On the dynamics of vortex modes within magnetic islands
On the dynamics of vortex modes within magnetic islands
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DOI：
10.1063/1.3692094
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发表时间：
2011-11
影响因子：
2.2
通讯作者：
W. Hornsby;A. Peeters;M. Siccinio;E. Poli
中科院分区：
文献类型：
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作者：
W. Hornsby;A. Peeters;M. Siccinio;E. Poli
最近的工作研究磁岛与微湍流的相互作用，揭示了在岛结构内形成的大尺度涡旋模式的惊人观察[W。A. Hornsby等人，等离子体17，092301（2010）]。这些静电涡被发现是岛的大小和振荡。正是这种振荡行为和湍流的存在，使我们相信，动态的测地线声学模式（GAM），这是本文研究的这个环节。在这里，我们推导出一个方程的GAM在MHD极限，在磁岛修改的三维轴对称几何形状的存在下。的特征值和特征函数的数值计算，然后利用线性和非线性陀螺动力学模拟中看到的振荡大规模静电势结构的动态分析。
Recent work investigating the interaction of magnetic islands with micro-turbulence has uncovered the striking observation of large scale vortex modes forming within the island structure [W. A. Hornsby et al., Phys. Plasmas 17, 092301 (2010)]. These electrostatic vortices are found to be the size of the island and are oscillatory. It is this oscillatory behaviour and the presence of turbulence that leads us to believe that the dynamics are related to the geodesic acoustic mode (GAM), and it is this link that is investigated in this paper. Here, we derive an equation for the GAM in the MHD limit, in the presence of a magnetic island modified three-dimensional axisymmetric geometry. The eigenvalues and eigenfunctions are calculated numerically and then utilised to analyse the dynamics of oscillatory large-scale electrostatic potential structures seen in both linear and non-linear gyro-kinetic simulations.