Abstract: In order to realize multimode operation of ion thruster, the limitation factors of deep power throttling of ion thruster are analyzed and two throttling strategies are put forward. To meet the application requirement of Chinese asteroid exploration, the 30cm diameter multi-mode ion thruster has been developed and its power throttling limitation conditions are also determined. Meanwhile, the operation points under two throttling strategies are designed and compared. The results show that the minimum stable working power of the ion thruster can be extended and the uniformity of the beam current density can be improved to achieve a wide power range and multi working points of the ion thruster by reducing the magnetic field intensity of the discharge chamber. Multi-mode operations over a wide range of power are realized by adjusting beam current and screen grid voltage，however, they are constrained by grid system crossover limit and perveance limit. The thrust increases linearly with the increase of power, while the specific impulse increases rapidly first and then tends to be stable. The 30cm diameter multi-mode ion thruster can operate steadily over an input power envelope of 0.25kW~5kW, thrust rang of 10mN~186mN, specific impulse variation of 1522s~3586s.

Key words: Asteroid exploration;Ion thruster;Multi-mode;Deep Power throttling strategy;Beam current density uniformity

摘要： 为了实现离子推力器多模式化，分析了离子推力器功率宽范围调节限制因素，提出了两种宽范围调节策略；针对我国小行星探测任务，完成了30cm多模式离子推力器研制、功率宽范围调节限制条件确定、以及两种调节策略下多模式工作点设计及对比研究。结果显示，通过降低放电室磁场强度可延伸离子推力器最小稳定工作功率，提高束流均匀性，实现离子推力器更宽功率范围多工作点设计；功率宽范围调节主要是屏栅电压和束电流的宽范围调节，二者通过栅极导流系数限制和交叉限制而约束；推力随功率增加呈线性增加关系，比冲随功率的增加总体上呈先快速增加后趋于稳定的趋势；30cm多模式离子推力器在0.25kW~5kW内稳定工作，推力10mN~186mN，比冲1522s~3586s。

关键词: 小行星探测;离子推力器;多模式;功率宽范围调节策略;束电流密度均匀性