Improved confinement and related physics study in the Compact Helical System

S. Okamura, T. Akiyama, akihide fujisawa, K. Ida, H. Iguchi, M. Isobe, S. Kado, T. Minami, K. Nagaoka, Kazuo Nakamura, S. Nishimura, K. Matsuoka, H. Matsushita, H. Nakano, S. Ohshima, T. Oishi, A. Shimizu, C. Suzuki, C. Takahashi, K. Toi & 2 others Y. Yoshimura, M. Yoshinuma

Research output: Contribution to journalArticle

Abstract

Various types of transport barriers have been studied in the Compact Helical System. In addition to the neoclassical transport barrier, the edge transport barrier (H-mode) was studied using the high-power heating of two coinjection neutral beam injections. A density pedestal is formed after the transition that is indicated by the drop of Hα emission signal. The heating power threshold for the transition was investigated by varying the heating power. Its dependence on the density and the magnetic field is close to the H-mode scaling obtained in tokamaks. The dependence of the power threshold on the magnetic field configuration was also found. Local density fluctuation was measured with beam emission spectroscopy, which observed harmonic oscillations appearing after the density pedestal was formed. For L-mode plasma, long-distance coherence of the potential fluctuations were measured with two sets of heavy ion beam probes (HIBPs). Those coherent modes are supposed to be the geodesic acoustic mode part of zonal flow. Turbulent particle flux was also measured with HIBP, and its change with internal transport barrier formation is demonstrated.

Original languageEnglish
Pages (from-to)46-53
Number of pages8
JournalFusion Science and Technology
Volume51
Issue number1
DOIs
Publication statusPublished - Jan 1 2007

Fingerprint

Heavy Ions
Physics
Heavy ions
Heating
Ion beams
physics
Magnetic fields
Emission spectroscopy
heating
Laser modes
heavy ions
ion beams
harmonic oscillation
magnetic field configurations
thresholds
beam injection
probes
Fluxes
Plasmas
neutral beams

All Science Journal Classification (ASJC) codes

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

Cite this

Improved confinement and related physics study in the Compact Helical System. / Okamura, S.; Akiyama, T.; fujisawa, akihide; Ida, K.; Iguchi, H.; Isobe, M.; Kado, S.; Minami, T.; Nagaoka, K.; Nakamura, Kazuo; Nishimura, S.; Matsuoka, K.; Matsushita, H.; Nakano, H.; Ohshima, S.; Oishi, T.; Shimizu, A.; Suzuki, C.; Takahashi, C.; Toi, K.; Yoshimura, Y.; Yoshinuma, M.

In: Fusion Science and Technology, Vol. 51, No. 1, 01.01.2007, p. 46-53.

Research output: Contribution to journalArticle

Okamura, S, Akiyama, T, fujisawa, A, Ida, K, Iguchi, H, Isobe, M, Kado, S, Minami, T, Nagaoka, K, Nakamura, K, Nishimura, S, Matsuoka, K, Matsushita, H, Nakano, H, Ohshima, S, Oishi, T, Shimizu, A, Suzuki, C, Takahashi, C, Toi, K, Yoshimura, Y & Yoshinuma, M 2007, 'Improved confinement and related physics study in the Compact Helical System', Fusion Science and Technology, vol. 51, no. 1, pp. 46-53. https://doi.org/10.13182/FST07-A1286
Okamura, S. ; Akiyama, T. ; fujisawa, akihide ; Ida, K. ; Iguchi, H. ; Isobe, M. ; Kado, S. ; Minami, T. ; Nagaoka, K. ; Nakamura, Kazuo ; Nishimura, S. ; Matsuoka, K. ; Matsushita, H. ; Nakano, H. ; Ohshima, S. ; Oishi, T. ; Shimizu, A. ; Suzuki, C. ; Takahashi, C. ; Toi, K. ; Yoshimura, Y. ; Yoshinuma, M. / Improved confinement and related physics study in the Compact Helical System. In: Fusion Science and Technology. 2007 ; Vol. 51, No. 1. pp. 46-53.
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