Plasma and Fusion Research

Volume 8, 2402131 (2013)

Regular Articles

Particle Flow during Sawtooth Reconnection: Numerical Simulations of Experimental Observations

Timothée NICOLAS, Roland SABOT, Xavier GARBET, Hinrich LÜTJENS¹⁾, Jean-François LUCIANI¹⁾, Antoine SIRINELLI²⁾, Joan DECKER, Antoine MERLE and JET-EFDA Contributors³⁾

: CEA, IRFM, St-Paul-Lèz-Durance, France
1): Centre de Physique Théorique, École Polytechnique, Palaiseau, France
2): Euratom/CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK
3): JET-EFDA, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK

(Received 5 December 2012 / Accepted 2 August 2013 / Published 15 November 2013)

Abstract

The core plasma density in ohmic, sawtoothing regime in Tore Supra and JET tokamaks measured by fastsweeping reflectometry develops a central peak. This peak is surrounded by a density plateau, which extends up to the q = 1 reconnection surface. Such mexican hat like profiles differ from the smooth dome of the temperature profile. Detailed tomographic reconstructions of the density in the poloidal plane show the development of crescent and ring structures during the sawtooth cycle. 3D full MHD nonlinear simulations with the XTOR-2F code recover these structures and show that they can be explained by the MHD activity related to the sawtooth instability. They show also that the electron density evolution is dominated by the perpendicular MHD flows, while the temperature, obtained with ECE measurements is dominated by parallel diffusion.

Keywords

reflectometry, MHD simulation, sawtooth instability and kink mode, Tore Supra, JET

DOI: 10.1585/pfr.8.2402131

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This paper may be cited as follows:

Timothée NICOLAS, Roland SABOT, Xavier GARBET, Hinrich LÜTJENS, Jean-François LUCIANI, Antoine SIRINELLI, Joan DECKER, Antoine MERLE and JET-EFDA Contributors, Plasma Fusion Res. 8, 2402131 (2013).