Abstract
Predictions for ripple loss of fast ions from TFTR are investigated with a guiding centre code including both collisional and ripple effects. A synergistic enhancement of fast ion diffusion is found for toroidal field ripple with collisions. The total loss is calculated to be roughly twice the sum of ripple and collisional losses calculated separately. Discrepancies between measurements and calculations of plasma beta at low current and large major radius are resolved when both effects are included for neutral beam ions. A 20 to 30% reduction in alpha particle heating is predicted for qa=6-14, R=2.6 m DT plasmas on TFTR owing to first orbit and collisional stochastic ripple diffusion