Application of the theory of mixing systems to nonlinear Landau damping

Using a simple model of particles in a discrete spectrum of waves, we investigate the influence of stochastic instability of particle motion on the mechanism of nonlinear Landau damping. We show that, as long as particle trajectories in the spectrum are stochastically unstable (at the beat resonances under consideration), diffusion of particles takes place. We discuss the influence of this effect on the normal nonlinear Landau mechanism, and consider briefly the possibility of consequent heating in beam–plasma experiments.