High-current diode with ferroelectric plasma source-assisted hollow anode

The operation of a ferroelectric plasma source-assisted hollow anode (HA) electron source in a vacuum diode powered by an similar to 200 kV and similar to 400 ns pulsed generator was studied using time-and space-resolved laser induced fluorescence diagnostics. It was found that the plasma ion "temperature" in the vicinity of the HA output grid increases up to similar to 15 eV during the accelerating pulse, which is consistent with a model of the potential screening of the grid by the randomly moving ions [Phys. Plasmas 13, 073506 (2006)]. Also it was shown that the increase in the HA plasma potential up to several kilovolts because of the appearance of a noncompensated ion charge in the HA bulk plasma due to electrons fast extraction, leads to explosive emission centers being generated at the HA grid and to nonuniformity in the cross-sectional electron beam current density. Finally, the plasma prefilled mode of diode operation was studied using a simple one-dimensional model of the plasma erosion and the HA plasma electron heating by energetic ions was considered. (C) 2010 American Institute of Physics. [doi:10.1063/1.3486450]