Acceleration of the Sn Equations with Highly Anisotropic Scattering using the Fokker-Planck Equation

Abstract: The discrete ordinates method can model forward-peaked transport problems accurately. However, convergence of discrete ordinates solution can become arbitrarily slow upon use of standard iterative procedures like source iteration and GMRES. Standard zeroth and first moment-based acceleration methods like nonlinear diffusion acceleration and diffusion synthetic acceleration are ineffective in accelerating such problems because these methods do not correct higher order Legendre-moments of angular flux. We explore the idea of using Fokker-Planck as a preconditioner to accelerate forward-peaked transport problems in this paper.