Spatial characterization of a divertor in the presence of an X-point MARFE by collisional-radiative modeling and line profile calculations

Abstract

High-resolution C IV n=6–7 (λ=722.6nm) line spectra measured in the divertor of JT-60U in presence of an X-point MARFE are analyzed using line profiles accounting for Stark and Doppler broadenings but excluding Zeeman effect which was suppressed experimentally. Spectra are fitted assuming either a single or two plasma layers depending on the crossed part of the MARFE. The ion temperature is taken equal to that of the electrons, the latter being deduced from C IV line intensity ratios. A density of 1020m−3 has been determined after fitting peripheral spectra with respect to the MARFE. For spectra related to central parts of the MARFE, two homogeneous plasma layers were assumed: a low-density layer (Ne(l)=1020m-3) and a high-density one with Te(h)=1-3eV. For few values of Te(h), a fitting procedure was used in which Te(l) (low-density layer temperature) and Ne(h) (high-density layer density) were searched for in the domains 1–25eV and 1020–1021m−3.