Turbulence and transport suppression scaling with flow shear on the Large Plasma Devicea)
Turbulence and transport suppression scaling with flow shear on the Large Plasma Devicea)
复制标题
大型等离子体装置上流动剪切的湍流和传输抑制缩放a)
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
B. Friedman
中科院分区：
文献类型：
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作者：
D. Schaffner;T. Carter;G. Rossi;D. Guice;J. Maggs;S. Vincena;B. Friedman
大型等离子体装置（LAPD）边缘方位流和剪切的连续控制[W. Gekelman等人，Rev. Sci. Instr. 62，2875（1991）]已经使用双折射限制器实现。这种流动控制允许仔细研究流动剪切对压力梯度驱动的湍流和粒子输运的影响。结合外部可控剪切在湍流等离子体沿着与详细的空间诊断能力LAPD使实验剪切抑制模型的验证一个有用的测试平台。受这些模型的启发，幂律拟合的密度和径向速度波动幅度，粒子通量，密度势交叉，和径向相关长度。数据表明，当剪切率（γs= Δ Vθ/Δ r）与湍流去相关率（1/τac）相当时，这些量的趋势出现了突变。没有一个模型能捕捉到所有剪切率值下的所有湍流量的变化趋势，但有些模型成功地捕捉到了所有湍流量的变化趋势。
Continuous control over azimuthal flow and shear in the edge of the Large Plasma Device (LAPD) [W. Gekelman et al., Rev. Sci. Instr. 62, 2875 (1991)] has been achieved using a biasable limiter. This flow control has allowed a careful study of the effect of flow shear on pressure-gradient-driven turbulence and particle transport in LAPD. The combination of externally controllable shear in a turbulent plasma along with the detailed spatial diagnostic capabilities on LAPD makes the experiment a useful testbed for validation of shear suppression models. Motivated by these models, power-law fits are made to the density and radial velocity fluctuation amplitudes, particle flux, density-potential crossphase, and radial correlation length. The data show a break in the trend of these quantities when the shearing rate (γs=∂Vθ/∂r) is comparable to the turbulent decorrelation rate (1/τac). No one model captures the trends in the all turbulent quantities for all values of the shearing rate, but some models successfull...