Investigation of radial distribution of the current density for the tubular relativistic electron beam in the transport channel

Variations of the radial profile of the current density for the tubular relativisttic electron beam (REB) in a long vacuum channel have been studied with the help of the sectional collector. In the experiments, the REB wall thickness was observed to increase with an increase in the transport channel length and a decrease in the guiding magnetic field. It has been shown that when a certain critical value of the magnetic field strength is exceeded, the REB wall thickness ceases to change along the drift channel length. The results obtained agree with the estimates made according to the theory of diocotron instability.