The effects of nitrogen gas seeding in the edge and scrape-off layer (SOL) regions of a tokamak plasma are studied through 2D fluid simulations using the BOUT++ code. Proper account is taken of the presence of multiple charged states of nitrogen ions due to ionization, recombination, and dissociation processes, and a self-consistent study of the interaction of these ions with the turbulent plasma in the edge and SOL regions is carried out. The self-consistent model includes the effects of polarization drifts of the main plasma and impurity ions for determining the plasma vorticity. Nitrogen seeding is found to modify the turbulence as well as to influence the profiles of the equilibrium plasma density and the electron temperature. The densities of N 3 + to N 5 + ions are found to be relatively higher than the other charged states. This is understood and further validated by a 0D simulation. The radial profiles of these impurity ions are mapped, and their radiation energy losses are estimated. The radial profile of the radiation losses is maximum near to the edge-to-SOL transition region and becomes broader in the edge region than the SOL region.

中文翻译：

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托卡马克等离子体中氮接种的影响

通过使用 BOUT++ 代码的 2D 流体模拟，研究了氮气在托卡马克等离子体边缘和刮削层 (SOL) 区域中的影响。由于电离、复合和解离过程，适当考虑了氮离子的多种带电状态，并对这些离子与边缘和 SOL 区域中的湍流等离子体的相互作用进行了自洽研究。自洽模型包括用于确定等离子体涡度的主等离子体和杂质离子的极化漂移的影响。发现氮注入可以改变湍流并影响平衡等离子体密度和电子温度的分布。发现 N 3 + 到 N 5 + 离子的密度相对高于其他带电状态。这可以通过 0D 模拟来理解和进一步验证。绘制了这些杂质离子的径向分布图，并估计了它们的辐射能量损失。辐射损耗的径向分布在边缘到 SOL 过渡区域附近最大，并且在边缘区域变得比 SOL 区域更宽。