J. Phys. IV France
Volume 133, June 2006
Page(s) 129 - 133
Publié en ligne 16 juin 2006
Inertial Fusion Sciences and Applications 2005
J.-C. Gauthier, et al.
J. Phys. IV France 133 (2006) 129-133

DOI: 10.1051/jp4:2006133025

Radiation hydrodynamics with backscatter and beam spray in gas filled hohlraum experiments at the National Ignition Facility

S.R. Goldman1, J.C. Fernández1, N.M. Hoffman1, J.L. Kline1, J.B. Workman1, H.A. Rose1, E.S. Dodd1, J.P. Grondalski1, G.D. Pollak1, M.J. Schmitt1, W.J. Powers1, D.G. Braun2, D.E. Hinkel2, J.P. Holder2 and L.J. Suter2

1  Los Alamos National Laboratory, Los Alamos, NM 87545, USA
2  Lawrence Livermore National Laboratory, Livermore, CA 94551, USA

Several experiments using either CO2 or propane gas filled halfraums [i.e. hohlraums with a single laser entry hole (LEH)] have been shot at the National Ignition Facility (NIF) in a joint Los Alamos/Livermore collaboration. The experiments have been modeled by the Lasnex code. The possibility of beam spray due to filamentation of the incident laser beam is assessed through simulations which parametrically decrease the f-number of the beam at times of high intensity. The uncertainty in heat transport is evaluated through parametric variations in the electron thermal flux limit (fe). Each calculation in the resulting two parameter set is post-processed to simulate outputs which can be compared with Dante detector results for the soft X-ray flux through the LEH, and gated, framed images of hard X-rays (FXI) through the hohlraum side walls. Simulations which well match the data for both gases indicate that the laser energy is penetrating the gas filled hohlraum even towards the end of the pulse. This suggests that the gas fill is useful in keeping the hohlraum open to laser energy throughout the pulse.

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