Shock Ignition Laser-Plasma Interactions in Ignition-Scale Plasmas

TY - JOUR

T1 - Shock Ignition Laser-Plasma Interactions in Ignition-Scale Plasmas

AU - Scott, R. H.H.

AU - Glize, K.

AU - Antonelli, L.

AU - Khan, M.

AU - Theobald, W.

AU - Wei, M.

AU - Betti, R.

AU - Stoeckl, C.

AU - Seaton, A. G.

AU - Arber, T. D.

AU - Barlow, D.

AU - Goffrey, T.

AU - Bennett, K.

AU - Garbett, W.

AU - Atzeni, S.

AU - Casner, A.

AU - Batani, D.

AU - Li, C.

AU - Woolsey, N.

N1 - Funding Information: This work was funded by EPSRC Grants No. EP/P023460/1, No. EP/P026486/1, and No. EP/P026486/1. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the EuroFUSION research and training programme under Grant Agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. The involved teams have operated within the framework of the Enabling Research Project: ENR-IFE19.CEA-01 Study of Direct Drive and Shock Ignition for IFE: Theory, Simulations, Experiments, Diagnostics development. Publisher Copyright: © 2021 American Physical Society.

PY - 2021/8/6

Y1 - 2021/8/6

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85112383744&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.127.065001

DO - 10.1103/PhysRevLett.127.065001

M3 - Article

AN - SCOPUS:85112383744

SN - 0031-9007

VL - 127

JO - Physical Review Letters

JF - Physical Review Letters

IS - 6

M1 - 065001

ER -