Speaker
Mr
Akihiro Terakado
(Plasma Research Center, University of Tsukuba)
Description
$\quad$Understanding of divertor plasma phenomena is one of the most important issues for the stable plasma sustainment. A divertor plate was exposed to high heat and particle fluxes. To reduce the heat load on the divertor plate, divertor detachment is effective. In GAMMA 10/PDX, a divertor simulation experimental module (D-module) has been installed in the west-end region to study divertor detachment and plasma-wall interaction. The plasma was sustained by ion cyclotron heating, and the V-shaped target which is installed in the D-module was exposed to the end-loss plasma. Moreover, additional hydrogen gas was injected in the D-module. The electron density near the target plate increased with increase in the hydrogen neutral pressure due to the additional hydrogen gas supply and then it decreased. This density roll-over indicates the plasma was detached.
$\quad$In this study, we have measured spatial distribution of the intensities of Balmer lines in front of the V-shaped target indicating that the plasma detachment was occurred due to molecular activated recombination (MAR). We observed the ratio of Balmer α and β line intensities to study the spatial distribution of MAR. The strong region of intensity ratio of Balmer α and β line intensities moved to upstream from the corner of V-shaped target with increase in gas pressure. This means that the region of MAR moved to the upstream. We will discuss the relation between the spatial distribution of MAR and plasma parameters such as electron temperature and hydrogen molecular density.
Primary author
Mr
Akihiro Terakado
(Plasma Research Center, University of Tsukuba)
Co-authors
Prof.
Junko Kohagura
(Plasma Research Center, University of Tsukuba)
Dr
Kazuya Ichimura
(Plasma Research Center, University of Tsukuba)
Mr
Kunpei Nojiri
(Plasma Research Center, University of Tsukuba)
Prof.
Mizuki Sakamoto
(Plasma Research Center, University of Tsukuba)
Prof.
Naomichi Ezumi
(Plasma Research Center, University of Tsukuba)
Prof.
Yousuke Nakashima
(Plasma Research Center, University of Tsukuba)
