Electromagnetic Instabilities, Filamentation, and Focusing of Relativistic Electron Beams

We report nonlinear studies of the Weibel instability of a relativistic electron beam in a plasma. If nbnₚ, the beam splits into self-pinched filaments at density nₚ. These filaments then recombine into a single dense beam, from which the return current is expelled. The ratio of final magnetic to final streaming energy is O(νγ), and significant plasma heating occurs.