LH transition by a biased hot cathode in the Tohoku University Heliac

S. Kitajima, H. Takahashi, Y. Tanaka, H. Utoh, M. Sasao, M. Takayama, K. Nishimura, S. Inagaki, M. Yokoyama

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

In the Tohoku University Heliac (TU-Heliac), a helical axis stellarator, an electron injection electrode using a hot cathode made of LaB6 was developed and the transition mechanism to an improved mode has been intensively studied. In the electrode current-sweep mode of biasing experiments, a bifurcation phenomenon, i.e. a negative resistance feature in the electrode characteristics was observed accompanied with transition to an improved mode (H-mode) or transition from H-mode to L-mode, in helium plasma discharges of a wide range of collisionality. The ion viscous damping force was estimated from the J × B driving force for poloidal rotation. The local maxima in viscosity were found at the poloidal Mach number around -Mp ∼ 1-3, as predicted by neoclassical theory. It was also found that the negative resistance (a bifurcation phenomenon) was observed when the poloidal viscosity showed a local maximum.

Original languageEnglish
Pages (from-to)200-206
Number of pages7
JournalNuclear Fusion
Volume46
Issue number2
DOIs
Publication statusPublished - Feb 1 2006
Externally publishedYes

Fingerprint

hot cathodes
electrodes
viscosity
viscous damping
helium plasma
stellarators
Mach number
plasma jets
injection
ions

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Kitajima, S., Takahashi, H., Tanaka, Y., Utoh, H., Sasao, M., Takayama, M., ... Yokoyama, M. (2006). LH transition by a biased hot cathode in the Tohoku University Heliac. Nuclear Fusion, 46(2), 200-206. https://doi.org/10.1088/0029-5515/46/2/002

LH transition by a biased hot cathode in the Tohoku University Heliac. / Kitajima, S.; Takahashi, H.; Tanaka, Y.; Utoh, H.; Sasao, M.; Takayama, M.; Nishimura, K.; Inagaki, S.; Yokoyama, M.

In: Nuclear Fusion, Vol. 46, No. 2, 01.02.2006, p. 200-206.

Research output: Contribution to journalArticle

Kitajima, S, Takahashi, H, Tanaka, Y, Utoh, H, Sasao, M, Takayama, M, Nishimura, K, Inagaki, S & Yokoyama, M 2006, 'LH transition by a biased hot cathode in the Tohoku University Heliac', Nuclear Fusion, vol. 46, no. 2, pp. 200-206. https://doi.org/10.1088/0029-5515/46/2/002
Kitajima S, Takahashi H, Tanaka Y, Utoh H, Sasao M, Takayama M et al. LH transition by a biased hot cathode in the Tohoku University Heliac. Nuclear Fusion. 2006 Feb 1;46(2):200-206. https://doi.org/10.1088/0029-5515/46/2/002
Kitajima, S. ; Takahashi, H. ; Tanaka, Y. ; Utoh, H. ; Sasao, M. ; Takayama, M. ; Nishimura, K. ; Inagaki, S. ; Yokoyama, M. / LH transition by a biased hot cathode in the Tohoku University Heliac. In: Nuclear Fusion. 2006 ; Vol. 46, No. 2. pp. 200-206.
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