High-Field Conduction in Dielectric Liquids Revisited

The various mechanisms proposed to explain the conductivity of organic dielectric liquids at high fields (50 to 2000 kV/cm) are considered and their range of validity assessed. Avalanche ionization and field-increased mobility are negligible, while Onsager enhanced dissociation of electrolytes can be very effective, but only in hydrocarbons. An ubiquitous phenomenon is oxidoreduction of neutrals followed by ion injection; the quantitative law depends on the shape of the barrier the ions must surmount. At very high fields, however, field emission of electrons at the cathode must be dominant. Abatement of highfield conduction is possible and shows promise of new applications.