Perturbation analysis of electromagnetic geodesic acoustic modes

Journal Article · Sun Jun 15 00:00:00 EDT 2014 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4883643· OSTI ID:22304062

Ren, Haijun ^[1]

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1. CAS Key Laboratory of Geospace Environment and Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

Lagrangian displacement and magnetic field perturbation response to the geodesic acoustic mode is analyzed by using the ideal magnetohydrodynamic equations in a large-aspect-ratio tokamak. δB{sub θ}, the poloidal component of magnetic field perturbation, has poloidal wave number m = 2 created by the poloidal displacement ξ{sub θ}. The parallel perturbation of magnetic field, δB{sub ∥}, has a poloidally asymmetric structure with m = 1 and is on the same order of magnitude with δB{sub θ} to the leading order. The radial displacement ξ{sub r} is of order O(βϵξ{sub θ}) but plays a significant role in determining δB{sub ∥}, where β is the plasma/magnetic pressure ratio and ϵ is the inverse aspect ratio.

• OSTI ID: 22304062
• Journal Information: Physics of Plasmas, Vol. 21, Issue 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ASYMMETRY
DISTURBANCES
EQUATIONS
LAGRANGIAN FUNCTION
MAGNETIC FIELDS
PERTURBATION THEORY
PLASMA
TOKAMAK DEVICES