Enhanced emission mode of a ferroelectric plasma cathode

An enhanced electron emission mode of the ferroelectric plasma cathode operation is reported. The enhanced emission is achieved due to the generation of a dense plasma (10(13)-10(14) cm(-3)) by the ionization of a thin neutral layer. The neutral layer is formed by a desorption process that accompanies the generation of a surface flashover plasma which has been induced by a driving current pulse applied to the ferroelectric sample. It was found that the application of a second driving current pulse with a several hundred mus delay with respect to the first driving current pulse causes an intense and uniform ionization of this neutral layer. Fast framing photographs of the light emission from this plasma and some parameters of the plasma and neutral flows are reported. Diode parameters were investigated under an accelerating voltage of 150-300 kV and pulse duration of 350 ns. Generation of an electron beam with current amplitude up to 2.5 kA is demonstrated. Also, it is shown that using the ferroelectric cathode in a reflex triode configuration allows the generation of high-power microwaves at a much smaller diode current amplitude as compared with explosive emission cathodes. (C) 2002 American Institute of Physics.