Random boundary condition for low-frequency wave propagation |

In theory, this random boundary condition can be easily extended to wavefields at all temporal frequency ranges. However, due to memory and computational requirements, overly large boundary regions are unfavorable. Therefore, problems arise when we move to low frequencies. In that case, increased spatial wavelengths mandate larger boundary regions if we are to use the same random boundary scheme. For low-frequency applications such as waveform inversion, if we can keep the size of the random boundary approximately the same as that used in RTM, computational efficiency will be greatly improved, especially in 3D by avoiding extra computation of waves propagating in the boundary domain. In this paper, we introduce a scheme of perturbing the grain shape of the random boundary condition to keep the boundary region small but still effective with low frequency wave propagation. The same random boundary is also effective for high-frequency wave propagation. We briefly discuss the theory and illustrate the method using synthetic examples.

Random boundary condition for low-frequency wave propagation |

2011-05-24