瑞樹 坂本

Impact of target temperature on hydrogen recycling in divertor plasma of GAMMA 10/PDX tandem mirror

In GAMMA 10/PDX, a temperature-controlled V-shaped target has been utilized to study an effect of target temperature on hydrogen recycling. The V-shaped tungsten target in the divertor simulation experimental module (D-module) is heated up to 573 K and it is exposed to the end loss plasma. It is found that the Hα intensity and the electron density of the plasma in front of the target are positively correlated with the target temperature, indicating that the recycling is enhanced due to increase in the target temperature. Moreover, additional hydrogen gas is injected into the D-module with the temperature-controlled target. As the amount of hydrogen gas injection increased, enhancement of hydrogen recycling by high temperature target becomes smaller.

Deuterium trapping properties of plasma sprayed tungsten layers irradiated by low energy and high flux plasma

Deuterium retention and trapping in tungsten plasma sprayed layers after low energy plasma irradiation was investigated by means of thermal desorption technique. Plasma irradiation at low temperatures ( 650 K) showed significant increase of the retention in the plasma sprayed layers contrary to the polycrystalline material. Thermal desorption spectra showed extremely high temperatures of the peak positions which are non-typical for the tungsten materials. The possible reasons for such high deuterium retention in the plasma sprayed layers after irradiation at high temperatures and the possible trapping mechanisms are discussed.

Study on Plasma Shape Reproduction of Spherical

Cauchy-Condition Surface (CCS) method is a numerical approach to reproduce plasma shape which has good precision in conventional tokamak. In order to apply it in the plasma shape repro-duction of Compact PWI experimental Device (CPD) which is a new spherical tokamak in Kyushu University, the calculation results of CCS method on CPD is reported in the paper.