On the solution of azimuthally dependent transport problems with the ANISN code

The method of discrete ordinates, as implemented in the ANISN code, is used to solve the problem of a slab subject to a uniform beam of particles inciding obliquely on one of its surfaces. A Fourier decomposition is used, in the manner of Chandrasekhar, to reduce the original problem to a series of azimuthally independent problems for the Fourier components of the solution. These problems are solved with a conveniently modified version of the ANISN code. In particular, a new quadrative that facilitates the implementation of the code for computing the Fourier components of the solution is introduced. Numerical results are given for some selected problems in the form of percent deviations from highly accurate results generated with the spherical-harmonics method. (C) 1997 Elsevier Science Ltd.