Design of X-Type Armature of Electromagnetic Pellet Injection System on J-TEXT Tokamak
Chen Zhongyong1,2, Zhang Weikang1,2, Tang Junhui3, Li Feng1,2, Xia Shengguo3
1. International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China; 2. State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China; 3. Key Laboratory of Pulsed Power Technology Ministry of Education Huazhong University of Science and Technology Wuhan 430074 China
Abstract：The International Thermonuclear Experimental Reactor (ITER) program is the largest international scientific and technological cooperation project that China has participated in, which goal is to verify the scientific and technical feasibility of using large tokamak devices to obtain fusion energy. The major plasma disruption is the biggest threat to the safe operation of ITER, resulting in the damage of the device. Therefore, the disruption mitigation is a key scientific and technical problem to be solved urgently. At present, the basic strategy for disruption mitigation is to actively inject a large number of particles, but the existing disruption mitigation systems cannot fully meet the requirements of ITER. By analyzing the characteristics of existing systems, this paper introduces a new generation of Electromagnetic Pellet Injection system (EMI) for disruption mitigation on J-TEXT tokamak. The system uses electromagnetic force to launch pellets, which can effectively improve the injection speed and reduced response time, overcoming the limitations of other systems. The armature is the core component of EMI. By introducing the structure and function of the tail contact armature, it is shown that when this type of armature is used in EMI, there are insufficient armature-rail electrical contact performance and motion stability in the deceleration stage. According to the special requirements of the armature performance in the EMI deceleration stage, a new solid armature with an X-shaped structure is designed. The simulation results show that the electromagnetic and mechanical properties of the armature meet the launch requirements, and the electrical contact characteristics are brilliant. In the launch performance test, the armature is accelerated to 520m/s and then actively decelerated to 0m/s; in the armature-pellet separation test, the stable separation of the armature and pellet is achieved, and the flight velocity of pellet is 358m/s, and this velocity can be further increased with the increase of acceleration energy. EMI provides an advanced scheme for efficient disruption mitigation on tokamak, and the X-type armature proposed in this paper has good launch performance which provides an excellent new type of armature structure and design method for EMI.
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2022, Vol. 37 
