Spectroscopic Analysis of Erosion Rate from Electrode Surfaces on the ZaP-HD Device

Plasma interactions with material surfaces introduce impurities into plasma devices that contribute to radiative losses and limit operational lifetimes. The development of a diagnostic for monitoring erosion yields is crucial for understanding impurity dynamics in plasmas and for the evaluation of mitigation methods to minimize electrode erosion. Spectroscopy provides a non-perturbative tool to quantify impurity production rates and transport. The ionization per photon (S/XB) method in spectroscopy correlates line emission intensity to particle flux using empirical coefficients based on temperature and density. On the ZaP-HD Device, the graphite cathode that interacts with high-temperature, high-density plasmas is prone to physical erosion. Initial efforts in implementing an SXB calibration to an existing spectrometer and photomultiplier tube (PMT) setup are presented. Preliminary data analysis of carbon erosion rate using calibrated data and S/XB coefficients is discussed, with future work extending the diagnostic system to monitor additional carbon charge states and emissions at varying axial locations.