Electromagnetic droplets created by stimulated Brillouin backscattering

Recent particle-in-cell simulations of the stimulated Brillouin backscattering (SBBS) of electromagnetic radiation have shown that non-drifting solitary waves are easily produced even at subrelativistic intensities (I lambda^2 = 10^16 W microm^2/cm^2), and remain almost unchanged all along the simulation time. The associated formation of strong density depressions disrupts the resonant SBBS amplification, enables strong electron and ion heating and leads to a final low-level saturated regime for the reflected radiation. In this paper, we review the main phases which characterize this regime of interaction, as resulting from the numerical simulations. A theoretical model of electromagnetic solitons in hot and dense plasmas is used to derive the physical characteristics of the resulting electromagnetic solitons and to compare these predictions with the numerical results.