Large amplitude electromagnetic solitons in intense laser plasma interaction

This paper shows that the standing, backward- and forward-accelerated largeamplitude relativistic electromagnetic solitons induced by intense laser pulse inlong underdense collisionless homogeneous plasmas can be observed by particlesimulations. In addition to the inhomogeneity of the plasma density, theacceleration of the solitons also depends upon not only the laser amplitude but alsothe plasma length. The electromagnetic frequency of the solitons is between abouthalf and one of the unperturbed electron plasma frequency. The electrostatic fieldinside the soliton has a one-cycle structure in space, while the transverse electricand magnetic fields have half-cycle and one-cycle structure respectively. Analyticalestimates for the existence of the solitons and their electromagnetic frequenciesqualitatively coincide with our simulation results.