Study on the effect of auxiliary electrode materials on the performance of wire-to-plate ionic wind thrusters

Traditional wire-to-plate ionic wind thrusters often suffer from low thrust density and limited efficiency. Adding a passive auxiliary electrode upstream of the emitter improves performance, yet the intrinsic mechanisms governing different auxiliary electrode materials remain systematically unexplored. This study investigated four materials ranging from conductors to insulators (aluminum foil, carbon fiber, wood, and glass fiber) using comparative experiments and electrohydrodynamic (EHD) simulations. Experimental results demonstrated that the macroscopic performance enhancement is fundamentally driven by the material's electrical conductivity. The aluminum foil rod yielded the highest gains, increasing thrust by 31.2% and the thrust-to-power ratio by 72.5% at 60 kV compared to the baseline. To theoretically uncover the physical origins, simulations utilized equivalent dielectric constants to effectively model the distinct material responses. The visualization revealed that highly conductive materials act as floating equipotential bodies, creating a rigid electrostatic shielding effect that completely blocks upstream ion leakage. In contrast, insulators permit electric field penetration and surface charge adsorption. Both mechanisms successfully redirect space charges into the downstream drift region, significantly increasing the forward driving force and reducing reverse drag. This study elucidates the equivalent numerical modeling of these distinct mechanisms and confirms that utilizing lightweight conductive auxiliary electrodes is an optimal, passive strategy for enhancing ionic wind propulsion systems.