氪气工质同轴环尖场电推力器束流特性与性能分析

The Axial Ring-Cusp Hybrid field thruster is an optimal propulsion device suitable for precision space exploration missions such as gravitational wave detection and gravity gradient measurement. The application of krypton gas as the propellant in the Axial Ring-Cusp Hybrid field thruster is expected to achieve low-cost and high-efficiency micro-newton-level propulsion capability. The performance of an Axial Ring-Cusp Hybrid field thruster under different operating conditions with krypton propellant was indirectly measured using the beam flow method. Within the operating range of a main cathode power of 10 W, a discharge voltage of 30~40 V, and a propellant flow rate of 0.3~0.5 mL/min, the Axial Ring-Cusp Hybrid field thruster with krypton propellant can achieve a beam current of 10.12~20.77 mA, a thrust of 453~929 μN, a specific impulse of 1 846~4 854 s, a propellant utilization efficiency of 35.1%~92.3%, and a total efficiency of 26%~62%. These results verify that the Axial Ring-Cusp Hybrid field can enhance the propellant utilization efficiency and overall efficiency of micro DC ion thrusters. The effects of operating parameters and acceleration grid hole on thruster performance were investigated. The increase in propellant flow rate significantly increases the beam current and thrust, but reduces the propellant utilization efficiency, along with a decrease in specific impulse and total efficiency. The increase in discharge voltage simultaneously increases the beam current, thrust, specific impulse, and total efficiency, but increases the accelerator grid interception current ratio. The decrease in the acceleration grid hole is beneficial for improving the beam current, thrust, and specific impulse. However, in experiments with different acceleration grid holes, a variation in the acceleration grid interception current ratio ranging from 0.4% to 28.3% was measured. This indicates that changes in the acceleration grid aperture significantly affect the beam focusing characteristics and the acceleration grid interception current ratio, and thus the acceleration grid hole needs to be optimized to ensure the life of optical system. Within the experimental operating range, the acceleration grid interception current ratio of the 1.4 mm grid hole is 0.4%~1.2%, which is significantly lower than that of other holes, making it the preferred value for the acceleration grid hole of the Axial Ring-Cusp Hybrid field thruster.