Alfvén waves in inhomogeneous magnetic fields

Gajewski, Ryszard; Winterberg, F.

doi:10.1016/0003-4916(65)90021-7

Cited by 9 publications

(7 citation statements)

References 3 publications

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“…Such a study was initiated by Gajewski and Winterberg (1961). Actually, the equation arrived at by Gajewski and Winterberg did not show any singular behavior, because these investigators neglected the effect of pressure perturbations.…”

Section: Spectral Analysis Of Ideal Magnetic Fields 3 Alfvin Wave In mentioning

confidence: 99%

Alfven wave. DOE Critical Review Series

Hasegawa¹,

Uberoi²

1982

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Books published by the Center include undergraduate, graduate, and workshop textbooks; handbooks and manuals; reference books; monographs; specialized reviews; and DOE-sponsored symposium, workshop, and short-course proceedings. FOR E w ORD This publication is the second in the Advances in Fusion Science and Engineering series, a part of the DOE Critical Review Series. The purpose of the Advances in Fusion Science and Engineering series is to provide the fusion research community with high-quality reviews in specialized areas of fusion science and engineering. Although Alfvtn waves have been the subject of study in space plasmas for a long time, only recently have plasma dimensions and betas reached sufficiently high values to make it possible to study Alfvtn waves in the laboratory. Auxiliary heating by means of Alfvdn waves has been tried both in the United States and abroad. Preliminary indications are that heating may be possible with the very high absorption efficiency predicted by theory. Because of the localized nature of wave conversion, Alfvin waves have the potential of providing plasma profile control. Alfvdn waves have recently been proposed for space-resolved measurement of magnetic fields in tokamaks and may become important as a diagnostic tool in the future. This monograph deals with. the properties of Alfvin waves and with their application to fusion. The book is divided into seven chapters dealing with linear properties in homogeneous and inhomogeneous plasmas. Absorption is treated by means of kinetic theory. Instabilities and nonlinear processes are treated in Chapters 1 to 6 , and the closing chapter is devoted to theory and experiments in plasma heating by Alfvtn waves. V vi FOREWORD I n view of the growink importance to the tokamak program of auxiliary heating by means of electromagnetic waves, I believe this monograph will fill a need for an exposition of the essential elements of AlfvCn waves, with emphasis on geometries relevant to tokamaks. The extensive reference section at the end of each chapter will assist the reader in expanding his knowledge of the subject.

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Section: Spectral Analysis Of Ideal Magnetic Fields 3 Alfvin Wave In mentioning

confidence: 99%

Alfven wave. DOE Critical Review Series

Hasegawa¹,

Uberoi²

1982

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“…Equation (1) indicates that SAW is an anisotropic electromagnetic wave; i.e., while its phase velocity can propagate in any direction, its group velocity, v g = v A b 0 , propagates only along B 0 . This property, of course, has the direct bearing on the feature of Alfvén wave resonant absorption (Gajevski and Winterberg 1965;Pridmore-Brown 1966;Grad 1969;Chen and Hasegawa 1974a, b).…”

Section: Introductionmentioning

confidence: 98%

Physics of kinetic Alfvén waves: a gyrokinetic theory approach

Chen

Zonca

Lin

2021

Rev. Mod. Plasma Phys.

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The transverse shear Alfvén wave (SAW) is a fundamental anisotropic electromagnetic oscillation in plasmas with a finite background magnetic field. In realistic plasmas with spatial inhomogeneities, SAW exhibits the interesting spectral feature of a continuous spectrum. That is, the SAW oscillation frequency varies in the non-uniform (radial) direction. This continuum spectral feature then naturally leads to the phase-mixing process; i.e., time asymptotically, the effective radial wave-number increases with time. Any initial perturbation of SAW structures will, thus, evolve eventually into short-wavelength structures; termed as kinetic Alfvén wave (KAW). Obviously, one needs to employ kinetic theory approach to properly describe the dynamics of KAW; including effects such as finite ion-Larmor radius (FILR) and/or wave–particle interactions. When KAW was first discovered and discussed in 1975–1976, it was before the introduction of the linear electromagnetic gyrokinetic theory (1978) and nonlinear electromagnetic gyrokinetic theory (1982). Kinetic treatments then often involved the complicated procedures of taking the low-frequency limit of the Vlasov kinetic theory and/or employing the drift-kinetic theory approach; forsaking, thus, the FILR effects. In recent years, the powerful nonlinear gyrokinetic theory has been employed to re-examine both the linear and nonlinear physics of KAWs. This brief review will cover results of linear and nonlinear analytical theories, simulations, as well as observational evidences. We emphasize, in particular, that due to the enhanced electron–ion de-coupling in the short-wavelength regime, KAWs possess significantly enhanced nonlinear coupling coefficients and, thereby, play important roles in the heating, acceleration, and transport processes of charged particles in magnetized plasmas.

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“…The properties of Alfvén waves are found to vary in magnetic field. Many studies in the past have been done using magneto hydro dynamical equations (see [7,15,5]). Let us consider an incompressible fluid with infinite conductivity, lying in a homogeneous magnetic field (B o ).…”

Section: Study Of Alfvén Waves Using Magneto Hydrodynamic Equations I...mentioning

confidence: 99%

STUDY OF Alfvén WAVES USING MAGNETO HYDRODYNAMIC EQUATIONS IN SOLAR ATMOSPHERE

Pande¹,

Bisht²,

Mathpal³

et al. 2020

jnanabha

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This paper presents a three dimensional analysis of the properties of magneto hydrodynamic waves. A quantitative formulation of magneto hydrodynamic Alfvén waves is studied. On considering the motion in ordinary fluid, it is observed that the propagation of low frequency waves is only in the form of pressure waves. We have focused on such modes of propagation of incompressible fluid or plasma in magnetic field for which, the speed does not surpass the speed of sound. The value of conductivity is taken to be infinity and viscosity negligible. In such a case, the sum of the pressures of the field induced and the pressure of the plasma is independent of all the coordinates. The kinetic energy density of wave motion and the energy density of the field induced by the perturbation come out to be equal in both phase and amplitude. The study of the effect of large but finite conductivity for small Joule losses reveal that the waves remain periodic, but it is observed that the amplitude of the waves decreases continuously and exponentially at a slow pace.

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Alfvén waves in inhomogeneous magnetic fields

Cited by 9 publications

References 3 publications

Alfven wave. DOE Critical Review Series

Alfven wave. DOE Critical Review Series

Physics of kinetic Alfvén waves: a gyrokinetic theory approach

STUDY OF Alfvén WAVES USING MAGNETO HYDRODYNAMIC EQUATIONS IN SOLAR ATMOSPHERE

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