Experimental analysis of electron beam extracting from a device with hollow-anode vacuum-arc-plasma cathode

At a low residual gas pressure the vacuum arc produces high electron density plasmas, which can be used to form an electron beam source. In this paper, an experimental research on the discharge mechanisma of a novel hollow anode plasma cathode structure is conducted. At the same voltage and the same distance between anode and cathode, the discharge experiments on the novel structure and two-planar electrodes are carried out and the characteristics of the two structures are generalized by comparing the cathode voltage, discharge loop current (arc current) and collector current waveforms. It can be concluded that there is a cathode potential droop in the novel structure, and the collector current waveform is like a half-sine and lower than zero most of the time. The half-sine phenomenon is analyzed in detail based on vacuum arc discharge mechanism, and the equivalent circuit model and equivalent potential function serve as an interpretation for cathode potential droop. It is proposed that massive concentration of electrons around anode corresponds to incompensated negative space charges, which induce sharp potential drop at anode and newtral arc plasma, and cathode potential drop. ©, 2015, Science Press. All right reserved.