Ion-temperature-gradient modes in noncircular tokamak geometry

Journal Article · Thu Oct 01 04:00:00 EDT 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860377· OSTI ID:7250419

Hua, D D; Xu, X Q; Fowler, T K ^[1]

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1. Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States)

The work of Xu and Rosenbluth (Phys. Fluids B {bold 3}, 627 (1991)) on ion-temperature-gradient modes in toroidal geometry is extended to noncircular cross sections to examine the scaling with the elongation {kappa}. The growth rate, wave numbers, and stability thresholds are calculated for a flat density profile characteristic of H-mode operation, and a mixing-length estimate of the ion thermal diffusivity {chi}{sub {ital i}} is calculated. It is found that in the plasma core, growth rates decrease as the central elongation {kappa} increases, due to finite-Larmor-radius effects. The calculated {chi}{sub {ital i}} is approximately of the form {chi}{sub {ital i}}={ital DT}{sub {ital i}}{sup 3/2}(({ital L}{sub {ital Ti}}){sub {ital c}}{minus}{ital L}{sub {ital Ti}}) where {ital D} and ({ital L}{sub {ital Ti}}){sub {ital c}} depend on {tau}=({ital T}{sub {ital e}}/{ital T}{sub {ital i}}) and geometry, and {ital L}{sub {ital Ti}}={vert bar}{ital T}{sub {ital i}}/{del}{ital T}{sub {ital i}}{vert bar}. Preliminary evidence indicates fair agreement with experimental data near the plasma edge, where {ital L}{sub {ital Ti}}{much lt} ({ital L}{sub {ital Ti}}){sub {ital c}}, but the fit is poorer in the core where {ital L}{sub {ital Ti}}{similar to}({ital L}{sub {ital Ti}}){sub {ital c}} and the theoretical {chi}{sub {ital i}} is very sensitive to the accuracy in calculating ({ital L}{sub {ital Ti}}){sub {ital c}}.

• DOE Contract Number: FG03-89ER51116; FG03-90ER54079
• OSTI ID: 7250419
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 4:10; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
ANNULAR SPACE
CLOSED CONFIGURATIONS
CLOSED PLASMA DEVICES
CONFIGURATION
INSTABILITY
INSTABILITY GROWTH RATES
ION TEMPERATURE
LARMOR RADIUS
MAGNETIC FIELD CONFIGURATIONS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SPACE
TEMPERATURE GRADIENTS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TOROIDAL CONFIGURATION
TURBULENCE