微阴极电弧推力器放电寿命特性研究

微阴极电弧推力器（micro cathode arc thruster，μCAT)在微纳卫星空间任务中有良好的应用前景，但寿命问题是目前制约其发展的重要因素。研制了自动数据采集系统，进行了不同放电频率下全寿命试验，观察分析了失效后阴极材料及导电薄膜的形貌变化。研究结果表明：推力器工作初期，放电特性为不稳定阶段，该阶段在μCAT的全寿命占比小于10%。薄膜电阻放电前期相对稳定，为百欧量级，在临近失效时迅速升高至千欧量级，峰值电流在临近失效时急剧下降直至失效。放电频率升高会使阴极坑区域热量累积，增强了导电薄膜破碎程度，导致推力器提前失效，寿命降低。电弧烧蚀位置分布不均匀，导致阴极利用率降低，是制约μCAT寿命的重要因素。

Study on discharge life characteristics of micro-cathode arc thruster

Micro cathode arc thruster (μCAT) has a good application prospect in micro nano satellite space missions, but the life span is an important factor restricting its development at present. An automatic data acquisition system was developed, and the whole life tests at different discharge frequencies were carried out. The morphology changes of cathode materials and conductive films after failure were observed and analyzed. The results show that, at the initial stage of the thruster, the discharge characteristic is an unstable stage, which accounts for less than 10% of the whole life of μCAT. The discharge of thin film resistance is relatively stable in the early stage, which is of the order of several hundred euros, and increases rapidly to the order of thousands of euros when it is close to failure, and the peak current decreases sharply until failure. The increase of discharge frequency makes the heat accumulation in the cathode pit area, enhances the breakage of the conductive film, leads to the early failure of the thruster and reduces the life of the thruster. The uneven distribution of arc ablation position leads to the decrease of cathode utilization, which is an important factor restricting the life of μCAT.