THE REFLECTION OF RELATIVISTIC ELECTRON-BEAM BY VIRTUAL CATHODE

We studied the formation of Virtual Cathode (VC) by a Relativistic Ele ctron Beam (REB) propagating through a terminating foil into a vacuum region in experimental devices REBEX. The beam properties (homogeneity and angular spread of particle velocities) and arising electromagneti c fields (e.g. equipotentials of VC, internal azimuthal magnetic field ) were determined numerically with the help of 2d relativistic electro magnetic currentline code 'POISSON 2'. We were interested in obtaining the dependence of the reflection coefficient of the scattered REB by the created VC on the total beam current, beam energy, external magnet ic field and on the length of vacuum drift tube. The results obtained are useful for an additional plasma heating mechanism via a two stream instability generated by the oscillating REB.