Changzhi Jiang, Shunwen Wang, Zhenyu Zhou, Di Hu, Bo Li, Jorek team
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引用次数: 0
摘要
具有细长横截面的托卡马克等离子体很容易受到垂直位移事件(VDE)的影响,这种事件会通过热通量或电磁(EM)力损坏第一壁。我们介绍了热淬火后冷 VDE 期间 CFETR 等离子体的三维非线性还原 MHD 仿真,重点研究了电磁力、等离子体位移和 n = 1 模式之间的关系。当大部分电流收缩在 q = 2 表面内时,主导模式(m/n = 2/1)会变得不稳定。由于开放场线区域存在 SOL 电流,等离子体电流中心点的位移小于磁轴的位移。因此,诱导真空容器电流的对称分量明显减弱。与真空容器电流和 SOL 电流的非对称分量相比,侧向力的方向保持近似恒定的相位。它们的振幅也与主导模式的增长密切相关。这些发现为今后控制 VDE 期间侧向力的相位和振幅的潜在方法提供了启示。
Simulation of rotating asymmetric sideways forces during Vertical Displacement Events in CFETR
Tokamak plasmas with elongated cross-sections are susceptible to Vertical Displacement Events (VDEs), which can damage the first wall via heat flux or electromagnetic (EM) forces. We present a 3D nonlinear reduced MHD simulation of CFETR plasma during a cold VDE following the thermal quench, focusing on the relationship between the EM force, plasma displacement, and the n = 1 mode. The dominant mode, identified as m/n = 2/1, becomes destabilized when most of the current is contracted within the q = 2 surface. The displacement of the plasma current centroid is less than that of the magnetic axis due to the presence of SOL current in the open field line region. Hence, the symmetric component of the induced vacuum vessel current is significantly mitigated. The direction of the sideways force keeps a constant phase approximately compared with the asymmetric component of the vacuum vessel current and the SOL current, which in turn keep in-phase with the dominant 2/1 mode, respectively. Their amplitudes are also closely associated with the growth of the dominant mode. These findings provide insights into potential methods for controlling the phase and amplitude of sideways forces during VDEs in the future.