Relativistic solitons generated by high intensity laser pulses in plasmas

With 2(1/2)D Particle in Cell (PIC) simulations of the interaction of ultra-short, high-intensity laser pulses with plasmas we show the formation of long-lived electromagnetic solitons. These solitons consist of electron density depressions and intense cylindrical electromagnetic field concentrations with a bigger amplitude and a lower frequency than those of the laser pulse. During the interaction of an ultra-short high-intensity laser pulse with a plasma a significant portion of the electromagnetic energy is trapped in the form of solitons. We show that that in an inhomogeneous plasma the solitons propagate toward the plasma-vacuum interface, where they radiate away their energy in the form of bursts of low frequency electromagnetic radiation. (author)