Plasma-Wall-Interaction Diagnostics for Steady-State Fusion Plasmas

聚变装置中的等离子体-壁相互作用(PWI)，特别是对于未来具有高性能和稳态等离子体操作的反应堆，如ITER和CFETR，将决定面向等离子体的部件(PFC)的寿命，影响等离子体的性能，并通过滞留来控制氚循环。因此，诊断和了解PWI过程，如材料的侵蚀、传输和沉积以及通过注入和共沉积保持燃料的过程，对于控制这些过程以确保反应堆的高可用性安全运行至关重要。为了预测当今装置如EAST托卡马克(合肥，中国)和W7-X星化器(德国格雷夫斯瓦尔德)到未来装置的PWI，必须进行数值模拟。为了获得对预测的信心，必须使用现代实验中的测量来验证PWI的代码和基本物理。此外，优化或新颖的诊断方法需要适用于长脉冲设备中的现场PWI分析，以便出于安全原因获得燃料库存等关键数量。本提案包括开发现场诊断系统，如石英微天平(QMBs)和基于激光的诱发粒子烧蚀方法(LIBS，LIAS)，以及在中国和德国的实验室设备中进行测试(ASIPP/合肥，DUT/大连，FZJ/Jülich和HHU/Düsseldorf)。QMBs通过记录作为探测器的石英晶体对质量敏感的共振频率的变化来测量就地局部侵蚀和沉积。需要在热稳定性、灵敏度和校准方面进行优化。激光诱导烧蚀/击穿光谱(LiAS/LIBS)可以在较远的探测距离内进行原位测量，以监测放电过程中和放电之间第一壁上的氢保持和杂质沉积成分。需要优化激光-材料相互作用时间、激光-等离子体生产工艺和校准；所有这些都必须伴随建模。然后，优化的系统将被集成到金属长脉冲设备EAST的诊断套件中，例如中面操纵器(MAPES)和可见光谱系统，并将在该提议的框架内进行专门的PWI实验。一个主要的重点将是描述存在于上偏滤器中的钨(W)PFC，其中光谱与激光应用和量子分子束相结合将被用于确定包括W、D和种子气体的主要PWI过程。用二维等离子体流体程序SOLPS-ITER和三维蒙特卡罗程序ERO对等离子体边缘进行了数值模拟，并将用于支持对实验结果的解释。最后，优化和合格的诊断程序和代码子集将在未来适应目前使用石墨的W7-X和金属CFETR的条件。

Plasma-Wall Interactions (PWI) in fusion devices, especially for future reactors with high performance and steady-state plasma operations such as ITER and CFETR, will determine the life time of Plasma-Facing Components (PFCs), impact the performance of plasmas, and govern the tritium cycle by retention. Therefore, diagnosis and understanding of the PWI processes such as material erosion, transport, and deposition as well as fuel retention by implantation and co-deposition, is crucial in order to control these processes for a safe operation of a reactor at high availability. In order to predict from the PWI in present day devices such as the EAST tokamak (Hefei, China) and the W7-X stellarator (Greifswald, Germany) to future devices numerical simulations are mandatory. Measurements in present-day experiments must be used to verify the codes and the underlying physics of PWI in order to gain confidence in the predictions. Moreover, optimized or novel diagnostics are required to be applicable for in-situ PWI analysis in long-pulse devices to permit access to crucial quantities like the fuel inventory for safety reasons.The present proposal covers the development of in-situ diagnostics systems such as Quartz-Micro Balances (QMBs) and laser-based methods inducing particle ablation (LIBS, LIAS) and testing in laboratory set-ups in China and Germany (ASIPP/Hefei, DUT/Dalian, FZJ/Jülich and HHU/Düsseldorf). QMBs measure in-situ local erosion and deposition by recording the change in the mass-sensitive resonance frequency of the quartz crystal which acts as detector. Optimization concerning thermal stability, sensitivity and calibration is required. Laser-Induced Ablation/Breakdown spectroscopy (LIAS/LIBS) can be performed in-situ and at long detection distance to monitor the hydrogen retention and impurities deposition compositions on the first wall during and between discharges. Optimization concerning the laser-material interaction time, the laser-plasma production process, and calibration is required; all must be accompanied by modelling. Optimized systems will then be integrated in the suite of diagnostics in the metallic long-pulse device EAST, such as the midplane manipulator (MAPES) and visible spectroscopic systems, and dedicated PWI experiments will be carried in the framework of this proposal. A major emphasis will be in the characterization of tungsten (W) PFCs as present in the upper divertor , where spectroscopy combined with LASER-applications and QMBs will be used to determine the major PWI processes covering W, D and seeding gases. Numerical simulations of the plasma edge with the 2D plasma fluid code SOLPS-ITER and the PWI with the 3D Monte-Carlo code ERO are performed jointly and will be applied to support the interpretation of experimental findings. Finally, the optimized and qualified diagnostics and a subset of codes will be adapted in future to the conditions of W7-X, currently operationg with graphite, and the metallic CFETR.