Simulation Study of Spontaneous Flow Formation in toroidal Plasma System with Open Field Region

磁聚变等离子体的约束特性受等离子体流动的影响很大。热和粒子的控制依赖于溶胶区的等离子体流动。然而，到目前为止，对环形等离子体中流动的形成机制还没有很好的了解。本文的目的是研究具有开场区域的环形等离子体中的等离子体流动，如溶胶/偏滤器。用粒子模拟的方法研究了偏滤器托卡马克系统流动的形成机理和控制方法，将之前开发的二维改进的直线托卡马克系统粒子程序改进为二维环形遮阳伞，可用于偏滤器托卡马克的全局模拟。我们在阳伞上配备了物理模型；ELM坠毁时温度较高的等离子体的突发源模型用于研究瞬变等离子体流动，中性束注入源模型用于直接控制流动。我们一直在完善一个全面的偏滤器流体代码SONIC和一个集成托卡马克传输代码的主题-IB。研究了杂质输运与等离子体流之间的相互依赖关系，以及溶胶等离子体流对ELM能量损失的影响；利用一维遮阳伞，研究了SOL/偏滤器等离子体对非对称ELM的暂态响应，阐明了开场区非对称热流和等离子体流的结构。利用二维遮阳伞，我们发现随着拉莫尔半径的增大，封闭场区的径向电场由正向负的转变。我们利用环形2D遮阳伞，进一步研究了囚禁离子的香蕉宽度对径向电场和自发流形成的影响。这些研究成果有望对聚变环形等离子体的输运/约束的物理理解，以及改进的约束和热/粒子处理的控制方法的发展有所帮助。

Confinement properties of magnetic fusion plasmas are affected much by the plasma flow. Heat and particle control is dependent on the plasma flow in SOL region. The formation mechanism of the flow in toroidal plasmas, however, has not well understood so far. The present aim is to research the plasma flow in toroidal plasmas with open-field region such as SOL/diveror. The formation mechanism and control method of the flow are investigated with the particle simulation.We improved a two-dimensional advanced particle code PARASOL for the straight tokamak system developed beforehand to a 2D toroidal PARASOL, which becomes the code available for global simulations of divertor tokamaks. We equipped-physics models in PARASOL ; the abrupt source model of hotter temperature plasma at an ELM crash for the study of the transient plasma flow and the neutral beam injection source model for the direct control of the flow. We have been improving a comprehensive divertor fluid code SONIC and an integrated tokamak transport code TOPICS-IB. We studied the mutual dependence between impurity transport and plasma flow, and the effect of SOL plasma flow on the ELM energy loss.By using 1D PARASOL, we investigated the transient response of SOL/divertor plasmas against the asymmetric ELM, and clarified structures of asymmetric heat flow and plasma flow in the open-field region. Using 2D PARASOL, we found the transition of radial electric field from positive to negative in the closed field region with the increase of Larmor radius. We studied further, using toroidal 2D PARASOL, the effect of banana width of trapped ions on the formation of radial electric field and spontaneous flow.Present achievements are expected useful for the physics understanding of transport/confinement of fusion toroidal plasmas, and for the development of control methods of improved confinement and heat/particle handling.