TRANSPORT MEASUREMENTS FOR CONFINED NON-THERMAL ALPHA PARTICLES IN TFTR DT PLASMAS

摘要

Fusion produced non-thermal alpha particle radial profile measurements are obtained with the α-CHERS diagnostic in deuterium-tritium (DT) supershot plasmas on the Tokamak Fusion Test Reactor (TFTR). Alpha particles in the energy range 0.15 <= E_α <= 0.6 MeV are observed spectroscopically over a five point radial profile. The extracted non-thermal alpha signal is <= 1/100 of the background bremsstrahlung intensity for typical total fast alpha densities in the range (0.5-1.0)× 10~17 m~-3. The profiles obtained in two sets of discharges vary slightly, and are best described by a slowing down alpha distribution subject to neoclassical diffusion pins a small anoma- lous cross-field diffusion. The data are consistent with an effective anomalous diffusion coefficient in the range 0.00 <= D_α,a < 0.10 m~2/s, where D_α,a is constant with alpha energy and with radius.