Collisional-radiative modelling of an Ar helicon plasma discharge

We report on recent modelling results of emission observed from a helicon plasma, comparing theoretical and observed line intensities and line ratios of Ar, Ar$^+$ and Ar$^{2+}$. Our Helicon plasma is from the ASTRAL device at Auburn University, with spectral measurements from 275 nm through to 1015 nm. We concentrate on the Ar$^+$ ion stage, and present the results of a collisional-radiative model using various qualities of atomic data. In particular, we compare the modelling results using Plane-Wave Born, Distorted-Wave and R-matrix electron impact excitation data with those observed from the plasma. As part of the modelling work, we investigate the potential use of various lines as plasma diagnostic tools.