Surface waves and other acoustic modes in semi-infinite anisotropic media

A brief survey is presented of the theory of acoustic eigen-modes in elastic half-spaces of unrestricted anisotropy with or without piezo-electric, piezo-magnetic and magnetoelectric couplings. Existence conditions and possible numbers of different wave modes for various boundary-value problems are considered. Subsonic, supersonic, quasi-bulk and leaky surface waves as well as homogeneous and inhomogeneous exceptional bulk waves and some other modes are described. Relations between group, ray and tracing velocities of surface waves in piezolelectrics are established. The reflection problem is considered in the same terms theory of surface waves. The condition for a simple reflection is found. A resonance reflection of bulk waves with the tracing speed close to that of a leaky surface waves is discussed.