Some iterative methods for radiative transfer problems

In the mathematical computation of many physical problems we have to work with the numerical solution of non-linear problems. Even in case that a direct solution does in principle exist, its feasibility is however actually restricted to a very limited number of instances. Therefore, in this study we will disregard this possibility. Consequently, we assume that an iterative procedure shall be necessary in order to tackle, in practice, all kind of non-linear problems.