O E Garcia et al 2007 Plasma Phys. Control. Fusion 49 B47 doi:10.1088/0741-3335/49/12B/S03
O E Garcia1,4, R A Pitts2, J Horacek3, J Madsen1, V Naulin1, A H Nielsen1 and J Juul Rasmussen1
Show affiliationsResults are presented from probe measurements in the low field side scrape-off layer (SOL) region of TCV during plasma current scan experiments. It is shown that with decreasing plasma current the radial particle density profile becomes broader and the fluctuation levels and turbulence driven radial particle flux increase. In the far SOL the fluctuations exhibit a high degree of statistical similarity and the particle density and flux at the wall radius scale inversely with the plasma current. Together with previous TCV density scan experiments, this indicates that plasma fluctuations and radial transport increase with plasma collisionality. Such a collisionality dependence is consistent with a recent theory for radial blob motion, which suggests that filamentary structures become electrically disconnected from the target sheaths at large collisionality and thus experience less sheath dissipation. This increases the radial convective transport and is possibly linked to the discharge density limit.
52.70.Ds Electric and magnetic measurements
52.25.Gj Fluctuation and chaos phenomena
52.40.Hf Plasma-material interactions; boundary layer effects
Issue 12B (December 2007)
Received 6 July 2007
Published 14 November 2007
O E Garcia et al 2007 Plasma Phys. Control. Fusion 49 B47
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Marcel Zemp et al 2009 ApJ 705 L186
E. Soydugan et al. 2003 The Astronomical Journal 126 1933
B D Poust et al 2003 J. Phys. D: Appl. Phys. 36 A102
B. T. Gänsicke et al 2004 ApJ 613 L141
Carol E. Thornton et al. 2009 ApJ 705 1196
Sumanta Das and G S Agarwal 2009 J. Phys. B: At. Mol. Opt. Phys. 42 229801
Peter R Saulson 2000 Class. Quantum Grav. 17 2441
Hongjuan Wang et al. 2009 ApJ 700 1716