Application of a microwave cathode to a 200-W Hall thruster with comparison to a hollow cathode
Application of a microwave cathode to a 200-W Hall thruster with comparison to a hollow cathode
复制标题
微波阴极在 200 W 霍尔推进器中的应用与空心阴极的比较
DOI：
10.1016/j.actaastro.2020.06.049
复制
发表时间：
2020
影响因子：
3.5
通讯作者：
Nishiyama Kazutaka
中科院分区：
文献类型：
--
作者：
Morishita Takato;Tsukizaki Ryudo;Yamamoto Naoji;Kinefuchi Kiyoshi;Nishiyama Kazutaka
空心阴极是利用放电功率的自加热模式中的有效电子源。然而，在亚安电流下，需要保持功率来维持热电子放电，这可能会降低推力效率。为了解决这个问题，我们建议使用微波阴极，这是基于飞行模型的微波离子推力器中和器阴极，作为一个替代的空心阴极。首先，我们重新设计了一个微波阴极放电室的磁场，并在二极管模式下进行了测试。与原始性能相比，电子发射电流增加了一倍。接下来，我们将改进的微波阴极与200 W级霍尔推力器耦合，并与空心阴极的特性和性能进行比较。证实了磁场极性对点火特性的影响。我们用倒置的推力台测量了推力，用阻滞势分析仪测量了离子能量分布函数，用离子收集器测量了束流剖面。对于两种类型的阴极，推力和推力效率是相等的。在微波阴极的情况下，比冲高10%。由于微波阴极和地之间的电位差在高于600 mA的电流下迅速增加，这可以被认为是相对于空心阴极的折衷点。
A hollow cathode is an efficient electron source in the self-heating mode utilizing the discharge power. However, in sub-ampere currents, it needs keeper power to maintain the thermionic electron discharge, which could decrease the thrust efficiency. To address this problem, we propose using a microwave cathode, which is based on the flight model of a microwave ion thruster neutralizer cathode, as an alternative to a hollow cathode. First, we redesigned the magnetic field of a microwave cathode discharge chamber and tested it in the diode mode configuration. The electron emission current is doubled compared to the original performance. Next, we coupled the improved microwave cathode with a 200-W class Hall thruster and compared the characteristics and performance with a hollow cathode. We confirmed that the magnetic field polarity affects the ignition characteristics. We measured the thrust by an inverted thrust stand, the ion energy distribution functions by a retarding potential analyzer, and the beam profiles by an ion collector. The thrust and thrust efficiency are equivalent for both types of cathode. The specific impulse is 10% higher in the case of the microwave cathode. Since the potential difference between the microwave cathode and ground rapidly increased at currents above 600 mA, this could be taken to be the trade-off point against the hollow cathode.