Stability of ablation flows in inertial confinement fusion: Nonmodal effects

Fast transient growth of hydrodynamic perturbations due to nonmodal effects is shown to be possible in an ablation flow relevant to inertial confinement fusion (ICF). Likely to arise in capsule ablators with material inhomogeneities, such growths appear to be too fast to be detected by existing measurement techniques, cannot be predicted by any of the methods previously used for studying hydrodynamic instabilities in ICF, yet could cause early transitions to nonlinear regimes. These findings call for reconsidering the stability of ICF flows within the framework of nonmodal stability theory.

Automated summary

The study reveals the possibility of fast transient growth of hydrodynamic perturbations in ablation flows relevant to inertial confinement fusion (ICF) due to nonmodal effects. Such growths, likely to arise in capsule ablators with material inhomogeneities, are too fast to be detected by existing measurement techniques and may lead to early transitions to nonlinear regimes. These findings call for a reconsideration of the stability of ICF flows within the framework of nonmodal stability theory.