Insulation, breakdown and switching in high pressure gases — A review

Ionization of neutral atoms and molecules by electrons to produce more electrons is the principal cause of electrical breakdown of insulation whether it be solid, liquid or gas. If the medium is to insulate, then the above process must be kept under control to prevent successive electron avalanches increasing in magnitude and leading to breakdown. There are two ways to do this: 1. Prevent the initiating electrons from leaving the cathode or its immediate vicinity. 2. Prevent the initiating electrons from gaining enough energy between collisions to ionize the neutrals sufficient to lead to a non-reversible breakdown process.