Theory of Fine-scale Zonal Flow Generation From Trapped Electron Mode Turbulence

[摘要] Most existing zonal flow generation theory has been developed with a usual assumption of qrρθ¥ << 1 (qr is the radial wave number of zonal flow, and ρθ¥ is the ion poloidal gyrora- dius). However, recent nonlinear gyrokinetic simulations of trapped electron mode (TEM) turbulence exhibit a relatively short radial scale of the zonal flows with qrρθ¥ ~ 1 [Z. Lin et al., IAEA-CN/TH/P2-8 (2006); D. Ernst et al., Phys. Plasmas 16, 055906 (2009)]. This work reports an extension of zonal flow growth calculation to this short wavelength regime via the wave kinetics approach. A generalized expression for the polarization shielding for arbitrary radial wavelength [Lu Wang and T.S. Hahm, to appear in Phys. Plasmas (2009)] which extends the Rosenbluth-Hinton formula in the long wavelength limit is applied.

[发布日期] 2009-06-11

[学科分类] 原子、分子光学和等离子物理

[关键词] KINETICS;POLARIZATION;SHIELDING;TRAPPED ELECTRONS;TURBULENCE;WAVELENGTHS Drift Instability;Turbulence;Trapped-particle Instability