Pulsed plasma electron sources

There is a continuous interest in research of electron sources which can be used for generation of uniform electron beams produced at E≤105 V/cm and duration ≤10−5 s. In this review, several types of plasma electron sources will be considered, namely, passive (metal ceramic, velvet and carbon fiber with and without CsI coating, and multicapillary and multislot cathodes) and active (ferroelectric and hollow anodes) plasma sources. The operation of passive sources is governed by the formation of flashover plasma whose parameters depend on the amplitude and rise time of the accelerating electric field. In the case of ferroelectric and hollow-anode plasma sources the plasma parameters are controlled by the driving pulse and discharge current, respectively. Using different time- and space-resolved electrical, optical, spectroscopical, Thomson scattering and x-ray diagnostics, the parameters of the plasma and generated electron beam were characterized.