We have indigenously developed a twenty-stage vertical structure type Marx generator. At a matched load of 90-100 , for 25 kV DC charging, an output voltage pulse of 230 kV, and duration 150 ns is obtained. This voltage pulse is applied to a relativistic electron beam (REB) planar diode. For a cathodeanode gap of 7•5 mm, an REB having beam voltage 160 kV and duration 150 ns is obtained. Brass as well as aluminum explosive electron emission-type cathodes have been used.

An analytical and numerical study of backward wave oscillator (BWO) in linear regime is presented to get an insight into the exeitatiot~ of electromagnetic w,'tves as a result of the interaction of the relativistic electron beam wi~h a slow wave structure. The effect of background plasma on the BWO instabitky is also presented,

No abstract

The effect of axial energy spread on the linear gain in a Backward Wave Oscillator is considered. The electron beam is assumed to be monoenergetic with a momentum spread. The results obtained are used to discuss the effects of a finite spread in the beam axial momentum on the BWO instability and frequency of electromagnetic wave generation.

Analytical and numerical study of the stability of sheet electron beam in periodically cusped magnetic field (PCM) is made. The beam has been considered as having diffused density profile. The conditions for beam focusing are discussed.