Modeling of Electromagnetic Scattering by Discrete and Discretely Heterogeneous Random Media by Using Numerically Exact Solutions of the Maxwell Equations

In this paper, we discuss some aspects of numerical modeling of electromagnetic
scattering by discrete random medium by using numerically exact solutions
of the macroscopic Maxwell equations. Typical examples of such media are clouds of
interstellar dust, clouds of interplanetary dust in the Solar system, dusty atmospheres of
comets, particulate planetary rings, clouds in planetary atmospheres, aerosol particles
with numerous inclusions and so on. Our study is based on the results of extensive
computations of different characteristics of electromagnetic scattering obtained by using
the superposition T-matrix method which represents a direct computer solver of the
macroscopic Maxwell equations for an arbitrary multisphere configuration. As a result,
in particular, we clarify the range of applicability of the low-density theories of radiative
transfer and coherent backscattering as well as of widely used effective-medium
approximations.