Radial ablation uniformity of cathode and design of double anode micro-cathode arc thruster

Micro-cathode arc thruster offers promising applications in micro–nanosatellite space missions owing to its simple structure, high specific impulse, and low power consumption. However, the non-uniform ablation of the cathode poses a significant limitation on the total impulse of micro-cathode arc thruster. This non-uniformity can be categorized into circumferential and radial types, with previous research primarily focusing on the influence of circumferential ablation non-uniformity. Nevertheless, it has been observed that radial ablation non-uniformity also affects the stability of the thruster, despite the lack of studies in this area. To investigate the mechanism behind the cathode radial ablation, a slice model has been designed to study the motion process of the cathode spots during a single discharge using a high-speed camera. From this analysis aims to identify the root cause of uneven cathode radial ablation. Building upon these findings, a double anode micro-cathode arc thruster has been devised to enhance the uniformity of cathode ablation. Experimental verification has been conducted to assess the performance of the double anode micro-cathode arc thruster. The results indicate that in the traditional micro-cathode arc thruster discharge process, the cathode spots do not migrate towards the outer layer covered by the shell. Instead, they extend to the surface of the shell along the contact area between the shell and cathode. This leads to unequal ablation between the inner and outer layers of the cathode. The double anode micro-cathode arc thruster effectively addresses these issues by providing two discharge channels that maintain the dynamic balance of electrode resistance and increase the ablation amount on the outer layer of the cathode. Consequently, the total impulse of the thruster improved significantly while ensuring the desired performance index.