Numerical investigation of nonlinear ablative single-mode Rayleigh–Taylor instability in the presence of preheating

Abstract

Nonlinear ablative single-mode Rayleigh–Taylor instability (RTI) with weak and strong preheatings has been investigated numerically. The numerical results for the linear growth rates obtained are in general agreement with a self-consistent linear stability analysis (Goncharov et al 1996 Phys. Plasmas 3 4665). The effects of preheating on the ablative RTI (ARTI) are shown to reduce its linear growth rate and mitigate the weakly nonlinear growth. It was found that the nonlinear evolution of the ARTI is strongly dependent on the preheating intensity and perturbation wavelength. There are three typical wavelength perturbations for the nonlinear evolution of the ARTI. In the ARTI with weak preheating, for a short-wavelength perturbation the spike can be ruptured in the highly nonlinear regime and for a middle/long-wavelength perturbation the Kelvin–Helmholtz mushroom-shaped patterns appear at the spike heads. In the ARTI with strong preheating for a middle-wavelength perturbation, jet-like spikes can be formed though the spikes can still be ruptured in its classical RTI (without thermal conductivity) counterpart. In summary, our numerical studies indicate that the preheating can have a pronounced influence on the nonlinear evolutions of the ARTI. Thus, it should be included in applications where preheating plays a vital role, such as inertial confinement fusion implosions and supernova explosions.