Hollow cathodes are widely used in electric thrusters due to their high emission electron density and low maintained voltage. The hollow cathode performance may significantly change under different keeper working conditions. In this study, a series of ground experiments were carried out to study the effects of the keeper current and the distance between keeper and cathode top on the emission characteristics and plume structure of the hollow cathode. The experimental results show that the working state of the keeper electronic circuit is less likely to be disturbed by the anode electronic circuit when the ratio of keeper current to anode current rises up. The plasma potential does not always rise up with the emission current in the far-field (>6 cm) when the keeper current is not high (<3 A). The extend of the distance between keeper and cathode top forms a high obstacle to the anode electronic circuit, this obstacle not only causes an increase of anode voltage, but also leads to a significant discharge instability of hollow cathode. In this case, a higher keeper current and xenon flow rate are required to keep a stable working state of hollow cathodes. The experimental results contribute to research on the discharge instability mechanism of hollow cathodes and provide useful information for instructing hollow cathode design.

空心阴极由于其高发射电子而被广泛用于电动推进器密度和低保持电压。在不同的保持器工作条件下，空心阴极性能可能会发生显着变化。本研究开展了一系列地面实验，研究了保持器电流和保持器与阴极顶部之间的距离对空心阴极发射特性和羽流结构的影响。实验结果表明，当保持器电流与阳极电流之比升高时，保持器电子电路的工作状态更不容易受到阳极电子电路的干扰。当保持电流不高 (<3 A) 时，等离子体电势并不总是随着远场 (>6 cm) 中的发射电流上升。保持器与阴极顶部之间距离的延伸对阳极电子电路形成高障碍，阳极电压，还会导致空心阴极显着的放电不稳定性。在这种情况下，需要更高的保持电流和氙气流量来保持空心阴极的稳定工作状态。实验结果有助于研究空心阴极的放电失稳机理，为指导空心阴极的设计提供有用的信息。