Study on the influence of ignitor position on a coaxial pulsed plasma thruster

Because of their unique advantages, coaxial pulsed plasma thrusters are competitive propulsion systems for microsatellites. The ignitor of a coaxial pulsed plasma thruster can be mounted on the side or at the center, but previous studies have not compared the effects of the two mounting positions on the thruster. Therefore, this study designs and investigates a coaxial pulsed plasma thruster that permits the ignitor position to be changed while keeping the electrode geometry constant. The discharge circuit parameters, plume plasma characteristics, and propulsion performance are measured, and long-exposure photographs are taken. While the impulse bit of the thruster with a coaxially-mounted ignitor is slightly lower than with a side-mounted ignitor (319.5 μNs vs. 334.5 μNs), the ablated mass bit of the former is significantly lower (15.2 μg vs. 24 μg). The thruster with a coaxially-mounted ignitor achieves higher specific impulse and efficiency (2139 s and 16.74%). Because of the match between the electric field and the neutral gas supply during discharge in the thruster with a coaxially-mounted ignitor, its energy and propellant utilization is higher, thus achieving a better propulsion performance.