Flashover strength improvement in vacuum using surface microstructure of printed metal wires

Vacuum plays a vital role in the high-voltage insulation field as a special dielectric. For most of the vacuum-dielectric devices, vacuum flashovers usually occur at the solid-vacuum interface due to its weaker surface strength, leading to the damage of the whole insulation system. In this paper, an investigation is conducted regarding the vacuum flashover inhibition and positive charge accumulation reduction using microstructure of embedded silver wires. The mechanism of multipactor suppression through surface printed metal structure is studied by establishing a particle-in-cell (PIC) simulation based on secondary electron emission avalanche (SEEA) theory. Meanwhile, the multipactor expansion and the charge accumulation process on the interface are simulated to study the multipactor mitigation phenomenon of printed metal wires. Different widths, positions and numbers of metal wires are also simulated. It is found that a certain amount of negative charge can gather on the silver metal microstructure due to its low secondary emission yield (SEY), forming an electric field to scatter electrons and inhibit multipactor propagation. Increasing width of printed metal wires is beneficial for improving this suppression effect on vacuum flashover. At last, some relative experiments are conducted and a considerable improvement in flashover strength is acquired, to provide further confirmation of the simulation results.