Fast-Ion D-Alpha spectroscopy studies at NSTX-U

Knowledge on fast-ion confinement properties is important since fast-ions heat the background plasma and, if lost before thermalization, can damage the vessel walls. One method to study the fast-ion distribution function is Fast-Ion D-Alpha (FIDA) spectroscopy which measures the Doppler shifted Balmer-Alpha emission emitted by neutralized fast-ions following charge-exchange reactions. Here we present the design and first calibration results of an upgraded FIDA spectrometer system at NSTX-U. Moreover, we introduce a novel python version of the FIDASIM code that models synthetic FIDA spectra based on an input 4D fast-ion distribution function. A detailed benchmark between the new code, using a less memory intensive simulation scheme, and the FORTRAN version of FIDASIM will be presented.