毛细管放电瞬态高热负荷对钨靶侵蚀损伤特性研究

Research on Corrosion and Damage Characteristics of Tungsten Caused by Capillary Discharge Transient High Thermal Load

托卡马克装置高约束运行模式(H模)会周期性地爆发边缘局域模(edge-localized mode,ELM)产生瞬态高热负荷侵蚀第一壁材料。该文使用毛细管等离子体等效模拟ELM高热负荷,并对三电极毛细管结构进行优化;结合仿真总结毛细管等离子体热负荷规律,并提出相应定标关系,以此建立高热负荷靶面冲击实验流程,对在ELM等价的热负荷作用下钨靶板材料侵蚀特性进行研究;获得在单次、重频瞬态热负荷作用下钨靶板融化、开裂、溅射等侵蚀特征,并得到开裂热负荷阈值为1.4GW×m^(-2)。基于钨材料韧脆转变温度,分析在瞬态热负荷下钨靶材局部变形与残余应力累积的物理机制,认为材料烧蚀主要为重频热冲击积累导致的材料融化和溅射。

The high-confinement mode(H mode)of Tokamak device will periodically explode edge localized mode(ELM)in the boundary region,generating transient high thermal load plasma to erode the first wall material.In this paper,capillary plasma is used to simulate the high thermal load of ELM and optimize the structure of three-electrode capillary.The heat load law of the capillary plasma is simulated and analyzed,and the heat load calibration relationship is proposed.Based on this,the high thermal load target impact test process is established and the research on the erosion characteristics of tungsten target plate materials under the effect of ELM equivalent thermal load is carried out.The erosion characteristics such as melting,cracking and sputtering of tungsten target under single and repeated frequency transient thermal load are obtained,and the threshold of cracking thermal load is 1.4 GW•m^(-2).Based on the ductile-to-brittle transition temperature of tungsten,the physical mechanism of local deformation and residual stress accumulation of tungsten target under transient thermal load is analyzed.It is considered that the ablation is mainly caused by melting and sputtering caused by repeated thermal shock accumulation.