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），特别是对于未来的高性能和稳态等离子体运行的反应堆，如ITER和CFETR，将决定面向等离子体部件（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PWI过程，如材料腐蚀，运输和沉积，以及通过注入和共沉积的燃料保留的理解，是至关重要的，以控制这些过程的反应堆在高可用性的安全运行。为了预测从目前的设备，如EAST托卡马克（合肥，中国）和W7-X仿星器（格赖夫斯瓦尔德，德国）到未来的设备的PWI数值模拟是强制性的。在当今的实验测量必须用来验证代码和PWI的基本物理，以获得信心的预测。此外，需要优化或新颖的诊断方法，以适用于长脉冲装置中的原位PWI分析，从而允许出于安全原因而访问关键量，例如燃料库存。本提案涵盖了原位诊断系统（例如石英微天平（QMB））和基于激光的诱导粒子烧蚀方法的开发（LIBS，LIAS）以及在中国和德国的实验室设置中进行测试（ASIPP/合肥，DUT/大连，FZJ/Jülich和HHU/杜塞尔多夫）。QMB通过记录作为检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）可以在原位和长检测距离处进行，以监测放电期间和放电之间第一壁上的氢保留和杂质沉积成分。优化有关的激光材料相互作用的时间，激光等离子体的生产过程，和校准是必需的;所有必须伴随着建模。然后，优化的系统将被集成在金属长脉冲设备EAST的诊断套件中，例如中板操纵器（MAPES）和可见光谱系统，并将在该提案的框架内进行专用PWI实验。一个主要的重点将是在钨（W）PFC的特性，目前在上偏滤器，光谱结合激光应用和QMB将用于确定主要的PWI过程，包括W，D和种子气体。等离子体边缘的数值模拟与二维等离子体流体程序SOLPS-ITER和PWI与三维蒙特-卡罗代码ERO联合进行，并将应用于支持实验结果的解释。最后，优化和合格的诊断和一个子集的代码将在未来适应的条件下的W7-X，目前运行与石墨，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.