  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.
