The Rayleigh–Taylor instability in ablatively accelerated targets with 1, 1/2 , and 1/4 μm laser light

Abstract

The results of a series of detailed numerical simulations of the Rayleigh–Taylor instability in laser ablatively accelerated targets are presented for a fairly wide range of initial conditions. It is shown that the Rayleigh–Taylor growth rate in an ablative environment is a strong function of the laser wavelength. For perturbation wavelengths about three times the in-flight target thickness, the ratios of the numerical growth rates to the classical growth rates are of the order of 1/1.5, 1/2.5, and 1/3.5 for 1, 1/2 , and 1/4 μm laser light, respectively. The numerical results are in good agreement with the theoretical model presented here based on the ablative convection of vorticity away from the unstable ablation front. These results provide strong evidence for the viability of high-aspect-ratio shells in direct-drive laser fusion.