Mishchenko M. Electromagnetic scattering in discrete random media: fundamental theory and applications

The dissertation describes the development and application of a microphysical approach to the modeling of electromagnetic scattering by individual particles and discrete random media. The T-matrix method for the numerically exact solution of the Maxwell equations has been drastically improved. A package of efficient T-matrix computer codes developed by the author has been posted on a publicly accessible internet site. A detailed analysis of the optical properties of nonspherical particles and effects of multiple scattering in discrete random media has been performed. The examination of the limit of a very large number and very small packing density of particles in the framework of the Foldy-Lax equations has led to the general radiative transfer equation and the general theory of weak localization of electromagnetic waves. The classical radiative transfer theory has been generalized to encompass the case of a plane-parallel layer of anisotropic rarefied discrete random medium. A detailed analysis of the accuracy of the scalar radiative transfer equation has shown that the errors of the scalar approximation become insignificant for particle size parameters exceeding 3. The dependence of various characteristics of weak localization on the optical thickness of a turbid layer and physical parameters of scattering particles has been studied theoretically. A theoretical prediction of the polarization opposition effect has been made. Simultaneous existence of opposition effects in intensity and polarization for a class of high-albedo Solar System objects has been explained in terms of weak localization of electromagnetic waves. Quantitative requirements to satellite programs for remote sensing of terrestrial aerosols have been formulated. A significant decrease in the global average optical thickness of tropospheric aerosols as well as strong regional changes in the past 20 years have been identified.