Multiple Scattering of Electromagnetic Waves by Random Scatterers of Finite Size

Abstract

The problem of multiple scattering of waves by randomly positioned objects has been treated by several authors, for example, Foldy, Lax, Twersky, Waterman, and Truell. The present work extends the theory to electromagnetic vector fields and to scatterers of arbitrary size and properties. A general formulation has been made for scattering by any type of discrete and identical scatterers which are similarly oriented. The case of spherical scatterers has been treated by using the rigorous Mie theory both for sparse and dense concentration. Results indicate that in case of sparse concentration, the statistical expectation of the total field has a polarization similar to that of the normally incident wave and the distribution of scatterers is equivalent to a homogeneous medium with a modified refractive index. In case of dense concentration the medium can sustain a number of plane-wave modes. A dispersion relation for the modified medium has been obtained. When the special cases of small spheres is considered, the well-known results obtained by other authors are recovered.