Application of Particle-in-Cell Simulation to the Description of Ion Acoustic Solitary Waves

1-D particle-in-cell simulations are used to investigate the propagation and decomposition of the ion acoustic solitary waves (IASWs) in plasmas. Our results show that for small-amplitude conditions, IASWs are stable and the simulation results are consistent with the theoretical predictions of the reductive perturbation method. As the amplitudes of IASWs increase, the waves become unstable and trains of oscillating waves are emitted behind the main waves. When the amplitude is large enough, the wave cannot exist and will decay into a series of waves with a small amplitude. By comparing our simulations with the theoretical solutions of Kortewag-de Vries soliton, the upper limitation of the amplitude of IASWs in plasmas is found. Moreover, our results show that although the reductive perturbation method is valid only for small perturbations, the application scope of the reductive perturbation method can be expanded to describe the potential profiles of IASWs with any amplitude. Meanwhile, the application scope for the density profiles is still limited in the perturbation cases.