Theory of a high- n toroidicity-induced shear Alfven eigenmode in tokamaks

Journal Article · Tue May 01 04:00:00 EDT 1990 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859245· OSTI ID:6896532

Fu, G Y ^[1]; Cheng, C Z ^[2]

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1. Center for Fusion Engineering, The University of Texas at Austin, Austin, TX (USA) Institute for Fusion Studies, The University of Texas at Austin, Austin, TX (USA)
2. Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ (USA)

A high-{ital n} WKB-ballooning mode equation is employed to study toroidicity-induced shear Alfven eigenmodes (TAE) in {ital s}-{alpha} space, where {ital s}=({ital r}/{ital q})({ital dq}/{ital dr}) is the magnetic shear and {alpha}={minus}(2{ital Rq}{sup 2}/{ital B}{sup 2})({ital dp}/{ital dr}) is the normalized pressure gradient for tokamak plasmas. In the ballooning mode first stability region, TAE modes are found to exist only for {alpha} less than some critical value {alpha}{sub {ital c}}. It is found that these TAE modes reappear in the ballooning mode second stability region for bands of {alpha} values. The global envelope structures of these TAE modes are studied by the Wentzel--Kramers--Brillouin (WKB) method and are found to be bounded radially if the local mode frequency has a maximum in radius.

• DOE Contract Number: AC02-76CH03073; FG05-80ET53088
• OSTI ID: 6896532
• Journal Information: Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 2:5; ISSN 0899-8221; ISSN PFBPE
• 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 CONFIGURATIONS
CLOSED PLASMA DEVICES
CONFIGURATION
EIGENVALUES
EQUATIONS
HIGH-BETA PLASMA
HYDROMAGNETIC WAVES
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PRESSURE GRADIENTS
SHEAR
SPACE
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TOROIDAL CONFIGURATION
USES
WKB APPROXIMATION