Measurements and spectral modeling of neutral Argon as a diagnostic in the ALEXIS plasma

We present spectral measurements and theoretical results for an argon plasma experiment on the ALEXIS (Auburn Linear~Experiment for Instability Studies) device. Langmuir probe measurements for the electron temperature and density profiles along the line of sight were taken for a wide range of plasma B-field settings. Comparisons with theoretical models show that the plasma is not in ionization equilibrium. A theoretical spectrum is constructed using the line of sight profiles and recently calculated R-matrix atomic data. We also investigate the role of a non-equilibrium population in the neutral Ar metastable and how that affects the spectrum.