Electron beam generation in an arc plasma source with an auxiliary anode plasma

Abstract

In a plasma-cathode electron source with a grid-stabilized emission boundary, a discharge in crossed fields was used to create an auxiliary anode plasma before the generation of an electron beam. Such a plasma formed in the beam transport region shortens the rise time of the beam current and eliminates or at least minimizes its high-frequency oscillations at low pressures, making possible electron beams of several microseconds long and stable lower-pressure modes with less probable acceleration gap breakdowns. These effects are explained primarily by gas pre-ionization in the beam acceleration and transport region and by ion flows from the acceleration gap to the plasma cathode of the source.