Geodesic Acoustic Waves in Hydromagnetic Systems

Winsor, N. K.

doi:10.1063/1.1691835

Cited by 657 publications

(772 citation statements)

References 4 publications

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“…[21] Two new features in the present work are that (1) we retain the effect of ion compressibility, thereby enabling the description of sound waves and drift Kelvin-Helmholtz instabilities [26] and (2) we account for the role of magnetic curvature, thereby enabling our model to describe geodesic acoustic modes (GAM). [27,28] The present paper is organized as follows. Sec.…”

Section: Introductionmentioning

confidence: 99%

A compressible Hamiltonian electromagnetic gyrofluid model

Waelbroeck

Tassi

2012

Communications in Nonlinear Science and Numerical Simulation

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A Lie-Poisson bracket is presented for a four-field gyrofluid model with compressible ions and magnetic field curvature, thereby showing the model to be Hamiltonian. In particular, in addition to commonly adopted magnetic curvature terms present in the continuity equations, analogous terms must be retained also in the momentum equations, in order to have a Lie-Poisson structure.The corresponding Casimir invariants are presented, and shown to be associated to four Lagrangian invariants, that get advected by appropriate "velocity" fields during the dynamics. This differs from a cold ion limit, in which the Lie-Poisson bracket transforms into the sum of direct and semidirect products, leading to only three Lagrangian invariants.

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Section: Introductionmentioning

confidence: 99%

A compressible Hamiltonian electromagnetic gyrofluid model

Waelbroeck

Tassi

2012

Communications in Nonlinear Science and Numerical Simulation

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“…They ascribed these modulations to the geodesic acoustic mode (GAM) [21] excited in the tokamak plasma. We started to analyze in detail the large potential oscillations in the tokamak plasma since our measurement of local potential gives directly zonal flows and streamers through −∇Φ × B/B 2 .…”

Section: Short Historymentioning

confidence: 99%

Heavy Ion Beam Probe, Present Status and Future Development

Hamada

Nishizawa

Watari

et al. 2007

Plasma and Fusion Research

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Present status of the analysis of HIBP data on zonal flows, streamers and drift-wave turbulence of the JIPPT-IIU tokamak plasmas, is reviewed. Limiting factors and improvements of heavy ion beam probe towards better understanding of tokamak turbulence, beam attenuation, beam quality of the probing beam, multiple energy analyzers for simultaneous measurement at various cross-sections of the plasmas, proposal for 2-dimensional measurement of the plasma turbulence, are discussed.

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“…The relative radial distance of two HIBPs is varied, and it was found that (1) the radial wavelength of the zonal flows is one or two cm, and that (2) the correlation length of the zonal flows is longer than a few cm. (A peak in the power spectrum around 20 kHz is an oscillating zonal flow, which has been named geodesic acoustic modes (GAMs) [17]. )…”

Section: Zonal Flows and Microscopic Fluctuations In Toroidal Plasmasmentioning

confidence: 99%

On Imaging of Plasma Turbulence

Itoh

Fujisawa

Nagashima

et al. 2007

Plasma and Fusion Research

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We discuss aspects of imaging of plasma turbulence, taking the standpoint that the imaging is a path for induction of law from complex signals. An example of induction of symbol from signals is illustrated. Then the image of plasma turbulence is extended, putting an emphasis on the identification of the nonlinear interaction in turbulence. By employing the bipspectral method, magnitudes of interactions among excited modes are estimated. Interactions between microscopic turbulence and large-scale structures are demonstrated, providing our understanding of structure formation in turbulent plasmas.

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Geodesic Acoustic Waves in Hydromagnetic Systems

Abstract: In toroidal systems with geodesic curvature an electrostatic acoustic mode occurs with plasma motion in the magnetic surfaces, perpendicular to the field. In typical stellarators this mode should dominate ordinary sound waves associated with motion along the field.

Cited by 657 publications

References 4 publications

A compressible Hamiltonian electromagnetic gyrofluid model

A compressible Hamiltonian electromagnetic gyrofluid model

Heavy Ion Beam Probe, Present Status and Future Development

On Imaging of Plasma Turbulence

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