative implementation of the PML is presented. We call this method residual perfectly matched layer (RPML) because it is based on residual calculation between the original equations and the PML formulations. This new approach has the same form as the original governing equations, and the auxiliary differential equation has only one partial derivative with respect to time, which is the simplest compared to other PMLs. Therefore, the RPML shows great advantages of implementation simplicity and computational efficiency over the standard complex stretched coordinate PML. At the same time, the absorption performance is improved by adopting the complex frequency shifted stretching function; the stability of the boundary is enhanced by applying the double damping profile.