Evaluation of Electron Temperature and Density Using Ion Sensitive Probes on Open Field Plasma in the End-Region of GAMMA 10/PDX

Abstract

Ion sensitive probe (ISP) enables simultaneous measurement of ion temperature, electron temperature, and density. So far, we have observed a difference between electron temperature, and density data obtained using ISP and Langmuir probe (LP) in divertor experimental module of GAMMA 10/PDX. To clarify the difference observed, in this study comparisons of two kinds of ISPs are performed. In Type-I ISP, in which guard electrode is aligned with outer dielectric tube, shows an influence of temperature anisotropy on the electron temperature measurement. The electron density detected using Type-I ISP is considerably smaller than the one detected using LP. In the case of Type-II ISP, in which the guard electrode protrudes from the outer dielectric tube, the electron temperature and density detected are similar to the data obtained using LP. Furthermore, the discovered effects of hydrogen (H₂) gas pressure change are presented here.