GROWTH-RATES OF THE ABLATIVE RAYLEIGH-TAYLOR INSTABILITY IN INERTIAL CONFINEMENT FUSION

A simple procedure is developed to determine the Froude number Fr, the effective power index for thermal conduction nu, the ablation-front t hickness L-0, the ablation velocity V-a, and the acceleration g of las er-accelerated ablation fronts. These parameters are determined by fit ting the density and pressure profiles obtained from one-dimensional n umerical simulations with the analytic isobaric profiles of Kull and A nisimov [Phys. Fluids 29, 2067 (1986)]. These quantities are then used to calculate the growth rate of the ablative Rayleigh-Taylor instabil ity using the theory developed by Goncharov et al. [Phys. Plasmas 3, 4 665 (1996)]. The complicated expression of the growth rate (valid for arbitrary Froude numbers) derived by Goncharov et al, is simplified by using reasonably accurate fitting formulas. (C) 1998 American Institu te of Physics.