ICRF-Induced DD Fusion Product Losses in TFTR

Abstract

When ICRF power is applied to TFTR plasmas in which there is no externally supplied minority species, an enhanced loss of DD fusion products results. The loss occurs at the passing/trapped boundary, and consists of particles at or near their birth energy. The process appears to be the addition of perpendicular velocity to the fusion products as they interact with the ICRF waves, so that marginally passing particles are moved across the passing/trapped boundary into the first orbit loss cone. A simplified model of this process predicts losses of a magnitude similar to those seen. Extrapolations based upon these data for hypothetical ICRF ash removal from reactor plasmas suggest that the technique will not be energy efficient for removing fast alphas from the core.