High voltage vacuum insulation: new horizons

It is well established that the insulating capability of a high-voltage (HV) vacuum gap is ultimately limited by electrode surface processes and, in particular, by the field-induced emission of electrons from anomalous microscopic `sites´ that occur randomly on an electrode surface. The author reviews the fundamental studies that have led to an understanding of this phenomenon. Issues discussed are the location and identification of electron emission sites, the emission characteristics of sites, and the emission mechanism. The author concludes with a discussion of the technological implications of his knowledge, particularly in relation to the many emerging applications associated with the development of space-based power systems