Spontaneous rotation sources in a quiescent tokamak edge plasma

Spontaneous rotation sources in a quiescent tokamak edge plasma are studied without an external momentum source, such as, beam injected or wall-born neutrals. Discussions are based upon example neoclassical solutions from an edge gyrokinetic particle code. The main study is performed in a DIII-D pla...

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Veröffentlicht in:Physics of plasmas 2008-06, Vol.15 (6), p.062510-062510-9
Hauptverfasser: Chang, C. S., Ku, S.
Format: Artikel
Sprache:eng
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Zusammenfassung:Spontaneous rotation sources in a quiescent tokamak edge plasma are studied without an external momentum source, such as, beam injected or wall-born neutrals. Discussions are based upon example neoclassical solutions from an edge gyrokinetic particle code. The main study is performed in a DIII-D plasma [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] with the ion Grad-B drift directed toward the single-null divertor. Comparison with a reversed Grad-B drift case is also shown. It is found that there is a robust spontaneous co-current toroidal plasma rotation source in the far scrape-off plasma due to the wall sheath effect. As the edge pedestal width becomes narrower, the co-current rotation in the far scrape-off becomes weaker, but there appears a stronger co-current rotation in the pedestal top/shoulder from the X-point orbit loss effect, possibly providing a co-rotation boundary condition to the core plasma. Reversal of the magnetic field and plasma current brings down the overall co-rotation, especially in the far scrape-off plasma.
ISSN:1070-664X
1089-7674
DOI:10.1063/1.2937116