EAST中性束注入射频离子源放电模拟研究

Simulation study on the discharge of radio frequency ion source for EAST neutral beam injector

中性束注入加热是核聚变中非常重要的一种辅助加热手段,离子源所能达到的性能决定了东方超环(Experimental Advanced Superconducting Tokamak, EAST)中性束注入所能达到的指标。为了实现长脉冲和高功率加热的需求,采用射频离子源取代传统的热阴极离子源已成为未来离子源发展的一种趋势。本文对射频离子源的结构设计和放电特性进行了理论模拟研究,给出了线圈匝数、匝间距、驱动器尺寸、放电气压和射频功率等参数与等离子体参数间的关系,为接下来射频离子源的研制和实验奠定一定的理论基础。

[Background] Neutral beam injection heating is a very important auxiliary heating method in nuclear method in nuclear fusion. The high current ion source is one of the key components of neutral beam injector. Its performance determines the achievable goals of the NBI for the Experimental Advanced Superconducting Tokamak (EAST).[Purpose] This study aims at the fundamental physical characteristics of radio frequency plasma discharge by simulating the discharge of radio frequency (RF) ion source.[Methods] The structure design and discharge characteristics of radio frequency ion source were simulated theoretically. Two-dimensional inductively coupled plasma model was used to simulate the RF ion source. The relationship between turns of coil, turn space, size of driver, air pressure, RF power and the discharge characteristics was analyzed.[Results] The simulation results gave the optimal parameters of the RF ion source for EAST NBI that can meet the future needs of long pulse operation and the future demands of high energy ion source of NBI.[Conclusions] The simulation results lay a foundation for the development and experimental study of RF ion source.