The Interaction of Elastic Waves with Inhomogeneous Media

Abstract

Beginning with the potential representation of the elastic field a second order wave vector is defined for which the interaction term is at a lower frequency order than in the standard method. This wave vector is examined from the point of, view of the reflection Properties of a second order layer. At the leve1 of geometric optics the interaction is described in terms of the geometry of the ray congruence. A formalism is developed which has numerous applications in the ray theoretical approach.