Observation of the L-H confinement bifurcation triggered by a turbulence-driven shear flow in a tokamak plasma.
Observation of the L-H confinement bifurcation triggered by a turbulence-driven shear flow in a tokamak plasma.
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DOI：
10.1103/physrevlett.112.125002
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发表时间：
2014-03
影响因子：
8.6
通讯作者：
Z. Yan;G. Mckee;R. Fonck;P. Gohil;R. Groebner;T. Osborne
中科院分区：
文献类型：
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作者：
Z. Yan;G. Mckee;R. Fonck;P. Gohil;R. Groebner;T. Osborne
在DIII-D上进行的全面的二维湍流和涡流速度测量表明，在低约束（L模式）到高约束（H模式）的转变之前，一个快速增加的连续性驱动的剪切流发展了大约100 μs，并似乎触发了它。这些变化局限于磁边界内1-2 cm的狭窄层。增加加热功率会增加雷诺应力、从湍流到极向流的能量传递以及随后超过去相关率的边缘流剪切率，从而抑制湍流并触发过渡。
Comprehensive 2D turbulence and eddy flow velocity measurements on DIII-D demonstrate a rapidly increasing turbulence-driven shear flow that develops ∼100 μs prior to the low-confinement (L mode) to high-confinement (H mode) transition and appears to trigger it. These changes are localized to a narrow layer 1-2 cm inside the magnetic boundary. Increasing heating power increases the Reynolds stress, the energy transfer from turbulence to the poloidal flow, and the edge flow shearing rate that then exceeds the decorrelation rate, suppressing turbulence and triggering the transition.