Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma

K. Toi; F. Watanabe; T. Tokuzawa; K. Ida; S. Morita; T. Ido; A. Shimizu; M. Isobe; K. Ogawa; D. A. Spong; Y. Todo; T. Watari; S. Ohdachi; S. Sakakibara; S. Yamamoto; S. Inagaki; K. Narihara; M. Osakabe; K. Nagaoka; Y. Narushima; K. Y. Watanabe; H. Funaba; M. Goto; K. Ikeda; T. Ito; O. Kaneko; S. Kubo; S. Murakami; T. Minami; J. Miyazawa; Y. Nagayama; M. Nishiura; Y. Oka; R. Sakamoto; T. Shimozuma; Y. Takeiri; K. Tanaka; K. Tsumori; I. Yamada; M. Yoshinuma; K. Kawahata; A. Komori

doi:10.1103/PhysRevLett.105.145003

Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma

K. Toi, F. Watanabe, T. Tokuzawa, K. Ida, S. Morita, T. Ido, A. Shimizu, M. Isobe, K. Ogawa, D. A. Spong, Y. Todo, T. Watari, S. Ohdachi, S. Sakakibara, S. Yamamoto, S. Inagaki, K. Narihara, M. Osakabe, K. Nagaoka, Y. NarushimaK. Y. Watanabe, H. Funaba, M. Goto, K. Ikeda, T. Ito, O. Kaneko, S. Kubo, S. Murakami, T. Minami, J. Miyazawa, Y. Nagayama, M. Nishiura, Y. Oka, R. Sakamoto, T. Shimozuma, Y. Takeiri, K. Tanaka, K. Tsumori, I. Yamada, M. Yoshinuma, K. Kawahata, A. Komori

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Abstract

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 shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfvén eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes.

Original language	English
Article number	145003
Journal	Physical Review Letters
Volume	105
Issue number	14
DOIs	https://doi.org/10.1103/PhysRevLett.105.145003
State	Published - Oct 1 2010

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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., ... Komori, A. (2010). Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma. Physical Review Letters, 105(14), Article 145003. https://doi.org/10.1103/PhysRevLett.105.145003

@article{fb0e64279881473f937326b6f534c77f,

title = "Observation of reversed-shear Alfv{\'e}n eigenmodes excited by energetic ions in a helical plasma",

abstract = "Reversed-shear Alfv{\'e}n eigenmodes were observed for the first time in a helical plasma having negative q0′′ (the curvature of the safety factor q at the zero shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfv{\'e}n eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes.",

author = "K. Toi and F. Watanabe and T. Tokuzawa and K. Ida and S. Morita and T. Ido and A. Shimizu and M. Isobe and K. Ogawa and Spong, {D. A.} and Y. Todo and T. Watari and S. Ohdachi and S. Sakakibara and S. Yamamoto and S. Inagaki and K. Narihara and M. Osakabe and K. Nagaoka and Y. Narushima and Watanabe, {K. Y.} and H. Funaba and M. Goto and K. Ikeda and T. Ito and O. Kaneko and S. Kubo and S. Murakami and T. Minami and J. Miyazawa and Y. Nagayama and M. Nishiura and Y. Oka and R. Sakamoto and T. Shimozuma and Y. Takeiri and K. Tanaka and K. Tsumori and I. Yamada and M. Yoshinuma and K. Kawahata and A. Komori",

year = "2010",

month = oct,

day = "1",

doi = "10.1103/PhysRevLett.105.145003",

language = "English",

volume = "105",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "14",

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Toi, K, Watanabe, F, Tokuzawa, T, Ida, K, Morita, S, Ido, T, Shimizu, A, Isobe, M, Ogawa, K, Spong, DA, Todo, Y, Watari, T, Ohdachi, S, Sakakibara, S, Yamamoto, S, Inagaki, S, Narihara, K, Osakabe, M, Nagaoka, K, Narushima, Y, Watanabe, KY, 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 2010, 'Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma', Physical Review Letters, vol. 105, no. 14, 145003. https://doi.org/10.1103/PhysRevLett.105.145003

TY - JOUR

T1 - Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma

AU - Toi, K.

AU - Watanabe, F.

AU - Tokuzawa, T.

AU - Ida, K.

AU - Morita, S.

AU - Ido, T.

AU - Shimizu, A.

AU - Isobe, M.

AU - Ogawa, K.

AU - Spong, D. A.

AU - Todo, Y.

AU - Watari, T.

AU - Ohdachi, S.

AU - Sakakibara, S.

AU - Yamamoto, S.

AU - Inagaki, S.

AU - Narihara, K.

AU - Osakabe, M.

AU - Nagaoka, K.

AU - Narushima, Y.

AU - Watanabe, K. Y.

AU - Funaba, H.

AU - Goto, M.

AU - Ikeda, K.

AU - Ito, T.

AU - Kaneko, O.

AU - Kubo, S.

AU - Murakami, S.

AU - Minami, T.

AU - Miyazawa, J.

AU - Nagayama, Y.

AU - Nishiura, M.

AU - Oka, Y.

AU - Sakamoto, R.

AU - Shimozuma, T.

AU - Takeiri, Y.

AU - Tanaka, K.

AU - Tsumori, K.

AU - Yamada, I.

AU - Yoshinuma, M.

AU - Kawahata, K.

AU - Komori, A.

PY - 2010/10/1

Y1 - 2010/10/1

N2 - 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 shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfvén eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes.

AB - 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 shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfvén eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes.

UR - http://www.scopus.com/inward/record.url?scp=77957356754&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.105.145003

DO - 10.1103/PhysRevLett.105.145003

M3 - Article

AN - SCOPUS:77957356754

SN - 0031-9007

VL - 105

JO - Physical Review Letters

JF - Physical Review Letters

IS - 14

M1 - 145003

ER -

Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma

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