In this paper we reexamine the one-dimensional interaction of electromagnetic and ion acoustic waves in a plasma. Our model is similar to one solved by Rao et al. [Phys. Fluids 26, 2488 (1983)] under a number of analytical approximations. Here we perform a numerical investigation to examine the stability of the model. We find that for slightly overdense plasmas, the propagation of stable solitary modes can occur in an adiabatic regime where the ion acoustic electric-field potential is enslaved to the electromagnetic field of a laser. However, if the laser intensity or plasma density increases or the laser frequency decreases, the adiabatic regime loses stability via a transition to chaos. Different asymptotic states are attained when the adiabatic regime no longer exists. In these states the plasma becomes rarefied and the laser field tends to behave like a vacuum field.

• Received 31 October 1996

DOI:https://doi.org/10.1103/PhysRevE.55.3423