Direct-Drive Cylindrical Implosions on the OMEGA Laser
Abstract
Studies of convergent hydrodynamics in cylindrical geometry are being conducted at the OMEGA laser facility at the Laboratory for Laser Energetics at the University of Rochester. Polystyrene cylinders that are 20-μm thick, 2.25-mm long, and 0.9-mm in diameter with 60 mg/cc polystyrene foam are directly illuminated with 19 kJ from 50 laser beams in a 2.5-nsec linear ramp pulse shape. The imploding cylinder is then radiographed from the x-rays generated using laser beams to illuminate a titanium foil. Very symmetric implosions (few percent asymmetries at ablator convergence ratios of ~ 7) are achieved. Targets both unperturbed and with machined sinusoidal perturbations of varying wavelength (m=14 to 58) and amplitude (0.5 μm to 1.5 μm) are used to study the ablative Rayleigh-Taylor instability in this convergent geometry. Using either deuterated or chlorinated doped foams, neutron and spectroscopic diagnostics are used to determine the temperature and density of the cylindrical implosion. Details of the experiment and its comparison to hydrodynamic simulation will be presented. This work was performed under the auspices of the U. S. Department of Energy by the Los Alamos National Laboratory under contract No. W-7405-Eng-36.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 1998
- Bibcode:
- 1998APS..DPP.R8Q10B