Computation ofqP-wave rays, traveltimes and slowness vectors in orthorhombic media

Slowness Surface Wave Surface

A Slowness Matching Nite Diierence Method for Traveltimes beyond Transmission Caustics

Conventional nite diierence eikonal solvers produce only the rst arrival time. However suitable solvers (of suuciently high order of accuracy) may be extended via Fermat's principle to yield a simple algorithm which computes all traveltimes to each subsurface point, with cost on the same order as that of a rst arrival solver.

Finite-difference quasi-P traveltimes for anisotropic media

The first-arrival quasi-P wave traveltime field in an anisotropic elastic solid solves a first-order nonlinear partial differential equation, the q P eikonal equation. The difficulty in solving this eikonal equation by a finitedifference method is that for anisotropic media the ray (group) velocity direction is not the same as the direction of the traveltime gradient, so that the traveltime gra...

Charge density wave transport in irradiated orthorhombic TaS3

2014 Dynamic resistance, noise spectrum and electron diffraction studies on electron irradiated orthorhombic TaS3 were performed in the temperature range of 75 K-280 K. At low defect concentrations ( 10-4 displacement per Ta atoms) the threshold field of the nonlinear conductivity (ET) increases linearly with the irradiation dose in spite of the fact that there is hardly any effect on the Peier...

Wave packets, rays, and the role of real group velocity in absorbing media

In an absorbing medium, where the vector W5]v/]k usually is complex for real values of the wave vector k, the group velocity W may become real for some complex values of k. The role of real group velocity in the propagation of one-dimensional wave packets in homogeneous absorbing media is examined. Applying the saddle point method to an analysis of the asymptotic behavior of the Gaussian wave p...