Calculations of alpha particle loss for reversed magnetic shear in the Tokamak Fusion Test Reactor

Hamiltonian coordinate, guiding center code calculations of the toroidal field ripple loss of alpha particles from a reversed shear plasma in the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)] predict 40% total alpha losses and 20% ripple diffusion losses. This is about double the loss rate of a comparable non-reversed magnetic shear plasma. High central $q$ is found to increase alpha ripple losses as well as first orbit losses of alphas in the reversed shear simulations. Alpha ripple transport on TFTR affects ions within $r/a=0.5$⁠, not at the plasma edge. The entire plasma is above threshold for stochastic ripple loss of alpha particles at birth energy in the reversed shear case simulated, so that all trapped 3.5 MeV alphas are lost stochastically or through prompt losses.