Evidence for a wave induced particle pinch in the presence of toroidally asymmetric ICRF waves

The first experimental observation of a radio frequency (rf) wave-induced particle pinch of trapped ions has been made in experiments at the Joint European Torus with nearly on-axis high power toroidally asymmetric ICRF (ion cyclotron range of frequencies) heating. Significant differences have been detected in discharges when waves have been directed in opposite toroidal directions. In particular, fast-ion-driven Alfven eigenmode activity, sawtooth behavior, and proton distribution functions have been found to be strongly affected. The analysis of the discharges shows that the observed differences are consistent with an ICRF-induced particle pinch predicted by theory.