Density fluctuations in currentless high beta plasmas in Heliotron E
Density fluctuations in currentless high beta plasmas in Heliotron E
复制标题
Heliotron E 中无电流高 β 等离子体的密度波动
DOI：
10.1088/0029-5515/27/6/002
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
K. Uo
中科院分区：
文献类型：
--
作者：
H. Zushi;O. Motojima;M. Wakatani;F. Sano;S. Sudo;H. Kaneko;K. Kondo;T. Mizuuchi;K. Yaguchi;M. Sato;A. Iiyoshi;K. Uo
通过改变气体膨化条件和颗粒注入，研究了当前高β等离子体在很大范围内的密度分布ne(r)的稳定性。采用多通道远红外激光干涉仪测量了线密度波动与压力驱动MHD不稳定性的关系。当等离子体β的增加伴随着ne(r)的峰值时，周期性地出现频率为2-5千赫的线密度波动。波动的重复时间一般为2 ~ 5 ms。确定了波动的极向和环向模态数分别为m=l和n=l。对于极尖峰型等离子体，观察到对应于m=3/n=2模式的密度波动。随着这种模式的发展，内部出现了中断。由于这些破坏，ne(r)的轮廓迅速从峰值变为较宽的。破坏引起的密度剖面变化中相位反转的归一化平均半径r/a约为0.5，大致对应于ι =2/3面，ι为合理化旋转变换。很可能是m=3/n=2的大振幅模态触发了内部扰动。MHD不稳定的起始区域也被研究了不同的密度分布和β值。
The stability properties of currentless high beta plasmas have been investigated over a wide range of density profiles ne(r), by varying the gas puffing conditions and by pellet injection. Line density fluctuations correlated with a pressure driven MHD instability were measured by a multi-channel far-infrared laser interferometer. When an increase in the plasma beta was accompanied by a peaking of ne(r), line density fluctuations with a frequency of 2–5 kHz periodically appeared. The repetition time of the fluctuations was typically 2–5 ms. The poloidal and toroidal mode numbers of the fluctuations were identified as m=l and n=l. For plasmas with an extremely peaked profile, density fluctuations corresponding to the m=3/n=2 mode were observed. With the growth of this mode, internal disruptions occurred. Because of these disruptions, the profile of ne(r) rapidly changed from a peaked one to a broader one. The normalized average radius, r/a, of the phase reversal in the density profile variation caused by the disruption is about 0.5, which roughly corresponds to the ι =2/3 surface, ι being the rationalized rotational transform. It is most likely that the large amplitude mode with m=3/n=2 triggers the internal disruptions. The onset regions for MHD instability have also been investigated for various density profiles and beta values.
影响因子：
3.3
作者：
A. Gibson;T. Sekiguchi;K. Lackner;S. Bodner;R. Hancox
通讯作者：
A. Gibson;T. Sekiguchi;K. Lackner;S. Bodner;R. Hancox