Study of the impurity transport by injecting the gas to D-module in GAMMA 10/PDX

In this study, spectroscopic measurement at the plug/barrier-cell, near the midplane in GAMMA 10/PDX was carried out for the first time. From the comparison of the spectroscopic data measured in the end-cell and plug/barrier-cell, transport of impurities injected to divertor simulation module in the end-cell is investigated. It was found that Ne hardly ionized at both observation points. On the other hand, N2 dissociated and ionized before reaches or at the plug/barrier-cell while emission spectrum derived from N2 was dominated at the end-cell. From the comparison of the emission spectrum at the end-cell and plug/barrier-cell, it suggests that Ne was more likely to transport toward upstream region through the plasma than N2. Time evolution of specific emission spectra, electron temperature and density suggests the reduction of the impurity transport during ECH pulse.