Xu G S, Wan B N, Song M, Li J
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, People's Republic of China.
Phys Rev Lett. 2003 Sep 19;91(12):125001. doi: 10.1103/PhysRevLett.91.125001. Epub 2003 Sep 16.
The poloidal long-wavelength E x B time-varying flows were directly measured using a forked Langmuir probe in the HT-7 tokamak. Low-frequency (<10 kHz) E x B flows were observed at the plasma edge, which possess many of the characteristics of zonal flows, including a poloidal long-wavelength (k(theta)rho(i) approximately 0) and narrow radial extent (k(r)rho(i) approximately 0.1). The cross bicoherence of turbulent Reynolds stress indicates the existence of nonlinear three-wave coupling processes and the generation of low-frequency E x B flows. The estimated flow-shearing rate is of the same order of magnitude as the turbulence decorrelation rate and may thus regulate the fluctuation level and thereby the turbulence-driven transport.
利用HT-7托卡马克装置中的叉形朗缪尔探针直接测量了极向长波长E×B时变流。在等离子体边缘观测到了低频（<10kHz）E×B流，其具有带状流的许多特征，包括极向长波长（k(θ)ρ(i)约为0）和较窄的径向范围（k(r)ρ(i)约为0.1）。湍流雷诺应力的交叉双相干表明存在非线性三波耦合过程以及低频E×B流的产生。估计的流剪切率与湍流去相关率具有相同的量级，因此可能调节波动水平，进而调节湍流驱动的输运。
