Effects of Plasma Shaping on Nonlinear Gyrokinetic Turbulence

E. A. Belli  Hammett, G. W.¹  Dorland, W.² 

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

关键词: CRITICAL TEMPERATURE;    ELONGATION;    HEAT FLUX;    INSTABILITY;    MAGNETIC SURFACES;    PLASMA;    SHAPE;    STABILITY;    TEMPERATURE GRADIENTS;    TRANSPORT;    TURBULENCE Tokamaks;   

DOI  :  10.2172/939431
RP-ID  :  PPPL--4342
PID  :  OSTI ID: 939431
Others  :  TRN: US0806853

学科分类：原子、分子光学和等离子物理

美国|英语

来源: SciTech Connect

【 摘 要 】

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.