Progress on the Collisional-Radiative Modeling and the Analysis of Local Line Emission Profiles of Carbon Impurities from TJ-II Plasmas

In a simple previous analysis the ratio of local emission profiles of carbon impurities (C$^{4+}$ at 227.1 nm and C$^{5+}$ at 529.0 nm) measured from TJ-II plasmas was found to have a significant dependence of neutral density profile. Hence, the aim of this work is to have a better theoretical understanding of this system and finally validate or discard the carbon spectral line ratio as a useful tool to estimate the neutral density profile in ECRH TJ-II plasmas. To assist in the theoretical modeling of this carbon system we use the collisional-radiative code ABAKO, which has been successfully applied to different ICF problems. Progress on the collisional-radiative modeling and simulation of MCF TJ-II plasmas are reported, paying particular attention to the influence of the charge-exchange recombination processes on the charge state distribution and carbon line ratio radial profiles.