Abstract: To address the issue of insufficient ionization caused by rapid propellant diffusion in Planar Hall Thruster (PHT), a modified PHT with a shallow gas chamber (PHT-C) was designed. A comparative experimental study was conducted to investigate the discharge characteristics, thrust performance, and beam properties of the PHT-C and the conventional PHT. The results show that the shallow gas chamber effectively concentrates the propellant, leading to a lower ignition voltage for the PHT-C. The thrust and specific impulse of the PHT-C outperform those of the PHT, reaching maximum values of 15.8mN and 1828.0s, respectively, at a power below 500W. Under high anode voltage and low-to-medium anode flow rates, the PHT-C achieves higher propellant utilization and beam divergence efficiency, resulting in a maximum relative improvement in anode efficiency of 35.0% compared with the conventional PHT. Additionally, its beam transitions from the triple-peak structure of the conventional PHT to a more focused double-peak structure, which helps reduce sputtering on components at large angles. This study introduces a shallow gas chamber into the PHT, which mitigates the excessive propellant diffusion in open space and enhances performance, providing a novel method for the optimization of PHTs.

Key words: low-power electric propulsion, planar Hall thruster, propellant transport optimization, anode efficiency, propellant utilization efficiency