Investigation into the performance effect on carbon-carbon composite grid of 10 cm ion thruster with different configurations

To address the future application requirements of carbon-based material grids for ion thrusters characterized by high thrust, elevated specific impulse, and extended operational life, research was conducted using the LIPS-100 ion thruster developed by the Lanzhou Institute of Physics. This study focused on small-diameter configurations of carbon-carbon composite material grids. Successful development was achieved for both a 10 cm split carbon-carbon planar grid and an integrated carbon-carbon convex grid component. Performance variations among different configurations were investigated through extensive performance tests across the wide-range from 1 to 25 mN, as well as 200 h lifespan assessments under typical conditions at 20 mN. The results indicate that the two configurations of the carbon-carbon grid can achieve stable operation across the broad range of 1–20 mN, with beam current fluctuations ranging from 368 to 379 mA and accel grid current fluctuations between 1.58 and 1.81 mA. Furthermore, the key performance parameters of these grids were comparable to those of the traditional molybdenum grids. Under conditions of high thrust and power, the carbon-carbon grid demonstrated a significant reduction in the intercepted current at the accel grid. In comparison to the split carbon-carbon planar grid, the weight of the integrated carbon-carbon convex composite grid was reduced by 17.5%, the anode voltage decreased by approximately 2.4%–8.6%, and the cathode keeper voltage was reduced by approximately 3.5%–12.4%. It can be concluded that the integrated carbon-carbon convex grid offers distinct advantages in terms of hot-state structural stability, suppression of grid etching rates, and enhancement of thruster discharge efficiency.