Effect of non-uniform illumination in laser driven planar targets

The non-uniformity of ablation pressure due to non-uniform illumination is calculated in laser-heated plasma by means of a steady-state planar model. We show that the knowledge of five boundary conditions in the absorption region is necessary. The coupling between flow and heat flux perturbations leads to results different from the previous models: the non-uniformity smoothing is significantly less efficient and does not decrease as an exponential of kD (where k is the wave number of the non-uniformity and D the distance between the absorption region and the ablation surface). Comparison with irradiance smoothing experiments show a quite good agreement