scholarly journals Erratum: ‘‘Analytical mode conversion calculations for the full wave equations at the ion second harmonics’’ [Phys. Fluids 28, 2808 (1985)]

1986 ◽  
Vol 29 (8) ◽  
pp. 2761 ◽  
Author(s):  
S. C. Chiu
Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. S85-S93 ◽  
Author(s):  
Jun Cao ◽  
Ru-Shan Wu

Directional illumination analysis based on one-way wave equations has been studied extensively; however, its inherent limitations, e.g., one-way propagation, wide-angle error, and amplitude inaccuracy, can severely hinder its applications for accurate survey design and true-reflection imaging corrections in complex media. We have analyzed the illumination in the frequency domain using full two-way wave propagators considering the extensive computation and huge storage required for time-domain methods, and the fact that the illumination is frequency dependent. This full-wave analysis can provide frequency-dependent full-angle true-amplitude illumination not only for the downgoing waves but also for the upgoing waves, including turning waves and reflected waves. Two methods were considered to decompose the full wavefield into the local angle domain: a direct full-dimensional decomposition and more efficient split-step decomposition composed of three lower-dimensional decompositions. The results of illumination analysis demonstrated the advantages of this method. The two decomposition methods produced similar results.


2011 ◽  
Author(s):  
A. Köhn ◽  
J. Jacquot ◽  
M. W. Bongard ◽  
S. Gallian ◽  
E. T. Hinson ◽  
...  

1995 ◽  
Vol 43 (11) ◽  
pp. 2532-2538 ◽  
Author(s):  
Ming-Dong Wu ◽  
Sheng-Ming Deng ◽  
Ruey-Beei Wu ◽  
Powen Hsu

Geophysics ◽  
2018 ◽  
Vol 83 (5) ◽  
pp. S399-S408 ◽  
Author(s):  
Yunyue Elita Li ◽  
Yue Du ◽  
Jizhong Yang ◽  
Arthur Cheng ◽  
Xinding Fang

Elastic wave imaging has been a significant challenge in the exploration industry due to the complexities in wave physics and numerical implementation. We have separated the governing equations for P- and S-wave propagation without the assumptions of homogeneous Lamé parameters to capture the mode conversion between the two body waves in an isotropic, constant-density medium. The resulting set of two coupled second-order equations for P- and S-potentials clearly demonstrates that mode conversion only occurs at the discontinuities of the shear modulus. Applying the Born approximation to the new equations, we derive the PP, PS, SP, and SS imaging conditions from the first gradients of waveform matching objective functions. The resulting images are consistent with the physical perturbations of the elastic parameters, and, hence, they are automatically free of the polarity reversal artifacts in the converted images. When implementing elastic reverse time migration (RTM), we find that scalar wave equations can be used to back propagate the recorded P-potential, as well as individual components in the vector field of the S-potential. Compared with conventional elastic RTM, the proposed elastic RTM implementation using acoustic propagators not only simplifies the imaging condition, it but also reduces the computational cost and the artifacts in the images. We have determined the accuracy of our method using 2D and 3D numerical examples.


2008 ◽  
Vol 36 (4) ◽  
pp. 1220-1221 ◽  
Author(s):  
A. Kohn ◽  
E. Holzhauer ◽  
U. Stroth

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