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在弹性波有限差分正演模拟中,完全匹配层(PML)吸收边界条件是使用广泛、吸收效果最好的吸收边界条件.在目前的两种PML实现方法中,分裂形式的完全匹配层(SPML)方法计算存储量大、编程实现复杂;非分裂形式的完全匹配层(NPML)方法计算效率低、计算过程复杂.针对传统PML吸收边界条件在实现过程中存在的问题,推导出了一种简洁有效的非卷积实现的NPML吸收边界条件,既不需要对场分量进行分裂,也不需要做复杂的卷积运算.分析结果表明,本文实现的NPML吸收边界条件不仅具有良好的吸收衰减性能,而且计算方程简单,编程实现容易,占有内存更小.
In the finite difference forward modeling of elastic wave, the perfectly matched layer (PML) absorption boundary condition is the most widely used and well-absorbed absorption boundary condition.In the current two methods of PML implementation, the split-perfectly matched layer (SPML ) Method is computationally expensive and complex in programming, NPML method is inefficient and complicated in calculation process.According to the existing problems in the implementation process of traditional PML absorption boundary conditions, a simple The effective non-convolutional NPML absorption boundary conditions do not need to split the field components or do complex convolution calculations.The analysis results show that the NPML absorption boundary conditions achieved in this paper not only have good absorption and attenuation properties, And the calculation equation is simple, easy to program, possession of memory smaller.