Asymptotic Radiative Transfer

Abstract

Asymptotic radiative transfer (ART), like diffusion theory, assumes the angular intensity distribution incident at a boundary is identical with that in the depth of the scattering medium. However, the asymptotic intensity profile and accurate attenuation coefficient corresponding to the scattering phase function are used in preference to the P1 approximations of diffusion theory, thereby extending the range of asymptotic radiative transfer to the lowest particle scattering albedoes. Asymptotic calculations for scattering media with refracting boundaries are compared with diffusion theory and accurate radiative transfer data to illustrate this. The error involved can be further reduced by the addition of a suitable boundary transient