Speaker
Mr
Md. Shahinul ISLAM
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Description
GAMMA 10/PDX is the world's largest linear device which is 27 m long. In GAMMA 10/PDX, divertor simulation experiments have been started by using a divertor simulation experimental module (D-module) in which a V-shaped target made of tungsten has been installed [1]. In order to understand the effect of impurity injection into the D-module, we injected impurity Ar gas into the D-module and measured the electron density, electron temperature, heat flux and ion flux. It has been found that the plasma parameters in the D-module depend on the gas throughput. Reduction of electron temperature, heat and ion fluxes has been observed according to the increase of impurity injection [1]. These outcomes indicate that detached plasma is generated.
A numerical simulation study by using a Multi-fluid code [2-3] has been started in order to understand the energy loss processes and the plasma behaviors under the same conditions of the divertor simulation experiments in the GAMMA 10/PDX. This fluid code consists of five equations based on the same model as B2 code. The B2 code, which is the core of SOLPS4.0 code package, was originally developed by B.J. Braams [4]. The numerical meshes have been created on the basis of the GAMMA 10/PDX magnetic field configuration approximately same manner as B2 code. The convergence of the equations has been checked by analyzing the residual error of each equation. The tungsten target has been designed at the end of the mesh. The effect of neutral hydrogen and Ar impurity injection on the plasma parameters has been investigated numerically. Recycling hydrogen atoms and molecules by the target plate have been also included in this model. In the present study, the neutral model has been improved. Simulation results based on the new neutral model will be presented in this paper. Reduction of electron and ion temperature, heat flux has been observed with the increasing injected neutral Ar and hydrogen density. At lower injected Ar density, it has been observed that electron density increases almost linearly. However, at higher Ar injection, electron density goes to be saturated. The tendency of saturation in electron density is observed at higher injected Ar density region, which indicates that the plasma in the end region approaches to the plasma detachment state. In order to investigate energy loss processes, atomic processes of Ar and hydrogen have been included in this model. It has been found that the charge-exchange (CX) loss between hydrogen neutral and hydrogen ion is the dominant process. More detailed results will be presented at the conference.
[1] Y. Nakashima *et al.*, Trans. Fus. Sci. Technol **68**, No.1, 28 (2015). $\\$
[2] H. Takeda *et al.*, Trans. Fus. Sci. Technol **63**, No.1T, 414 (2013).$\\$
[3] H. Takeda *et al.*, Contrib. Plasma Phys **54**, No. 4-6, 605 (2013). $\\$
[4] B.J. Braams, NET Report,**68**, EUR-FU/XII-80/87/68 (1987).$\\$
Primary author
Mr
Md. Shahinul ISLAM
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Co-authors
Prof.
Akiyoshi HATAYAMA
(Graduate School of Science and Technology, Keio University, Hiyoshi, Yokohama 223-8522, Japan)
Dr
Kazuya Ichimura
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Mr
MD Maidul ISLAM
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Mr
Masato Ohuchi
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Prof.
Mizuki Sakamoto
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Dr
Naomichi EZUMI
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Ms
Ryoko TATSUMI
(Graduate School of Science and Technology, Keio University, Hiyoshi, Yokohama 223-8522, Japan)
Mr
Takayuki yokodo
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Prof.
Tsuyoshi IMAI
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Prof.
Yousuke Nakashima
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Mr
kazuma fukui
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
Mr
keita shimizu
(Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan)
