Fusion product losses due to fishbone instabilities in deuterium JET plasmas

During development of a high-performance hybrid scenario for future deuterium-tritium experiments on the Joint European Torus, an increased level of fast ion losses in the MeV energy range was observed during the instability of high-frequency n = 1 fishbones. The fishbones are excited during deuterium neutral beam injection combined with ion cyclotron healing. The frequency range of the fishbones, 10-25 kHz, indicates that they are driven by a resonant interaction with the NBI-produced deuterium beam ions in the energy range