High-n collisionless ballooning modes in axisymmetric toroidal plasmas

Technical Report · Thu Oct 01 04:00:00 EDT 1981

DOI:https://doi.org/10.2172/5790055· OSTI ID:5790055

Cheng, C Z

A collisionless kinetic ballooning mode equation, which includes the full ion finite Larmor radius (FLR), the magnetic drift, and the trapped electron effects is derived and investigated for a large aspect ratio circular flux surface equilibrium in the frequency regime, ..omega../sub bi/, ..omega../sub ti/ < ..omega.. < ..omega../sub be/, ..omega../sub te/. The finite Larmor radius effects can reduce the growth rate, but do not stabilize the ballooning modes due to the destabilizing influence of the ion magnetic drift reonances. It is, in general, incorrect to simulate the FLR effects by employing the often used FLR modified MHD model for (k/sub theta/rho/sub i/)/sup 2/approx. greater than or equal to 0.1 and epsilon/sub n/ approx. greater than or equal to 0.1, where k/sub theta/rho/sub i/ is the ion FLR parameter and epsilon/sub n/ = L/sub n//R measures the magnetic drift frequency. The trapped electrons have a stabilizing effect due to the reduction of the destabilizing circulating electron parallel current perturbation. For typical tokamak aspect ratio, the critical ..beta.. can be improved by 40%.

• Research Organization: Princeton Univ., NJ (USA). Plasma Physics Lab.
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 5790055
• Report Number(s): PPPL-1841; ON: DE82002831
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
ASPECT RATIO
BALLOONING INSTABILITY
CLOSED PLASMA DEVICES
COLLISIONLESS PLASMA
EQUATIONS
INSTABILITY
KINETIC EQUATIONS
LARMOR RADIUS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES