Four-flux model for a multilayer, plane absorbing and scattering medium: application to the optical degradation of white paint in a space environment

We generalize the four-flux radiative transfer model to the case of a multi layer medium. A concrete application, that of the study of the optical degr adation of white paint in a simulated space environment, is presented. The degraded material is decomposed in a damaged layer and in an unaffected lay er, and we assume that the degradation is due to a variation AK of the imag inary part of the refractive index in the damaged layer. Then we find an em pirical law for variation AK with dose, taking into account possible satura tion. (C) 2001 Optical Society of America.