Effects of Plasma Shaping on Nonlinear Gyrokinetic Turbulence

Technical Report · Fri Aug 01 04:00:00 EDT 2008

DOI:https://doi.org/10.2172/939431· OSTI ID:939431

Hammett, G. W. ^[1]; Dorland, W. ^[2]

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1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
2. Univ. of Maryland, College Park, MD (United States)

The effects of flux surface shape on the gyrokinetic stability and transport of tokamak plasmas are studied using the GS2 code [M. Kotschenreuther, G. Rewoldt, and W.M. Tang, Comput. Phys. Commun. 88, 128 (1995); W. Dorland, F. Jenko, M. Kotschenreuther, and B.N. Rogers, Phys. Rev. Lett. 85, 5579 (2000)]. Studies of the scaling of nonlinear turbulence with shaping parameters are performed using analytic equilibria based on interpolations of representative shapes of the Joint European Torus (JET) [P.H. Rebut and B.E. Keen, Fusion Technol. 11, 13 (1987)]. High shaping is found to be a stabilizing influence on both the linear ion-temperature-gradient (ITG) instability and the nonlinear ITG turbulence. For the parameter regime studied here, a scaling of the heat flux with elongation of χ ~ κ^-1.5 or κ^-2.0, depending on the triangularity, is observed at fixed average temperature gradient. While this is not as strong as empirical elongation scalings, it is also found that high shaping results in a larger Dimits upshift of the nonlinear critical temperature gradient due to an enhancement of the Rosenbluth-Hinton residual zonal flows.

• Research Organization: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• OSTI ID: 939431
• Report Number(s): PPPL--4342
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CRITICAL TEMPERATURE
ELONGATION
HEAT FLUX
INSTABILITY
MAGNETIC SURFACES
PLASMA
SHAPE
STABILITY
TEMPERATURE GRADIENTS
TRANSPORT
TURBULENCE
Tokamaks