Powerful electron beam transport from a plasma–cathode electron source at forevacuum pressure

Abstract

We discuss the results of our investigations on the transport of a powerful (up to 10 kW) low-energy electron beam generated by a plasma–cathode electron source in the forevacuum range of pressure (30 Pa). We have studied the processes of plasma generation by the electron beam and determined the conditions for initiation of a ‘beam-plasma discharge’. We show that at a working gas pressure of 30 Pa, the beam-plasma discharge manifests itself most clearly in the range of accelerating voltage of 6–10 kV at electron beam currents of more than 200 mA. The onset of the beam-plasma discharge is characterized by an increase in the density of the beam plasma by approximately an order of magnitude, up to 1016 m−3, and an increase in the plasma electron temperature from 2 to 4.0 eV.