多轴卷积完全匹配层吸收边界条件

在通常情况下，完全匹配层（PML）吸收边界条件较其他吸收边界条件具有更优越的吸收性能，已广泛用于地震波正演模拟。但传统的PML吸收边界条件也存在一定缺陷，如不分裂卷积完全匹配层（C-PML）吸收边界在某些介质中不稳定，分裂的多轴完全匹配层（M-PML）吸收边界的吸收效果不好。为此，本文提出了多轴卷积完全匹配层（MC-PML）吸收边界条件，既可提高C-PML吸收边界的稳定性，又可改善M-PML吸收边界的吸收效率，且采用不分裂算法实现，可有效降低计算成本。正演模拟结果表明，MC-PML吸收边界条件具有更高的计算稳定性和较好的吸收效果。

Multi-axial convolution perfectly matched layer absorption boundary condition

The perfectly matched layer (PML) absorption boundary condition is widely used in numerical forward modeling of elastic wave equation since it has been proved to have a superior absorption performance than other absorption boundary condition method. But this PML absorption boundary condition also has some defects. For example, unsplit convolution perfectly matched layer (C-PML) absorption boundary is not stable in some media, and the split multi-axial perfectly matched layer (M-PML) absorption boundary is not efficient. Therefore we propose multi-axial convolution PML (MC-PML) based on the combination of C-PML and M-PML. The MC-PML can enhance the stability of C-PML as well as improve the absorption effect of M-PML. And the computational expense is lower because of the unsplit implementation method. Test results on a numerical forward modeling show that MC-PML obtains both higher stability and better absorption.