Influence of Contamination and Structural Defects

Abstract

Contamination of the interelectrode medium and electrodes by free or loosely bound particles reduces their electric strength via several effects, including:

• a microdischarge between the electrode and an oncoming particle which initiates breakdown between the electrodes in vacuum or gas

• the collision of a high-velocity particle with an electrode accompanied by the emission of vapor and liquid electrode and particle fragments and plasma structures in vacuum

• collisions of particles with electrodes that alter electrode microrelief, thereby producing field amplification centers

• single particles and particle bridges produced when particles enter the strong field region, which distort the field distribution

• impurity particles in insulating liquids, which influence electrohydrodynamic processes during long-term voltage exposure.