Ignition Stability of Electrothermal Pulsed Plasma Thruster

The Electrothermal pulsed plasma thruster (EPPT) is widely used in microsatellite propulsion systems because of its simple structure, high impulse bit, and precise control over thrust. The EPPT consists of an ignitor, electrode, and propellant, and the cavity is located in the center of the propellant. The ignitor generates the initial plasma that, under the control of the electric field, makes the propellant melt, detach and ionize. This process leads to the formation of a plasma jet, which is the source of thrust. Ignition stability is crucial for EPPT since it affects the formation process of the plasma jet. In this paper, an EPPT has been designed and the effects of various factors associated with the ignitor on the ignition stability were investigated, including the structure parameters, discharge parameters, and installation position. The results showed that, within a reasonable range, increasing the ignitor diameter and ignition voltage improves discharge stability. In addition, the discharge surface of the ignitor should not be too far from the cavity and should be tangential to the inner wall of the cathode to improve ignition stability.