Extended Cylindrical Low-Pressure Arc Discharge Plasma Emitter for Generation of a Radially Diverging Electron Beam

The paper presents the results of studies of processes of generation of a beam-plasma formation in an extended cylindrical hollow mesh anode with a diameter of 115 mm and a length of about 1 m of a non-self-sustaining low-pressure arc discharge with thermionic and hollow cathodes. The probe method was used to measure the longitudinal distributions of the plasma parameters inside the mesh hollow anode of the arc discharge for burning conditions with/without a flow of ions injected from the plasma of the main glow discharge, for which the hollow anode was the plasma emitter of electrons. The distributions of the ion current density on the probe inside the cylindrical anode of the arc discharge (electron emitter) as functions of the operating pressure, the longitudinal magnetic field in the hollow cathode of the arc plasma source, and the arc discharge current are experimentally determined. In an extended plasma emitter, unequal conditions of plasma formation are formed, leading to the formation of a potential barrier for the propagation of the arc plasma. The emission of ions from the glow discharge plasma in the beam-plasma formation allows the inhomogeneity of the plasma formed in the hollow plasma emitter to be reduced significantly. The results obtained show the possibility of forming relatively uniform extended beam-plasma formations inside the extended mesh anode of the arc discharge under conditions of injection of an external ion flow through the mesh cells.