Confinement of Fusion Reaction Products during the Fishbone Instability

The presence of fishbone events in the PDX tokamak is correlated with a reduction in the burnup of 0.8-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ ions. This reduction is probably caused by distortion of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ drift orbits in the helical magnetic fields associated with the instability, resulting in the loss of about 70% of the confined ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ ions in a moderately strong fishbone. Such a nonresonant loss of particles with large orbits indicates that fishbone events may influence 3.5-MeV alphas in ignition experiments.