Electron transport and small angle collisions

Anisotropic Coulomb scattering of electrons necessitates high order Legendre cross-section expansions or restricted angular quadratures in numerical multigroup, discrete ordinates transport calculations. We investigate the monoenergetic (Spencer-Lewis) collision operator in a small scattering angle approximation and give comparative results for electrons. Equivalence between the small-angle collision operator and diffusion-in term of the Fokker-Planck expansion is also exhibited. Such procedure reduces the forward scattering singularity and the number of moments required in applications. An overview of multigroup discrete-ordinates methodology for electron scattering is briefly detailed. To span diffusive to transport phenomena, a diffusion synthetic technique is also employed. Agreement with exact analytic and Monte Carlo predictions is good.