髙电荷态ECR离子源微波与等离子体相互作用机制的数值模拟研究

The mechanism of the interaction between microwave and plasma in electron cyclotron resonance ion sources has not been reasonably explained by existing physical theory. In this project, a physical and computational model of ECR ion source has been proposed to study the interaction between microwave and plasma. A three-dimensional electromagnetic particle-in-cell plus Monte Carlo method is used to simulate the detailed microscopic information about the distributions of electromagnetic fields and charged particles from the initial stage to the steady state of ECR ion source, and the spatio-temporal evolution of the movements of charged particles and the absorption of microwave are shown. The macroscopic features of ECR ion source are also found by the statistical treatment of microscopic information. This study will provide a better understanding of the interaction between microwave and plasma, and meanwhile facilitate the development of ECR ion source and its design in the next generation.

髙电荷态ECR离子源微波与等离子体的相互作用机制，目前并没有令人信服的理论解释。本项目拟构建完整的ECR离子源物理模型，通过粒子模拟（PIC）与蒙特卡罗（MC）相结合的方法对髙电荷态ECR离子源从放电初期到放电稳态过程中微波与等离子体的相互作用机制开展系统的数值模拟与理论研究，重点研究此过程中的微波场分布、带电粒子相空间分布以及它们随时间、空间的演化，同时通过对大量微观信息进行统计平均给出电子（离子）密度、温度、能量分布及速度分布等宏观的ECR等离子体特性，揭示高电荷态ECR离子源微波与等离子体相互作用的瞬态特性与微观机制。本项目的研究将进一步加深对ECR离子源物理机制的理解，对进一步提高ECR离子源性能、改进离子源设计提供更高效的理论指导。

本项目基于LAPECR1U离子源构建了完整的三维ECR离子源物理模型，并通过粒子模拟（PIC）与蒙特卡罗（MC）相结合的方法数值实现该模型。重点研究了ECR离子源从放电初始到放电稳态过程中的微波场分布、带电粒子相空间分布及其演化，同时通过对大量微观信息进行统计平均给出电子密度、温度分布等宏观的ECR等离子体特征参数，得到微波与ECR等离子体相互作用的瞬态特性与微观细节。在实验验证方面，系统研究了离子源外部参数对ECR等离子体热电子特性的影响，证实了微波加热导致的螺距角散射（microwave induced pitch angle scattering）这一热电子损失机制，并利用共振场平均梯度这一表征量解释热电子加热机制。本项目的研究加深了对ECR离子源物理机制的理解，对进一步提高ECR离子源性能、改进离子源设计提供一定的理论指导。