Surface defect evolution in direct-drive ICF targets

Imperfections in ICF targets come in many forms, all of which generate seeds for hydrodynamic instability growth that ultimately degrade implosion performance. Surface defects, such as domes or divots on the surface of the outer-most plastic layer, have been shown to reduce areal density and compromise shell integrity during shock-transit and at the beginning of the acceleration phase. A recent campaign at the OMEGA facility performed in-depth surface characterizations and back-lit cone-in-shell implosions to image defect growth. Results from 2D axisymmetric simulations and experimental data will be presented.