Plasma heating by relativistic electron beams. I. Two-stream instability

A one-dimensional model of the two-stream instability between a relativistic electron beam and a plasma shows that the saturated level of the wave electric field is determined by a single parameter. Due to relativistic effects, the efficiency of energy transfer via the hydrodynamic two-stream instability is a decreasing function of total beam energy in the strongly relativistic regime. The model is supported by numerical simulation experiments. The spectrum of the spatial harmonics generated during the buildup of the primary spectrum obeys a power law dependence. Anomalous heating of the electrons via parametric instability driven by the primary spectrum is observed. For long times the beam energy loss is proportional to the initial beam kinetic energy and most of this energy is picked up by the hot tail of the plasma electron distribution.