Instability of tubular high-current relativistic electron beams

During the last few years, experimental and theoretical studies of high-current relativistic electron beams have been conducted. This was done in connection with the employment of such beams for a number of applications, including those related to plasma microwave electronics. Studies of electron beams under nonrelativistic conditions have led to the observation of the 'ribbon instability'. Studies with high-current relativistic electron beams have been carried out by Garmel (1973), Kapetanakos et al. (1973), Uhm and Siambis (1979), and Ivanov et al. (1981). The present investigation has the objective to provide a generalization of the results obtained in the previous investigations, taking into account beams produced with the aid of various approaches. Attention is given to details regarding the considered problem, the derivation and analysis of the equation describing the dispersion, and a discussion of the results.