Comparison of bounce‐averaged quasilinear theory with charge exchange measurements during minority fundamental and majority second harmonic ICRF heating in PLT

Previous studies in PLT using charge‐exchange, edge probe, and fusion product diagnostics all indicate that ICRF tends to produce energetic trapped particles whose banana tips are near the resonance layer. A bounce‐averaged quasilinear operator which predicts this ‘‘resonance localization’’ has been implemented in a Fokker‐Planck code in order to make detailed comparisons with measurements. Good agreement is found with data from the horizontally‐scanning, mass‐resolving, charge‐exchange analyzer, although the RF power profile seems to be broader than expected. We have recently observed a deuterium tail during hydrogen minority heating. The shape of this tail and its scaling with RF power agree well with the quasilinear theory. These measurements indicate that as much as 30% of the central RF power goes into direct second harmonic deuterium heating.