Numerical analysis of key factors for the appearance of grassy ELMs in tokamak plasmas
Numerical analysis of key factors for the appearance of grassy ELMs in tokamak plasmas
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DOI：
10.1088/0029-5515/52/11/114002
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发表时间：
2012-11
期刊：
影响因子：
3.3
通讯作者：
N. Aiba;N. Oyama
中科院分区：
文献类型：
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作者：
N. Aiba;N. Oyama
基于当前对气球模式稳定性动力学影响的理解，对边缘局部 MHD 模式进行数值稳定性分析，以确定小幅度“草 ELM”的起源。这些定性和定量分析表明，即使考虑到动力学效应，短波长气球模式也可以在草地 ELM 稳定性中发挥重要作用。在展示了动力学效应对于讨论草 ELM 物理的重要性之后，从包括这些动力学效应在内的边缘局域 MHD 稳定性的角度，对通过实验实现草 ELM 等离子体重要的等离子体参数的影响进行了数值研究。这些分析表明，低等离子体椭圆率更适合实现草状 ELM 等离子体，因为通过阻止进入气球模式的第二稳定区域来破坏气球模式的稳定性。
Numerical stability analysis of edge-localized MHD mode is performed to identify the origin of small-amplitude ‘grassy ELMs’ on the basis of current understanding of kinetic effects on ballooning mode stability. These qualitative and quantitative analyses show that short wavelength ballooning mode can play an important role in a grassy ELM stability even when kinetic effects are taken into account. After showing the importance of kinetic effects for discussing grassy ELM physics, impacts of plasma parameters important for realizing a grassy ELM plasma experimentally are investigated numerically from the viewpoint of the edge-localized MHD stability including these kinetic effects. These analyses show that low plasma ellipticity is preferable to realize a grassy ELM plasma due to destabilizing ballooning mode by preventing access to the second stability region of the ballooning mode.