Abstract: The kernel of formulating the performance regulation optimal control algorithm is to obtain thevariation of discharge and beam current extraction characterizations of RF Ion thruster(RIT). To obtain the dis. charge and beam current extraction characterizations of RIT，the discharge and beam current extraction character.izations of LRIT-40 have been studied by the numerical and experimental methods in this paper. The simulationresults agree well with the experimental results，which mean that the numerical model can be applied to the dis.charge and beam current extraction investigations for kinds of RF Ion thruster. Further researches reveal that theRF power which as a fine adjustment parameter is suitable for the continuous and smoothing control of the thrusterperformance. Meanwhile，the screen voltage which has an adjusted turning can be used to the performance man.agement as well as the RF power，when the voltage is lower than this turning point. But if the screen grid voltage is higher than that turning point，it fits for the fast adjustment parameters. In addition，the ranges of thrust from1.5mN to 4.7mN and the specific impulse from 1300s to 3920s can be achieved with the RF power from 65W to85W and the screen grid voltage from 800V to 1500V. And the parameters adjustment interval should be as smallas possible according to the optimal control algorithm in the practice application.

Key words: Ion thruster；Electrical parameters；Performance tuning；Fluid model

摘要： 获得射频离子推力器放电与引出特性调节规律，是制定性能调节控制优化算法的核心问题。为了获得射频离子推力器放电与引出特性，采用数值计算与试验研究的手段，对 LRIT-40射频离子推力器放电与引出特性调节规律开展了研究。研究结果表明:模型能够正确描述放电与引出特性调节规律；射频功率适合作为精调参数，用于连续平滑地调节性能；屏栅电压调节存在明显拐点，当屏栅电压低于拐点，可配合射频功率对性能进行精调；当屏栅电压高于拐点，适合作为快速响应调节参数； 65W～85W射频功率、 800V～1500V屏栅电压能够实现推力 1.5mN～4.7mN，比冲 1300s～3920s宽范围调节，制定性能调节优化控制算法时，应根据需要选取最小参数调节区间。

关键词: 离子推力器；电参数；性能调节；流体模型