Approaches to the Cascade Acceleration of Subnanosecond Electron Beams

We consider the cascade acceleration of subnanosecond electron beams. A brief review is given of experiments with coaxial diodes in which the electron emission and acceleration processes occur in two successive gaps. An experiment on the emission of runaway electrons in a gas diode of this configuration gave rise to a study of magnetically insulated explosive emission vacuum diodes. It has been demonstrated that in this type of diode the spread in energies of electrons emitted within the rise time of the accelerating pulse can be significantly reduced. A numerical simulation has shown that the energy of the electrons of a high-current beam increases if they are accelerated in the successive gaps, formed by a drift tube and powered with precisely timed voltage pulses, generated by independent RADAN-type sources.