Electromagnetic effects on geodesic acoustic modes

Bashir, M. F.; Smolyakov, Andrei; Elfimov, A. G.; Melnikov, A. V.; Murtaza, G.

doi:10.1063/1.4891883

Cited by 16 publications

(47 citation statements)

References 37 publications

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“…This approach was followed in [100,107,113,114], in particular, for studies of the GAM dispersion [111]. Note that in this approach no restriction is placed on the value of the ω di /ω t parameter.…”

Section: Coupling Of Transit and Toroidal Resonancesmentioning

confidence: 99%

“…The representation in equations ( 66)-( 68) directly captures the toroidal resonances effects 1/ ω 2 − ω 2 d /2 for the GAM mode involving the φ 0 and φ s perturbations without any additional expansions. The addition of second harmonics makes the coupling more complicated; the expressions for f s , f c , f 2c and f 2s with the second order resonant propagator Δ 2 were obtained in [114]. It would be important to compare the GAM damping obtained with the full propagator Δ in equation (68), or Δ 2 from [114], with the results of the summation of multiple harmonics as in [78,79,112].…”

Section: Coupling Of Transit and Toroidal Resonancesmentioning

confidence: 99%

“…The addition of second harmonics makes the coupling more complicated; the expressions for f s , f c , f 2c and f 2s with the second order resonant propagator Δ 2 were obtained in [114]. It would be important to compare the GAM damping obtained with the full propagator Δ in equation (68), or Δ 2 from [114], with the results of the summation of multiple harmonics as in [78,79,112]. The representation ( 66)-(68) will also be useful in the EGAM theory discussed in section 3.…”

Section: Coupling Of Transit and Toroidal Resonancesmentioning

confidence: 99%

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Geodesic acoustic modes in magnetic confinement devices

Smolyakov

Ido

2021

Nucl. Fusion

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Geodesic acoustic modes (GAMs) are ubiquitous oscillatory flow phenomena observed in toroidal magnetic confinement fusion plasmas, such as tokamaks and stellarators. They are recognized as the non-stationary branch of the turbulence driven zonal flows which play a critical regulatory role in cross-field turbulent transport. GAMs are supported by the plasma compressibility due to magnetic geodesic curvature—an intrinsic feature of any toroidal confinement device. GAMs impact the plasma confinement via velocity shearing of turbulent eddies, modulation of transport, and by providing additional routes for energy dissipation. GAMs can also be driven by energetic particles (so-called EGAMs) or even pumped by a variety of other mechanisms, both internal and external to the plasma, opening-up possibilities for plasma diagnosis and turbulence control. In recent years there have been major advances in all areas of GAM research: measurements, theory, and numerical simulations. This review assesses the status of these developments and the progress made towards a unified understanding of the GAM behaviour and its role in plasma confinement. The review begins with tutorial-like reviews of the basic concepts and theory, followed by a series of topic orientated sections covering different aspects of the GAM. The approach adopted here is to present and contrast experimental observations alongside the predictions from theory and numerical simulations. The review concludes with a comprehensive summary of the field, highlighting outstanding issues and prospects for future developments.

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Section: Coupling Of Transit and Toroidal Resonancesmentioning

confidence: 99%

Section: Coupling Of Transit and Toroidal Resonancesmentioning

confidence: 99%

Section: Coupling Of Transit and Toroidal Resonancesmentioning

confidence: 99%

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Geodesic acoustic modes in magnetic confinement devices

Smolyakov

Ido

2021

Nucl. Fusion

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“…This approximation is valid for evaluation of the geodesic continuum or neoclassical polarization for symmetric perturbations in low beta limit, but not valid for Alfvénic eigenmodes [18,19]. Although a few studies considered the electromagnetic effects for ZFs and GAMs in recent years [20][21][22][23][24], most relevant works still focused on the electrostatic perturbations. We consider a turbulence driven by ion temperature gradient and neglect the electron response.…”

Section: The Physics Model and The General Formulation For Rzfsmentioning

confidence: 99%

The residual zonal flow in tokamak plasmas with a poloidal electric field

Wang¹,

Zhou²,

Yue³

2018

Plasma Sci. Technol.

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In a tokamak plasma with auxiliary heating by cyclotron waves, a poloidal electric field will be produced, and as a consequence influence the residual zonal flow (RZF) level. The poloidal electric field can also be induced through biasing electrodes at the edge region of tokamaks. Numerical evaluation for a large aspect ratio circular cross section tokamak for the electron cyclotron wave heating indicates that the RZF level decreases significantly when the poloidal electric field increases. Qualitatively, the ion cyclotron wave heating is able to increase the RZF level. It is difficult to apply the calculation to the real cyclotron wave heating experiments since we need to know factors such as the plasma profiles, the exact power deposition and the cross section geometry, etc. It is possible to use the cyclotron wave heating to control the zonal flow and then to control the turbulence level in tokamak experiments.

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“…Usando as aproximações potenciais do campo elétrico ignorando as pequenas perturbações magnéticas discutidas em [24].…”

Section: Influência Do Fluxo De Elétrons E íOns Na Instabilidade Por unclassified

Teoria de ondas em Tokamaks

Souza¹

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Electromagnetic effects on geodesic acoustic modes

Cited by 16 publications

References 37 publications

Geodesic acoustic modes in magnetic confinement devices

Geodesic acoustic modes in magnetic confinement devices

The residual zonal flow in tokamak plasmas with a poloidal electric field

Teoria de ondas em Tokamaks

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