[Table of Contents]

Plasma and Fusion Research

Volume 7, 2502148 (2012)

Overview Articles

Recent TCV Results - Innovative Plasma Shaping to Improve Plasma Properties and Insight
Antoine POCHELON, Paolo ANGELINO, Roland BEHN, Stephan BRUNNER, Stefano CODA, Nataliya KIRNEVA1), Sergei Yu MEDVEDEV2), Holger REIMERDES, Jonathan ROSSEL, Olivier SAUTER, Laurent VILLARD, Dávid WÁGNER, Alberto BOTTINO3), Yann CAMENEN4), Gustavo P. CANAL, Prabal K. CHATTOPADHYAY5), Basil P. DUVAL, Ambrogio FASOLI, Timothy P. GOODMAN, Sébastien JOLLIET, Alexander KARPUSHOV, Benoît LABIT, Alessandro MARINONI, Jean-Marc MORET, Andreas PITZSCHKE, Laurie PORTE, Mikael RANCIC, Victor S. UDINTSEV6) and the TCV Team
Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confédération Suisse, CH-1015 Lausanne, Switzerland
1)
NRC-Kurchatov Institute, Kurchatov Sq. 1, 123182 Moscow, Russia
2)
Keldysh Institute, Russian Academy of Sciences, Miusskaya Sq. 4, 125047 Moscow, Russia
3)
Max-Planck Institut für Plasmaphysik, IPP-Euratom Association, Garching bei München, Germany
4)
PIIM UMR7345, CNRS/Aix-Marseille University, France
5)
Institut for Plasma Physics, Bhat, Gandhinagar, Gujarat, India
6)
ITER Organisation, St Paul lez Durance, France
(Received 15 January 2012 / Accepted 10 August 2012 / Published 22 November 2012)

Abstract

The TCV tokamak facility is used to study the effect of innovative plasma shapes on core and edge confinement properties. In low collisionality L-mode plasmas with electron cyclotron heating (ECH) confinement increases with increasing negative triangularity δ. The confinement improvement correlates with a decrease of the inner core electron heat transport, even though triangularity vanishes to the core, pointing to the effect of non-local transport properties. TCV has recently started the study of the effects of negative triangularity in H-mode plasmas. H-mode confinement is known to improve towards positive triangularity, due to the increase of pedestal height, though plagued by increasingly large edge localised modes (ELMs). An optimum triangularity could thus be sought between steep edge barriers (δ > 0) with large ELMs, and improved core confinement (δ < 0) with small ELMs. This opens the possibility for a reactor of having H-mode-level confinement within an L-mode edge, or at least with mitigated ELMs. In TCV, ELMy H-modes with upper triangularity δtop < 0 are explored, showing a reduction of ELM peak energy losses compared to δtop > 0. Alternative shapes are proposed on the basis of ideal MHD stability calculations. Shaping has the potential to bring at the same time key solutions to confinement, stability and wall loading issues and, from the comparison of experimental and simulation results, to give deeper insight in transport and stability.

Keywords

confinement, plasma shape, triangularity, global transport, gyrokinetic simulation, H-mode, ELM

DOI: 10.1585/pfr.7.2502148

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This paper may be cited as follows:

Antoine POCHELON, Paolo ANGELINO, Roland BEHN, Stephan BRUNNER, Stefano CODA, Nataliya KIRNEVA, Sergei Yu MEDVEDEV, Holger REIMERDES, Jonathan ROSSEL, Olivier SAUTER, Laurent VILLARD, Dávid WÁGNER, Alberto BOTTINO, Yann CAMENEN, Gustavo P. CANAL, Prabal K. CHATTOPADHYAY, Basil P. DUVAL, Ambrogio FASOLI, Timothy P. GOODMAN, Sébastien JOLLIET, Alexander KARPUSHOV, Benoît LABIT, Alessandro MARINONI, Jean-Marc MORET, Andreas PITZSCHKE, Laurie PORTE, Mikael RANCIC, Victor S. UDINTSEV and the TCV Team, Plasma Fusion Res. 7, 2502148 (2012).