Influence of the Field Electron Emission from the Cathode with an Insulating Film on the Normal Glow Discharge Characteristics

A theoretical model of the cathode sheath of a normal glow discharge for the cathode with a thin insulating film is developed. In addition to the ion-electron emission, the field emission of electrons from the metal cathode substrate into the film under the action of the strong electric field generated in the insulator is taken into account in the model. It is established that the influence of the field electron emission on the glow discharge characteristics is determined by the emission efficiency of the film, equal to the fraction of electrons going out of it into the discharge volume. It is demonstrated that the calculated normal cathode voltage drop in the discharge in argon for the cathode with a barium oxide film coincides with its measured value for the emission efficiency of the film of the order of 0.1, which is in agreement with its experimental estimations.