Improving micro-cathode arc thruster durability through semiconductor surface flashover (SSF) ignition technique

The micro-cathode arc thruster is a promising micro-propulsion technology. However, the short service life of the conductive film-triggering units is one of the important factors limited its application. In this study, a novel semiconductor surface flashover (SSF) ignition method is proposed aiming at extending the ignition lifespan. Owing to the inherently different triggering mechanisms and physical processes, the SSF ignition system does not require a balance between ablation and re-deposition processes, which could potentially improve the reliability of the triggering process. It was found that the ignition voltage of the SSF unit increased with the gap distance, whereas that of the conductive carbon film triggering unit remained relatively constant. Furthermore, high-speed photography revealed that the discharge channel continuously ablated the conductive film system throughout the discharge cycle, whereas it had less contact with the semi-conductive ceramic surface, resulting in reduced erosion in the SSF system. Using the SSF unit, 500 000 consecutive ignition tests were conducted, and demonstrating its good reliability.