Line-Shape Code Comparison through Modeling and Fitting of Experimental Spectra of the C ii 723-nm Line Emitted by the Ablation Cloud of a Carbon Pellet

Abstract

International audienceVarious codes of line-shape modeling are compared to each other through the profile of the C II 723-nm line for typical plasma conditions encountered in the ablation clouds of carbon pellets, injected in magnetic fusion devices. Calculations were performed for a single electron density of 10 17 cm −3 and two plasma temperatures (T = 2 and 4 eV). Ion and electron temperatures were assumed to be equal (T e = T i = T). The magnetic field, B, was set equal to either to zero or 4 T. Comparisons between the line-shape modeling codes and two experimental spectra of the C II 723-nm line, measured perpendicularly to the B-field in the Large Helical Device (LHD) using linear polarizers, are also discussed

Model uncertainties of local-thermodynamic-equilibrium K-shell spectroscopy

“…Hence, further theoretical investigations and benchmark experiments are needed to refine our understanding of the line-broadening calculations and reliability of K-shell spectroscopy. The workshop of Spectral Line Shapes in Plasmas is held every two years to scrutinize the differences in the theoretical line-shape model details and their impact on the calculated line shapes [32][33][34][35]. Such workshops are an appropriate place for further scrutiny on the theoretical details and their impact on n e diagnostics.…”