TRANSPORT-EQUATIONS FOR ELASTIC AND OTHER WAVES IN RANDOM-MEDIA

We derive and analyze transport equations for the energy density of wa ves of any kind in a random medium. The equations take account of nonu niformities of the background medium, scattering by random inhomogenei ties, polarization effects, coupling of different types of waves, etc. We also show that diffusive behavior occurs on long time and distance scales and we determine the diffusion coefficients. The results are s pecialized to acoustic, electromagnetic, and elastic waves. The analys is is based on the governing equations of motion and uses the Wigner d istribution.