Investigation of C IV line broadening mechanisms for plasma diagnostics in magnetic fusion devices

The n = 5–6 (λ = 4658 Å) and n = 6–7 (λ = 7726 Å) spectral lines emitted by Li-like carbon ions C+3 from magnetic fusion devices based on carbon material are considered for plasma diagnostic purposes. The broadening mechanisms of these lines are examined for plasma conditions relevant to Tokamak divertors (electron densities and temperatures in the ranges 1019–1021 m−3 and 1–10 eV). Under these conditions, the broadening mechanisms affecting the above lines are examined with and without the retaining of the magnetic field. The uncertainties on the deduced plasma parameters are also qualitatively estimated when only Stark and Doppler effects are retained while Zeeman and fine structure effects are ignored. The results presented are based on theoretical calculations carried out with the PPP line shape code and an atomic data basis built using Cowan’s code and the most accurate available atomic data for carbon.