Nonlinear mode coupling induced high frequency axisymmetric mode on the HL-2A tokamak
Nonlinear mode coupling induced high frequency axisymmetric mode on the HL-2A tokamak
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HL-2A 托卡马克上非线性模式耦合引起的高频轴对称模式
DOI：
10.1088/1741-4326/ab1af8
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发表时间：
2019
期刊：
影响因子：
3.3
通讯作者：
Xu M
中科院分区：
文献类型：
--
作者：
Shi P W;Qiu Z Y;Chen W;Shi Z B;Duan X R;Xiao G L;Ji X Q;Yang Z C;Zhong W L;Jiang M;Yu L M;Zang L G;Ma R R;Wen J;Fang K R;Liu Yi;Yang Q W;Xu M
详细地给出了非线性模耦合驱动的高频轴对称模的实验观测和理论解释。在中性束注入加热等离子体中，发现环形Alfvén本征模（TAE）与撕裂模非线性相互作用，并导致产生其他Alfvénic边带（Chen等人，2014年，欧洲物理学。Lett. 107 25001）。然后，两个TAE耦合在一起，并有助于激发一个轴对称模式的频率在椭圆度诱导的阿尔文本征模（EAE）的频率区域。直接证据表明，轴对称模在非线性过程中起着能量传递通道的作用，并通过撕裂模拍频引起有限环模数的磁流体动力学不稳定性的增长。最后，用非线性陀螺动力学理论证明了高频n E= 0模产生的非线性过程。这里n E是环形模数，下标E表示位于EAE频率范围内的模频率。
Experimental observations and theoretical interpretations are presented in detail for the high frequency axisymmetric mode driven by nonlinear mode coupling. In the neutral beam injection heating plasma, toroidal Alfvén eigenmodes (TAEs) are found to nonlinearly interact with the tearing mode and result in the generation of other Alfvénic sidebands (Chen et al 2014 Europhys. Lett. 107 25001). Then two TAEs couple together and contribute to the excitation of an axisymmetric mode with frequency in the ellipticity-induced Alfvén eigenmode (EAE) frequency region. Direct evidence suggests the axisymmetric modes play an energy transfer channel role during the nonlinear procedure and cause the growth of magnetohydrodynamic instability with finite toroidal mode number via beating with tearing mode. Finally, the nonlinear process leading to high frequency n E= 0 mode generation is demonstrated using nonlinear gyrokinetic theory. Here n E is toroidal mode number and the subscript E represents the mode frequencies lying in the EAE frequency range.