Plastic deformation of electrode at collision with particles in vacuum gap

The discharge process in vacuum is usually classified into two types, micro particle type and field emission type. The influence of particles has been experimentally investigated using a high speed camera. However, few studies have reported the quantitative analysis on the particle type discharge. To understand the micro particle type discharge better, the collision phenomena between a sphere particle and an electrode were investigated in this paper. The contacting time and the plastic deformation length of the electrode at a collision were analyzed by solving the equation of motion with changing the initial velocity and the diameter of a particle. It was calculated that the contacting time varied from dozens of nanoseconds to hundreds of nanoseconds and plastic deformation length varied from 0.1 to several micron meters when particle diameter was 10 to 50 micron meters and the initial velocity was 1 to 100 meters per second. The heat generation related to particle collision was calculated and its results suggest that protrusion on a particle can induce vacuum discharge, but kinetic energy loss may not. These results will provide a basic view for understanding the micro particle type discharge in vacuum.