Response of the far scrape-off layer plasma to strong gas puffing in the high poloidal beta configuration of the QUEST spherical tokamak

T. Onchi, H. Zushi, K. Mishra, Y. Oyama, Y. Nagashima, K. Hanada, H. Idei, M. Hasegawa, A. Kuzmin, H. Miura, K. Nakamura, A. Fujisawa, K. Nagaoka

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The response of the far scrape-off layer (far-SOL) to strong gas puffing (SGP), and its role as the boundary condition for core plasma, are investigated using a two-point Langmuir probe measurement in the high poloidal beta configuration in the QUEST spherical tokamak. The temperature and heat flux behave in an opposite way in the far-SOL and end-plate region after SGP, although SGP increases the density globally. The apparent density decay time in the far-SOL area is much longer than that in the core. Significant co-current flow is driven solely by the electron cyclotron wave in the far-SOL flow. Sheared flow is also observed in the perpendicular velocity profile during the recovered current flat-top phase, and such flow profiles are flattened by SGP. These flow profiles are attributed not only to drift-driven flow but also to transport-driven flow, the sink effect on the end-plate, and the balance of the neutral particle source.

Original languageEnglish
Article number115004
JournalPlasma Physics and Controlled Fusion
Volume58
Issue number11
DOIs
Publication statusPublished - Sep 15 2016

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plasma layers
Plasmas
configurations
Gases
gases
end plates
Langmuir probes
Cyclotrons
Heat flux
Boundary conditions
neutral particles
electrostatic probes
profiles
Electrons
sinks
cyclotrons
heat flux
velocity distribution
boundary conditions
Temperature

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering
  • Condensed Matter Physics

Cite this

Response of the far scrape-off layer plasma to strong gas puffing in the high poloidal beta configuration of the QUEST spherical tokamak. / Onchi, T.; Zushi, H.; Mishra, K.; Oyama, Y.; Nagashima, Y.; Hanada, K.; Idei, H.; Hasegawa, M.; Kuzmin, A.; Miura, H.; Nakamura, K.; Fujisawa, A.; Nagaoka, K.

In: Plasma Physics and Controlled Fusion, Vol. 58, No. 11, 115004, 15.09.2016.

Research output: Contribution to journalArticle

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AU - Zushi, H.

AU - Mishra, K.

AU - Oyama, Y.

AU - Nagashima, Y.

AU - Hanada, K.

AU - Idei, H.

AU - Hasegawa, M.

AU - Kuzmin, A.

AU - Miura, H.

AU - Nakamura, K.

AU - Fujisawa, A.

AU - Nagaoka, K.

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