On Rytov's Method

Rytov's method (method of smooth perturbations) has been used extensively to solve problems involving wave propagation in turbulent media. The closure procedure employed in the Rytov theory is, however, questionable. In this paper the Rytov result is compared with the results of the perturbation theory of linear stochastic operators. It is shown that the Rytov method does not yield the field correct to first order in the pertur‐bation parameter, and it is concluded that the method is not generally valid beyond the limits of the Born (single‐scatter) approximation.