Alfven wave. DOE Critical Review Series

Abstract

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.

A novel mechanism for electron-cyclotron maser

“…When a fast electron beam with a thin density (n b n 0 ) and fast velocity (v b v A ) along the ambient magnetic field is present in a magnetized plasma, it carries a field-aligned electric current j b = −en b v b passing through the plasma, where n 0 is the ambient plasma density and v A the Alfvén velocity. This current may cause magnetic fluctuations via the Alfvén waves (AW) instability in the low-frequency (ω ω ci ) and long-wavelength (k ω ci /v T i ) limit (Hasegawa 1975;Hasegawa & Uberoi 1982;Wu 2012), where ω and k are the frequency and wavenumber of AWs, respectively, and ω ci and v T i the ion gyrofrequency and thermal speed, respectively.…”

Exact nonlinear dust kinetic Alfvén waves in a dust–ion plasma

“…Solitary kinetic Alfvén waves (SKAWs) arise when the dispersion relation of ordinary Alfvén waves is modified by the finite Larmor radius effect or simply by the finite electron inertial effect [1]. Recent data from the Freja satellite [2,3] showed that the auroral low-frequency turbulence is dominated by strong electromagnetic spikes, which resemble solitary structures and can be interpreted as SKAWs.…”

Effect of thermal pressure on upward plasma fluxes due to ponderomotive force of Alfvén waves

“…As is known (e.g. Hasegawa and Uberoi, 1982;Voitenko and Goossens, 2004), this contribution for Alfvén waves ω ω i and N 2 1 is the following: ω = k z c A 1 + k 2 ⊥ ρ 2 s 1/2 , where ρ s is the ion acoustic gyroradius and k ⊥ is the wave number across the background magnetic field. In the case k 2 ⊥ ρ 2 s 1 which is here considered, this term can be neglected in our calculations for the real value N 2 1.…”