Spectroscopic study of impurity ion radial distribution in an advanced beam-driven field reversed configuration

Impurity ion spectra ranging from vacuum ultra violet (vuv) to visible wavelengths was observed in an advanced beam-driven field-reversed configuration (FRC) plasmas1. Main impurity spectral lines were identified and modeled with the help of the collisional-radiative code NOMAD2. Impurity concentrations were estimated, based on the modeling results. Radial distribution of impurity charge states was reconstructed for the first time in an FRC experiment. Analysis of vuv spectra revealed quite low Zeff both inside and outside the FRC separatrix.