Correlation Theory of Wavefields Generated by Fluctuating, Three-dimensional, Primary, Scalar Sources

Abstract

An analysis is presented of the second-order correlations in scalar wavefields generated by any finite, three-dimensional, statistically stationary, primary scalar source. General expressions are derived for the radiant intensity and for the degree of spatial coherence of the far field produced by such a source. The extreme cases of radiation from a completely correlated and from a completely uncorrelated source are discussed in detail and are illustrated with reference to sources that are spherical and uniform. The limiting forms of the solutions, when the radius of the spherical source is either small or large compared with the wavelength, are also considered.