Hot-Electron Preheat in Hydrodynamically Scaled Direct-Drive Implosions at the National Ignition Facility and OMEGA
ORAL
Abstract
The scaling of hot-electron preheat with capsule size or laser energy has been studied in warm polar-direct-drive implosions at the National Ignition Facility (NIF) and OMEGA. The experiments were designed to produce hydrodynamically equivalent implosion conditions despite differences of a factor of 3.4 in capsule diameter and 40 in laser energy (2.3 mm, 720 kJ on the NIF; 0.69 mm, 18 kJ on OMEGA). Hard x-ray emission from Ge-doped layers was used to infer the hot-electron energy deposited in the unablated shell. Although the hot-electron mechanism is different at each scale---two-plasmon decay on OMEGA and stimulated Raman scattering on the NIF---both experiments demonstrate 0.2{\%} of laser energy deposited as hot-electron preheat in the inner 80{\%} of unablated shell at a hard-sphere intensity of 1.2 \texttimes 10$^{\mathrm{15}}$ W/cm$^{\mathrm{2}}$ despite more hot-electron generation on the NIF. This result is partially attributed to electron stopping in the thicker shell on the NIF. Implications for scaling of direct-drive cryogenic implosion performance on OMEGA to NIF scales will be discussed. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856.
–
Authors
M.J. Rosenberg
Laboratory for Laser Energetics, University of Rochester, NY
LLE
University of Rochester, Laboratory for Laser Energetics
University of Rochester
LLE, Univ. of Rochester
Laboratory for Laser Energetics, University of Rochester
A.A. Solodov
Laboratory for Laser Energetics, University of Rochester, NY
Laboratory for Laser Energetics, U. of Rochester
Laboratory for Laser Energetics, University of Rochester
A.R. Christopherson
Laboratory for Laser Energetics, U. of Rochester
Laboratory for Laser Energetics, University of Rochester
R. Betti
Laboratory for Laser Energetics, U. of Rochester
LLE
University of Rochester
LLE, Univ. of Rochester
Laboratory for Laser Energetics, University of Rochester
Lab for Laser Energetics
P. B. Radha
Laboratory for Laser Energetics
LLE-UR
Laboratory for Laser Energetics, University of Rochester
University of Rochester
C. Stoeckl
University of Rochester
Laboratory for Laser Energetics, U. of Rochester
Laboratory for Laser Energetics, University of Rochester
C. J. Forrest
Laboratory for Laser Energetics, U. of Rochester
Laboratory of Laser Energetics
Laboratory for Laser Energetics, University of Rochester
University of Rochester
V. Yu. Glebov
Laboratory for Laser Energetics, U. of Rochester
University of Rochester
Laboratory for Laser Energetics, University of Rochester
F. J. Marshall
Laboratory for Laser Energetics, University of Rochester
University of Rochester, Laboratory for Laser Energetics
University of Rochester
Sean Regan
University of Rochester
Laboratory for Laser Energetics - University of Rochester
Laboratory for Laser Energetics, U. of Rochester
Laboratory for Laser Energetics
LLE-UR
LLE, Univ. of Rochester
Laboratory for Laser Energetics, University of Rochester
Lab for Laser Energetics
T. J. B. Collins
Laboratory for Laser Energetics, University of Rochester
LLE, Univ. of Rochester
University of Rochester
D.H. Froula
Laboratory for Laser Energetics, U. of Rochester
Laboratory for Laser Energetics
Laboratory for Laser Energetics, University of Rochester
Laboratory for Laser Energetics University of Rochester
University of Rochester, Laboratory for Laser Energetics, Rochester, New York 14623, USA
J.P. Palastro
Laboratory for Laser Energetics, U. of Rochester
Laboratory for Laser Energetics
University of Rochester, Laboratory for Laser Energetics
Laboratory for Laser Energetics University of Rochester
U. of Rochester, Laboratory laser Energetics
Laboratory for Laser Energetics, University of Rochester
V. N. Goncharov
University of Rochester
Laboratory for Laser Energetics
LLE, Univ. of Rochester
Laboratory for Laser Energetics, University of Rochester
