Closed Loop Sawtooth Period Control Using Variable ECCD Injection Angles on Tore Supra

Lennholm, M.; Eriksson, L.‐G.; Turco, F.; Bouquey, F.; Darbos, C.; Dümont, R.; Giruzzi, G.; Jung, Matthias; Lambert, R.; Magne, R.; Molina, Diego Alonso Restrepo; Moreau, Ph.; Rimini, F.; Ségui, J. L.; Song, Seok Goo; Traisnel, E.

doi:10.13182/fst09-a4052

Cited by 29 publications

(45 citation statements)

References 12 publications

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“…Various studies on different tokamaks, like TCV [8], TEXTOR [9] and ASDEX [10], have shown that the period can be altered using a spatially localized Electron Cyclotron Current Drive (ECCD). Recently, some first experimental feedback results with ECCD have been reported on TCV [11] and Tore Supra [12]. However, these results do not provide a basis for structured controller design, which requires a control-oriented model of the sawtooth behavior.…”

Section: Introductionmentioning

confidence: 99%

Closed loop control of the sawtooth instability in nuclear fusion

Witvoet

Steinbuch

Westerhof

et al. 2010

Proceedings of the 2010 American Control Conference

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In nuclear fusion the sawtooth instability is an important plasma phenomenon, having both positive and negative effects on the tokamak plasma. Control of its period is essential in future nuclear fusion reactors. This paper presents a control oriented model of the sawtooth instability, with current drive as input and sawtooth period as output, and validates it with a more extended model and experimental data. This model is numerically implemented and combined with PI-controllers in a feedback loop. Simulations show that closed loop control of the system to a desired sawtooth period is indeed possible, even when time delay is added to the feedback loop.

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Section: Introductionmentioning

confidence: 99%

Closed loop control of the sawtooth instability in nuclear fusion

Witvoet

Steinbuch

Westerhof

et al. 2010

Proceedings of the 2010 American Control Conference

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“…In section VII recent JET experiments are described briefly which aim to verify the control mechanism, and minimise the effect of ICRH on the current profile. Without such experiments, it could be argued that sawtooth control occurred because of a magnetic shear change, as in ECCD experiments of TCV [30,18] and TORE-SUPRA [31,19]. Finally, it should be pointed out that despite the apparent applicability of asymmetric NBI and RF distributions to control sawteeth in ITER, there is a downside.…”

Section: The Theory Of the Sawtooth Triggermentioning

confidence: 99%

Recent Advances in Sawtooth Control

Graves

Chapman

Coda

et al. 2011

Fusion Science and Technology

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“…Consequently, recent experiments have focussed on destabilizing sawteeth using ECCD in the presence of energetic particles. Sawtooth destabilization of long period sawteeth induced by ICRH generated core fast ions with energies 0.5 MeV was achieved in Tore Supra, even with modest levels of ECCD power [30,31]. Similarly, ECCD destabilization has also been achieved in the presence of ICRH accelerated NBI ions in ASDEX Upgrade [32] as well as with normal NBI fast ions in ASDEX Upgrade [7] and JT-60U [33].…”

Section: Introductionmentioning

confidence: 99%

Sawtooth control using electron cyclotron current drive in ITER demonstration plasmas in DIII-D

et al. 2012

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Sawtooth control using electron cyclotron current drive (ECCD) has been demonstrated in ITER-like plasmas with a large fast ion fraction, wide q = 1 radius and long uncontrolled sawtooth period in DIII-D. The sawtooth period is minimized when the ECCD resonance is just inside the q = 1 surface. Sawtooth destabilization using driven current inside q = 1 avoids the triggering of performance-degrading neoclassical tearing modes (NTMs), even at much higher pressure than required in the ITER baseline scenario. Operation at β N = 3 without 3/2 or 2/1 NTMs has been achieved in ITER demonstration plasmas when sawtooth control is applied using only modest ECCD power. Numerical modelling qualitatively confirms that the achieved driven current changes the local magnetic shear sufficiently to compensate for the stabilizing influence of the energetic particles in the plasma core.

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Closed Loop Sawtooth Period Control Using Variable ECCD Injection Angles on Tore Supra

Cited by 29 publications

References 12 publications

Closed loop control of the sawtooth instability in nuclear fusion

Closed loop control of the sawtooth instability in nuclear fusion

Recent Advances in Sawtooth Control

Sawtooth control using electron cyclotron current drive in ITER demonstration plasmas in DIII-D

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