Criteria for the onset of flux-limited thermal conduction in laser-induced compression

Abstract

The conditions under which flux limitation of thermal conductivity begins to affect laser-induced compression by restricting the energy flow to the ablation zone are considered. On the assumption that the maximum thermal flux is given by F_m = α (1/4 n_e v_e ) kT, a simple analytic model is used to show that flux limiting commences when the ratio of the critical radius to the ablation radius r_c/r_a (α/16)[(8 AM)/(πmZ)]^½. The laser power at which this occurs varies as α³/λ². Computer modelling is used to check the validity of these predictions.