SELF-CONSISTENT STABILITY ANALYSIS OF ABLATION FRONTS WITH LARGE FROUDE NUMBERS

The linear stability analysis of accelerated ablation fronts is carrie d out self-consistently by retaining the effect of finite thermal cond uctivity. Its temperature dependence is included through a power law ( kappa similar to T-nu) with a power index nu > 1. The growth rate is d erived for Fr much greater than 1 (Fr is the Froude number) by using a boundary layer analysis. The self-consistent Atwood number and the ab lative stabilization term depend on the mode wavelength, the density g radient scale length, and the power index nu. The analytic formula for the growth rate is shown to be in excellent agreement with the numeri cal fit of Takabe, Mima, Montierth, and Morse [Phys. Fluids 28, 3676 ( 1985)] for nu = 2.5 and the numerical results of Kull [Phys. Fluids B 1, 170 (1989)] over a large range of nu's. (C) 1996 American Institute of Physics.