Preheating stabilization formula of linear growth rate for ablative Rayleigh-Taylor instability

An a accurate evaluation of the growth rate of ablative Rayleigh-Taylor (RT ) instability is a critical issue for inertial confinement fusion (ICF). Wh en the preheat is considered,the growth rates of ablative RT instability by two-dimensional (2D) simulations are lower and agree with those of the exp eriment at Lawrence Livermore National Laboratory (LLNL). In this case, big ger difference occurs between the Lindl formula gamma = root kg/(1 + kL) - beta kV(a) and 2D simulations. The lower Atwood stabilization due to the pr eheat is observed in simulations. A new growth rate formula gamma = root Ak g/(1 + AkL) - 2kV(a) is obtained and agrees well with all of 2D simulations . It includes the density gradient stabilization,the lower Atwood stabiliza tion and the ablative convection stabilization. It reduces to the Lindl for mula when A = 1 and is close to the Takabe formula when the ablation front is sharp.