Radiative Transfer in Anisotropically Scattering Media: Allowance for Fresnel Reflection at the Boundaries

Abstract

An analysis of the effect of Fresnel reflection at the interface of a slab containing isotropic or anisotropic scatterers is presented. A closed form solution for the effect of refractive index on the absorptance of an optically thin slab containing isotropic scatterers shows that allowance for internal reflection leads to absorptances severalfold those obtained with reflection ignored. Allowance for interface reflection also increases the computational effort to obtain solutions to the transport equation by the method of discrete ordinates. Representative numerical results are used to illustrate how interface reflection causes a significant decrease in the magnitude of both reflectance and transmittance, and a marked alteration in the angular distribution of the energy reflected and transmitted by a slab containing scattering centers.