title: Fixed scatterer in a random medium: shadowing, enhanced backscattering, and the inner structure of the Bethe-Salpeter equation.
abstract: An unperturbing theory of a fixed scatterer embedded in a random medium based on the Bethe-Salpeter (BS) equation formalism is developed. The BS equation is subject to a coordinate-interchange invariance, and from that we can, to a considerable extent, find a basic structure of the BS equation without knowing details of the specific random medium involved, which leads to enhanced backscattering. A fixed scatterer embedded in the medium changes the basic equations, according to a simple principle, insuch a way that the BS equation formally remains unchanged. Effective scattering matrices of the fixed scatterer are investigated in detail, including both a shadowing effect and enhanced backscattering.
authors.forename: K
authors.initials: K
authors.lastname: Furutsu