Study of neutral-hydrogen-sensitive variations in C V line ratios of the TJ-I tokamak

It has been shown previously that charge exchange that involves slow collisions between hydrogen-like carbon and neutral hydrogen are responsible for variations in the intensity ratio between the helium-like carbon triplet lines, 1s2s3S1−1s2p3P2 (2271.59 Å) and 1s2s3S1-1s2p3P0,1 (227.841 nn), which were seen in line-of-sight measurements across the TJ-I tokamak. We compare how this process may cause anomalies in the associated intercombination to the resonance line ratio G, and we shown how line-of-sight measurements across a plasma radius and the equations developed here may be used to estimate the plasma neutral concentration. Finally, we estimate the sensitivities of these line ratios to the neutral density for tokamak plasmas.