ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

4pSA3. Scattering from complex elastic structures.

Douglas M. Photiadis

Naval Res. Lab., Washington, DC 20375-5000

The scattering cross section of elastic structures is modified in a nontrivial fashion by the presence of effectively random internal structure. The locus of the highlights in frequency-angle space can often be modeled reasonably by considering the behavior of the associated average structure, but the influence of the internal structure on the levels of the scattering cross section cannot be determined in this way. In terms of the development of effective scattering models, the mean Green's function does not contain enough information in this context and higher-order averages are required, at a minimum the mean intensity . The perturbative computation of such quantities is relatively well understood for a medium which is uniform, but for the structures of most interest, those whose properties on average vary spatially, the problem is much more difficult. The theoretical approach to the solution in this case will be discussed, and the approximate results obtained will be compared with the results from direct Monte Carlo simulations.