Inverse problems for a perturbed dissipative half-space

This paper addresses the scattering of acoustic and electromagnetic waves from a permrbed dissipative half-space. For simplicily, the perturbation is assumed to have compact support. Section 1 discusses the application that motivated this work and explains how the scalar model used here is related to Maxwell's equations. Section 2 introduces three formulations for direct and inverse problems for the half-space geometry. Two of these formulations relare to scattering problems, and the third to a boundary value problem. Section 3 shows how the scattering problems can be related to the boundary value problem. This shows that the three inverse problems are equivalent in B certain sense. In section 4, the boundary value problem is used to outline a simple way to formulate a multi-dimensional layer stripping procedure. This procedure is unstable and does not constitute a practical algorithm for solving the inverse problem. The paper concludes with t h e appendices, the fint two of which carry out a careful construction of solutions of the direct problem and the third of which contains a discussion of some properties of the scattering operator.