10 Multiphysics Coupling Mechanism of Copper Vapor Diffusion–Extinction Vacuum Arc Plasma: Experiments, Simulations, and Theoretical Analysis

The phenomenon of vacuum arc plasma reignition has a significant impact on the safe and stable operation of the power system. In order to reveal the mechanism of the reignition phenomenon, a vacuum arc plasma experimental platform based on a removable interrupter chamber is constructed. The evolution of the vacuum arc plasma morphology in the interrupter chamber is captured by a high-speed camera during the opening and closing process. The evolutionary behavior of plasma morphology under multiphysics fields in the diffusion–extinction phase of vacuum arc plasma is experimentally investigated, and the effects of electromagnetic field, temperature field, and metal vapor flow on vacuum arc plasma reignition are studied. Furthermore, the copper vapor diffusion–extinction multiphysics (CVDEM) model is developed. Specifically, the distributions of key parameters, such as temperature (electrons and ions), density (electrons and ions), pressure, velocity, current density, and magnetic flux density, during the plasma combustion process are calculated. Finally, the multiphysics field coupling mechanism is investigated. The results of the simulation are in good agreement with the experimental data. The results indicate that the evolution of the vacuum arc plasma morphology is effectively captured by the detachable interrupter experimental platform designed in this article. The maximum values of the plasma temperature field, current density field, and pressure field are concentrated at the cathode position. The maximum electron and ion density is located above the cathode. The maximum value of the magnetic induction is at the edge of the plasma column. As the current decreases, the interpolar temperature field and the current density field contract, leading to the dissipation of the interpolar plasma pressure. The temperature field decays at an accelerated rate during the diffusion phase, and the temperature field has the highest sensitivity to external influences. During the extinction phase, the overall temperature of the plasma is characterized by the ion temperature, and the rapid decay of the ion temperature field and current density field is the main cause of plasma extinction.