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，将决定等离子体面向组件（pfc）的寿命，影响等离子体的性能，并通过保留来控制氚循环。因此，诊断和了解PWI过程，如物质侵蚀、输送、沉积以及注入和共沉积引起的燃料保留，对于控制这些过程以保证反应堆在高可用性下的安全运行至关重要。为了预测当前设备的PWI，如EAST托卡马克（中国合肥）和W7-X仿星器（德国Greifswald）到未来设备的PWI，必须进行数值模拟。为了获得对预测的信心，必须使用当今实验中的测量来验证代码和PWI的潜在物理特性。此外，需要优化或新颖的诊断方法，以适用于长脉冲设备的原位PWI分析，以便出于安全原因访问关键数量，如燃料库存。目前的建议涵盖了原位诊断系统的开发，如石英微天平（qmb）和基于激光的诱导颗粒烧蚀方法（LIBS， LIAS），以及在中国和德国（ASIPP/合肥，DUT/大连，FZJ/ j<s:1>利希和HHU/ d<e:2> sseldorf）的实验室设置中进行测试。qmb通过记录作为探测器的石英晶体的质量敏感共振频率的变化来测量原位局部侵蚀和沉积。需要对热稳定性、灵敏度和校准进行优化。激光诱导烧蚀/击穿光谱（LIAS/LIBS）可以在原位和远距离检测，以监测放电期间和放电间隙第一壁上的氢保留和杂质沉积成分。需要对激光-材料相互作用时间、激光-等离子体生产工艺和校准进行优化；所有这些都必须伴随着模型。然后将优化的系统集成到金属长脉冲设备EAST的诊断套件中，例如背板操纵器（MAPES）和可见光谱系统，并且将在本提案的框架内进行专用的PWI实验。重点将是表征上部分流器中存在的钨(W) PWI，其中将使用光谱与激光应用和qmb相结合来确定包括W， D和播种气体的主要PWI过程。用二维等离子体流体代码SOLPS-ITER和三维蒙特卡罗代码ERO对等离子体边缘进行了数值模拟，并将用于支持实验结果的解释。最后，优化和合格的诊断和代码子集将在未来适应W7-X的条件，目前使用石墨和金属CFETR。

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.