边界局域模对EAST钨偏滤器靶板腐蚀程度的数值模拟研究

在高约束模式下发生的边界局域模会释放高能量等离子体,其中主要部分会辐照到面积相对较小的偏滤器靶板,偏滤器钨靶板发生热腐蚀的可能性最大.本文建立了包括了熔化、汽化和热辐射效应的一维热传导模型,采用数值模拟的方法,研究了EAST未来偏滤器钨靶板在边界局域模作用下的热腐蚀程度.根据现有的边界局域模热流数据和多种未来可能的高能量边界局域模热流数据,计算了钨靶板的表面温度分布.结果显示当前的第一类边界局域模作用在钨靶板上,在高约束模式运行时间取32 s情况下,靶板表面温度从350 K增加到373 K,表明在当前的参数范围内,只要避免其他更严重的瞬时事件如破裂的发生,边界局域模还不会带来严重的威胁;如果边界局域模的能量增加到接近未来托卡马克边界局域模的能量范围1 MJ/m2,沉积时间为600μs,表面最大熔化厚度将达到6.8—6.9μm.

Numerical study of the erosion of the EAST tungsten divertor targets caused by edge localized modes

Edge localized modes (ELMs) in company with high-confinement mode (H-mode) will release high energy plasma fluxes to the scrape of layer (SOL). Large portions of these high heat fluxes will eventually irradiate the divertor target plates, and may erode, even melt them. In this paper, we develope a one-dimensional heat conductivity model including evaporation, radiation, melting processes of tungsten to study the erosion of the divertor tungsten targets caused by ELMs in EAST at the current and possible future operation parameters. Based on both experimental data of heat fluxes on the carbon-fibre composites divertor in EAST and possible future data of high heat fluxes, the surface temperature of slab-shaped tungsten is evaluated numerically by solving the one-dimensional model. It is found that the current Type I ELMs do not cause any noticeable changes of the tungsten target, the surface temperature being raised only several tens of degrees. Simulation results show that ELMs will not become a problem for EAST tungsten wall for the time being and the near future as long as much more severe transient events, e.g., disruption, can be avoided. When deposition energy is increased to 1 MJ/m² with a duration of 600 μs, the tungsten plate will melt for a layer as thick as 6.8 μm.