基于正交试验法的FEEP聚焦电极阵列设计策略

Design Strategy of FEEP Focus Electrode Array based on Orthogonal Experiment

关键词:  场致发射电推力器  聚焦离子束  正交试验  聚焦电极阵列  优化设计  羽流发散角

Key words:  Field emission electric propulsion  Focus ion beam  Orthogonal experiment  Focus electrode array  Optimum design  Plume divergence angle

摘要:

为消除场致发射电推力器（Field emission electric propulsion，FEEP）羽流发散角度过大给推进器寿命和可靠性带来的不利影响，研究了聚焦电极阵列空间位置对羽流聚焦效果的影响，并通过正交试验法给出了最优电极分布。通过数值仿真对FEEP的离子运动过程建模，采用正交试验方法电极阵列进行研究，关注其在不同空间位置下的聚焦效果，得到了离子出射半角分布和推力大小。结果表明，聚焦极的位置决定了羽流的聚焦效果，其次是提取极和加速极；聚焦极径向距离发射极1600μm，且提取极径向和轴向坐标为（800μm，500μm）时能得到最优的聚焦效果。本文验证了正交试验方法在聚焦电极阵列设计上的可行性，同时还为聚焦电极阵列设计提供了有效的分析方法和设计策略。

Abstract:

During the operation of the field emission electric propulsion （FEEP），it would produce lots of divergent ions which can reduce its life and reliability. The poly-electrode array position was studied which can focus the ion beam to eliminate the negative impact， and a design strategy of the electrode arrangement was given in this paper. Therefore， the ions motion process from emission to ejection is simulated in different electrode arrays that were obtained by orthogonal experiment method. The relationship between the electrodes position， divergence half-angle and thrust force was analyzed， which indicate that the position of the focus electrode determines the focusing effect of the ion beam， and the extract electrode can be a secondary factor influencing thrust force. The focusing effect is best when the electrode radial position is 1600μm and when the vertex radial and axis positions of the extract electrode is 800μm and 500μm. Finally， the result verifies the feasibility of orthogonal experiment in the design of focus electrode array， provides an effective analysis method and a design strategy for the design of focus electrode array.