ELM frequency dependence on toroidal rotation in the grassy ELM regime in JT-60U
ELM frequency dependence on toroidal rotation in the grassy ELM regime in JT-60U
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DOI：
10.1088/0741-3335/49/3/005
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发表时间：
2007-02
影响因子：
2.2
通讯作者：
N. Oyama;Y. Kamada;A. Isayama;H. Urano;Y. Koide;Y. Sakamoto;M. Takechi;N. Asakura
中科院分区：
文献类型：
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作者：
N. Oyama;Y. Kamada;A. Isayama;H. Urano;Y. Koide;Y. Sakamoto;M. Takechi;N. Asakura
本文系统地研究了离子温度座顶部的环形等离子体旋转水平对JT-60U边缘局域模式（ELM）特性的影响。通过使用不同组合的切向和垂直中性束注入（NBI），改变了环形等离子体的旋转水平。在高三角度（δ）和高安全系数(q)的草地ELM状态下，当计数器（ctr）等离子体旋转增加时，ELM频率明显增加到~ 1400 Hz。在0.84 ~ 0.53范围内，ELM频率的响应与β (βp)无关。即使在具有平衡nbi的非旋转等离子体中，也观察到~ 400 Hz的高ELM频率而没有大的能量损失。当等离子体在等离子体电流共方向旋转的频率高于~ 1 kHz时，观察到频率为~ 20 Hz的I型elm。在I型elm等离子体和草型elm等离子体中，获得的基座压力和等离子体约束相似。从电子温度降低的角度评价了绿草elm的能量损失，能量损失与基座储存能量的比值小于1%。
A systematic study of the effect of the level of toroidal plasma rotation at the top of the ion temperature pedestal ( ) on the edge localised mode (ELM) characteristics in JT-60U has been performed. The level of toroidal plasma rotation was varied by using different combinations of tangential and perpendicular neutral beam injection (NBI). In the grassy ELM regime at high triangularity (δ) and high safety factor (q), the ELM frequency clearly increased up to ∼1400 Hz, when counter (ctr) plasma rotation was increased. The response of the ELM frequency was independent of poloidal beta (βp) in the range 0.84 0.53. Even in non-rotating plasma with balanced-NBIs, a high ELM frequency of ∼400 Hz was observed without a large energy loss. When the frequency of the plasma rotation in the co-direction of the plasma current became higher than ∼1 kHz, type I ELMs with a frequency of ∼20 Hz was observed. The achieved pedestal pressure and plasma confinement were similar both in plasmas with type I ELMs and in plasmas with grassy ELMs. The energy loss due to grassy ELMs was evaluated from the reduction in the electron temperature, and the ratio of the energy loss to the pedestal stored energy was less than 1%.