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Scintillation from extended incoherent sources


  • Johanan L. Codona,

  • R. G. Frehlich


The Green's function formalism is used to derive a series solution for the correlation of the intensity fluctuations of waves propagating through a random phase screen or an extended random medium from a spatially extended, incoherent source. The satistics of the random medium are assumed to be homogeneous in the direction transverse to the propagation direction. The spatial incoherence of the source produces two terms for the intensity correlation. One is the “standard” intensity correlation obtained by summing the intensity contributions from different regions of the source. The second describes the correlation of the rapid temporal fluctuations observed by Hanbury Brown and Twiss with their intensity interferometer. The introduction of a model narrowband receiver clarifies the role of these two contributions in a typical observation. The intensity spectrum of each contribution is expressed as a high and low spatial-frequency series. When possible, these expressions are compared with previous results.

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