Initial active MHD spectroscopy experiments exciting stable Alfvén eigenmodes in Alcator C-Mod
Initial active MHD spectroscopy experiments exciting stable Alfvén eigenmodes in Alcator C-Mod
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初始主动 MHD 光谱实验在 Alcator C-Mod 中激发稳定的 Alfvén 本征模
DOI：
10.1088/0741-3335/46/4/003
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发表时间：
2004
影响因子：
2.2
通讯作者：
R. Parker
中科院分区：
文献类型：
--
作者：
J. Snipes;D. Schmittdiel;A. Fasoli;R. Granetz;R. Parker
Alcator C-Mod中的一对环形局部化容器内天线用于在400-500 kHz的频率范围内激发和检测稳定的环形Alfven本征模（TAE）共振。通过斜变环向场，等离子体TAE频率扫过恒定的天线激励频率以找到谐振，并且测量谐振的宽度以确定模式的有效阻尼率。观察到共振处的环向场和密度与n（e）（0.5）成比例的B-T成比例，正如Alfven本征模所预期的那样。TAE阻尼率测量在内壁限制和分流放电。这些放电的内壁限制阻尼率在1% < \gamma/omega\ <4%的范围内。另一方面，转向等离子体需要在最后闭合通量表面和外侧限制器之间的小于1 cm的非常小的外部间隙来观察共振，并且阻尼率非常低，γ/ω <1%。
A pair of toroidally localized in-vessel antennas in Alcator C-Mod were used to excite and detect stable toroidal Alfven eigenmode (TAE) resonances in the frequency range of 400-500 kHz. By ramping the toroidal field, the plasma TAE frequency was swept through the constant antenna excitation frequency to find a resonance and the width of the resonance was measured to determine the effective damping rate of the mode. The toroidal field and density at the resonances were observed to scale as B-T proportional to n(e)(0.5), as expected for Alfven eigenmodes. TAE damping rates were measured in both inner wall limited and diverted discharges. The inner wall limited damping rates for these discharges were in the range of 1% < \gamma/omega\ < 4%. Diverted plasmas, on the other hand, required a very small outer gap between the last closed flux surface and the outboard limiter of less than 1 cm to observe the resonances and the damping rates were then very low with \gamma/omega\ < 1%.