Computer simulation of coherent structures in turbulent plasmas

The classical problem of the collisionless relaxation of a one-dimensional gentle electron beam injected into a half-bounded background Maxwellian plasma is considered. It is shown that, upon reaching sufficiently high oscillation amplitudes, a stable coherent wave packet is formed near the permanent beam source. The growth of the packet's amplitude is limited by the trapping and acceleration of background plasma electrons, which allows the transition to the quasi-stationary regime and the stability of spatial dissipative structures thus formed. It is emphasized that the anomalously deep penetration of the electric field into the plasma due to coherent phenomena appears to be most vivid and experimentally verifiable macroscopic consequence of the collisionless relaxation of the high-energetic electron beam, not in a weak turbulent regime, but in a partly ordered turbulent regime. The results are obtained using the cloud-in-cell method generalized for the case of open plasma systems