Destabilization of tokamak pressure-gradient driven instabilities by energetic alpha populations

Conference · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5423826

Spong, D A; Holmes, J A; Leboeuf, J-N; Christenson, P J ^[1]

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1. Oak Ridge National Lab., TN (USA)

Alpha particle populations can significantly alter existing MHD in stabilities in tokamaks through kinetic effects and coupling to otherwise stable shear Alfven waves. Here we consider resonances of the trapped alpha precessional drift with both the usual ballooning mode diamagnetic frequency ({omega}{sub *i}/2) and the toroidicity induced Alfven eigenmode (TAE). This is examined for noncircular tokamaks in the high-n ballooning limit using an isotropic alpha slowing down distribution and retaining the full energy and pitch angle dispersion in the alpha drift frequency. Applying this to CIT and ITER indicates that ballooning instabilities can persist at {Beta}'s below the ideal MHD threshold. These are especially dominated by the destabilization of the TAE mode. In addition, a hybrid fluid-particle approach for simulating alpha effects on pressure-gradient driven instabilities is described. 13 refs., 6 figs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5423826
• Report Number(s): CONF-8910259-3; ON: DE90003716
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
ALFVEN WAVES
ALPHA PARTICLES
BALLOONING INSTABILITY
CHARGED PARTICLES
CLOSED PLASMA DEVICES
HYDROMAGNETIC WAVES
INSTABILITY
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PRESSURE GRADIENTS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES