Ignition research of spark plug-free gas-fed pulse plasma thruster

To address the issue of spark plug erosion in gas-fed pulsed plasma thrusters, a spark plug-free, self-igniting gas-fed pulsed plasma thruster with parallel-plate electrodes was designed. Ignition tests were conducted on four gas-fed pulsed plasma thrusters with different electrode gaps. The results demonstrate that all four thrusters achieved reliable ignition with a 100% success rate. Furthermore, breakdown does not occur immediately after ammonia injection into the discharge channel; instead, a distinct breakdown late time is observed. Both experimental and simulation results indicate that under consistent ammonia mass bit and electrode voltage conditions, an increase in the electrode gap prolongs the breakdown late time. While a smaller gap leads to faster breakdown, this reduces the propellant utilization efficiency of the gas-fed pulsed plasma thruster with parallel-plate electrodes. A larger electrode gap may be more favorable for enhancing thruster performance.