Reflection from an Inhomogeneous Medium

The reflection coefficient, at oblique incidence, for a plane wave encountering a medium in which the wave velocity decreases exponentially has been computed by the author and presented in an earlier paper. In this paper, the reflection coefficient for several other values of ω/g, ω being the angular frequency and g the velocity gradient at the start of the exponential variation, will be given as a function of the angle of incidence. The positive exponential gradient has been treated and shows total reflection at all (except normal) angles of incidence, as one would expect from ray theory. A more realistic positive velocity gradient which remains finite yields a critical angle which depends on the entire velocity structure. The positive gradient in an absorbing medium is also being studied.