Pitch Angle Resolved Measurements of Neutral Beam Ion Loss from NSTX Plasmas

Pitch angle resolved measurements of neutral beam ion losses from NSTX plasmas have been made under a range of MHD-quiescent conditions. The loss is at the injection energy (80 keV), and a constants-of-the-motion model of the beam ion phase space predicts the range of pitch angles seen, indicating the measurements are attributable to prompt loss. A loss at high pitch angle and localized in pitch angle is often observed during MHD activity.