NSTX-U Multiple Fast Ion Diagnostics are Needed to Constrain/Invert Fast Ion Distribution Function 2  Goal: measure beam ion distribution in NSTX-U  transport of beam ions due to MHD and Alfven eigenmode activity  interaction between high-harmonic fast waves and beam ions  neutral beam current drive  Different fast ion diagnostics weight phase space differently  FIDA: sensitive to a swath in velocity space  NPA: very localized in pitch; o ssNPA: measure trapped fast ions at different radii; fast time resolution, no energy resolution o E||B NPA: diagnose co-passing fast ions; excellent energy resolution  Neutron: strongly weighted toward high energy fast ions; insensitive to pitch angle; volume averaged  Charged fusion product diagnostic: strongly weighted toward high energy fast ions; spatial profile  Fast ion loss detector: lost fast ions; narrow in pitch …
{}