Coherent attenuation in a white-noise random medium
= Coherent attenuation in a white-noise random medium
{title2=$\gamma=k_0^2\mu^2 B(0)/2$}
For a <parabolic wave equation> driven by longitudinal <Gaussian white noise> with transverse <covariance kernel> $B$, the mean envelope obeys $\partial_x m=i\Delta_\perp m/(2k_0)-\gamma m$. This closure requires <independent increments> in the longitudinal direction; <statistical homogeneity> and one-point <Gaussian distributions> alone are insufficient.