Scattering by a composite sphere with an absorbing inclusion and effective medium approximations

Abstract

We investigate the accuracy of three effective medium approximations when applied to the scattering by inhomogeneous spherical particles. We compare gross scattering properties (extinction, scattering, and absorption cross sections, single scattering albedo, and the asymmetry parameter) and the scattering phase functions calculated using the effective medium approximations to those scattering properties obtained using an exact solution of the boundary value problem for a water droplet (sphere) containing an arbitrarily located spherical carbon inclusion. For small inclusion size parameters ( x inc<0.5), all effective medium approximations predict gross scattering properties to within 1% accuracy. As the inclusion size increases, the extended effective medium approximation provides greater accuracy than the other approximations. In addition, the extended effective medium approximation more accurately reproduces the structure of the scattering phase function.