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

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. • An original discharge cell is proposed for auxiliary anode plasma formation in a plasma-cathode electron source. • It eliminates or at least minimizes the amplitude of high-frequency current oscillations (if any). • It facilitates the ignition of an arc. • It shortens the time the acceleration gap current takes to reach a steady value. • It decreases the probability of acceleration gap breakdowns more than four times (within 10–50 μs of a pulse).