Estimation of Post-Arc Neutral Vapor Density in the Gap Volume Generated by Evaporating Macroparticles in a Diffuse Vacuum Arc

This paper presents a mathematical model of calculations of the density of atoms evaporated from macroparticles in a diffuse vacuum arc. The influence of the initial temperature, diameter, and average velocity of the droplets, as well as the kind of the cathode metal on vapor density in the volume surrounding the electrodes was investigated. Both the initial density and the decay of vapor density were calculated for Cu and Cd electrodes following the extinction of the arc. The calculated densities constitute the basis for evaluating the influence of evaporating droplets on the development of electrical breakdown in a vacuum gap after arcing.