Research and Deveropement of a Sheath-Type Hall Thruster for Space Propulsion

1.放电振荡现象的研究从我们在1998年进行的线性型霍尔推力器的研究，它被预测，了解在加速通道中的等离子体振荡和补救的等离子体振荡引起的放电不稳定性将需要获得一个稳定的运行在鞘型霍尔推力器。因此，我们研究了振荡的原因，使用线性型霍尔推进器。结果表明，主要的不稳定性是由于电离振荡。此外，从离子和中性粒子的动量方程的基础上的不稳定性分析推导出的分析预测与实验观察显示出很好的协议5。这些结果在AIAA/ASME/SAE/ASEE联合推进会议上发表（AIAA Paper 98-3638），并发表在日本航空航天科学学会会刊上。鞘型霍尔推力器的性能评价鞘型霍尔推力器已在东京大学设计和制造。阳极的设计避免了电离不稳定性：引入了中空型阳极，它附着在加速区的上游。总电离电流的大约一半将在中空阳极内部产生。结果表明，尽管常规加速电离区很小，但我们能够很容易地找到稳定放电区。从推力测量结果来看，Isp为1400秒，推力效率为25%。这些结果在1999年的国内研讨会上发表。通过考虑缩放优化，性能将得到改善。

1. Research on Discharge Oscillation PhenomenaFrom our previous study on a linear-type Hall thruster conducted in 1998, it was predicted that understanding of plasma oscillations in an acceleration channel and remedy to the discharge-instability caused by the plasma oscillation would be required to obtain a stable operation in a sheath-type Hall thruster. Therefore, we examined the cause of oscillations using a linear-type Hall thruster. As a result, the main instability was found due to the ionization oscillation. Furthermore, the analytical prediction deduced from the instability analysis based on momentum equations of both ions and neutral particles have shown very good agreement 5 with the experimental observations. These results were presented at the AIAA/ASME/SAE/ASEE Joint Propulsion Conference (AIAA Paper 98-3638), and published on the Transactions of Japan Society for Aeronautical and Space Sciences.2. Performance evaluation of the sheath-type Hall thrusterA sheath-type Hall thruster has been designed and manufactured at the university of Tokyo. The anode has been designed to avoid the ionization instability : The hollow-type anode has been introduced, It was attached at the upstream of the acceleration region. About half of the total ionization current will be produced inside of the hollow anode. As a result, we were able to find the stable-discharge region easily, though the conventional acceleration-ionization region is very small. From the thrust measurements, Isp of 1400 sec and thrust efficiency of 25% have been marked. These results were presented at the domestic symposium in 1999. The performance will be improved by taking account of the scaling optimization.