T. Yokodo
University of Tsukuba
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Publication
Featured researches published by T. Yokodo.
2017 International Conferences on Research and Applications of Plasmas, PLASMA 2017 | 2018
M. M. Islam; Yousuke Nakashima; Shinji Kobayashi; N. Nishino; K. Ichimura; Takaaki Iijima; M. S. Islam; T. Yokodo; Guanyi Lee; Tsubasa Yoshimoto; Sotaro Yamashita; M. Yoshikawa; Junko Kohagura; M. Hirata; Ryutaro Minami; T. Kariya; R. Ikezoe; M. Ichimura; Mizuki Sakamoto; T. Imai
Establishment of fueling system is one of the critical issues for the future fusion reactors. Fueling experiment supersonic molecular beam injection (SMBI) have been carried out in the central-cell of GAMMA 10. In GAMMA 10, electron cyclotron resonance heating (ECRH) is used at plug/barrier-cells for the formation of the axial confining potential. Recently, ECRH was applied during SMBI to plug the loss particles and increased the plasma density in the central-cell compared to without ECRH. This result suggests that the particles are confined during SMBI due to the injection of ECRH at plug/barrier-cells in GAMMA 10.
OPEN MAGNETIC SYSTEMS FOR PLASMA CONFINEMENT (OS2016): Proceedings of the 11th International Conference on Open Magnetic Systems for Plasma Confinement | 2016
M. S. Islam; Yousuke Nakashima; R. Tatsumi; A. Hatayama; Kazuya Ichimura; M. M. Islam; K. Shimizu; K. Fukui; M. Ohuchi; T. Yokodo; Guanyi Lee; N. Ezumi; Masanori Sakamoto; T. Imai
The effect of neutral Ar injection on the plasma parameters is investigated numerically by using a multi-fluid code in this research. Reduction of electron and ion temperature has been observed according to the increment in injected neutral Ar density. The heat flux on the target plate has been also reduced with the increasing of injected neutral Ar density. For Ar: 2.0 × 1018u2005m−3 injection, electron temperature on the target plate reduced to about 1.5 eV. Increase in electron and ion density has been observed at lower injected Ar density. However, at higher Ar injection, electron density and ion density goes to be saturated. These outcomes indicate that the plasma in the end region approaches towards the plasma detachment state.
OPEN MAGNETIC SYSTEMS FOR PLASMA CONFINEMENT (OS2016): Proceedings of the 11th International Conference on Open Magnetic Systems for Plasma Confinement | 2016
M. M. Islam; Yousuke Nakashima; Shinji Kobayashi; N. Nishino; K. Hosoi; Kazuya Ichimura; M. S. Islam; K. Fukui; K. Shimizu; M. Ohuchi; M. Arai; T. Yokodo; Guanyi Lee; M. Yoshikawa; J. Kohagura; M. Hirata; R. Ikezoe; M. Ichimura; Masanori Sakamoto; T. Imai
Results of supersonic molecular bean injection (SMBI) with Laval nozzle has been carried out in the GAMMA 10 tandem mirror. The neutral transport during SMBI was investigated by the two-dimensional image of the light emission captured by the high-speed camera. We used the value of full width at half maximum (FWHM) of the distribution of emission intensity as an index of neutral transport. The FWHM value decreases with the increase of the plenum pressure which indicates that the particle diffusion was more convergent at high plenum pressure. Fully three-dimensional neutral transport simulation using a Monte-Carlo code DEGAS is applied to SMBI experiment and simulation results qualitatively explained the experimental results.
OPEN MAGNETIC SYSTEMS FOR PLASMA CONFINEMENT (OS2016): Proceedings of the 11th International Conference on Open Magnetic Systems for Plasma Confinement | 2016
T. Yokodo; Yousuke Nakashima; K. Shimizu; K. Ichimura; M. M. Islam; M. S. Islam; K. Fukui; M. Ohuchi; A. Terakado; K. Nojiri; M. Yoshikawa; N. Ezumi; Masanori Sakamoto; T. Imai
In this study, spectroscopic measurement at the plug/barrier-cell, near the midplane in GAMMA 10/PDX was carried out for the first time. From the comparison of the spectroscopic data measured in the end-cell and plug/barrier-cell, transport of impurities injected to divertor simulation module in the end-cell is investigated. It was found that Ne hardly ionized at both observation points. On the other hand, N2 dissociated and ionized before reaches or at the plug/barrier-cell while emission spectrum derived from N2 was dominated at the end-cell. From the comparison of the emission spectrum at the end-cell and plug/barrier-cell, it suggests that Ne was more likely to transport toward upstream region through the plasma than N2. Time evolution of specific emission spectra, electron temperature and density suggests the reduction of the impurity transport during ECH pulse.
OPEN MAGNETIC SYSTEMS FOR PLASMA CONFINEMENT (OS2016): Proceedings of the 11th International Conference on Open Magnetic Systems for Plasma Confinement | 2016
K. Fukui; Yousuke Nakashima; S. Nagata; K. Ichimura; M. M. Islam; M. S. Islam; K. Shimizu; M. Ohuchi; T. Yokodo; M. Arai; K. Ohkawa
In this research, the effect of beam convergence with magnetic field of GAMMA 10/PDX has been investigated. The hydrogen ion beam is injected to the tungsten target under the various strength of magnetic field. The spatial distribution of emission light and rising temperature of the target are measured with a fast camera and a calorimeter, respectively. Effectiveness of beam convergence due to the magnetic field expansion is evaluated from the viewpoint of beam-material Interaction studies.
OPEN MAGNETIC SYSTEMS FOR PLASMA CONFINEMENT (OS2016): Proceedings of the 11th International Conference on Open Magnetic Systems for Plasma Confinement | 2016
M. Ohuchi; Yousuke Nakashima; H. Matsuura; K. Ichimura; M. S. Islam; M. M. Islam; K. Fukui; T. Yokodo; Guanyi Lee; N. Ezumi; Masanori Sakamoto; K. Tsumura; R. Minami; T. Kariya; T. Imai
In this paper, detailed results of the heat flux measurements are presented and the improvement of heat flux evaluation method is also discussed. We measured the heat flux in the case that additional heating with electron cyclotron resonance heating (ECRH). The heat flux reaches about 17 MW/m2 in the case with ECRH power 380kW. It is found that solving one-dimensional inverse heat conduction problems provides a possibility of improving time response of the heat flux measurement under the condition of changing heat flux in 20Hz.
Fusion Engineering and Design | 2017
M. S. Islam; Yousuke Nakashima; A. Hatayama; K. Ichimura; M. M. Islam; K. Fukui; M. Ohuchi; T. Yokodo; Guanyi Lee; S. Togo; N. Ezumi; Masanori Sakamoto; T. Imai
Plasma and Fusion Research | 2018
K. Ichimura; Sotaro Yamashita; Yousuke Nakashima; M. Fukumoto; M. Shoji; Mizuki Sakamoto; N. Ezumi; M. M. Islam; M. S. Islam; T. Yokodo; Guanyi Lee; A. Terakado; K. Nojiri; Tsubasa Yoshimoto; Hiromasa Takeno
Plasma and Fusion Research | 2018
T. Yokodo; Yousuke Nakashima; A. Hatayama; Takaaki Iijima; M. S. Islam; Tsubasa Yoshimoto; K. Ichimura; M. M. Islam; Guanyi Lee; Sotaro Yamashita; A. Terakado; K. Nojiri; M. Yoshikawa; Junko Kohagura; N. Ezumi; Mizuki Sakamoto; T. Imai
Plasma and Fusion Research | 2018
M. S. Islam; Yousuke Nakashima; A. Hatayama; K. Ichimura; Takaaki Iijima; M. M. Islam; T. Yokodo; Guanyi Lee; Tsubasa Yoshimoto; Sotaro Yamashita; N. Ezumi; Mizuki Sakamoto