Study on the extension of AN and SPN methods to the analysis of heterogeneous media

The AN and SPN methods to solve the linear transport equation are rigorously valid for a finite, homogeneous medium or for heterogeneous, one-dimensional problems. In the present work, two distinct cases are considered, each of them close to one of these situations, and it is shown that the correct equations that take into account for the heterogeneity and the multidimensionality can be obtained by adding suitable extra terms to the model.