Nagashima Y, Hoshino K, Ejiri A, Shinohara K, Takase Y, Tsuzuki K, Uehara K, Kawashima H, Ogawa H, Ido T, Kusama Y, Miura Y
University of Tokyo, Tokyo 113-0033, Japan.
Phys Rev Lett. 2005 Aug 26;95(9):095002. doi: 10.1103/PhysRevLett.95.095002. Epub 2005 Aug 23.
Two types of electrostatic modes with small-poloidal wave numbers (approximately 1 and 10-15 kHz) are observed in the edge region of Ohmically heated plasmas in the JFT-2M tokamak. The envelope of the higher frequency coherent mode is modulated at the frequency of the lower frequency mode. A bispectral analysis revealed that a significant nonlinear coupling among the two types of fluctuations and the broadband background turbulent potential fluctuations occurs inside the last closed magnetic flux surface, suggesting that a nonlinear process such as the parametric-modulational instability is involved.
在JFT - 2M托卡马克欧姆加热等离子体的边缘区域观察到两种具有小极向波数（约1至15千赫兹）的静电模式。高频相干模式的包络以低频模式的频率被调制。双谱分析表明，在最后封闭磁通量表面内部，两种波动类型与宽带背景湍流势波动之间存在显著的非线性耦合，这表明涉及到诸如参量调制不稳定性等非线性过程。
