Plasma Characterization in Divertor Simulation Experiments with a V-Shaped Target on GAMMA 10/PDX

Abstract

The divertor simulation experimental module (Dmodule) has been installed in the west end region in GAMMA 10/PDX. By use of Langmuir probes and spectroscopic measurement of intensity ratios of He I lines, temporal evolution of electron temperature and that of electron density of the plasma in the D-module with the V-shaped tungsten target are obtained. When the additional ICRF heating is applied to the anchor cell, the electron temperature evaluated with He I intensity ratios decreases from ~60 eV to ~25 eV and that from the probe measurement decreases from ~27 eV to ~14 eV. The difference between both measurements seems to be attributed to the difference of their measurement positions. The electron density measured by the Langmuir probe increases 2.3 times due to the RF3 power but it is rather low (< 1017 m-3). The electron density at the end region is expected to be increased by enhancement of ICRF heating and additional gas puffing at the plug/barrier cell which is the upstream cell of the end region.