M. Dusek, SPECTRAL PROPERTIES OF STOCHASTIC ELECTROMAGNETIC-FIELDS WITH SPHERICAL-SYMMETRY, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 49(2), 1994, pp. 1671-1676
We discuss the general solution of equations of the second-order corre
lation theory in the space-frequency domain for classical, statistical
ly stationary vector electromagnetic fields. The spectral properties o
f radiation are studied in detail for fields which are spherically sym
metric in the statistical sense. The formalism of cross-spectral tenso
rs and mode decomposition are used. It is shown that the frequency dep
endence of the spectrum of radiation may differ in different points of
space.