High-n ideal and resistive shear Alfven waves in tokamaks

Technical Report · Tue May 01 04:00:00 EDT 1984

DOI:https://doi.org/10.2172/6871381· OSTI ID:6871381

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 (n) 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 (..delta..' < 0) with frequencies approaching zero as n/sup 3/5/, (3) Resistive periodic shear Alfven waves which approach the finite frequency end points of the continuum bands and n/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 ..-->.. O and ..beta.. ..-->.. O.

• Research Organization: Princeton Univ., NJ (USA). Plasma Physics Lab.
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6871381
• Report Number(s): PPPL-2107; ON: DE84013099
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
ALFVEN WAVES
CLOSED PLASMA DEVICES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
INSTABILITY GROWTH RATES
MAGNETOHYDRODYNAMICS
MECHANICS
PHYSICAL PROPERTIES
SHEAR
THERMONUCLEAR DEVICES
TOKAMAK DEVICES