Plasma performance and impurity behaviour in long pulse discharges on LHD

Y. Nakamura, Y. Takeiri, R. Kumazawa, M. Osakabe, T. Seki, B. J. Peterson, K. Ida, H. Funaba, M. Yokoyama, N. Tamura, A. Komori, S. Morita, K. Sato, K. Narihara, Inagaki Shigeru, T. Tokuzawa, S. Masuzaki, J. Miyazawa, N. Noda, T. Mutoh & 71 others T. Shimozuma, K. Kawahata, Y. Oka, H. Suzuki, N. Ohyabu, T. Akiyama, N. Ashikawa, M. Emoto, P. Goncharov, M. Goto, Hiroshi Idei, K. Ikeda, S. Imagawa, M. Isobe, O. Kaneko, H. Kawazome, K. Khlopenkov, T. Kobuchi, A. Kostrioukov, S. Kubo, Y. Liang, T. Minami, T. Morisaki, S. Murakami, S. Muto, K. Nagaoka, Y. Nagayama, H. Nakanishi, Y. Narushima, K. Nishimura, T. Notake, H. Nozato, S. Ohdachi, S. Okamura, T. Ozaki, A. Sagara, T. Saida, K. Saito, S. Sakakibara, R. Sakamoto, M. Sasao, M. Sato, M. Shoji, N. Takeuchi, K. Tanaka, M. Y. Tanaka, K. Toi, Y. Torii, K. Tsumori, K. Y. Watanabe, T. Watari, Y. Xu, H. Yamada, I. Yamada, S. Yamamoto, T. Yamamoto, S. Yoshimura, Y. Yoshimura, M. Yoshinuma, K. Itoh, T. Mito, K. Ohkubo, I. Ohtake, T. Satow, S. Sudo, T. Uda, K. Yamazaki, K. Matsuoka, O. Motojima, Y. Hamada, M. Fujiwara

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The superconducting machine LHD has conducted long pulse experiments for four years to achieve long-duration plasmas with high performance. The operational regime was largely extended in discharge duration and plasma density. In this paper, the plasma characteristics, in particular, plasma performance and impurity behaviour in long pulse discharges are described. Confinement studies show that global energy confinement times are comparable to those in short pulse discharges. Long sustainment of high performance plasma, which is equivalent to the previous achievement in other devices, was demonstrated. Long pulse discharges enabled us to investigate impurity behaviour in a long timescale. Intrinsic metallic impurity accumulation was observed in a narrow density window (2-3 × 1019 m-3) only for hydrogen discharges. Impurity transport study by using active impurity pellet injection shows a long impurity confinement time and an inward convection in the impurity accumulation window, which is consistent with the intrinsic impurity behaviour. The pulsed neon gas injection experiment shows that the neon penetration into the plasma core is caused by the inward convection due to radial electric field. Finally, impurity accumulation control with an externally induced magnetic island at the plasma edge was demonstrated.

Original languageEnglish
Pages (from-to)219-227
Number of pages9
JournalNuclear Fusion
Volume43
Issue number4
DOIs
Publication statusPublished - Apr 1 2003

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impurities
pulses
neon
convection
gas injection
magnetic islands
pellets
plasma density
penetration
injection
electric fields
hydrogen
energy

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Nakamura, Y., Takeiri, Y., Kumazawa, R., Osakabe, M., Seki, T., Peterson, B. J., ... Fujiwara, M. (2003). Plasma performance and impurity behaviour in long pulse discharges on LHD. Nuclear Fusion, 43(4), 219-227. https://doi.org/10.1088/0029-5515/43/4/301

Plasma performance and impurity behaviour in long pulse discharges on LHD. / Nakamura, Y.; Takeiri, Y.; Kumazawa, R.; Osakabe, M.; Seki, T.; Peterson, B. J.; Ida, K.; Funaba, H.; Yokoyama, M.; Tamura, N.; Komori, A.; Morita, S.; Sato, K.; Narihara, K.; Shigeru, Inagaki; Tokuzawa, T.; Masuzaki, S.; Miyazawa, J.; Noda, N.; Mutoh, T.; Shimozuma, T.; Kawahata, K.; Oka, Y.; Suzuki, H.; Ohyabu, N.; Akiyama, T.; Ashikawa, N.; Emoto, M.; Goncharov, P.; Goto, M.; Idei, Hiroshi; Ikeda, K.; Imagawa, S.; Isobe, M.; Kaneko, O.; Kawazome, H.; Khlopenkov, K.; Kobuchi, T.; Kostrioukov, A.; Kubo, S.; Liang, Y.; Minami, T.; Morisaki, T.; Murakami, S.; Muto, S.; Nagaoka, K.; Nagayama, Y.; Nakanishi, H.; Narushima, Y.; Nishimura, K.; Notake, T.; Nozato, H.; Ohdachi, S.; Okamura, S.; Ozaki, T.; Sagara, A.; Saida, T.; Saito, K.; Sakakibara, S.; Sakamoto, R.; Sasao, M.; Sato, M.; Shoji, M.; Takeuchi, N.; Tanaka, K.; Tanaka, M. Y.; Toi, K.; Torii, Y.; Tsumori, K.; Watanabe, K. Y.; Watari, T.; Xu, Y.; Yamada, H.; Yamada, I.; Yamamoto, S.; Yamamoto, T.; Yoshimura, S.; Yoshimura, Y.; Yoshinuma, M.; Itoh, K.; Mito, T.; Ohkubo, K.; Ohtake, I.; Satow, T.; Sudo, S.; Uda, T.; Yamazaki, K.; Matsuoka, K.; Motojima, O.; Hamada, Y.; Fujiwara, M.

In: Nuclear Fusion, Vol. 43, No. 4, 01.04.2003, p. 219-227.

Research output: Contribution to journalArticle

Nakamura, Y, Takeiri, Y, Kumazawa, R, Osakabe, M, Seki, T, Peterson, BJ, Ida, K, Funaba, H, Yokoyama, M, Tamura, N, Komori, A, Morita, S, Sato, K, Narihara, K, Shigeru, I, Tokuzawa, T, Masuzaki, S, Miyazawa, J, Noda, N, Mutoh, T, Shimozuma, T, Kawahata, K, Oka, Y, Suzuki, H, Ohyabu, N, Akiyama, T, Ashikawa, N, Emoto, M, Goncharov, P, Goto, M, Idei, H, Ikeda, K, Imagawa, S, Isobe, M, Kaneko, O, Kawazome, H, Khlopenkov, K, Kobuchi, T, Kostrioukov, A, Kubo, S, Liang, Y, Minami, T, Morisaki, T, Murakami, S, Muto, S, Nagaoka, K, Nagayama, Y, Nakanishi, H, Narushima, Y, Nishimura, K, Notake, T, Nozato, H, Ohdachi, S, Okamura, S, Ozaki, T, Sagara, A, Saida, T, Saito, K, Sakakibara, S, Sakamoto, R, Sasao, M, Sato, M, Shoji, M, Takeuchi, N, Tanaka, K, Tanaka, MY, Toi, K, Torii, Y, Tsumori, K, Watanabe, KY, Watari, T, Xu, Y, Yamada, H, Yamada, I, Yamamoto, S, Yamamoto, T, Yoshimura, S, Yoshimura, Y, Yoshinuma, M, Itoh, K, Mito, T, Ohkubo, K, Ohtake, I, Satow, T, Sudo, S, Uda, T, Yamazaki, K, Matsuoka, K, Motojima, O, Hamada, Y & Fujiwara, M 2003, 'Plasma performance and impurity behaviour in long pulse discharges on LHD', Nuclear Fusion, vol. 43, no. 4, pp. 219-227. https://doi.org/10.1088/0029-5515/43/4/301
Nakamura Y, Takeiri Y, Kumazawa R, Osakabe M, Seki T, Peterson BJ et al. Plasma performance and impurity behaviour in long pulse discharges on LHD. Nuclear Fusion. 2003 Apr 1;43(4):219-227. https://doi.org/10.1088/0029-5515/43/4/301
Nakamura, Y. ; Takeiri, Y. ; Kumazawa, R. ; Osakabe, M. ; Seki, T. ; Peterson, B. J. ; Ida, K. ; Funaba, H. ; Yokoyama, M. ; Tamura, N. ; Komori, A. ; Morita, S. ; Sato, K. ; Narihara, K. ; Shigeru, Inagaki ; Tokuzawa, T. ; Masuzaki, S. ; Miyazawa, J. ; Noda, N. ; Mutoh, T. ; Shimozuma, T. ; Kawahata, K. ; Oka, Y. ; Suzuki, H. ; Ohyabu, N. ; Akiyama, T. ; Ashikawa, N. ; Emoto, M. ; Goncharov, P. ; Goto, M. ; Idei, Hiroshi ; Ikeda, K. ; Imagawa, S. ; Isobe, M. ; Kaneko, O. ; Kawazome, H. ; Khlopenkov, K. ; Kobuchi, T. ; Kostrioukov, A. ; Kubo, S. ; Liang, Y. ; Minami, T. ; Morisaki, T. ; Murakami, S. ; Muto, S. ; Nagaoka, K. ; Nagayama, Y. ; Nakanishi, H. ; Narushima, Y. ; Nishimura, K. ; Notake, T. ; Nozato, H. ; Ohdachi, S. ; Okamura, S. ; Ozaki, T. ; Sagara, A. ; Saida, T. ; Saito, K. ; Sakakibara, S. ; Sakamoto, R. ; Sasao, M. ; Sato, M. ; Shoji, M. ; Takeuchi, N. ; Tanaka, K. ; Tanaka, M. Y. ; Toi, K. ; Torii, Y. ; Tsumori, K. ; Watanabe, K. Y. ; Watari, T. ; Xu, Y. ; Yamada, H. ; Yamada, I. ; Yamamoto, S. ; Yamamoto, T. ; Yoshimura, S. ; Yoshimura, Y. ; Yoshinuma, M. ; Itoh, K. ; Mito, T. ; Ohkubo, K. ; Ohtake, I. ; Satow, T. ; Sudo, S. ; Uda, T. ; Yamazaki, K. ; Matsuoka, K. ; Motojima, O. ; Hamada, Y. ; Fujiwara, M. / Plasma performance and impurity behaviour in long pulse discharges on LHD. In: Nuclear Fusion. 2003 ; Vol. 43, No. 4. pp. 219-227.
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T1 - Plasma performance and impurity behaviour in long pulse discharges on LHD

AU - Nakamura, Y.

AU - Takeiri, Y.

AU - Kumazawa, R.

AU - Osakabe, M.

AU - Seki, T.

AU - Peterson, B. J.

AU - Ida, K.

AU - Funaba, H.

AU - Yokoyama, M.

AU - Tamura, N.

AU - Komori, A.

AU - Morita, S.

AU - Sato, K.

AU - Narihara, K.

AU - Shigeru, Inagaki

AU - Tokuzawa, T.

AU - Masuzaki, S.

AU - Miyazawa, J.

AU - Noda, N.

AU - Mutoh, T.

AU - Shimozuma, T.

AU - Kawahata, K.

AU - Oka, Y.

AU - Suzuki, H.

AU - Ohyabu, N.

AU - Akiyama, T.

AU - Ashikawa, N.

AU - Emoto, M.

AU - Goncharov, P.

AU - Goto, M.

AU - Idei, Hiroshi

AU - Ikeda, K.

AU - Imagawa, S.

AU - Isobe, M.

AU - Kaneko, O.

AU - Kawazome, H.

AU - Khlopenkov, K.

AU - Kobuchi, T.

AU - Kostrioukov, A.

AU - Kubo, S.

AU - Liang, Y.

AU - Minami, T.

AU - Morisaki, T.

AU - Murakami, S.

AU - Muto, S.

AU - Nagaoka, K.

AU - Nagayama, Y.

AU - Nakanishi, H.

AU - Narushima, Y.

AU - Nishimura, K.

AU - Notake, T.

AU - Nozato, H.

AU - Ohdachi, S.

AU - Okamura, S.

AU - Ozaki, T.

AU - Sagara, A.

AU - Saida, T.

AU - Saito, K.

AU - Sakakibara, S.

AU - Sakamoto, R.

AU - Sasao, M.

AU - Sato, M.

AU - Shoji, M.

AU - Takeuchi, N.

AU - Tanaka, K.

AU - Tanaka, M. Y.

AU - Toi, K.

AU - Torii, Y.

AU - Tsumori, K.

AU - Watanabe, K. Y.

AU - Watari, T.

AU - Xu, Y.

AU - Yamada, H.

AU - Yamada, I.

AU - Yamamoto, S.

AU - Yamamoto, T.

AU - Yoshimura, S.

AU - Yoshimura, Y.

AU - Yoshinuma, M.

AU - Itoh, K.

AU - Mito, T.

AU - Ohkubo, K.

AU - Ohtake, I.

AU - Satow, T.

AU - Sudo, S.

AU - Uda, T.

AU - Yamazaki, K.

AU - Matsuoka, K.

AU - Motojima, O.

AU - Hamada, Y.

AU - Fujiwara, M.

PY - 2003/4/1

Y1 - 2003/4/1

N2 - The superconducting machine LHD has conducted long pulse experiments for four years to achieve long-duration plasmas with high performance. The operational regime was largely extended in discharge duration and plasma density. In this paper, the plasma characteristics, in particular, plasma performance and impurity behaviour in long pulse discharges are described. Confinement studies show that global energy confinement times are comparable to those in short pulse discharges. Long sustainment of high performance plasma, which is equivalent to the previous achievement in other devices, was demonstrated. Long pulse discharges enabled us to investigate impurity behaviour in a long timescale. Intrinsic metallic impurity accumulation was observed in a narrow density window (2-3 × 1019 m-3) only for hydrogen discharges. Impurity transport study by using active impurity pellet injection shows a long impurity confinement time and an inward convection in the impurity accumulation window, which is consistent with the intrinsic impurity behaviour. The pulsed neon gas injection experiment shows that the neon penetration into the plasma core is caused by the inward convection due to radial electric field. Finally, impurity accumulation control with an externally induced magnetic island at the plasma edge was demonstrated.

AB - The superconducting machine LHD has conducted long pulse experiments for four years to achieve long-duration plasmas with high performance. The operational regime was largely extended in discharge duration and plasma density. In this paper, the plasma characteristics, in particular, plasma performance and impurity behaviour in long pulse discharges are described. Confinement studies show that global energy confinement times are comparable to those in short pulse discharges. Long sustainment of high performance plasma, which is equivalent to the previous achievement in other devices, was demonstrated. Long pulse discharges enabled us to investigate impurity behaviour in a long timescale. Intrinsic metallic impurity accumulation was observed in a narrow density window (2-3 × 1019 m-3) only for hydrogen discharges. Impurity transport study by using active impurity pellet injection shows a long impurity confinement time and an inward convection in the impurity accumulation window, which is consistent with the intrinsic impurity behaviour. The pulsed neon gas injection experiment shows that the neon penetration into the plasma core is caused by the inward convection due to radial electric field. Finally, impurity accumulation control with an externally induced magnetic island at the plasma edge was demonstrated.

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