Study on near-field plume plasma characteristics of a 10 kW double-stage anode layer Hall thruster

Based on a modular high-speed moving Langmuir probe system, multi-parameter joint diagnosis (including electron temperature, space potential, ion density and electron density) was conducted on the near-field plume of a 10 kW double-stage anode layer Hall thruster under varying discharge voltages, accelerating voltages, magnetic field strengths and propellant flow rates. The system resolves the challenge of current–voltage (I–V) curve acquisition in the high-potential near-plume region via the superposition of bias and scanning power supplies, and reduces the risk of probe ablation with a rapid reciprocating motion mode within 300 ms. Diagnostic results reveal significant axial distribution of plasma parameters: space potential, electron temperature and plasma density generally decay with increasing distance from the exit, with intense fluctuations in the near field and stabilization in the far field. Elevated discharge voltage or propellant flow rate increase electron temperature; there exists an optimal magnetic field strength for maximum electron temperature. The dynamic measurement method for the high-speed probe system not only diagnoses the near-plume plasma characteristics of the two-stage thruster but also, via its modular and efficient design, lays a technical foundation for plasma diagnosis and engineering development of thrusters across a wide power range.