Vacuum discharge phenomena under non-uniform field conditions

For the development of space power applications, the analysis of the discharge phenomena in low and medium vacuum, in particular under nonuniform electric field, is required. Although the data under such conditions are very important for the insulation design of space power apparatus, few studies have been reported. This paper describes the review results of the research activities on discharge phenomena under nonuniform fields in low and medium vacuum conditions. DC discharge inception voltage for various electrode configurations in He gas, Ar gas and air in vacuum range from 10⁵ to 10^-1 Pa were measured. In order to discuss quantitatively the change of the discharge characteristics with the vacuum pressure, an image processing method was introduced. Based on the analysis, the dependence on the discharge inception voltage and length of the discharge path on the residual gas pressure under nonuniform field conditions was clarified and agreed well with the dependence formerly obtained for the uniform field condition