Electron Beam Generation During The Hollow Cathode Phase Of Pseudospark Operation

Abstract

Pseudosparks are triggerable, transient gas discharges which occur in a special hollow cathode geometry and which can produce electron beams of very high brightness with a beam energy comparable to the voltage across the discharge and a peak beam current reaching 10 to 1,000 Amps. In this communication the authors report theoretical and experimental studies of the properties of the electron beam generated during the hollow cathode phase of pseudospark operation. The purpose of this work is to develop a predictive model to guide the development of high energy, high brightness electron beams generated during the initiation phase of the pseudospark discharge. A self-consistent, two dimensional model of the electrical properties of transient hollow cathode discharges has been developed. In companion experiments, they measure the total discharge current and the electron beam current in a phototriggered, pseudospark discharge of 3.5 cm in diameter and 2.5 cm in length and filled with hydrogen at pressures on the order of 100 mtorr. The model results are in good qualitative agreement with the experimental measurements; that is, the simultaneous onset of the electron beam current and the discharge current, beam currents reaching up to some 30% of the total discharge current, and twomore » distinct energy components in the beam.« less