RF-driven Energetic Tritium Ion Tail Measurements in TFTR Using the Pellet Charge Exchange Diagnostic

Charge exchange interactions of ions with the ablation cloud of an injected lowZ impurity pellet can be used to measure the energy spectrum and radial profile of confined fast ions in a fusion plasma. On TFTR, we use this technique to directly measure energetic alphas from D-T reactions, tritons from D-D reactions, and RFdriven minority tail ions (e.g., H, 3He, T). This paper describes the status of the Pellet Charge Exchange (PCX) diagnostic including a brief description of the measurement technique and discussion of operational experience. PCX measurements of the energy spectrum, radial density distribution, and heating deposition profile of RFdriven tritium ions during 2WT heating of L-mode plasmas are presented.