The cusped field thruster has become a candidate thruster in next-generation space science missions due to its low complexity and potential long life over a wide range of thrust conditions. However, the reduction of propellant utilization and, as a result, the total performance degradation has emerged in works on cusped field thruster downscaling. In this work, a coaxial resonator is utilized to feed the microwave (MW) into the near-anode region of the cusped field thruster, which contributes to ionization at a relatively low mass flow rate. With a LaB6 thermionic emission cathode, the thruster can operate in two modes: MW excited mode and the MW-DC mixed mode. The results show that the thruster can operate with a minimum mass flow rate minimum of 0.004 mg/s and achieves a continuously adjustable thrust from 1.9 μN to 30.8 μN. The performance variation characteristics over the three control parameters (anode voltage, mass flow rate, and MW power) are considered. Additionally, a plume plasma diagnosis is performed with a Faraday probe and a retarding potential analyzer to analyze the discharge performance and plasma characteristics with different operating conditions.

尖头场推进器由于其低复杂性和在广泛的推力条件下的潜在长寿命，已成为下一代空间科学任务的候选推进器。然而，推进剂利用率的降低以及由此导致的总性能下降已经出现在尖头推进器缩小规模的工作中。在这项工作中，同轴谐振器用于将微波 (MW) 馈送到会聚场推进器的近阳极区域，这有助于以相对较低的质量流量进行电离。使用 LaB6 热离子发射阴极，推进器可以在两种模式下运行：MW 激发模式和 MW-DC 混合模式。结果表明，推进器可以以 0.004 mg/s 的最小质量流量运行，并实现从 1.9 μN 到 30.8 μN 的连续可调推力。考虑了三个控制参数（阳极电压、质量流量和 MW 功率）的性能变化特性。此外，还使用法拉第探头和阻滞电位分析仪进行羽流等离子体诊断，以分析不同操作条件下的放电性能和等离子体特性。