Increased nonlinear coupling between turbulence and low-frequency fluctuations at the L-H transition.
Increased nonlinear coupling between turbulence and low-frequency fluctuations at the L-H transition.
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DOI：
10.1103/physrevlett.87.135001
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发表时间：
2001-09
影响因子：
8.6
通讯作者：
R. Moyer;G. Tynan;Christopher Holland;M. Burin
中科院分区：
文献类型：
--
作者：
R. Moyer;G. Tynan;Christopher Holland;M. Burin
在DIII-D托卡马克中，小尺度高频湍流与大尺度低频波动之间的非线性耦合在过渡到改进约束时瞬态增加。这种增加开始于湍流的快速抑制和E x B剪切流在成为h型输运障壁/剪切流区的区域发展之前。转换之后，耦合返回到l模式级别。这些结果与湍流驱动的剪切流引发的自发过渡到改进约束的预期一致。
The nonlinear coupling between small scale high-frequency turbulence and larger scale lower-frequency fluctuations increases transiently in transitions to improved confinement in the DIII-D tokamak. This increase starts before the rapid turbulence suppression and E x B shear-flow development in the region that becomes the H-mode transport barrier/shear flow region. After the transition, the coupling returns to L-mode levels. These results are consistent with expectations for spontaneous transitions to improved confinement triggered by a turbulence-driven sheared flow.