TY - JOUR
T1 - Response of the far scrape-off layer plasma to strong gas puffing in the high poloidal beta configuration of the QUEST spherical tokamak
AU - Onchi, T.
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.
N1 - Funding Information:
This work was supported by JSPS KAKENHI Grant Numbers S24226020 and 15K17800, the NIFS Collaboration Research Program (NIFS15KUTR110), and the Collaborative Research Program of the Research Institute for Applied Mechanics, Kyushu University.
Publisher Copyright:
© 2016 IOP Publishing Ltd.
PY - 2016/9/15
Y1 - 2016/9/15
N2 - 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.
AB - 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.
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U2 - 10.1088/0741-3335/58/11/115004
DO - 10.1088/0741-3335/58/11/115004
M3 - Article
AN - SCOPUS:84994060613
SN - 0741-3335
VL - 58
JO - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
IS - 11
M1 - 115004
ER -