Impact of the Electric Field Distribution on the Generation Characteristics of Vacuum-Arc Discharge Plasmas

To investigate the impact of the electric field distribution on the generation characteristics of vacuum-arc discharge plasmas, three types of coaxial electrodes, namely, a tubular electrode, a trumpet electrode, and a bowknot electrode, are designed and employed as anodes. A tubular Teflon insulator is mounted covering the cathode and in close contact with the cathode and anode in a coaxial geometry. The electric field distributions for different electrodes are simulated by the MAXWELL 3-D simulation software. The parameters for metal plasmas, such as the electron density, electron temperature, and space potential, are measured using a Langmuir probe. Furthermore, a poly(vinylidene fluoride) sensor is used to evaluate the plasma thrust characteristics. In addition, a series of contrast experiments are performed using the trumpet electrode to determine the impact of other factors that affect the electric field distribution. The experimental and simulation results indicate that plasmas generated using electrodes with greater cathode-tip electric field strength exhibit lower breakdown voltage, larger discharge current, higher density, and greater thrust. Suitable positioning of the insulator and the electrodes can increase the electric field strength of the cathode tip, revealing that the density and thrust of the plasma would be effectively increased.