Nonlinear dispersion relation of geodesic acoustic modes.
Nonlinear dispersion relation of geodesic acoustic modes.
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DOI：
10.1103/physrevlett.108.035004
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发表时间：
2011-09
影响因子：
8.6
通讯作者：
R. Hager;K. Hallatschek
中科院分区：
文献类型：
--
作者：
R. Hager;K. Hallatschek
采用双流体湍流数值模拟方法研究了托卡马克边缘等离子体中湍流引起的测地声学模的能量输入和频移。令人惊讶的是，湍流GAM色散关系是定性等价的线性GAM色散，但可以大大提高群速度。在上下不对称的几何形状中，由于湍流传输的能量输入可能有利于激发具有相对于磁漂移的径向相速度的一个特定符号的GAM，并且可能导致脉冲GAM活动。
The energy input and frequency shift of geodesic acoustic modes (GAMs) due to turbulence in tokamak edge plasmas are investigated in numerical two-fluid turbulence studies. Surprisingly, the turbulent GAM dispersion relation is qualitatively equivalent to the linear GAM dispersion but can have drastically enhanced group velocities. In up-down asymmetric geometry the energy input due to turbulent transport may favor the excitation of GAMs with one particular sign of the radial phase velocity relative to the magnetic drifts and may lead to pulsed GAM activity.