Particle-in-cell modeling of electron oscillation inside a vacuum arc plasma source duct

Vacuum arc or cathodic arc metal plasma sources can deposit high quality thin metal films and metallurgical coatings. A metal plasma consisting of positive metal ions and electrons is created when an arc discharge is triggered between two metal electrodes in vacuum. Metal plasma immersion ion implantation can improve the wear and corrosion resistance of the treated surface. A three-dimensional particle-in-cell (PIC) numerical model has been developed to simulate the motion of electrons inside the duct of a vacuum arc metal plasma source. It is found that electrons will travel back and forth inside the duct tube. This new phenomenon can be explained by the combined effects of the electric and magnetic fields. The electron oscillation will increase the charged state of the positive ions and the ions will consequently gain more energy. Due to the influence of electron oscillation, the plasma throughput of the duct will be different from that of a duct under the influence of only the magnetic field. This novel finding should be taken into account when designing metal arc sources and optimizing their performance.