The signal structure in the vicinity of the background simple caustic of a randomly-inhomogeneous medium

This report presents results of the analysis of such characteristics as the mean intensity of the short-wave signal, its angular and frequency spectra, the scintillation index depending on parameters of random and regular irregularities, as well as on the propagation range for a wave reflected from a regularly and randomly inhomogeneous layer, under conditions of strong and weak fluctuations in the vicinity of a simple caustic and in the zone of a regular caustic shadow. It is known that geometrical optics generalizations must be invoked in the vicinity caustics where a geometrical optics approach is inapplicable. Therefore, with the purpose of solving such problems, using the Maslov method and the interference integral method, this report discusses an approach to deriving an integral representation for a two-point propagator in a randomly-inhomogeneous ionosphere medium which takes into account the presence of regular and random caustics.