Experimental and modeling researches of dust particles in the HL-2A tokamak

• Published in: Chinese physics B 2015-02, Vol.24 (2), p.313-319
• Main Author: 黄治辉 严龙文 冨田幸博 冯震 程钧 洪文玉 潘宇东 杨青巍 段旭如
• Format: Article
• Language: English
• Subjects: Centrifugal force; Computer programs; Devices; Dust; Dynamic characteristics; Flaking; Friction; HL-2A装置; Scanning electron microscopy; Tokamak devices; X射线光谱法; 国际热核实验反应堆; 尘埃颗粒; 建模; 扫描电子显微镜; 等离子体; 计算机程序
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/24/2/025204

The investigation of dust particle characteristics in fusion devices has become more and more imperative.In the HL-2A tokamak,the morphologies and compositions of dust particles are analyzed by using scanning electron microscopy（SEM） and energy dispersive x-ray spectroscopy（EDX） with mapping.The results indicate that the sizes of dust particles are in a range from 1 μm to 1 mm.Surprisingly,stainless steel spheres with a diameter of 2.5μm-30 μm are obtained.The production mechanisms of dust particles include flaking,disintegration,agglomeration,and arcing.In addition,dynamic characteristics of the flaking dust particles are observed by a CMOS fast framing camera and simulated by a computer program.Both of the results display that the ion friction force is dominant in the toroidal direction,while the centrifugal force is crucial in the radial direction.Therefore,the visible dust particles are accelerated toriodally by the ion friction force and migrated radially by the centrifugal force.The averaged velocity of the grain is on the order of~100 m/s.These results provide an additional supplement for one of critical plasma-wall interaction（PWI） issues in the framework of the International Thermonuclear Experimental Reactor（ITER） programme.