Laser driven ablative surface instability in inertial fusion energy

Abstract

In recent years there has been a considerable theoretical and experimental interest in a laser driven ablative surface in inertial fusion energy (IFE). The existing studies of nonuniformities will not prevent the surface instabilities which originate at the ablation surface due to acceleration of high density plasma by low density plasma, known as the Rayleigh-Taylor instability (RTI). The present work is aimed at controlling the growth rate of RTI in a laser irradiated porous target (that is a hollow target filled with a porous material) at moderate intensities. This RTI has been studied using the moment method. The dispersion relation is obtained in terms of Bond number B connected with the surface tension and the modified Reynolds number R. This dispersion relation is computed for different values of B, R and several particular cases for long and short wave length perturbation and the results are depicted graphically. It is shown that the permeability of the porous region scaled with the Reynolds number decreases considerably the growth rate of RTI compared to that of a hollow shell.