Hybrid ray-mode parametrization of high frequency propagation in an open waveguide with inhomogeneous transverse refractive index: formulation and application to a bilinear surface duct

The authors discuss a general complex spectral approach to representing high-frequency source-excited fields in open guiding environments characterized by a continuously varying refractive index in the cross section transverse to the propagation direction. The authors use problem parameters that are motivated by electromagnetic wave propagation in the Earth´s atmosphere, in particular, a tropospheric surface duct adjacent to the Earth´s surface. The main objective is the development of an observable-based algorithm that self-consistently incorporates various wave objects that synthesize the high-frequency propagation process in a numerically efficient and physically incisive manner. The authors concentrate on ray fields and mode fields, either individually or, most generally, in a rigorous self-consistent hybrid combination. Explicit solutions are generated for a bilinear refractive index profile that generates a leaky surface duct. For numerical results see ibid., vol.39, no.6, p.789-97 (1991)