SELF-CONSISTENT CUTOFF WAVE-NUMBER OF THE ABLATIVE RAYLEIGH-TAYLOR INSTABILITY

The cutoff wave number of the ablative Rayleigh-Taylor instability is calculated self-consistently by including the effects of finite therma l conduction. The derived cutoff wave number is quite different from t he one obtained with the incompressible fluid (del .(v) over tilde=0) or sharp boundary models, and it is strongly dependent on thermal cond uctivity (K similar to T-nu) and the Froude number (Fr). The derivatio n is carried out for values of nu>1, Fr>1, and it is valid for some re gimes of interest to direct and indirect-drive inertial confinement fu sion (ICF). The analytic formula for the cutoff wave number is in exce llent agreement with the numerical results of Kull [Phys. Fluids B 1, 170 (1989)]. (C) 1995 American Institute of Physics.