The mutual coherence function Γ12(τ) of the light scattered by turbulent-density fluctuations of a plasma has been derived. The starting point is the analytic signal associated with the electric field of the scattered light. Time dependence of the refractive-index fluctuations has been taken into account, which is an extension to the results obtained by other authors, for instance, Beran. In the same approximations as he used, coincidence of the results is shown. Extension of the theory is considered for calculation of higher-order correlation functions of electron-density fluctuations. Their determination is connected with the statistical properties of the medium, and is therefore of great interest for plasma diagnostics.
L. PIERONI and H. BREMMER, "Mutual Coherence Function of the Light Scattered by a Turbulent Medium," J. Opt. Soc. Am. 60, 936-947 (1970)