[Table of Contents]

Plasma and Fusion Research

Volume 9, 3402081 (2014)

Regular Articles

Physics and Control of External Kink Instabilities with Realistic 3D Boundaries: a Challenge for Modern Experiments and Modeling
Tommaso BOLZONELLA, Matteo BARUZZO, Yueqiang LIU1), Giuseppe MARCHIORI, Go MATSUNAGA2), Leonardo PIGATTO3), Anton SOPPELSA, Manabu TAKECHI2) and Fabio VILLONE4)
Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova, Italy
1)
Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, UK
2)
Japan Atomic Energy Agency, Naka 311-0193, Japan
3)
Università di Padova, Italy
4)
Ass. Euratom/ENEA/CREATE, DAEIMI, Università di Cassino, Italy
(Received 10 December 2013 / Accepted 28 February 2014 / Published 29 July 2014)

Abstract

In present day devices, the external kink ideal MHD instability establishes hard operational boundaries for both the tokamak and the Reversed Field Pinch (RFP) configurations. An interesting feature of it is that its growth rate critically depends on the device passive boundary characteristics and this can slow it down to time scales accessible to modern real time feedback control systems, normally using external active coils as actuators. 3D passive structures and external fields play a key role in determining physics and control of this instability. This is in particular true for equilibria with multimodal unstable RWM spectra where modes can couple to specific 3D features of passive and active magnetic boundary. In the paper we will present recent data and simulations from RFX-mod, a medium size (R = 2 m, a = 0.459 m) device able to confine RFP and tokamak plasmas with currents up to 2 MA and 120 kA, respectively. Successful quantitative modeling of multimodal RWM control experiments performed using different actuator configurations will be presented and commented.

Keywords

MHD stability, MHD feedback control, Resistive Wall Modes, 3D modeling, FEM modeling, tokamak, Reversed Field Pinch

DOI: 10.1585/pfr.9.3402081

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This paper may be cited as follows:

Tommaso BOLZONELLA, Matteo BARUZZO, Yueqiang LIU, Giuseppe MARCHIORI, Go MATSUNAGA, Leonardo PIGATTO, Anton SOPPELSA, Manabu TAKECHI and Fabio VILLONE, Plasma Fusion Res. 9, 3402081 (2014).