COHERENT SCATTERING INDICATRIX FOR ARBITRARY MEDIUM INHOMOGENEITIES -THE GENERAL MATHEMATICAL SOLUTION AND FEASIBILITY OF A FAST COMPUTER CODE

A general solution of Equation (1) in a three-dimensional inhomogeneou s medium is found. Use is made of the available ray-optical approximat e solution of (1) and the Riemann geometry of wave rays. This allows a n exact solution in series form, where the first term coincides with t he approximate solution. The second term of the exact solution contain s the major part of the scattered wave and its computation gives the r ight value of the coherent scattering. The second term and its transfo rmation leading to easier computation are analysed. The main result of this work is that the mathematical approach used is convenient for a description of the coherent scattering in inhomogeneous media when sol ving direct and inverse problems of wave propagation. The description is of a very general character and contains Bragg scattering as a part icular case. The application of this approach to the development of th e computer codes can provide a powerful tool for studying inhomogeneou s media. Developing these codes would be time consuming but provide a fast solution of many difficult problems. (C) 1996 Elsevier Science Lt d.