Transport bifurcation in a rotating tokamak plasma.
Transport bifurcation in a rotating tokamak plasma.
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旋转托卡马克等离子体中的输运分岔。
DOI：
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发表时间：
2010
影响因子：
8.6
通讯作者：
S. Cowley
中科院分区：
文献类型：
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作者：
E. Highcock;E. Highcock;E. Highcock;Michael Barnes;Michael Barnes;A. Schekochihin;A. Schekochihin;F. I. Parra;F. I. Parra;C. Roach;C. Roach;S. Cowley;S. Cowley
在实验相关的零磁剪切极限下，数值研究了流动剪切对托克马克湍流输运的影响。结果发现，等离子体是线性稳定的所有非零的流动剪切值，但亚临界湍流可以维持在很宽的温度梯度范围内的非线性。流动剪切增加了湍流的非线性温度梯度阈值，但也增加了热通量对温度梯度变化的敏感性，除了在阈值附近的小范围内敏感性降低。在平衡梯度的分叉被发现：对于一个给定的输入的热量，它是可能的，通过改变所施加的扭矩，触发过渡到显着更高的温度和流量梯度。
The effect of flow shear on turbulent transport in tokamaks is studied numerically in the experimentally relevant limit of zero magnetic shear. It is found that the plasma is linearly stable for all nonzero flow shear values, but that subcritical turbulence can be sustained nonlinearly at a wide range of temperature gradients. Flow shear increases the nonlinear temperature gradient threshold for turbulence but also increases the sensitivity of the heat flux to changes in the temperature gradient, except over a small range near the threshold where the sensitivity is decreased. A bifurcation in the equilibrium gradients is found: for a given input of heat, it is possible, by varying the applied torque, to trigger a transition to significantly higher temperature and flow gradients.