On geometric acoustic in random, locally anisotropic media

When considering spatially inhomogeneous media with smooth variability, it is natural to admit local anisotropy – a non-spherical indicatrix – in place of a more restrictive assumption of isotropy. On that basis, ray dynamics and the eikonal equation that govern geometric optics (and geometric acoustics) in inhomogeneous media are formulated to take into account the dependence of local propagation velocity on the direction of the ray. All the equations reduce to classical forms when anisotropy vanishes.