Influence of copper vapor contamination on dielectric properties of hot air at 300-3500 K in atmospheric pressure

The influence of copper vapor contamination on the dielectric properties of hot air at atmospheric pressure was numerically predicted in heavy particle temperature range 300-3500 K. Dielectric properties of hot gases are very important for effective design of switching devices and other applications. Copper vapor is known to be injected from the electrodes into the hot gas during arc interruption in a circuit breaker, which may substantially affect the dielectric strength of the hot gas. Analysis of equilibrium composition for a hot air contaminated with copper vapor and computations of Boltzmann equation made it possible to study the dielectric properties of interest. The result indicates that 1.0% copper vapor contamination remarkably increases the effective ionization coefficient /spl alpha/~ and thereby decreases the critical electric field (E/N)/sub cr/ drastically. This arises from a much lower ionization potential of the copper atom.