低杂波缓解ELM过程中台基结构演化行为研究

低杂波缓解边界局域模（ELM）已得到初步验证，但最新实验发现低杂波有时会触发更大的ELM，这与台基结构或碰撞率有关，具体机制尚不清楚。对于确立和推广低杂波控制方法，阐明其对台基结构的作用过程是必需的核心环节。研究发现低杂波控制ELM存在功率阈值，本项目拟在临界阈值附近开展针对性物理实验，基于高时空分辨汤姆逊散射精准局域、同时测量电子温度和密度的特点，结合其他边界分布和涨落诊断，研究台基电子温度、密度和压强梯度等对低杂波的响应时序和演化行为，弄清碰撞率等对台基结构演化的影响，揭示低杂波作用期间台基剥离气球模不稳定性边界的移动规律；结合ELITE等分析模拟程序，对低杂波控制方法的阈值现象及对应的台基不稳定性跃变行为获得较为深刻的理解。本项目的开展，将深化对低杂波缓解ELM物理过程的认知，使其更好服务于EAST全金属壁条件下高功率长脉冲运行，并为其在未来聚变装置中应用提供实验和理论依据。

The LHW controlling ELM has been verified by experiments, but the latest experiment found that LHW sometimes can trigger larger ELMs, which may be related to the pedestal structure or collisionality. For establishing and popularizing the scientific method of LHW controlling ELM, it is necessary to clarify its influence on the evolution of the pedestal structure. It is found that there are the power threshold of LHW mitigating ELM. This project plans to carry out targeted physical experiments near the critical threshold. Based on the high-resolution Thomson scattering diagnostic, and combined with other boundary diagnostic, investigating the pressure gradient evolution and response time sequence of electron temperature and density, to identify its dependence on the key parameters such as the pedestal collisionality and revealing the movement law of the instability boundary of the pedestal Peeling-Ballooning. Combined with the simulation program, to understand the threshold phenomenon and the corresponding jump behavior of pedestal instability. The development of this project will deepen the understanding of the physical process of LHW mitigating ELM, to make it better to serve the operation of high power long pulse under the condition of all metal wall of EAST, and to provide the experimental basis of exploring its application for the future fusion device.