Long-distance correlation and zonal flow structures induced by mean E×B shear flows in the biasing H-mode at TEXTOR

Xu, Yuhong; Jachmich, S.; Weynants, R.; Schoor, M. Van; Vergote, M.; Krämer‐Flecken, A.; Schmitz, O.; Unterberg, B.; Hidalgo, C.; Team, Textor

doi:10.1063/1.3265367

Cited by 30 publications

(36 citation statements)

References 24 publications

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“…Indeed, the existence of zonal flows in toroidal plasmas has been experimentally confirmed [5] and references therein. Recent experiments have shown that long-range correlations are present during the development of the edge shear flows and how these correlations are amplified by externally imposed radial electric fields [6], [7], [8]. As a consequence, multi-scale physics (i.e.…”

Section: Introductionmentioning

confidence: 99%

Long‐Range Correlations During Plasma Transitions in the TJ‐II Stellarator

Pedrosa¹,

Hidalgo²,

Silva

et al. 2010

Contrib. Plasma Phys.

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The mechanism underlying the development of edge transport barriers is still one of the fundamental issues confronting the magnetic fusion community. The results presented show the importance of long-range correlation as approaching plasma bifurcations in different plasma scenarios, including biasing induced and spontaneous edge transport bifurcations in ECRH and NBI plasmas. These findings are consistent with the theory of zonal flows, pointing out the importance of both mean and fluctuating electric fields during the development of edge plasma transitions.

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Section: Introductionmentioning

confidence: 99%

Long‐Range Correlations During Plasma Transitions in the TJ‐II Stellarator

Pedrosa¹,

Hidalgo²,

Silva

et al. 2010

Contrib. Plasma Phys.

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“…The level of long-distance correlation (LDC) structures in potential fluctuation, which behaves in the similar way as the zonal flows, was observed to be amplified under positive bias on tokamaks [22][23][24] and stellarators [14,15]. Further studies showed that the LDC strength is sensitive to the polarity of bias [23] as well as magnetic perturbation, and reduces at high-density level [25].…”

Section: Introductionmentioning

confidence: 99%

The influence of electrode biasing on plasma confinement in the J-TEXT tokamak

Sun

Chen

Zhu

et al. 2013

Plasma Phys. Control. Fusion

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The influence of both positive and negative bias on global and plasma-edge parameters has been comparatively studied with a newly designed electrode biasing system in J-TEXT tokamak. Comparing to the 0V bias case, the global particle confinement of plasma is enhanced under bias with both polarities, with the increments of central line-averaged density and soft-X ray emission as well as the reduction of edge H α radiation level. The suppression of plasma-edge fluctuations and turbulent particle transport are obviously observed under bias, in different degrees with different polarities. The potential fluctuation amplitude is observed to be increased at the vicinity of limiter under positive bias, with the existence of a peaked low frequency mode (LFM) characterized as high coherence and near-zero cross-phase poloidally in the edge region, which is not found in the negative bias case. The poloidal correlation length of turbulence is greatly enhanced under bias with both polarities, and shows a positive correlation with the amplitude of poloidal phase velocity, which is mainly driven by the local J r × B torque at plasma edge under bias. The characteristic parameters of intermittent events (i.e. blobs), including amplitude, radial velocity, related particle flux and radial size, are decreased dramatically under bias in the edge region.

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“…In some cases they have been identified with Geodesic-Acoustic-Mode type (GAM) oscillations [1,[6][7][8][9]. Recently, long range correlations in potential have been measured in different fusion devices [10][11][12][13][14] that could be associated to ZFs.…”

Section: Introductionmentioning

confidence: 99%

Collisionless damping of flows in the TJ-II stellarator

Sánchez¹,

Kleiber

Hatzky

et al. 2012

Plasma Phys. Control. Fusion

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Abstract. The results of global linear gyrokinetic simulations of residual flows carried out with the code EUTERPE in the TJ-II three dimensional geometry are reported. The linear response of the plasma to potential perturbations homogeneous in a magnetic surface shows several oscillation frequencies: a GAMlike frequency, in qualitative agreement with the formula given by Sugama et al [1], and a much lower frequency oscillation in agreement with the predictions of Mishchenko et al [2,3] for stellarators. The dependency of both oscillations with ion and electron temperatures and the magnetic configuration is studied. The low frequency oscillations are in the frequency range supporting the longrange correlations between potential signals experimentally observed in TJ-II.

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Long-distance correlation and zonal flow structures induced by mean E×B shear flows in the biasing H-mode at TEXTOR

Cited by 30 publications

References 24 publications

Long‐Range Correlations During Plasma Transitions in the TJ‐II Stellarator

Long‐Range Correlations During Plasma Transitions in the TJ‐II Stellarator

The influence of electrode biasing on plasma confinement in the J-TEXT tokamak

Collisionless damping of flows in the TJ-II stellarator

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