Transport theory in stellarators

Stellarator transport is studied numerically by solving the linearized drift kinetic equation for realistic toroidal magnetic geometries. In the plateau regime, a resonant enhancement factor for diffusion that agrees with analytic results is found. In the lower collisionality regimes, the structure of the particle distribution function in phase space is computed to examine the validity of approximate boundary conditions empolyed in analytic calculations. A diffusion coefficient D in the collisionless detrapping regime is computed. The effect on diffusion of a resonance between parallel and E x B motions is studied. Diffusion coefficients for a σ-optimized configuration are calculated and shown to compared favorably with those obtained from a Monte Carlo code