Three-Dimensional Modeling of Capsule Implosions in OMEGA Tetrahedral Hohlraums

90 LLE Review, Volume 82 Introduction To achieve ignition and gain in inertial confinement fusion (ICF), a spherical target must be compressed with a highly uniform drive mechanism.1–3 Perturbations in the drive can lead to a distorted fuel core as well as hydrodynamic instabilities, which cause the colder ablator material to mix with the fuel in the central hot spot, effectively quenching the nuclear burn.4–6 The direct-drive approach to achieving this uniform implosion uses an intense laser pulse to ablate a glass or plastic shell and compress the fuel inside like a spherical rocket.7 The nonuniformities inherent in the laser beam tend to imprint the target with a “seed” that can cause debilitating hydrodynamic instabilities. To avoid these high-spatial-frequency perturbations, the lasers can alternatively be pointed at the inside of a high-Z cavity called a hohlraum, which converts the laser energy into a smooth x-ray radiation field that then compresses a similar capsule, again through a rocket-type ablation.2