Effect of ion motion on plasma oscillation phase mixing and breaking
The evolution of a given sinusoidal density perturbation in cold quasi neutral unmagnetized plasma is investigated using a fluid model by taking into account the ion response. Plasma oscillations at roughly the harmonics of the initial perturbation are generated until wave breaking appears. It is found that the ion response can enhance the plasma oscillations, leading to earlier occurrence of wave breaking (as compared with the ions at rest case) The dependence of wave breaking time on the amplitude of the initial perturbation is also discussed.