Estimates of required impurity fraction for EAST divertor detachment  

作　　者：Jing OU Jiamin LONG 欧靖;龙嘉敏(Institute of Plasma Physics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,People’s Republic of China;University of Science and Technology of China,Hefei 230026,People’s Republic of China)

机构地区：[1]Institute of Plasma Physics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,People’s Republic of China [2]University of Science and Technology of China,Hefei 230026,People’s Republic of China

出　　处：《Plasma Science and Technology》2025年第1期30-38,共9页等离子体科学和技术(英文版)

基　　金：supported by National Natural Science Foundation of China(No.12375227);Innovation in Fusion Engineering Technology of Institute(No.E35QT1080C)。

摘　　要：During the EAST radiative divertor experiments,one of the key challenges was how to avoid the occurrence of disruptive events caused by excessive impurity seeding.To estimate the required impurity fraction for divertor detachment,we introduce a reduced edge plasma radiation model.In the model,based on the momentum conservation along the magnetic field line,the upstream pressure is determined by the plasma density and temperature at the divertor target,and then the impurity radiation loss is obtained by the balance of the heat and particle fluxes.It is found that the required impurity fraction shows a non-monotonic variation with divertor electron temperature(T_(d))when 0.1 eV<T_(d)<10 eV.In the range of 0.1 eV<T_(d)<1 e V,the position near the valley of required impurity fraction corresponds to strong plasma recombination.Due to the dependence of the volumetric momentum loss effect on the T_(d)in the range of 1 eV<T_(d)<10 eV,the required impurity fraction peaks and then decreases as T_(d)is increased.Compared to neon,the usage of argon reduces the impurity fraction by about twice.In addition,for the various fitting parameters in the pressure-momentum loss model,it is shown that the tendency of required impurity fraction with T_(d)always increases first and then decreases in the range of 1 eV<T_(d)<10 eV,but the required impurity fraction decreases when the model that characterizes the strong loss in pressure momentum is used.

关 键 词：divertor detachment IMPURITY radiative divertor reduced physics model 

分 类 号：TL631.24[核科学技术—核技术及应用]