ALPHA-PARTICLE LOSSES FROM TOKAMAK FUSION TEST REACTOR DEUTERIUM-TRITIUM PLASMAS

Because alpha particle losses can have a significant influence on toka mak reactor viability, the loss of deuterium-tritium alpha particles f rom the Tokamak Fusion Test Reactor (TFTR) [K. M. McGuire et al., Phys . Plasmas 2, 2176 (1995)] has been measured under a wide range of cond itions. In TFTR, first orbit loss and stochastic toroidal field ripple diffusion are always present. Other losses can arise due to magnetohy drodynamic instabilities or due to waves in the ion cyclotron range of frequencies. No alpha particle losses have yet been seen due to colle ctive instabilities driven by alphas. Ion Bernstein waves can drive la rge losses of fast ions from TFTR, and details of those losses support one element of the alpha energy channeling scenario. (C) 1996 America n Institute of Physics.