Stimulated zonal flow generation in the case of TEM and TIM microturbulence

Gravier, Etienne; Lesur, Maxime; Réveillé, T.; Drouot, Thomas

doi:10.1063/1.4962845

Cited by 8 publications

(12 citation statements)

References 23 publications

(39 reference statements)

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“…The importance of the role played by the ratio T e /T i in the emergence of zonal flows has been already shown in a different kind of study in Ref. [29].…”

Section: A Two-step Process: Induced Effects By Of the Polarisation Smentioning

confidence: 77%

“…In particular, we present numerical results obtained from the numerical integration of a reduced hamiltonian (Vlasov) gyrokinetic model for the trapped particle modes, and based on the action-angle model discussed in [12,13,26] and in Refs. [27][28][29] for two species. We address here the physical mechanisms responsible to strong amplification of ZF and the resulting TB's formation.…”

Section: Introductionmentioning

confidence: 99%

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Transport Barrier Triggered by Resonant Three-Wave Processes Between Trapped-Particle-Modes and Zonal Flow

Ghizzo

Sarto

2019

Plasma

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We address the mechanisms underlying low-frequency zonal flow generation in a turbulent system through the parametric decay of collisionless trapped particle modes and its feedback on the stabilization of the system. This model is in connection with the observation of barrier transport in reduced gyrokinetic simulations (A. Ghizzo et al., Euro. Phys. Lett. 119(1), 15003 (2017)). Here the analysis is extended with a detailed description of the resonant mechanism. A key role is also played by an initial polarisation source that allows the emergence of strong initial shear flow. The parametric decay leads to the growth of a zonal flow which differs from the standard zero frequency zonal flow usually triggered by the Reynolds stress in fluid drift-wave turbulence. The resulting zonal flow can oscillate at low frequency close to the ion precession frequency, making it sensitive to strong amplification by resonant kinetic processes. The system becomes then intermittent. These new findings, obtained from numerical experiments based on reduced semi-Lagrangian gyrokinetic simulations, shed light on the underlying physics coming from resonant wave-particle interactions for the formation of transport barriers. Numerical simulations are based on a Hamiltonian reduction technique, including magnetic curvature and interchange turbulence, where both fastest scales (cyclotron and bounce motions) are gyro-averaged.

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“…The importance of the role played by the ratio T e /T i in the emergence of zonal flows has been already shown in a different kind of study in Ref. [29].…”

Section: A Two-step Process: Induced Effects By Of the Polarisation Smentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Transport Barrier Triggered by Resonant Three-Wave Processes Between Trapped-Particle-Modes and Zonal Flow

Ghizzo

Sarto

2019

Plasma

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“…More precisely, we look at the influence of the impurity profile on trapped particle driven modes, and study the transport of these impurities. This is done using the code TERESA, which is a semi-Lagrangian code based on a collisionless reduced bounce-averaged gyrokinetic model [17][18][19][20][21][22] . This code treats the passing particles adiabatically, and allows the study of Trapped Electron Modes (TEM) and Trapped Ion Modes (TIM).…”

Section: Introductionmentioning

confidence: 99%

Impurity density gradient influence on trapped particle modes

et al. 2018

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The effect of the presence of an impurity species on the trapped particle turbulence is studied using the gyro-bounce kinetic code TERESA, which allows the study of Trapped Electron Modes and Trapped Ion Modes. The impurity species is treated self-consistently and its influence on the nature of the turbulence, ion driven or electron driven, is investigated. It is found that the presence of heavy impurities with a flat density profile tends to stabilize the both electron and ion modes, whereas a peaked or hollow impurity density profile can change the turbulence from an electron driven turbulence to an ion driven turbulence. The effect of the turbulence regime on impurity transport is studied.

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“…in gyrokinetic simulations, it is possible to apply a control method to stimulate the appearance of zonal flows while minimizing the duration of the control process and the impact on plasma parameters [9]. We also report on our observation of a hysteresis in the relation between zonal flows and electron temperature [10].…”

mentioning

confidence: 80%

Transport hysteresis and zonal flow stimulation in magnetized plasmas

Gravier¹,

Lesur²,

Réveillé³

et al. 2017

Nucl. Fusion

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Understanding transport in tokamak plasma is an important step toward viable nuclear fusion [1]. A study of zonal flows generated by trapped-electron mode (TEM) and trapped-ion mode (TIM) micro turbulence is presented. For this purpose the gyrokinetic code TERESA (Trapped Element REduction in Semi lagrangian Approach), which considers only trapped particles, is used [2, 3, 4, 5, 6, 7, 8]. The model enables the processing of the full f problem for trapped ions and electrons at very low numerical cost. In this paper we show that in some parameter range

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Stimulated zonal flow generation in the case of TEM and TIM microturbulence

Cited by 8 publications

References 23 publications

Transport Barrier Triggered by Resonant Three-Wave Processes Between Trapped-Particle-Modes and Zonal Flow

Transport Barrier Triggered by Resonant Three-Wave Processes Between Trapped-Particle-Modes and Zonal Flow

Impurity density gradient influence on trapped particle modes

Transport hysteresis and zonal flow stimulation in magnetized plasmas

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