Excitation of geodesic acoustic modes by ion temperature gradient modes
Excitation of geodesic acoustic modes by ion temperature gradient modes
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DOI：
10.1088/0741-3335/50/2/025006
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发表时间：
2008-02
影响因子：
2.2
通讯作者：
P. Guzdar;N. Chakrabarti;R. Singh;P. Kaw
中科院分区：
文献类型：
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作者：
P. Guzdar;N. Chakrabarti;R. Singh;P. Kaw
定地声学模（GAM）可以通过与托卡马克等离子体中的漂移波和离子温度梯度模等主模耦合而激发。最近的全球离子温度梯度模式的数值模拟显示的GAM的激发，并表明，径向波数的激发的GAM的比例成反比的离子拉莫尔半径。此外，模式主要在器件的边缘区域被激发。此外，与预测的线性模式频率相比，存在GAM频率的非线性下移。本文提出的模式耦合分析提供了一个解释的径向波数的标度，在外半的等离子体的GAM的优先激发和GAM的频率的非线性下移。
Geodesic acoustic modes (GAMs) can be excited by mode coupling to primary modes such as the drift waves and ion temperature gradient modes in tokamak plasmas. Recent global numerical simulations of ion temperature gradient modes show excitation of GAMs and indicate that the radial wave-number of the excited GAMs scales inversely as the ion Larmor radius. Also the modes are excited dominantly in the edge region of the device. Furthermore there is a nonlinear downshift of the GAM frequency compared with the predicted linear mode frequency. The mode-coupling analysis presented in this paper provides an explanation of the scaling of the radial wave-number, the preferential excitation of GAMs in the outer half of the plasma and the nonlinear downshift of the frequency of GAMs.