Search Results - "Watanabe, K Y"

Self-Sustained Divertor Oscillation Driven by Magnetic Island Dynamics in Torus Plasma by Kobayashi, T, Kobayashi, M, Narushima, Y, Suzuki, Y, Watanabe, K Y, Mukai, K, Hayashi, Y

“…A new type of self-sustained divertor oscillation is discovered in the Large Helical Device stellarator, where the peripheral plasma is detached from material…”
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Resistive interchange modes destabilized by helically trapped energetic ions in a helical plasma by Du, X D, Toi, K, Osakabe, M, Ohdachi, S, Ido, T, Tanaka, K, Yokoyama, M, Yoshinuma, M, Ogawa, K, Watanabe, K Y, Isobe, M, Nagaoka, K, Ozaki, T, Sakakibara, S, Seki, R, Shimizu, A, Suzuki, Y, Tsuchiya, H

“…A new bursting m=1/n=1 instability (m,n: poloidal and toroidal mode numbers) with rapid frequency chirping down has been observed for the first time in a…”
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Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma by Toi, K, Watanabe, F, Tokuzawa, T, Ida, K, Morita, S, Ido, T, Shimizu, A, Isobe, M, Ogawa, K, Spong, D A, Todo, Y, Watari, T, Ohdachi, S, Sakakibara, S, Yamamoto, S, Inagaki, S, Narihara, K, Osakabe, M, Nagaoka, K, Narushima, Y, Watanabe, K Y, Funaba, H, Goto, M, Ikeda, K, Ito, T, Kaneko, O, Kubo, S, Murakami, S, Minami, T, Miyazawa, J, Nagayama, Y, Nishiura, M, Oka, Y, Sakamoto, R, Shimozuma, T, Takeiri, Y, Tanaka, K, Tsumori, K, Yamada, I, Yoshinuma, M, Kawahata, K, Komori, A

“…Reversed-shear Alfvén eigenmodes were observed for the first time in a helical plasma having negative q₀'' (the curvature of the safety factor q at the zero…”
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Bifurcation phenomena of a magnetic island at a rational surface in a magnetic-shear control experiment by Ida, K, Inagaki, S, Yoshinuma, M, Narushima, Y, Itoh, K, Kobuchi, T, Watanabe, K Y, Funaba, H, Sakakibara, S, Morisaki, T

“…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…”
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Characteristics of electron heat transport of plasma with an electron internal-transport barrier in the large helical device by Ida, K, Shimozuma, T, Funaba, H, Narihara, K, Kubo, S, Murakami, S, Wakasa, A, Yokoyama, M, Takeiri, Y, Watanabe, K Y, Tanaka, K, Yoshinuma, M, Liang, Y, Ohyabu, N

“…Associated with the transition from ion root to electron root, an electron internal transport barrier (ITB) appears in the large helical device, when the…”
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Suppression of Trapped Energetic Ions Driven Resistive Interchange Modes with Electron Cyclotron Heating in a Helical Plasma by Du, X D, Toi, K, Ohdachi, S, Watanabe, K Y, Takahashi, H, Yoshimura, Y, Osakabe, M, Seki, R, Nicolas, T, Tsuchiya, H, Nagaoka, K, Ogawa, K, Tanaka, K, Isobe, M, Yokoyama, M, Yoshinuma, M, Kubo, S, Sakakibara, S, Bando, T, Ido, T, Ozaki, T, Suzuki, Y, Takemura, Y

“…The resistive interchange mode destabilized by the resonant interaction with the trapped energetic ions is fully suppressed when the injected power of electron…”
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Particle control in long-pulse discharge using divertor pumping in LHD by Motojima, G, Masuzaki, S, Morisaki, T, Watanabe, K Y, Kobayashi, M, Ida, K, Sakamoto, R, Yoshinuma, M, Seki, R, Nuga, H, Tsujimura, T, Suzuki, C, Emoto, M, Tsuchibushi, Y, Murase, T, Takeiri, Y

“…Abstract Density control is crucial for maintaining stable confined plasma. Divertor pumping, where neutral particles are compressed and exhausted in the…”
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Flow damping due to stochastization of the magnetic field by Ida, K., Yoshinuma, M., Tsuchiya, H., Kobayashi, T., Suzuki, C., Yokoyama, M., Shimizu, A., Nagaoka, K., Inagaki, S., Itoh, K.

“…The driving and damping mechanism of plasma flow is an important issue because flow shear has a significant impact on turbulence in a plasma, which determines…”
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Observation of helicity-induced Alfvén eigenmodes in large-helical-device plasmas heated by neutral-beam injection by Yamamoto, S, Toi, K, Nakajima, N, Ohdachi, S, Sakakibara, S, Watanabe, K Y, Goto, M, Ikeda, K, Kaneko, O, Kawahata, K, Masuzaki, S, Morisaki, T, Morita, S, Murakami, S, Narihara, K, Oka, Y, Osakabe, M, Takeiri, Y, Tanaka, K, Tokuzawa, T, Tsumori, K, Yamada, H, Yamada, I, Yamazaki, K

“…The helicity-induced Alfvén eigenmodes (HAEs) with the toroidal mode number n=2 and 3 are observed for the first time in the Large Helical Device plasmas…”
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Three-dimensional anisotropic pressure free boundary equilibria by Cooper, W.A., Hirshman, S.P., Merkel, P., Graves, J.P., Kisslinger, J., Wobig, H.F.G., Narushima, Y., Okamura, S., Watanabe, K.Y.

“…Free boundary three-dimensional anisotropic pressure magnetohydrodynamic equilibria with nested magnetic flux surfaces are computed through the minimisation of…”
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Study of High-Beta Plasmas in a Helical System by Yamada, H., Watanabe, K. Y., Sakakibara, S., Suzuki, Y., Ohdachi, S., Kobayashi, M., Funaba, H., LHD Experiment Group

“…Recent experiments in LHD have demonstrated reactor‐relevant high β plasmas. The high beta state with the volume averaged beta of 5 % has been maintained for…”
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System studies of helical reactors having continuous or modular coils by Yamazaki, K., Watanabe, K.Y., Amano, T., Motojima, O., Fujiwara, M.

“…The physics and engineering optimization studies are carried out for continuous-coil or modular-coil helical reactors based on the large helical device (LHD)…”
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Analysis of the ECH effect on the EPM/AEs stability in Heliotron J plasma using a Landau closure model by Varela, J, Nagasaki, K, Kobayashi, S, Nagaoka, K, Adulsiriswad, P, Cappa, A, Yamamoto, S, Watanabe, K. Y, Spong, D. A, Garcia, L, Ghai, Y, Ortiz, J

“…Nucl. Fusion 63 026009 (2023) The aim of the present study is to analyze the effect of the electron cyclotron heating (ECH) on the linear stability of Alfven…”
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Observation of the "self-healing" of an error field island in the large helical device by Narihara, K, Watanabe, K Y, Yamada, I, Morisaki, T, Tanaka, K, Sakakibara, S, Ida, K, Sakamoto, R, Ohyabu, N, Ashikawa, N, Emoto, M, Funaba, H, Goto, M, Hayashi, H, Idei, H, Ikeda, K, Inagaki, S, Inoue, N, Kaneko, O, Kawahata, K, Kobuchi, T, Komori, A, Kubo, S, Kumazawa, R, Masuzaki, S, Miyazawa, J, Morita, S, Motojima, O, Murakami, S, Muto, S, Mutoh, T, Nagayama, Y, Nakamura, Y, Nakanishi, H, Nishimura, K, Noda, N, Notake, T, Ohdachi, S, Oka, Y, Ohkubo, K, Osakabe, M, Ozaki, S, Peterson, B J, Sagara, A, Saito, K, Sasao, H, Sasao, M, Sato, K, Sato, M, Seki, T, Shimozuma, T, Shoji, C, Sudo, S, Suzuki, H, Takayama, A, Takechi, M, Takeiri, Y, Tamura, N, Toi, K, Tokuzawa, N, Torii, Y, Tsumori, K, Watari, T, Yamada, H, Yamaguchi, S, Yamamoto, S, Yamazaki, K, Yoshimura, Y

“…It was observed that the vacuum magnetic island produced by an external error magnetic field in the large helical device shrank in the presence of plasma. This…”
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Theoretical studies of equilibrium beta limit in heliotron plasmas by Suzuki, Y, Watanabe, K. Y, Sakakibara, S, Nakajima, N, Ohyabu, N

“…In this study, the MHD equilibrium limit of LHD plasmas is studied using a 3D MHD equilibrium calculation code, HINT, which is an initial value solver based on…”
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Simulation Study of the MHD Stability Beta Limit in LHD by TASK3D by Sato, M., Watanabe, K. Y., Nakamura, Y., Fukuyama, A., Murakami, S., Toda, S., Yokoyama, M., Funaba, H., Sakakibara, S., Ohdachi, S., Yamada, H., Nakajima, N.

“…The numerical method for analysis of the “MHD stability beta limit” based on a hierarchy integrated simulation code TASK3D has been developed. The numerical…”
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10 years of engineering and physics achievements by the Large Helical Device project by Yamada, H., Imagawa, S., Takeiri, Y., Kaneko, O., Mutoh, T., Mito, T., Chikaraishi, H., Hamaguchi, S., Ida, K., Igami, H., Ikeda, K., Kasahara, H., Kobayashi, M., Kubo, S., Kumazawa, R., Maekawa, R., Masuzaki, S., Miyazawa, J., Morisaki, T., Morita, S., Nagaoka, K., Nakamura, Y., Narushima, Y., Osakabe, M., Saito, K., Sakakibara, S., Sakamoto, R., Seki, T., Shimozuma, T., Shoji, M., Suzuki, Y., Takahata, K., Tamura, H., Tsumori, K., Watanabe, K.Y., Yamada, S., Yanagi, N., Yoshimura, Y., Kawahata, K., Ohyabu, N., Komori, A., Motojima, O.

“…This article reviews 10 years of engineering and physics achievements by the Large Helical Device (LHD) project with emphasis on the latest results. The LHD is…”
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Theoretical analysis of energetic-ion-driven resistive interchange mode stabilization strategies using a Landau closure model by Varela, J, Ohdachi, S, Watanabe, K. Y, Spong, D. A, Garcia, L, Seki, R

“…The aim of the present study is to perform a theoretical analysis of different strategies to stabilize energetic-ion-driven resistive interchange mode (EIC) in…”
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Experimental Study of the Effect of Poloidal Flow on Stability of Magnetic Islands in LHD and TJ-II by Narushima, Y., Castejón, F., Watanabe, K. Y., Sakakibara, S., Estrada, T., Medina, F., López-Bruna, D., Yokoyama, M., Ida, K., LHD Experiment Group

“…The effect of the poloidal flow on the magnetic island is studied. The self‐healing of the magnetic island has been observed in the Large Helical Device (LHD)…”
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Effect of carbon divertor plates on impurities, Zeff and density limit in large helical device by Morita, S, Goto, M, Funaba, H, Idei, H, Ikeda, K, Inagaki, S, Kaneko, O, Kawahata, K, Komori, A, Kubo, S, Kumazawa, R, Masuzaki, S, Miyazawa, J, Morisaki, T, Motojima, O, Muto, S, Mutoh, T, Nakamura, Y, Narihara, K, Nishimura, K, Noda, N, Ohdachi, S, Ohyabu, N, Oka, Y, Osakabe, M, Sagara, A, Sakakibara, S, Sakamoto, R, Seki, T, Shimozuma, T, Shoji, M, Suzuki, H, Takeiri, Y, Tanaka, K, Toi, K, Tokuzawa, T, Tsumori, K, Yamada, H, Watanabe, K Y, Watari, T

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