Investigation of linear perturbation growth in a planar ablation flow

Abstract

In inertial confinement fusion, pellet implosion efficiency can be severely limited by hydrodynamic instabilities. In particular, the ablation front instability -- ablative Rayleigh-Taylor instability -- plays a major role. Linear stability analyses of ablation fronts have been mostly performed under several assumptions: isobaricity, steadiness, continuous/discontinuous flows. In more general cases, such analyses inevitably resort to solving initial boundary value problems for linear perturbations. The physical model used here is that of ideal gas dynamics with nonlinear heat conduction. A general numerical approach for solving both one-dimensional flows and linear perturbations is briefly presented. Linear perturbation evolutions from initial external surface defects are investigated for a self-similar ablation flow of a semi-infinite slab, initiated from rest.