X-point Position Dependence of Edge Intrinsic Toroidal
 Rotation on TCV

Authors:  T. Stoltzfus-Dueck, A. N. Karpushov, O. Sauter, 
B. P. Duval, B. Labit, H. Reimerdes, W. A. J. Vijvers, 
Y. Camenen, and the TCV Team

Abstract:  Recent theoretical work predicts intrinsic toroidal rotation in the tokamak edge to depend strongly on the normalized major radial position of the X-point, R¯X . With this motivation, we conducted a series of Ohmic L-mode shots on TCV, moving the X-point from the inboard to the outboard edge of the LCFS in both USN and LSN configurations.  The edge toroidal rotation shifted strongly counter-current with increasing R¯X , either vanishing or changing sign to become counter-current for an outboard X-point, in agreement with the theoretical expectations. The whole rotation profile shifted roughly rigidly with the edge rotation, resulting in variation of the peak core rotation by more than a factor of 2. Core rotation reversals had little effect on the edge rotation. Edge rotation was slightly more counter-current for unfavorable than favorable ∇B discharges.  PACS numbers: 52.20.Dq, 52.25.Dg, 52.25.Fi, 52.25.Xz, 52.30.Gz, 52.35.We, 52.55.Dy, 52.55.Fa
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Submitted to: Physics of Plasmas
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Download PPPL-5130 (pdf 3.4 MB 13 pp)
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