圆柱形阳极层霍尔等离子体推进器中的Rotating Spoke研究

The hall plasma thruster has been used in satellites for position keeping and orbital transfer in Europe and United States because of its advantages of high efficiency, high specific impulse and long life, etc. In this program the rotating spoke instability in cylindrical anode layer hall thruster will be studied. The existence of rotating spoke is a disadvantage for hall thruster: It is very difficult to obtain higher discharge voltage at higher discharge current, also it decrease the thruster efficiency. This program will study the mechanism of production, the propagation process and the key parameters for rotating spoke in cylindrical anode layer hall plasma thruster trough theory analysis, numerical simulation, experiments. The influence of rotating spoke to anode layer hall plasma thruster will be studied as well. Additionally the suppression of rotating spoke instability will be studied. Numerical simulation will be performed to verified the feasibility. Finally the suppression will be achieved in experiment.

霍尔电流等离子体推进器由于具有高效率、高比冲和长寿命等优点，在欧美等发达国家已经广泛用于为人造卫星的位置保持和变轨等提供动力。本项目主要研究在圆柱形阳极层霍尔等离子体推进器中的Rotating Spoke不稳定性。Rotating Spoke的存在对于霍尔等离子体推进器的工作具有很多不利因素：它霍尔推进器无法在大放电电流条件下获得大的放电电压，使得推进器的工作效率降低等。本项目从理论，模拟，实验三个方面研究Rotating Spoke的产生机理，增长过程，关键参数。并分析Rotating Spoke对阳极层霍尔等离子体推进器的放电所产生的影响。最终将研究Rotating Spoke的抑制方法，使用数值模拟来验证可行性，并最终在实验中实现对Rotating Spoke的抑制。

Rotating Spoke不稳定性的存在使得霍尔推进器无法在大放电电流条件下获得大的放电电压，导致推进器的工作效率降低。本项目采用实验和数值模拟相结合的方式作为研究手段，使用数值模拟来验证抑制Rotating Spoke的可行性，并最终在实验中实现对 Rotating Spoke 的抑制。通过对圆柱形阳极层霍尔等离子体加速器进行三维Particle in Cell数值模拟，发现较强的磁场可以轻易地在等离子体中引起Rotating Spoke, Rotating Spoke的旋转速度大约为1.0×10^6 m/s,为霍尔漂移速度的37%。离子分布总是均匀的，必然会出现局部电荷分离而产生角向电场，角向电场存在两个相反的方向。推进器内部存在多团电子漂移，即多模Rotating Spoke现象存在。通过双探针测量实验发现装置在运行过程中Rotating Spoke放电不稳定性普遍存在，甚至在异常放电的条件下。Rotating Spoke的频率大小为几十Khz。减小工质流量，使装置处于高电压小电流的聚束放电模式是有利于抑制Rotating Spoke放电不稳定性的。