High-n ideal and resistive shear Alfven waves in tokamaks

Journal Article · Mon Apr 15 04:00:00 EST 1985 · Ann. Phys. (N.Y.); (United States)

DOI:https://doi.org/10.1016/0003-4916(85)90335-5· OSTI ID:5557405

Cheng, C Z; Chen, L; Chance, M S

Ideal and resistive MHD equations for the shear Alfven waves are studied in a low-..beta.. toroidal model by employing the high-n ballooning formalism. The ion sound effects are neglected. For an infinite shear slab, the ideal MHD model gives rise to a continuous spectrum of real frequencies and discrete eigenmodes (Alfven-Landau modes) with complex frequencies. With toroidal coupling effects due to nonuniform toroidal magnetic field, the continuum is broken up into small continuum bands and new discrete toroidal eigenmodes can exist inside the continuum gaps. Unstable ballooning eigenmodes are also introduced by the bad curvature when ..beta.. > ..beta../sub c/. The resistivity (eta) can be considered perturbatively for the ideal modes. In addition, four branches of resistive modes are induced by the resistivity: (1) resistive entropy modes which are stable with frequencies going to zero with resistivity as eta/sup 1/3/; (2) tearing modes which are stable (..delta..' < 0) with frequencies approaching zero as eta/sup 3/5/; (3) resistive periodic shear Alfven waves which approach the finite frequency end points of the continuum bands as eta/sup 1/2/; and (4) resistive ballooning modes which are purely growing with growth rate proportional to eta/sup 1/3/..beta../sup 2/3/ as eta..-->..0 and ..beta -->..0.

• Research Organization: Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08544
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 5557405
• Journal Information: Ann. Phys. (N.Y.); (United States), Journal Name: Ann. Phys. (N.Y.); (United States) Vol. 161:1; ISSN APNYA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
ALFVEN WAVES
ANNULAR SPACE
BALLOONING INSTABILITY
CLOSED PLASMA DEVICES
CONFIGURATION
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
INSTABILITY
LOW-BETA PLASMA
MAGNETOHYDRODYNAMICS
MECHANICS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SPACE
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TOROIDAL CONFIGURATION