Year: 2021
Type: article
Abstract: We use a subignition scale laser, the 30 kJ Omega, and a novel shallow-cone target to study laser-plasma interactions at the ablation-plasma density scale lengths and laser intensities anticipated for direct drive shock-ignition implosions at National Ignition Facility scale. Our results show that, under these conditions, the dominant instability is convective stimulated Raman scatter with experimental evidence of two plasmon decay (TPD) only when the density scale length is reduced. Particle-in-cell simulations indicate this is due to TPD being shifted to lower densities, removing the experimental back-scatter signature and reducing the hot-electron temperature. The experimental laser energy-coupling to hot electrons was found to be 1%-2.5%, with electron temperatures between 35 and 45 keV. Radiation-hydrodynamics simulations employing these hot-electron characteristics indicate that they should not preheat the fuel in MJ-scale shock ignition experiments.
Source: Physical Review Letters
Authors: R. H. H. Scott, K. Glize, L. Antonelli, M. Khan, W. Theobald, M. Wei, R. Betti, C. Stoeckl, A. G. Seaton, T. D. Arber, D. Barlow, T. Goffrey, K. Bennett, W. Garbett, S. Atzeni, A. Casner, D. Batani, C. Li, N. Woolsey
Institutions: Central Laser Facility, University of York, Laboratory for Laser Energetics, University of Rochester, Los Alamos National Laboratory, University of Warwick, AWE Nuclear Security Technologies, Sapienza University of Rome, Université de Bordeaux, Centre Lasers Intenses et Applications, Massachusetts Institute of Technology
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium, Plasma kinetics, pre-heat, and the emergence of strong shocks in laser fusion: the hydro-kinetic regime, G3562737245, CCP Flagship: A radiation-hydrodynamics code for the UK laser-plasma community, CCP Flagship: A radiation-hydrodynamics code for the UK laser-plasma community, Plasma kinetics, pre-heat, and the emergence of strong shocks in laser fusion, Physics of Ignition: Collaboration with the National Ignition Facility: Diagnosing Hot-Spot Mix via X-Ray Spectroscopy, G8164591549, Plasma kinetics, pre-heat, and the emergence of strong shocks in laser fusion, G829439530, G8636600277
OpenAlex ID: W3187344945