High β experiment and confinement regimes in a compact helical system

K. Matsuoka, S. Okamura, K. Nishimura, K. Tsumori, R. Akiyama, H. Yamada, S. Sakakibara, A. Lazaros, J. Xu, K. Ida, K. Tanaka, T. Morisaki, S. Morita, H. Arimoto, A. Ejiri, M. Fujiwara, Hiroshi Idei, H. Iguchi, O. Kaneko, T. KawamotoS. Kubo, T. Kuroda, O. Motojima, T. Ozaki, V. D. Pustovitov, A. Sagara, C. Takahashi, K. Toi, T. Watari, I. Yamada

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Abstract

A volume-averaged equilibrium β value 〈β eq 〉 of 2.14% is achieved in a compact helical system using two neutral beam lines with balanced injection and intense wall conditioning with Ti gettering. This value is the highest β value realized so far in helical systems. Reheat mode, where the stored energy increases after turn-off of a strong gas puff, is employed in the experiment. Discharge conditions are as follows: B t = 0.61 T; beam power through the port, 1.1 MW (coinjection) and 0.8 MW (counterinjection); line-averaged electron density n e = 6.5 × 10 13 cm -3 . Amplitudes of magnetic fluctuations integrated over the frequency range from 3 kHz to 100 kHz become saturated at 〈β eq 〉 higher than 1%. Dominant coherent modes are m n = 2 1 and 1 1 when 〈β eq 〉 is lower and higher respectively than 1%. Dependence of the energy confinement time τ E on n e (up to 8 × 10 13 cm -3 ) and B t (from 0.6 to 1.8T) is also studied in this high β experiment. When the density increases τ E degrades compared with the LHD scaling; the density dependence exhibits Bohm-like behaviour. On the contrary, τ E scales as B t ≈0.75 , which is rather close to the LHD scaling (gyro-Bohm-like behaviour).

Original languageEnglish
Pages (from-to)135-140
Number of pages6
JournalFusion Engineering and Design
Volume26
Issue number1-4
DOIs
Publication statusPublished - Jan 1 1995
Externally publishedYes

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Discharge (fluid mechanics)
Carrier concentration
Gases
Experiments

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Nuclear Energy and Engineering
  • Materials Science(all)
  • Mechanical Engineering

Cite this

Matsuoka, K., Okamura, S., Nishimura, K., Tsumori, K., Akiyama, R., Yamada, H., ... Yamada, I. (1995). High β experiment and confinement regimes in a compact helical system. Fusion Engineering and Design, 26(1-4), 135-140. https://doi.org/10.1016/0920-3796(94)00178-A

High β experiment and confinement regimes in a compact helical system. / Matsuoka, K.; Okamura, S.; Nishimura, K.; Tsumori, K.; Akiyama, R.; Yamada, H.; Sakakibara, S.; Lazaros, A.; Xu, J.; Ida, K.; Tanaka, K.; Morisaki, T.; Morita, S.; Arimoto, H.; Ejiri, A.; Fujiwara, M.; Idei, Hiroshi; Iguchi, H.; Kaneko, O.; Kawamoto, T.; Kubo, S.; Kuroda, T.; Motojima, O.; Ozaki, T.; Pustovitov, V. D.; Sagara, A.; Takahashi, C.; Toi, K.; Watari, T.; Yamada, I.

In: Fusion Engineering and Design, Vol. 26, No. 1-4, 01.01.1995, p. 135-140.

Research output: Contribution to journalArticle

Matsuoka, K, Okamura, S, Nishimura, K, Tsumori, K, Akiyama, R, Yamada, H, Sakakibara, S, Lazaros, A, Xu, J, Ida, K, Tanaka, K, Morisaki, T, Morita, S, Arimoto, H, Ejiri, A, Fujiwara, M, Idei, H, Iguchi, H, Kaneko, O, Kawamoto, T, Kubo, S, Kuroda, T, Motojima, O, Ozaki, T, Pustovitov, VD, Sagara, A, Takahashi, C, Toi, K, Watari, T & Yamada, I 1995, 'High β experiment and confinement regimes in a compact helical system', Fusion Engineering and Design, vol. 26, no. 1-4, pp. 135-140. https://doi.org/10.1016/0920-3796(94)00178-A
Matsuoka K, Okamura S, Nishimura K, Tsumori K, Akiyama R, Yamada H et al. High β experiment and confinement regimes in a compact helical system. Fusion Engineering and Design. 1995 Jan 1;26(1-4):135-140. https://doi.org/10.1016/0920-3796(94)00178-A
Matsuoka, K. ; Okamura, S. ; Nishimura, K. ; Tsumori, K. ; Akiyama, R. ; Yamada, H. ; Sakakibara, S. ; Lazaros, A. ; Xu, J. ; Ida, K. ; Tanaka, K. ; Morisaki, T. ; Morita, S. ; Arimoto, H. ; Ejiri, A. ; Fujiwara, M. ; Idei, Hiroshi ; Iguchi, H. ; Kaneko, O. ; Kawamoto, T. ; Kubo, S. ; Kuroda, T. ; Motojima, O. ; Ozaki, T. ; Pustovitov, V. D. ; Sagara, A. ; Takahashi, C. ; Toi, K. ; Watari, T. ; Yamada, I. / High β experiment and confinement regimes in a compact helical system. In: Fusion Engineering and Design. 1995 ; Vol. 26, No. 1-4. pp. 135-140.
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abstract = "A volume-averaged equilibrium β value 〈β eq 〉 of 2.14{\%} is achieved in a compact helical system using two neutral beam lines with balanced injection and intense wall conditioning with Ti gettering. This value is the highest β value realized so far in helical systems. Reheat mode, where the stored energy increases after turn-off of a strong gas puff, is employed in the experiment. Discharge conditions are as follows: B t = 0.61 T; beam power through the port, 1.1 MW (coinjection) and 0.8 MW (counterinjection); line-averaged electron density n e = 6.5 × 10 13 cm -3 . Amplitudes of magnetic fluctuations integrated over the frequency range from 3 kHz to 100 kHz become saturated at 〈β eq 〉 higher than 1{\%}. Dominant coherent modes are m n = 2 1 and 1 1 when 〈β eq 〉 is lower and higher respectively than 1{\%}. Dependence of the energy confinement time τ E on n e (up to 8 × 10 13 cm -3 ) and B t (from 0.6 to 1.8T) is also studied in this high β experiment. When the density increases τ E degrades compared with the LHD scaling; the density dependence exhibits Bohm-like behaviour. On the contrary, τ E scales as B t ≈0.75 , which is rather close to the LHD scaling (gyro-Bohm-like behaviour).",
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AU - Matsuoka, K.

AU - Okamura, S.

AU - Nishimura, K.

AU - Tsumori, K.

AU - Akiyama, R.

AU - Yamada, H.

AU - Sakakibara, S.

AU - Lazaros, A.

AU - Xu, J.

AU - Ida, K.

AU - Tanaka, K.

AU - Morisaki, T.

AU - Morita, S.

AU - Arimoto, H.

AU - Ejiri, A.

AU - Fujiwara, M.

AU - Idei, Hiroshi

AU - Iguchi, H.

AU - Kaneko, O.

AU - Kawamoto, T.

AU - Kubo, S.

AU - Kuroda, T.

AU - Motojima, O.

AU - Ozaki, T.

AU - Pustovitov, V. D.

AU - Sagara, A.

AU - Takahashi, C.

AU - Toi, K.

AU - Watari, T.

AU - Yamada, I.

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