Evolution of the explosive instability in a simulated beam plasma

The evolution of the explosive instability in a beam-plasma system has been studied using two different computer models; a particle-in-cell simulation as well as a fluid model. The initial development of the instability agrees well with the solution of the usual mode coupling equations. The results indicate that the instability in this system saturates because of trapping of electrons by more than one wave leading to a nonlinear frequency shift and a damping of the initially undamped waves.