Finite ion-relaxation and nonequilibrium radiation effects on laser-driven implosions

The implosion dynamics of recent experiments with high-aspect-ratio laser-driven targets are re-examined by taking account of finite mean free paths of the ion. The mean free path is found to be comparable to the fuel size and this can cause a significant departure from a fluid-like description. One of such effects stemming from the finite mean free path of the ion, real viscosity, seriously changes the results ; the compression ratio becomes 5 times smaller with this real viscosity. In addition to this, inclusion of non-LTE(local thermodynamic equilibrium) atomic process is shown to critically determine the implosion dynamics. (author)