Stability of coupled tearing modes in tokamaks
Stability of coupled tearing modes in tokamaks
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DOI：
10.1088/0029-5515/33/10/i11
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发表时间：
1993-10
期刊：
影响因子：
3.3
通讯作者：
R. Fitzpatrick;R. Hastie;T. J. Martin;C. Roach
中科院分区：
文献类型：
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作者：
R. Fitzpatrick;R. Hastie;T. J. Martin;C. Roach
在托卡马克中研究了一般耦合撕裂模式色散关系。人们发现高温装置中有理表面的差动旋转可以解耦低振幅模式，因此它们仅在等离子体中的一个表面处重新连接磁通量，并且在其余表面处表现理想。高于阈值模式幅度时，有理表面开始锁定在一起，从而允许形成同时重新连接多个表面处的磁通量的模式。这种模式通常比非耦合模式更不稳定。理想的有理表面（其上没有重连接）位于靠近等离子体边缘的位置，可以保护自由边界撕裂模式免受外部扭结模式的不稳定影响。锁定耦合有理面所需的阈值模式振幅随着机器尺寸的增加而迅速减小
The general coupled tearing-mode dispersion relation is investigated in tokamaks. A differential rotation of rational surfaces in high temperature devices is found to decouple low amplitude modes, so that they only reconnect magnetic flux at one surface in the plasma and behave ideally at the remaining surfaces. Above a threshold mode amplitude, the rational surfaces start to lock together, permitting modes to develop which simultaneously reconnect magnetic flux at more than one surface. Such modes are generally more unstable than uncoupled modes. Ideal rational surfaces, on which there is no reconnection, located close to the plasma edge are found to shield free-boundary tearing modes from the destabilizing influence of external-kink modes. The threshold mode amplitude required to lock coupled rational surfaces decreases rapidly with increasing machine dimensions