Evolution of edge turbulent transport induced by L-mode detachment in the HL-2A tokamak

This paper presents the characteristics of L-mode detachment,together with the behavior of edge turbulent transport and plasma confinement on the HL-2A tokamak.Partially detached and pronounced detached states have been achieved in L-mode plasma.Stored energy was maintained before and after detachment.Edge turbulence and its transport have increased obviously in the partially detached state.In the pronounced detached state,redistribution of the density and temperature profiles due to detachment leads to low amplitude of electron temperature and pressure,as well as very weak edge turbulence and transport.Despite strong plasma radiation in the pronounced detached state,reduced edge turbulent transport contributes to maintaining stored energy in detached L-mode plasma in HL-2A.Different detachment states play an important role in the redistribution of density and temperature profiles,which requires further study.

HL-2A装置实时在线硅化壁处理系统

为了实时控制等离子体杂质以获得良好的等离子体品质,在HL-2A装置上搭建了实时在线硅化壁处理系统,以开展实时在线硅化实验研究。系统采用压电晶体阀控制送气流量,并由HL-2A中控系统时序作为阀门控制的触发信号。在偏滤器位形和孔栏位形放电条件下开展了初步的实时在线硅化实验,研究不同硅化气体注入参数对不同位形等离子体放电参数的影响。实验结果表明,硅化气体注入后等离子体线平均密度整体增加;而Dα、SiV辐射强度以及等离子体总热辐射功率只在注入期间增加,随后基本恢复到本底水平。高幅值短脉冲注入对等离子体参数的扰动比低幅值长脉冲明显,因此在线硅化实验宜采用低幅值长脉冲的形式开展。由环向Dα诊断系统对硅化气体在环向的镀膜范围进行了大致评估,结果表明单个注入口的镀膜范围有限,需要适当增加送气口来实现均匀镀膜。