Diffraction echo signal generated by the incidence of a plane wave on a prolate spheroid

The problem of the diffraction of a plane wave by a prolate spheroid placed in a fluid is considered in the high-frequency approximation. The spheroid is hereby either a solid body or a shell. The contribution to the echo signal, i.e., the back-reflected field, of diffraction waves of creep and break-off type is investigated. Computational formulas for the geometric divergences of surface rays and also of creep and break-off waves are obtained.