2005 47th Annual Meeting of the Division of Plasma Physics
Monday–Friday, October 24–28, 2005;
Denver, Colorado
Session CI2: ICF Theory and Diagnostics
2:00 PM–5:00 PM,
Monday, October 24, 2005
Adam's Mark Hotel
Room: Plaza Ballroom EF
Chair: Patrick McKenty, University of Rochester
Abstract ID: BAPS.2005.DPP.CI2.5
Abstract: CI2.00005 : Direct-Drive Shock-Wave-Timing Experiments in Planar Targets
4:00 PM–4:30 PM
Preview Abstract
Abstract
Author:
T.R. Boehly
(Laboratory for Laser Energertics, U. of Rochester)
Inertial confinement fusion target designs use multiple shock waves to
condition the target material for optimal performance. These designs require
that the shock waves be accurately timed to coalesce at a particular point
in the target. It is essential that the propagation and dynamics of these
multiple shocks be understood and correctly modeled. The OMEGA Laser
Facility at the University of Rochester is used to perform direct-drive
experiments that measure the propagation and coalescence of two laser-driven
shock waves propagating in planar targets made of CH or cryogenic D$_{2}$.
Laser pulses with various temporal shapes generate two primary shocks that
propagate in these transparent targets. The velocity and self-emission
profiles of these shocks are temporally resolved and clearly show the first
shock wave propagating through the material and then being overtaken by the
second shock wave. The coalescence of these shocks forms a single, stronger
shock that eventually arrives at the rear surface of the target. The
measured velocity and emission profiles exhibit distinct features that
include the decay rate of unsupported shocks, coalescence and shock breakout
times, and curvature of the shock fronts. These results are presented for a
number of drive conditions and compared to 1-D and 2-D hydrodynamic codes.
The simulated velocity profiles and coalescence times are in good agreement
with experimental observations, as are many of the two-dimensional effects.
These experiments have also validated the dependence of laser--target
coupling on the angle of incidence. The effect of preheat by x rays on these
experiments is also discussed. Results of preliminary indirect-drive
experiments are also shown. This work was supported by the U.S. Department
of Energy Office of Inertial Confinement Fusion under Cooperative Agreement
No. DE-FC52-92SF19460. Contributors: E. Vianello, J. E. Miller, R. S.
Craxton, V. N. Goncharov, I. V. Igumenshchev, T. J. B. Collins \textit{LLE}; D. G. Hicks,
P. M. Celliers, G.W. Collins\textit{, LLNL}; R. E. Olson, \textit{Sandia National Lab}
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2005.DPP.CI2.5