General Atomics, San Diego, California 92121, USA.
Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
Phys Rev Lett. 2015 Mar 13;114(10):105001. doi: 10.1103/PhysRevLett.114.105001. Epub 2015 Mar 12.
Density pumpout and edge-localized mode (ELM) suppression by applied n=2 magnetic fields in low-collisionality DIII-D plasmas are shown to be correlated with the magnitude of the plasma response driven on the high-field side (HFS) of the magnetic axis but not the low-field side (LFS) midplane. These distinct responses are a direct measurement of a multimodal magnetic plasma response, with each structure preferentially excited by a different n=2 applied spectrum and preferentially detected on the LFS or HFS. Ideal and resistive magneto-hydrodynamic (MHD) calculations find that the LFS measurement is primarily sensitive to the excitation of stable kink modes, while the HFS measurement is primarily sensitive to resonant currents (whether fully shielding or partially penetrated). The resonant currents are themselves strongly modified by kink excitation, with the optimal applied field pitch for pumpout and ELM suppression significantly differing from equilibrium field alignment.
在低碰撞 DIII-D 等离子体中，通过施加 n=2 磁场实现密度排空和边缘局域模（ELM）抑制，与磁场轴高场区（HFS）而非低场区（LFS）中平面上驱动的等离子体响应幅度相关。这些不同的响应是多模态磁等离子体响应的直接测量，每个结构都优先由不同的 n=2 施加谱激发，并优先在 LFS 或 HFS 上检测到。理想和电阻磁流体动力学（MHD）计算发现，LFS 测量主要对稳定扭曲模的激发敏感，而 HFS 测量主要对共振电流（是否完全屏蔽或部分穿透）敏感。共振电流本身受到扭曲激发的强烈影响，用于排空和 ELM 抑制的最佳施加场节距与平衡场对准显著不同。
