Velocities of speckles in a smoothed laser beam propagating in a plasma

International audienceBy means of three-dimensional simulations, the paraxial propagation of a laser beam in a nonlinearplasma modeled by ion-acoustic waves is examined. The beam speckles are smoothed by aone-dimensional transverse spectral dispersion technique. In the case of weak smoothing and whenthe incident speckle velocity is subsonic, the propagation in the plasma is found to exhibit anasymptotic speckle velocity and to enhance filamentation. With contrary conditions, it is found toreduce simply the speckle velocity