IAEA Fusion Energy Conference 2010

Proceedings of the 23rd IAEA Fusion Energy Conference
Daejeon, 11-16 October 2010

Organized by the International Atomic Energy Agency
and hosted by the Government of the Republic of Korea


(EXC/P8-08) Transport and Turbulence with Innovative Plasma Shapes in the TCV Tokamak

B. Labit1), A. Pochelon1), M. Rancic1), F. Piras1), A. Bencze1), A. Bottino2), S. Brunner1), Y. Camenen3), P.K. Chattopadhyay4), S. Coda1), E. Fable2), T.P. Goodman1), S. Jolliet5), A. Marinoni1), L. Porte1), B.F. McMillan1), S.Yu. Medvedev6), O. Sauter1), V.S. Udintsev7), L. Villard1), TCV Team1)
1) Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association EURATOM-Confédération Suisse, CH-1015 Lausanne, Switzerland
2) Max-Planck-Institut für Plasmaphysik (IPP) Boltzmannstrasse 2, Garching, Germany
3) CSFA, Dpt. of Physics, University of Warwick, Coventry, UK
4) Institute for Plasma Reasearch, Bhat, Gandhinagar, Gujarat, India
5) Japan Atomic Energy Agency, Higashi-Ueno 6-9-3, Taitou, Tokyo 110-0015, Japan
6) Keldysh Institute, Russian Federation Academy of Sciences, Moscow, Russian Federation
7) ITER Organization, 13108 Saint-Paul-Lez-Durance CEDEX, France

Abstract.  We present recent results on turbulence measurements in TCV L-mode plasmas. It has been shown that the heat transport is reduced by a factor of two for a plasma at negative triangularity compared with a plasma at positive triangularity. This transport reduction is reflected in the reduction of the temperature fluctuation level, in the low frequency part of the spectrum (20-120 kHz), measured by correlation ECE in the outer equatorial plane. Nonlinear gyrokinetic simulations predict that the TEM turbulence might be dominant for these TCV plasmas. The TEM induced transport is shown to decrease with decreasing triangularity and increasing collisionality. Both dependences are in fairly good agreement with experimental observations. We also report on an innovative divertor magnetic configuration: the snowflake (SF) divertor whose properties are expected to affect the local heat load to the divertor plates in particular during ELMs when compared with the classical single-null (SN) divertor. In L-mode plasmas, the intermittent particle and heat transport in the SOL is associated with the presence of “blobs” propagating in the radial direction. Intermittency is compared between SN and SF configurations by looking at the statistical properties of the ion saturation current Jsat measured with Langmuir probes (LPs) in the LFS scrape-off layer. For ELMy H-mode SF plasmas, the time evolution of Jsat during ELMs is estimated with LPs covering the strike-points target zones.

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