Numerical simulation to study transient self-focusing and gigahertz acoustic generation in collisional plasma

This paper presents the study of a coupled system of equations for a laser beam and an ion acoustic wave (IAW) in a collisional plasma through numerical simulation. The pump beam has been perturbed by a periodic perturbation that leads to the nonlinear evolution of the laser beam. The filamentation of the laser beam has been found to change appreciably with varying perturbation number. It was observed that the frequency spectra of the IAW lie in the gigahertz (GHz) domain. For the sake of better understanding of the physical process involved, a simplified model has been developed. The model contains spatial harmonics (obtained through simulation) at different times, by which the time dependent localization of the beam has been investigated. Published by AIP Publishing.