Electron emission from a high-voltage Penning discharge

Abstract

This paper considers the features of various modes of the high-voltage Penning discharge, allowing its use as an emitter of electrons extracted from the discharge along the magnetic field through the emission slit of one of the cathodes. The external electric field eliminates the potential barrier in the emission slit and promotes the escape of electrons from the discharge. It also reflects the high-energy positive ions leaving the discharge into the discharge and onto the outer surface of the emitting cathode. The processes occurring in the acceleration gap and in the discharge itself, which determine the efficiency of electron extraction from the discharge, the overall efficiency of electron extraction from the emitter, and the current density distribution over the emitter surface in different modes of the high-voltage Penning discharge, have been investigated experimentally. The effect of changing the area from which electrons are extracted from the discharge on the emission parameters is investigated. An optimum mode and optimum geometrical dimensions of the Penning cell for providing maximum efficiency and uniformity of electron emission have been determined.