Review of Shock Ignition and Fast Ignition Studies on OMEGA

Wolfgang Theobald

Hot-spot self-ignition inside the compressed DT fuel in inertial confinement fusion (ICF) is extremely challenging, which has triggered the search for alternative ignition concepts. This talk provides an overview of experimental studies related to advanced ignition concepts, such as shock ignition (SI) and fast ignition (FI), on the OMEGA laser. It includes cone-in-shell experiments with time-resolved x-ray radiography and integrated experiments that study the coupling of MeV electrons into the compressed core. Laser channeling experiments of multi-kJ, high-intensity IR laser beams in inhomogeneous plasmas are discussed. Since the publication of the SI concept [R. Betti et al., PRL 98, 155001 (2007)], a series of SI related experiments in spherical and planar geometry were performed on major HED laser facilities. Examples on OMEGA are 60-beam implosions with spike-pulses and the 40+20 beam configuration that studied the implosion performance under increased illumination non-uniformities, laser-plasma instabilities, and hot electron preheating. Planar-target experiments studied the scaling of the ablation pressure with spike intensity. In spherical geometry, the spherical strong-shock (SSS) platform was developed to investigate the ablation pressure and the hot-electron production at incident laser intensities up to ~6×10¹⁵ W/cm². The talk concludes with a short outlook of upcoming SI experiments.

This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856.

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