Atomic data and UV spectroscopy of low charge states of W for use in Plasma Facing Component studies*

Tungsten spectroscopy is important for gross and net erosion diagnostics of Plasma Facing Components. Recent years have seen a significant improvement in the quality of the atomic data for W, including electron-impact excitation data for neutral W, W+, and W2+. An overview is given of the new atomic data, along with spectral comparisons of W I, W II, and W III emission lines from the Auburn CTH experiment and the DIII-D tokamak, using a high-resolution high-throughput UV spectrometer. Current spectral data from neutral W suggests that the excited state ionization cross sections in available datasets may be too low, thus our recent focus has been on improving the ionization data. We also report on wavelength windows showing emission from multiple tungsten charge states, allowing for redeposition measurements to be made. In addition, results are presented on magnetic field line broadening of tungsten spectral features, showing generally good agreement with observed spectra.