Verification and validation of neoclassical predictions of fast-ion distribution functions in gyrokinetic simulations

Fast ion distribution functions for MHD-quiescent plasmas in the Large Helical Device (LHD) are compared to neoclassical predictions. Fast ion D-alpha (FIDA) data and heavy ion beam probe (HIBP) data were collected during the 23rd LHD campaign for configurations with varying major radii. Variations in the major radius are shown to have an effect on the neoclassical confinement of fast ions. The experimental FIDA signals are compared to spectra generated by the fast ion diagnostic simulation code FIDASIM with inputs for the distribution function created by the gyrokinetic toroidal code (GTC). Distribution functions from GNET are also used for benchmarking GTC. Additionally, radial electric field profiles collected by the HIBP are compared to the calculated electric field from GTC.