J. Phys. IV France 07 (1997) C4-413-C4-419
Nonlinear Wave Phenomena in an Electron-Beam PlasmaK. Yamagiwa, T. Itoh and T. Nakayama
Department of Physics, Faculty of Science, Shizuoka University, Shizuoka 422, Japan
An experiment has been carried out to investigate one-dimensional nonlinear evolution and formation of the localized structure of unstable waves in an electron-beam plasma. The plasma system is linearly unstable against electrostatic perturbations of frequencies lower than the critical frequency ωcr (=ωpe, plasma frequency), but is stabilized in its nonlinear stage by generating wave packets irregularly. The amplitude of each wave packet never grows infinitely. The average time width of the packets is inversely proportional to the linear growth rate γ, where γ α (nb/n0)1/3ωpe (nb: beam density, n0 : plasma density). The system is also unstable for an external rf-burst with a narrow time-width, and then finally becomes stable by the emission of a series of burst waves. The number of emitted bursts increases with the beam density.
© EDP Sciences 1997