A random-motion model of fluctuations in a nearly transparent medium


  • D. A. de Wolf


Nearly transparent media are characterized by propagation constants k2(r) = k20 inline image (r)[1 + δε(r)] where inline image(r) is slowly varying and close to unity, whereas δε(r) ≪ 1. The statistics of wave amplitudes that are governed by those of δε itself is invoked; a spectral density Φ(K) follows from arguments about the form of the autocorrelation function of δε. In this work we provide a simple model of randomly moving circular eddies for δε. The connection between Φ(K) and the model is worked out, and the familiar example of Kolmogorov turbulence is analyzed in terms of the model parameters.