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Your search keyword '"Yoshiro Narushima"' showing total 2 results
Start Over Author "Yoshiro Narushima" Journal physical review letters
2 results on '"Yoshiro Narushima"'

1. Sawtooth Oscillation in Current-Carrying Plasma in the Large Helical Device

Author

Hiroshi Yamada, Naoko Ashikawa, Hisamichi Funaba, Takashi Shimozuma, Byron J. Peterson, S. Kitagawa, Kazuo Toi, Kunizo Ohkubo, Kazumichi Narihara, Yasuji Hamada, Katsuji Ichiguchi, J. Miyazawa, Katsuyoshi Tsumori, Hiroshi Idei, Yoshiro Narushima, K. Nishimura, Osamu Motojima, Nobuyoshi Ohyabu, Takeshi Ido, Tetsuo Seki, Yasuhiko Takeiri, Kenji Tanaka, Atsushi J. Nishizawa, K. Yamazaki, Yoshio Nagayama, Satoru Sakakibara, S. Morita, K.Y. Watanabe, Kazuo Kawahata, Noriyoshi Nakajima, Masayuki Yokoyama, Suguru Masuzaki, Hirotaka Chikaraishi, Mamoru Shoji, Y. Nakamura, Osamu Kaneko, A. Nishimura, Katsumi Ida, Ryuhei Kumazawa, Masaki Osakabe, Yoshihide Oka, Katsunori Ikeda, K. Saito, Shinsaku Imagawa, N. Noda, Shigeru Sudo, Shigeru Inagaki, Mitsutaka Isobe, Toshiyuki Mito, Ichihiro Yamada, T. Watari, Tokihiko Tokuzawa, Takashi Mutoh, Hajime Suzuki, Shin Kubo, Keisuke Matsuoka, S. Murakami, Ryuichi Sakamoto, Sadatsugu Muto, Akio Sagara, Mamiko Sasao, T. Ozaki, Nagato Yanagi, Kuninori Sato, Tomohiro Morisaki, Kazuya Takahata, Y. Yoshinuma, Akio Komori, Hideya Nakanishi, Masahiko Emoto, Yasuo Yoshimura, A. Iwamoto, Motoshi Goto, Satoshi Ohdachi, and Akihiko Isayama

Subjects
Physics, Large Helical Device, Physics::Plasma Physics, Oscillation, Beta (plasma physics), Physics::Space Physics, General Physics and Astronomy, Magnetic reconnection, Sawtooth wave, Plasma, Atomic physics, Current (fluid), Neutral beam injection
Abstract

Sawtooth oscillations have been observed in current-carrying helical plasmas by using electron-cyclotron-emission diagnostics in the Large Helical Device. The plasma current, which is driven by neutral beam injection, reduces the beta threshold of the sawtooth oscillation. When the central q value is increased due to the plasma current, the core region crashes, and, when it is decreased, the edge region crashes annularly. Observed rapid mixture of the plasma in the limited region suggests that these sawtooth crashes are reconnection phenomena. Unlike previous experiments, no precursor oscillation has been observed.

Published
2003
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2. Bifurcation Phenomena of a Magnetic Island at a Rational Surface in a Magnetic-Shear Control Experiment

Author

Tomohiro Morisaki, T. Kobuchi, Mikiro Yoshinuma, Shigeru Inagaki, Katsumi Ida, Yoshiro Narushima, K.Y. Watanabe, Satoru Sakakibara, Hisamichi Funaba, and Kimitaka Itoh

Subjects
Shear (sheet metal), Physics, Large Helical Device, Hysteresis, Rational surface, Condensed matter physics, General Physics and Astronomy, Magnetic reconnection, Magnetohydrodynamics, equipment and supplies, human activities, Flattening, Bifurcation
Abstract

Three states of a magnetic island are observed when the magnetic shear at the rational surface is modified using inductive current associated with the neutral beam current drive in the Large Helical Device. One state is the healed magnetic island with a zero island width. The second state is the saturated magnetic island with partial flattening of the T(e) profile. The third state is characterized by the global flattening of the T(e) profile in the core region. As the plasma assumes each of the three states consecutively through a bifurcation process a clear hysteresis in the relation between the size of the magnetic island and the magnetic shear is observed.

Published
2008

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