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

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 Fsub(m) = α(1/4nsub(e)vsub(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 rsub(c)/rsub(a) approximately greater than (α/16)[(8AM)/(πmZ)]sup(1/2). The laser power at which this occurs varies as α3/lambda2. Computer modelling is used to check the validity of these predictions. (author)