Two-dimensional model of thermal smoothing of laser imprint in a double-pulse plasma.

The laser prepulse effect on the thermal smoothing of nonuniformities of target illumination is studied by means of a two-dimensional Lagrangian hydrodynamics simulation, based on the parameters of a real experiment. A substantial smoothing effect is demonstrated for the case of an optimum delay between the prepulse and the main heating laser pulse. The enhancement of the thermal smoothing effect by the laser prepulse is caused by the formation of a long hot layer between the region of laser absorption and the ablation surface. A comparison with experimental results is presented.