Nonlinear gyrofluid models of shear Alfven instabilities in ignited and beam heated toroidal plasmas

Conference · Thu Jul 01 00:00:00 EDT 1993

OSTI ID:10168952

Spong, D A; Hedrick, C L; Carreras, B A

Shear Alfven instabilities driven by energetic beams and alpha populations are investigated using a reduced MHD-gyrofluid model with Landau closure. The moment equations for the fast ions are truncated in a way which incorporates the wave particle resonances that are required to destabilize the shear Alfven mode. These are coupled to an Ohm`s law and vorticity equations which have been generalized to include ion FLR, electron and ion Landau damping. This model has been applied to experimentally observed regimes in a number of tokamak and stellarator devices. Both linearized growth rates and the nonlinear evolution are obtained. The saturated nonlinear regimes indicate mode number and frequency spectra which are generally consistent with experiment. A detailed examination of one typical nonlinear state has allowed identification of the dominant saturation mechanisms. This indicates that generation of n = 0, m = 0 sheared poloidal velocity flows and quasi linear modification of the q(r) profile can be important factors in reaching saturation.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10168952
• Report Number(s): CONF-9305231-1; ON: DE93016235; TRN: 93:016296
• Resource Relation: Conference: International Atomic Energy Agency (IAEA) technical committee meeting,Trieste (Italy),10-14 May 1993; Other Information: PBD: [1993]
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA INSTABILITY
ALFVEN WAVES
INSTABILITY GROWTH RATES
CLOSED PLASMA DEVICES
NEUTRAL ATOM BEAM INJECTION
THERMONUCLEAR IGNITION
SHEAR
LANDAU DAMPING
MAGNETOHYDRODYNAMICS
TOKAMAK DEVICES
ALPHA PARTICLES
STELLARATORS
NONLINEAR PROBLEMS
700340
PLASMA WAVES, OSCILLATIONS, AND INSTABILITIES