Cutoff scattering angles for random acoustic media
Cutoff scattering angles for random acoustic media
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DOI：
10.1029/2001jb000429
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发表时间：
2002
影响因子：
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通讯作者：
Jun Kawahara
中科院分区：
文献类型：
--
作者：
Jun Kawahara
[1]R. S. Wu和H.佐藤关键是在评估散射衰减时消除截止散射角（CSA）内前向散射的贡献，以避免高估高频下的衰减。然而，CSA的价值并没有在理论中客观地确定，它的选择仍然是一个悬而未决的问题。我们调查的约束条件的因果关系的选择的CSA随机声学介质具有恒定的密度。在Kramers-Kronig关系的基础上，我们推导出了在高、低频极限下相速度与CSA的简单关系。我们进一步讨论了CSA的基础上的思想实验的可能值。令人惊讶的是，他们是独立的不均匀性的细节。
[1] The seismic scattering attenuation in randomly inhomogeneous media is successfully explained by a Born approximation-based theory, established by R. S. Wu and H. Sato. The key is to eliminate the contribution of forward scattering within a cutoff scattering angle (CSA) when evaluating the scattering attenuation in order to avoid overestimating attenuation at high frequencies. The value of the CSA is, however, not objectively determined in the theory, and the choice of it remains an open question. We investigate the constraint by causality on the choice of the CSA for random acoustic media with constant densities. On the basis of the Kramers-Kronig relation, we derive simple relations of the phase velocities in the high- and low-frequency limits with the CSA. We further discuss the probable values of the CSA on the basis of a thought experiment. Surprisingly, they are independent of the details of inhomogeneities.