Modulation of Core Turbulent Density Fluctuations by Large-Scale Neoclassical Tearing Mode Islands in the DIII-D Tokamak

Bardóczi, L.; Rhodes, T. L.; Carter, T. A.; Navarro, A. Bañón; Peebles, W. A.; Jenko, F.; McKee, G. R.

doi:10.1103/physrevlett.116.215001

Cited by 73 publications

(75 citation statements)

References 21 publications

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“…The turbulence is weak inside magnetic islands that is consistent with the observations of low gradient of electron temperature [20], and reduced electron thermal conductivity [21]. The NTM-induced islands modulate density fluctuations in the core plasmas [22].…”

Section: Introductionsupporting

confidence: 81%

Temporal-spatial structures of plasmas flows and turbulence around tearing mode islands in the edge tokamak plasmas

Zhao

Nagashima

et al. 2017

Nucl. Fusion

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The temporal-spatial structures of plasma flows and turbulence around tearing mode islands are presented. The experiments were performed using Langmuir probe arrays in the edge plasmas of J-TEXT tokamak. The correlation analyses clearly show that the flows have similar structures of m/n=3/1 as the magnetic island does (m and n are the poloidal and toroidal mode numbers, respectively). The sign of the potential fluctuations for the flows inverses and the powers significantly reduce at q=3 surface. Approaching to the last closed flux surface for the magnetic islands, the radially 2 elongated flow structure forms. The flows are concentrated near separatrix and show quadrupole structures. The turbulence is concentrated near X-point and partly trapped inside the magnetic islands.

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Section: Introductionsupporting

confidence: 81%

Temporal-spatial structures of plasmas flows and turbulence around tearing mode islands in the edge tokamak plasmas

Zhao

Nagashima

et al. 2017

Nucl. Fusion

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“…The measure of the impact of magnetic islands on turbulent fluctuations has been assessed experimentally recently. 17 One may therefore expect to evaluate the converse situation where by modifying the turbulence level, one could observe a modification of the island transport properties such as the pressure flattening. Before addressing through numerical simulations the role of the turbulence and the turbulent diffusivity in the pressure flattening of TDMI, we describe below the model we shall use.…”

Section: Experimental Limitations and Observationsmentioning

confidence: 99%

Nonlinear dynamics of turbulence driven magnetic islands. II. Numerical simulations

Agullo¹,

Muraglia²,

Benkadda³

et al. 2017

Physics of Plasmas

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The nonlinear dynamics of a turbulence driven magnetic island (TDMI) is investigated numerically in a reduced magnetohydrodynamic fluid model. The significance of identifying a characteristic signature of a TDMI for its experimental observation is discussed. The principal focus of our simulations is on the nature of the pressure profile flattening inside a TDMI, and we show that, in agreement with analytical predictions, a partial flattening occurs when the island size exceeds a critical value that is a function of the small scale interchange dynamics. We also present a model and test it numerically, which links explicitly the interchange turbulence and the island pressure flattening.

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“…with a uniform diffusivity [Kurita et al, 1994, Hegna and Callen, 1997, Lazzari and Westerhof, 2009. How-ever, numerical works [Hornsby et al, 2010, Hornsby et al, 2011, Zarzoso et al, 2015, Hill et al, 2015, Izacard et al, 2016, Navarro et al, 2017 and experimental analyzes [Inagaki et al, 2004, Ida et al, 2012, Bardòczi et al, 2016 have shown that heat diffusivity is far from being uniform in the vicinity of an island. It is strongly decreased inside the separatrix, and slightly increased just outside.…”

Section: Introductionmentioning

confidence: 99%

Numerical experiments of island stabilization by RF heating with stiff temperature profile

Maget

Widmer

Février

et al. 2018

Plasma Phys. Control. Fusion

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The nature of turbulent transport in tokamak plasmas results in temperature profiles that are called resilient or stiff, and the stabilization of magnetic islands by a localized heat source is expected to be extremely sensitive to the stiffness strength. Theoretical expectations are verified with nonlinear simulations, showing a good agreement and confirming the enhanced stabilization efficiency due to large profile stiffness when the power used for the control is small compared with the heating power producing the equilibrium profiles. Heat sources that are present in the island region before the RF heating is applied contribute to reduce the island size, but at the same time, they severely damp the control capability.

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Modulation of Core Turbulent Density Fluctuations by Large-Scale Neoclassical Tearing Mode Islands in the DIII-D Tokamak

Cited by 73 publications

References 21 publications

Temporal-spatial structures of plasmas flows and turbulence around tearing mode islands in the edge tokamak plasmas

Temporal-spatial structures of plasmas flows and turbulence around tearing mode islands in the edge tokamak plasmas

Nonlinear dynamics of turbulence driven magnetic islands. II. Numerical simulations

Numerical experiments of island stabilization by RF heating with stiff temperature profile

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