GROWTH-RATE REDUCTION OF THE RAYLEIGH-TAYLOR INSTABILITY BY ABLATIVE CONVECTION

A simple model for the instability of a steady ablation front is presented. The model is based on the sharp boundary approximation, but it is considered that, as far as the Rayleigh-Taylor instability regards, the front thickness is of the order of the minimum scale length of the density gradient. The model yields a general analytical expression for the linear growth rate, which does not depend explicitly on the particular process of energy deposition, which drives the ablation. For the specific case of electronic thermal conduction the model is in good agreement with previously reported numerical calculations. The growth rate results to be well fitted by the so-called Takabe formula, and the coefficients in such a formula are analytically derived. © 1995 American Institute of Physics.