Performance and discharge characteristics of Applied-Field MPD thruster in accordance with ring magnet position

The magnetic field has a significant impact on the performance and discharge characteristics of magnetoplasmadynamic (MPD) thrusters. A low-power MPD thruster with an operating power of 10 kW was developed, and its performance characteristics were examined by altering the applied magnetic field. The thrust increased from 92 mN to 310 mN, and specific impulse from 479 s to 1264 s, respectively, within the input power range of 4-10 kW. Spectral analysis of the plume revealed that the increase in performance was significantly affected by the ion current density rather than by the ion energy. Furthermore, the shape and flux density of the magnetic fields inside the discharge channel were altered by adjusting the position of the permanent magnets from z = 0 to -4 cm at 1 cm intervals relative to the alumina insulator inside the discharge channel. Consequently, the thrust increased by approximately 14-40 % at the specific magnetic field configuration with a ratio of B-r/B-z = 0.3, despite not being at the maximum magnetic field strength. The ratio of the radial to axial magnetic fields is strongly correlated with thruster performance and should be considered in optimizing design.