Shear-flow trapped-ion-mode interaction revisited. I. Influence of low-frequency zonal flow on ion-temperature-gradient driven turbulence

Ghizzo, A.; Palermo, F.

doi:10.1063/1.4928102

Cited by 20 publications

(26 citation statements)

References 37 publications

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“…This instability is commonly observed in the Earth's clouds, ocean surfaces, atmospheres of Jupiter and Saturn but also in the solar corona [4] and so on. Recently, it has been demonstrated that the KH instability can play an important role also in the zonal flow dynamics of the tokamak devices [5][6][7]. Generally, this instability is presented as a mechanism of saturation able to dissipate the energy related to the velocity shear layer.…”

Section: Introductionmentioning

confidence: 99%

Energy Transport by Kelvin-Helmholtz Instability at the Magnetopause

Palermo

2019

Fluids

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By means of the formation of vortices in the nonlinear phase, the Kelvin Helmholtz instability is able to redistribute the flux of energy of the solar wind that flows parallel to the magnetopause. The energy transport associated with the Kelvin Helmholtz instability contributes significantly to the magnetosphere and magnetosheath dynamics, in particular at the flanks of the magnetopause where the presence of a magnetic field perpendicular to the velocity flow does not inhibit the instability development. By means of a 2D two-fluid simulation code, the behavior of the Kelvin Helmholtz instability is investigated in the presence of typical conditions observed at the magnetopause. In particular, the energy penetration in the magnetosphere is studied as a function of an important parameter such as the solar wind velocity. The influence of the density jump at the magnetopause is also discussed.

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Section: Introductionmentioning

confidence: 99%

Energy Transport by Kelvin-Helmholtz Instability at the Magnetopause

Palermo

2019

Fluids

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“…Since the model has been already derived in a previous work [27], we just recall here the main features relevant to the ZF dynamics. Assuming that dn 0 dψ is zero, in order to simplify the treatment, we just consider an ITG instability driven only by an initial temperature gradient, which corresponds to suppressing the second term dn 0 dψ ψ ∂φ ∂ψ ∂φ ∂α α dψ in (24).…”

Section: The Kinetic Nature Of Zf Driven By Timmentioning

confidence: 99%

“…From the work described in Ref. [27], the answer appears to lie in the fact that the nature of the ZF is strongly modified by nonlinear effects induced by the resonant character of (kinetic) TIMs, at least for the case of turbulence met in tokamaks.…”

Section: Introductionmentioning

confidence: 99%

“…Assuming that the gyro-average operator J 0 → 1 and D = 0, and that the second order effects (i.e., the second moment in energy of the distribution function f κ,E ) are negligible, the mean pressure obeys an equation expressing, on average over α, a Lagrangian advection by the flow φ (see Ref. [27] for more details):…”

Section: The Kinetic Nature Of Zf Driven By Timmentioning

confidence: 99%

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Hasegawa–Wakatani and Modified Hasegawa–Wakatani Turbulence Induced by Ion-Temperature-Gradient Instabilities

Sarto

Ghizzo

2017

Fluids

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Abstract:We review some recent results that have been obtained in the investigation of zonal flow emergence, by means of a gyrokinetic trapped ion model, in the regime of ion temperature gradient instabilities for tokamak plasmas. We show that an analogous formulation of the zonal flow dynamics in terms of the Reynolds tensor applies in the fluid and kinetic regimes, where polarization effects play a major role. The kinetic regime leads to the emergence of a resonant mode at a frequency close to the drift frequency. With the objective of modeling both separate fluid and kinetic regimes of zonal flows, we used in this paper a methodology for deriving both Charney-Hasegawa-Mima (CHM) and Hasegawa-Wakatani models. This methodology is based on the trapped ion model and is analogous to the hierarchy leading from the Vlasov equation to the macroscopic fluid equations. The nature of zonal flows in the hierarchy of the Mima, Hasegawa and Wakatani models is investigated and discussed through comparisons with global kinetic simulations. Applications to the CHM equation are discussed, which applies to a broad variety of hydrodynamical systems, ranging from large-scale processes met in magnetically confined plasma to the so-called zonostrophy turbulence emerging in the case of small-scale forced, two-dimensional barotropic turbulence (Sukoriansky et al. Phys. Rev.

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“…While substantial effort has been devoted to the study of ZF generation by drift-wave or Ion Temperature Gradip-1 ent (ITG) modes, little work has been published on zonal flows driven by pure collisionless trapped ion modes or by their electron counterpart, the collisionless trapped electron modes (CTEMs) when electron dynamics is taken into account. Recently in Refs [11,12], we have identified a nonlinear coupling mechanism of ZF mediated by CTIMs in the collisionless regime, leading to a non-zero low-frequency ZF mode of resonant nature (with the possibility to an amplification by wave-"banana" resonance). While zero-frequency ZFs are quite non resonant, being relativily easy to drive up by the Reynolds tensor, this new low-frequency oscillating component of ZF becomes sensible to a strong amplification induced by the resonant interaction between CTIM and CTEM.…”

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confidence: 99%

Transport barriers associated to the resonant interaction between trapped particle modes triggered by plasma polarization injection

Ghizzo¹,

Sarto²,

Palermo³

et al. 2017

EPL

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This letter explores the parametric excitation of low-frequency zonal flow induced by the beating of collisionless trapped ion and trapped electrons modes (CTIMs and CTEMs) and its feedback on the formation of transport barrier (TB). The zonal flow generation and the associated intermittent transport are investigated using a semi-Lagrangian gyrokinetic Vlasov simulations based on a Hamiltonian reduction technique, where both the fastest scales (cyclotron and bounce motions) are gyro-averaged. The model confirms the possibility to trigger TB by means of polarization effects, recently observed in global gyrokinetic simulations by Strugarek A.

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Shear-flow trapped-ion-mode interaction revisited. I. Influence of low-frequency zonal flow on ion-temperature-gradient driven turbulence

Cited by 20 publications

References 37 publications

Energy Transport by Kelvin-Helmholtz Instability at the Magnetopause

Energy Transport by Kelvin-Helmholtz Instability at the Magnetopause

Hasegawa–Wakatani and Modified Hasegawa–Wakatani Turbulence Induced by Ion-Temperature-Gradient Instabilities

Transport barriers associated to the resonant interaction between trapped particle modes triggered by plasma polarization injection

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