Stabilization mechanism of ballooning modes by toroidal rotation shear in tokamaks
Stabilization mechanism of ballooning modes by toroidal rotation shear in tokamaks
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DOI：
10.1088/0029-5515/45/5/008
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发表时间：
2005-05
期刊：
影响因子：
3.3
通讯作者：
M. Furukawa;S. Tokuda
中科院分区：
文献类型：
--
作者：
M. Furukawa;S. Tokuda
本文将环形旋转托卡马克中的气球微扰展开为与静态等离子体中气球模相关的本征值问题的平方可积本征函数。选择一个特殊的权函数，使得特征值问题只有离散谱。由于环向旋转剪切，本征值随时间演化，导致它们之间的交叉数无限。交叉导致能量从不稳定模式转移到无限多的稳定模式;这种转移作为气球模式的稳定机制。一个简单的解析公式推导出估计所需的环形旋转剪切稳定气球模式。
A ballooning perturbation in a toroidally rotating tokamak is expanded by square-integrable eigenfunctions of an eigenvalue problem associated with ballooning modes in a static plasma. A special weight function is chosen such that the eigenvalue problem has only the discrete spectrum. The eigenvalues evolve in time owing to toroidal rotation shear, resulting in a countably infinite number of crossings among them. The crossings cause energy transfer from an unstable mode to the infinite number of stable modes; such a transfer works as the stabilization mechanism of the ballooning mode. A simple analytic formula is derived for estimating the toroidal rotation shear required to stabilize the ballooning mode.