无偏压射频等离子体原位清洗第一镜的机理研究

第一镜使用寿命对于保证托卡马克光学诊断信号的有效性和准确性、保障装置安全运行至关重要。原位清洗是目前延长第一镜使用寿命最有效的方法，ITER水冷第一镜只能采用无偏压射频等离子体实现原位清洗。世界上第一镜清洗研究大多在实验室条件下开展，缺乏托卡马克装置上的研究结果。本申请拟在与ITER具有相似磁场位形的EAST装置上，依托材料与等离子体测试平台和第一镜原位清洗系统，研究托卡马克强磁场条件下无偏压射频等离子体原位清洗第一镜沉积层的效率、均匀性及反射率恢复情况；同时，利用大型蒙特卡罗程序ERO，建立合理的物理模型，对实验进行数值模拟，进一步阐明托卡马克环境下无偏压射频等离子体原位清洗第一镜的机理，从而针对EAST诊断第一镜，提出原位清洗方案。本项研究可为未来ITER及CFETR第一镜原位清洗提供重要的科学依据和数据积累。

First mirror (FM) lifetime is essentially important to assure signal effectiveness and accuracy of optical diagnostics and to ensure safe operation of tokamak device. In situ cleaning is the most effective way to prolong FM lifetime. Water cooled FM of ITER can be in situ cleaned only by radio frequency (RF) plasma with no self-bias. Most FM cleaning researches are carried out in laboratory all over the world with lack of results from tokamak. This application plans to carry out FM in situ cleaning experiments with no self-bias relying on the material and plasma evaluation system and the FM in situ cleaning system in the ITER magnetic field like device - EAST, and investigate FM in situ cleaning efficiency, homogeneity and reflectivity recovery by RF plasma with no self-bias with strong magnetic field in tokamak. Then, this application will also build physical model and perform numerical modeling of experiment results using Monte Carlo ERO in order to further clarify influence mechanism of magnetic field on FM in situ cleaning by RF plasma with no self-bias and propose in situ cleaning method for EAST diagnostic FM. This study will provide important scientific basis and data accumulation for FM in situ cleaning of future ITER and CFETR.