Influence of Current and Cathode Material on Microexplosion of Cathode Microprotrusion

Microprotrusions on cathode surface might be melted and evaporated to form metal vapor and plasma in the vacuum gaps under the electron emission current caused by high electric field, which would seriously affect the vacuum insulation performance and the stability of high-voltage vacuum systems. To further study the dynamic characteristics of cathode microprotrusion under electron emission is of great importance in better understanding of the mechanism of electron emission induced vacuum breakdown. In this article, an established smoothed particle hydrodynamics (SPHs) model is used to simulate the dynamic evolution process of microexplosion phenomena of cathode microprotrusion. The dynamic characteristics of cathode microprotrusion under different current conditions and material are obtained and analyzed based on the SPH model to explore the effect of different factors on the dynamic characteristics of cathode microprotrusion under electron emission. The results show that both the current condition and the material properties would have significant influence on the dynamic characteristics of microprotrusion, such as the temperature rise, the temperature distribution, and the explosion delay time. The results of this article may provide some useful information to understand the mechanism of vacuum breakdown initiated by emission current.