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Your search keyword '"Ohkuma, Yasunori"' showing total 20 results
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20 results on '"Ohkuma, Yasunori"'

1. SDGsの観点を導入した研究リソースの利活用による探求・学科横断型授業の設計

Author

MADA, Jun, primary, ASAMOTO, Hiromichi, additional, IMATAKI, Nobuko, additional, AKITA, Hironaga, additional, ARAI, Kenichi, additional, OHKUMA, Yasunori, additional, OSAKA, Naoki, additional, KIKUCHI, Toshiki, additional, KITAJIMA, Yuichiro, additional, KOBAYASHI, Naoki, additional, SHIBAYAMA, Hitoshi, additional, TAKAHASHI, Tomoki, additional, TAKAYOSE, Masaki, additional, MIURA, Shinichiro, additional, MINAMISAWA, Hiroaki, additional, MORI, Kentarou, additional, and MATSUMOTO, Masakazu, additional

Published
2024
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6. Characteristics of the plasma jet by applying a pseudo-spark discharge

Author

Kamada, Takaharu, Watanabe, Masayuki, Matsukawa, Naofumi, Ishikawa, Toshiaki, Itagaki, Minoru, Fujiwara, Tamiya, Ohkuma, Yasunori, Shiina, Shoichi, Saito, Katsunori, Watanabe, Masayuki, Iwate University, Faculty of Engineering, Nihon University, Institute of Quantum Science, Tokyo University of Agriculture and Technology (TUAT), and National Institute of Advanced Industrial Science and Technology (AIST)

Subjects
[SPI.OTHER]Engineering Sciences [physics]/Other, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Instrumentation and Detectors, Physics::Plasma Physics, [SPI.OTHER] Engineering Sciences [physics]/Other, Astrophysics::High Energy Astrophysical Phenomena, [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Space Physics
Abstract

12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France); The PSD is a low-pressure gas discharge with an especially geometrical shape of a pair of parallel disk electrodes. In this paper, the pseudo-spark discharge (PSD) is applied to the source for a high current glow plasma jet. The mechanism of the plasma acceleration is an electromagnetic force. To accelerate the plasma, the diameter of the anode hole is enlarged as compared with that of the cathode. The electron temperature and density of the plasma jet is measured by using an electric probe technique. In this experiment of the discharge current is 10 kA in hydrogen gas, the temperature reached approximately 4eV. In addition, heat flux did not melt electrodes during a number of discharges, because PSD is glow mode. The geometrical shape of the electrodes plays an essential role in the characteristics of the PSD plasma jet. Thus, the high temperature and density plasma jet without the heat problem will become a useful tool for various technological applications.

Published
2004

18. Plasma diagnostic system using optical fibers with high numerical aperture.

Author

Ohkuma, Yasunori, Kanamaru, Yuki, Hasegawa, Yoshinori, Fujino, Toshiyuki, Fujimoto, Kayoko, Gota, Hiroshi, Asai, Tomohiko, Takahashi, Tsutomu, and Nogi, Yasuyuki

Subjects
*PLASMA diagnostics, *OPTICAL fibers, *HOLES, *FLUORESCENT lamps, *LIGHT sources, *VACUUM tubes, *EQUIPMENT & supplies
Abstract

A diagnostic system using optical fibers with high numerical apertures is constructed for investigating a structure of magnetically confined plasma. Since the fiber has no convex lens at its front facet, the radiation from all plasmas included in the viewing angle of the fiber is utilized. First, theoretical forms are derived to determine the structure of the plasma from optical signals of a few fibers arranged axisymmetrically around the plasma. Second, the numerical aperture is measured by a simple method using a circular fluorescent lamp. Third, the theoretical forms are ascertained by a mock-up experiment where a light source representing a model plasma is constructed by a matrix array of straight fluorescent lamps. In this experiment, the effect of a reflected light from a wall of a vacuum vessel is investigated. Finally, the optical system is applied to a field-reversed-configuration plasma. Obtained structures of the plasma for n=1 and 2 toroidal modes are compared with the results of the conventional method using the fibers with convex lenses. The former results agree well with the latter ones in spite of the use of one-sixth the number of fibers in the latter method. [ABSTRACT FROM AUTHOR]

Published
2006
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