Dense plasma formation on the surface of a ferroelectric cathode

Summary form only given, as follows. Summary form only given. An enhanced electron emission mode of ferroelectric plasma cathode operation is reported. The enhanced emission was achieved due to the generation of a dense plasma This dense plasma was formed either by a single driving pulse with fast fall time or by an additional, second driving pulse applied with a time delay of several hundreds of nanoseconds with respect to the first driving pulse. In the first case, it was shown that the shorter the fall time of the driving pulse, the more intense is the plasma formation. The most uniform and dense plasma formation occurs with a positive driving pulse. In addition, it was found that the shorter the fall time of the positive driving pulse the larger are the current amplitude, the energy and the divergence of the emitted electrons. In the second case plasma formation occurs by the ionization of the neutral layer formed by a desorption process that accompanies the generation of a surface flashover plasma. It was found that the application of a second driving current pulse with a several hundred ps delay with respect to the first driving current pulse causes an intense and uniform ionization of this neutral layer. Diode parameters were investigated under an accelerating voltage of 150-300 kV and pulse duration of 350 ns. The generation of an electron beam with current amplitude up to 2.5 kA is demonstrated.