Articolo in rivista, 2019, ENG, 10.1016/j.fusengdes.2019.01.051

Tracking of neoclassical tearing modes in TCV using the electron cyclotron emission diagnostics in quasi-in-line configuration

Rispoli, N.; Sozzi, C.; Figini, L.; Micheletti, D.; Galperti, C.; Fontana, M.; Alessi, E.; Coda, S.; Garavaglia, S.; Goodman, T.; Kong, M.; Maraschek, M.; Moro, A.; Porte, L.; Sauter, O.; Sheikh, U.; Testa, D.

Istituto di Fisica del Plasma "Piero Caldirola" - CNR, Milano, Italy; CNR ISTP, Istituto per la Scienza e Tecnologia dei Plasmi, Milano, Italy; Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne, Switzerland; Max Planck Institute for Plasma Physics, Garching, Germany.

An important goal of the control system in a tokamak is the suppression of magneto-hydrodynamic (MHD) instabilities with low m, n (poloidal and toroidal mode numbers), which can influence the confinement time of energy and particles and possibly lead to plasma disruption. These instabilities, which appear as rotating magnetic islands, can be reduced or completely suppressed by a current driven by electron cyclotron waves (ECW) accurately located within the island. A fundamental requisite for this control technique is the ability to identify the island parameters (amplitude and radial position) and to vary accordingly the ECW deposition location. Here we describe a control scheme of the steering mirror of the ECW source based on the real-time tracking of the island radial position realized using only the electron cyclotron emission (ECE) diagnostics in quasi-in-line configuration, i.e. with toroidal anti-parallel propagation of the ECW and ECE beams. The successful experimental proof of principle of this scheme, tested on the TCV tokamak, is here reported.

Fusion engineering and design 146 (SI), pp. 666–670

Keywords

TCV, Neoclassical tearing mode, Real time control, Tokamak

CNR authors

Moro Alessandro Andrea, Garavaglia Saul Francesco, Alessi Edoardo, Micheletti Daniele, Sozzi Carlo, Rispoli Natale, Figini Lorenzo

CNR institutes

IFP – Istituto di fisica del plasma "Piero Caldirola", ISTP – Istituto per la Scienza e Tecnologia dei Plasmi