摘要
栅极热变形是影响离子推力器性能和寿命的重要因素.采用三维粒子方法对栅极系统等离子体输运过程进行模拟,对比、分析栅极热变形前后栅极系统的电子返流限制、导流系数限制、离子通过率和发散角损失.结果表明:栅极热变形增大了屏栅离子通过率和推力器推力值,并由于加速栅截止电流阈值的提高拓展了推力器工作电流区间,但电子返流阈值的明显降低对栅极系统可靠工作造成了不利影响.
Optics thermal deformation is an important factor that impacts the performance and lifetime of ion thrusters. AI- though some theoretical research concerned with this problem was reported, its mechanism-has not been fully understood. In this study, numerical investigations are performed to explain the effect of thermal deformation on the performance and lifetime of ion thrusters. The transient behavior of charged particles is calculated using a particle-in-cell simulation, while the momentum transfer collision and the charge exchange collision are calculated by means of the Monte Carlo method. Electron backstreaming restriction, perveance restriction, ions through rate, and divergence angle losses are compared and analyzed for optics deformed and undeformed. And the influence of these factors on thruster＇s performance and lifetime is discussed. Results show that the ion through rate of the screen grid increases when optics begin deformed, and the thrust is slightly higher than the theoretical values predicted; the perveance threshold of the accelerator grid increases with optics haveing thermal deformation, while the crossover limit threshold is little changed, namely the thruster can be operated in conditions of a larger beam current; the electron backstreaming restriction threshold is significantly lower under a high beam current condition with optics deformed, which means that a lower accelerating gate bias is necessary to ensure thruster work. For the less obvious change of acceleratng grid current when the beam is focused, there is no more erosion and change of lifetime. Results provide a reference for the optimization design of optics and evaluation of thruster performance and lifetime.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第9期274-280,共7页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51276147
11105023
11275034)
中央高校基本科研业务费专项资金(批准号:3102014KYJD005
3132014328)
西北工业大学基础研究基金(批准号:NPU-FFR-JC20120201)资助的课题~~
作者简介
通信作者．E-mail：chenmaolin@nwpu．edu．cn
