Internal Perturbation Evolution and Amplification During the Early Phase of Inertial Confinement Fusion Implosions*

Performance degradation in direct-drive inertial confinement fusion (ICF) implosions can be caused by several effects including Rayleigh–Taylor (RT) instability growth. Defects in ICF targets such as internal voids and surface roughness create seeds for RT growth during the initial phase of implosions, and the perturbations created by these defects are propagated along acoustic waves. These perturbations can travel along reflected rarefaction waves or compression waves and become amplified because of converging characteristics. A comprehensive understanding of this wave evolution and perturbation amplification is essential to characterize the impact of internal defects on hydrodynamic-instability seeding. The evolution and amplification of 2-D perturbations within a planar target during early implosion phases will be presented. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856.