Generation of a Pulsed Electron Beam by a Forevacuum Plasma-Cathode Source Based on a Constricted Arc Discharge

Abstract

We describe the features of electron emission from the plasma formed by a constricted arc discharge, and the generation of a pulsed (100–150 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> ) low-energy (up to 10 keV) electron beam by a plasma-cathode electron source based on this type of arc in the forevacuum pressure range (5–20 Pa). The electron beam current pulse is delayed relative to the arc discharge current pulse. Limitation of the discharge current to the cylindrical part of the anode, increasing the gas pressure, and increasing the beam accelerating voltage all serve to reduce this delay time and provide a sharper rise time of the electron beam current pulse. The emission of electrons from the plasma formed by the constricted arc discharge is accompanied by a decrease in arc voltage and a corresponding increase in arc current. These characteristics are due to the specifics of operating the constricted arc discharge in the forevacuum pressure range and also the influence of backstreaming ions penetrating into the discharge system from the downstream electron beam region.