Equivalent refractive index of a sphere with multiple spherical inclusions

In this paper we analyse the scattering by a spherical particle with multiple spherical inclusions. Our analysis is focused on the equivalence between the inhomogeneous sphere and a homogeneous sphere with an equivalent refractive index. The equivalent sphere reproduces the differential scattering cross section of the inhomogeneous sphere reasonably accurately. This equivalence is investigated for small and large size parameters of the inclusions.