Nonresonant radiative Pierce instability and its saturation - Chaos

The review of theoretical investigations of a nonresonance stimulated Pierce radiation by the relativistic electron beam (REB) in a waveguide is presented. REB is supposed to be stabilized by an infinitely strong longitudinal magnetic field. Using the analytical methods of linear theory, the conditions leading to the rise of radiative Pierce instabilities, their growth rates and the radiation spectrum are determined. By numerical modeling of the problem, the efficiency of beam energy transformation into electromagnetic field energy as a function of the beam current, its relativism, and geometry are calculated. The physical nature of the instability is clarified and its saturation mechanisms are discussed. In particular, in the saturated state the chaotic motion of beam particles and chaos in the radiation spectrum are observed. (C) 2000 American Institute of Physics. [S1070- 664X(00)01011-9].