Spectroscopic Measurements in the Experiments of Gas Injection to the Divertor Simulation Experimental Module of GAMMA 10/PDX

In this paper, detailed results on spectral measurement are reported and the argument on impurity transport is presented from the comparison of the spectral measurements in the end-cell and the plug/barrier-cell. Spectroscopic measurement in the plug/barrier-cell was carried out for the first time. Ionization behavior in the plug/barrier-cell showed a significant difference from that in the end-cell. Discussion of detached plasma generation from the change of the electron temperature, density and emission spectrum by the gas injection conditions is also presented. In the case that the plenum pressure of noble gas was increased, the radiation of hydrogen neutrals decreased by 20~90% and the ion saturation current decreased by 90~95%, which indicated that electron density is reduced by recombination. It is suggested that the effect of molecular activated recombination may have appeared.