脉冲等离子体推力器等离子体羽流的光谱研究

脉冲等离子体推力器(pulsed plasma thruster, PPT)具有体积小、重量轻、比冲高等优点，特别适合作为执行微小卫星轨道转移、阻力补偿和姿态控制等任务的推进系统。为了深入理解PPT推力产生的机理，本文对采用具有张角的舌型极板的尾部馈送式PPT等离子体羽流开展了时空分辨光谱诊断研究。通过对光谱数据的分析发现： 等离子体羽流的主要成分为C，F，C+，F+，C2+，还含有少量的由于极板烧蚀产生的Cu+和Cu2+;等离子体在放电通道内的分布不均匀，通道中心的等离子体浓度最大，靠近阳极板的等离子浓度要明显大于靠近阴极板的等离子体浓度;在不同位置处等离子体成分也具有较大差别，F+和中性粒子主要分布在靠近阳极侧的区域;通过对各个分立谱线进行多普勒线性拟合，得到了放电通道内等离子体温度信息;以中轴线靠近工质的观测点为例，对该点在整个放电过程中不同时刻的谱线进行分析，得到了该点等离子体的具体演化过程，发现在放电的不同阶段羽流成分及各组分所占比例差别较大。

Study on Plasma Characteristics in a Pulsed Plasma Thruster by Optical Emission Spectroscopy

The pulsed plasma thruster(PPT ) is suited for various applications ,e .g .,attitude control ,station keeping and for‐mation flying due to its significant advantage with regard to the related savings of wet system mass ,small volume and high spe‐cific impulse .In order to elaborate the mechanism of PPT operation process ,the optical emission spectrum was conducted on a breech‐fed PPT with tongue electrodes .The results show that plasma plume mainly consists of C ,F ,C + ,F + and C2 + ,besides Cu+ and Cu2 + were detected in plasma which were produced by electrodes ablation .The plasma distribution is asymmetric in the discharge channel ,the maximum of plasma density of plasma appears at the central axis of discharge channel and the plasma den‐sity nearby the anode is much higher than that nearby the cathode .The composition of plasma is not symmetric and not uniform . The distribution of F + and neutral particle concentrate close to the anode .The electron temperature is about 6.67 eV derived from the optical emission spectra by Boltzmann linear fitting .Evolution of plasma emission spectrum was derived at the fourth measurement point ,the results show that there is much difference between different discharge stages for the composition of plume and the proportion of each component .