Core plasma confinement during detachment transition with RMP application in LHD
Core plasma confinement during detachment transition with RMP application in LHD
复制标题
LHD 中 RMP 应用分离过渡期间的核心等离子体限制
DOI：
10.1016/j.nme.2018.10.003
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发表时间：
2018
影响因子：
2.6
通讯作者：
Seki R.
中科院分区：
文献类型：
--
作者：
Kobayashi M.;Masuzaki S.;Tanaka K.;Tokuzawa T.;Yokoyama M.;Narushima Y.;Yamada I.;Ido T.;Seki R.
研究了共振磁扰动（RMP）场作用下LHD放电分离相的核心等离子体约束。RMP应用在边缘随机层中产生了一个剩余磁岛，这极大地改变了等离子体参数分布，包括杂质辐射。电子的温度和压力分布在岛平坦，而电子密度略有高峰在岛的边缘。估计的杂质辐射分布增强和固定在磁岛周围的分离阶段，在那里的放电是稳定的持续与控制水平的辐射。在没有RMP的情况下，辐射穿透限制区域，导致辐射崩塌。研究发现，在RMP应用的情况下，等离子体储存的能量在分离转变处不连续地增加。尽管由于边缘磁岛和增强的辐射而导致有效等离子体体积减小，但中心等离子体压力最终超过了没有RMP的情况。这是由于在使用RMP的情况下，压力分布在中心区域达到峰值。这些结果表明，在使用RMP的分离阶段，堆芯等离子体约束发生了明显的变化。
The core plasma confinement during detachment phase is investigated in the discharges with application of resonant magnetic perturbation (RMP) field in LHD. The RMP application creates a remnant magnetic island in the edge stochastic layer, which largely changes the plasma parameter profiles including impurity radiation. The electron temperature and pressure profiles are flattened at the island, while the electron density is slightly peaked at the edge of the island. The estimated impurity radiation profile is enhanced and fixed around the magnetic island during the detached phase, where the discharge is stably sustained with controlled level of radiation. Without RMP, the radiation penetrates the confinement region, leading to radiation collapse. It is found that in the case of the RMP application the plasma stored energy increases discontinuously at the detachment transition. In spite of the reduced effective plasma volume caused by the edge magnetic island and by the enhanced radiation there, the central plasma pressure finally exceeds the case without RMP. This is caused by the pressure profile peaking at the central region in the case with RMP. These results indicate clear change of core plasma confinement during the detached phase with RMP.