We report an experimental observation of destabilization of the Alfvénic activity by non-axisymmetric (3D) magnetic field induced toroidal rotation braking in the KSTAR tokamak. The toroidicity-induced Alfvén eigenmodes (TAEs) are destabilized when toroidal plasma rotation is reduced down to the minimum to approach near-zero rotational shear by 3D magnetic braking. This observation indicates that the stability of the TAEs is strongly correlated to the plasma rotation that modifies Alfvén continuum. The TAE frequency predicted by stability calculation with the reduced rotation is in a good agreement with the experimental measurement. It is suggested that the impact of 3D magnetic field and rotation on the Alfvénic modes and associated fast ion confinement should be considered for the operation of magnetic confinement fusion devices.
我们报告了在KSTAR托卡马克中，由非轴对称（3D）磁场引起的环向旋转制动导致阿尔芬活动失稳的实验观察。当环向等离子体旋转通过3D磁场制动降低到最小值，接近零旋转剪切时，环向性诱导的阿尔芬本征模（TAEs）被 destabilized。这一观察表明，TAEs的稳定性与修改阿尔芬连续谱的等离子体旋转密切相关。通过考虑降低旋转的稳定性计算预测的TAE频率与实验测量结果吻合良好。我们建议，在磁约束聚变装置的运行中，应考虑3D磁场和旋转对阿尔芬活动及相关快离子约束的影响。