Spectra from low-Z impurities, such as carbon, nitrogen, or oxygen are used to diagnose the plasma-edge conditions of tokamak plasmas. For example, the K-shell emission of nitrogen N5+ has used to model ion transport in H-mode and L-mode plasmas on the Alcator tokamak. Theoretical wavelength predictions have a large spread and prevented a definitive identification of the satellite lines in the spectrum.
To address the uncertainty in the line identification of the K-shell satellite lines, we made detailed measurements of the K-shell spectrum of nitrogen N5+ on EBIT. Based on our observations, we measured the line position accurately and confidently determined the line identities.
