Speaker
Prof.
Yousuke Nakashima
(Plasma Research Center, University of Tsukuba)
Description
In order to realize nuclear fusion reactors, it is one of the most important issues that the development of plasma facing materials. For example, the materials used in the divertor are exposed to high heat plasma-flow and are significantly damaged. Heat-load characteristics of the materials have been researched in all over the world by using various heat sources such as particle beams and laser light [1,2].
GAMMA 10/PDX is the largest tandem mirror device in the world and is structured by a central-cell, anchor-cells, plug/barrier-cells and end-cells. The divertor simulation experimental module (D-module) is installed in the west end-cell of GAMMA 10/PDX and investigation on plasma-wall interaction have been performed [3]. Recently, in order to study beam-material interaction, an ion beam injector was built up and installed at the west end-cell. Hydrogen ion beam is injected by using a bucket-type ion source in which a cusp magnetic field is applied. Maximum operation parameters of the ion source are 20 kV, 10 A, 3 ms. The ion beam system is placed on the end-cell axis and is injected the west end mirror coil. A magnetic field having 0 to 3 Tesla magnetic field intensity can be applied at the coil. The distance of the ion source and the coil is about 6 m and the mirror ratio is $\sim$1,300. Due to this magnetic field gradient, the ion beam is converged toward the mirror throat.
Our goal is to study beam-material interaction to reveal the physical mechanism of beam facing materials under the circumstances with converging magnetic field configuration. We choose the materials which are going to be used in ITER such as tungsten and molybdenum.
In order to investigate the beam characteristics, calorimeters, high-speed video cameras and tungsten targets are prepared. Calorimeters are mainly used for measuring beam intensity. Spatial distribution of light emission from beam-material interaction can be captured by high-speed video camera. In the present experiment, tungsten is used for target material.
First experiments have been carried out in order to evaluate the beam characteristics. By scanning the calorimeter installed at 0.8 m downstream of the ion source, the beam divergence angle is determined to be about 2.6 degrees. The beam spatial distribution and the light emission of beam-material interaction are converged as increasing the magnetic field strength. In the presentation, we describe the detail of the ion source characteristics, the examination method and results. We will also have discussion about the beam converging effect in magnetic field.
[1] H. Greuner, et al., Fus. Eng. 75-79(2004) 345.
[2] J. Boscary, et al., Nucl. Fusion 43(2003) 831.
[3] Y. Nakashima, et al., J. Nucl. Mater. 463(2015) 538.
Primary author
Mr
Kazuma Fukui
(Plasma Research Center, University of Tsukuba)
Co-authors
Mr
Kazuo Ohkawa
(Plasma Research Center, University of Tsukuba)
Mr
Keita Shimizu
(Plasma Research Center, University of Tsukuba)
Mr
MD SHAHINUL ISLAM
(Plasma Research Center, University of Tsukuba)
Mr
Masato Ohuchi
(Plasma Research Center, University of Tsukuba)
Mr
Md. Maidul Islam
(Plasma Research Center, University of Tsukuba)
Mr
Mizuho Arai
(Plasma Research Center, University of Tsukuba)
Mr
Takayuki Yokodo
(Plasma Research Center, University of Tsukuba)
Prof.
Yousuke Nakashima
(Plasma Research Center, University of Tsukuba)
Dr
kazuya ichimura
(Plasma Research Center, University of Tsukuba)
Prof.
shinji nagata
(Institute for Materials Research, Tohoku University)
Peer reviewing
Paper
Paper files:
