Section: New Results
Convolution PML (C-PML)
Participants : Dimitri Komatitsch, Roland Martin.
The Perfectly Matched Layer absorbing boundary  condition has proven to be very efficient from a numerical point of view for the elastic wave equation to absorb both body waves with non-grazing incidence and surface waves. However, at grazing incidence the classical discrete Perfectly Matched Layer method suffers from large spurious reflections that make it inefficient for instance in the case of very thin mesh slices, in the case of sources located very close to the edge of the mesh, and/or in the case of receivers located at very large offset. In addition, most classical Perfectly Matched Layer models use a split version of the fields, which makes them more difficult to implement and more expensive to use numerically. We have demonstrated how to improve the Perfectly Matched Layer at grazing incidence for the differential anisotropic elastic wave equation based on an unsplit convolution technique. We have illustrated the efficiency of this improved Convolution Perfectly Matched Layer based on two-dimensional numerical benchmarks using a finite-difference method on very thin mesh slices for an isotropic material and show that results are significantly improved compared to the classical Perfectly Matched Layer technique. We have also shown that the technique is efficient in the case of anisotropic materials.