The propulsion performance of a self-field MPD thruster under the
repetitive pulsed operation has been investigated numerically, where the
effects of the discharge duty ratio and the propellant gas puff injection on
the time-averaged thrust and thrust efficiency are examined for various
repetition frequencies. Under the condition of a fixed time-averaged input
power, the propulsion performance under the repetitive pulsed operation
with large discharge current can surpass the performance under the
continuous operation with small discharge current. The smaller discharge
duty ratio leads to the larger discharge current and the increase in the
electro-magnetic thrust. Since the decrease in the aerodynamic thrust under
the repetitive pulsed operation is suppressed with a repetition frequency
over 50 kHz, the improvement of the propulsion performance can be
enhanced for smaller discharge duty ratio. Then, the repetitive pulsed
propellant gas puff injection synchronized with the repetitive pulsed
discharge is no longer necessary.