An ablative pulsed electric thruster using metal wire propellant

Coaxial pulsed plasma thrusters (PPTs) are promising for microsatellite propulsion because of their simple structure, low power requirement, and high reliability, but the limited storage capability of conventional solid propellants restricts the attainable total impulse. Owing to their much higher density than polytetrafluoroethylene (PTFE), metal wire propellants may improve propellant storage capability. In this study, Pb, Sn, Zn, Cu, and Al wire propellants were experimentally investigated in a coaxial PPT, with PTFE used as the reference propellant. The ignition characteristics, ablated mass bit, and propulsion performance of different propellants were measured and compared. The results show significant material-dependent differences in discharge establishment, ablation, and propulsion response. Thermophysical analysis showed a clear correspondence between the ablated mass bit and the total energy required for effective ablation per unit mass, (Formula presented). By introducing an effective ablation energy partition coefficient, (Formula presented), a unified interpretation of the ablated mass bit was established, and the inferred (Formula presented) values remained within 0.226%–0.250%. In propulsion performance, PTFE achieved the highest impulse bit of 253.4 μN s at 1500 V, whereas Al exhibited the highest specific impulse of 5163 s and the highest efficiency of 22.98%. These results show that some metal wire propellants can achieve pulsed discharge and measurable propulsion performance in a coaxial PPT, and that the proposed unified ablation framework provides a physical basis for understanding the differences in ignition, ablation, and propulsion behavior among PTFE and metallic propellants.