Kinetic Limit for Wave Propagation in a Random Medium

Kinetic Limit for Wave Propagation in a Random Medium

We study crystal dynamics in the harmonic approximation. The atomic masses are weakly disordered, in the sense that their deviation from uniformity is of order √ ε. The dispersion relation is assumed to be a Morse function and to suppress crossed recollisions. We then prove that in the limit ε → 0 the disorder averaged Wigner function on the kinetic scale, time and space of order ε, is governed...

Wave Propagation in Micropolar Thermoelastic Diffusion Medium

The present investigation is concerned with the reflection of plane waves from a free surface of a micropolar thermoelastic diffusion half space in the context of coupled theory of thermoelastic diffusion. The amplitude ratios of various reflected waves are obtained in a closed form. The dependence of these amplitude ratios with an angle of propagation as well as other material parameter are sh...

Two-scale solution for the intensity fluctuations of two-frequency wave propagation in a random medium

We have solved the equation for the two-frequency fourth-order moment of two parallel monochromatic plane waves having different frequencies and propagating through a randomly inhomogeneous medium. The solution procedure uses a two-scale expansion based on the smallness of a new parameter whose magnitude does not depend on the scattering strength. The results are shown to be valid for all value...

Kinetic limits for waves in a random medium

2 Diffusive limit for a particle in a random flow 7 2.1 Diffusion of a particle in a time-dependent random flow . . . . . . . . . . . . . . . . 7 2.1.1 The central limit theorem, purely time-dependent flows, and diffusion . . . . 8 2.1.2 Using formal asymptotic expansions . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.3 Random flows with spatial-temporal dependence . . . . . . . . . . . . ...

Wave Propagation in an Inhomogeneous Medium