Laser driven Rayleigh-Taylor instability experiments on Nova

Technical Report · Fri Jul 19 00:00:00 EDT 1991

OSTI ID:5499370

Glendinning, S G; Weber, S V; Dixit, S; Henesian, M A; Kilkenny, J D; Powell, H T; Wallace, R J; Wegner, P J ^[1]; Knauer, J M; Verdon, C P ^[2]

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1. Lawrence Livermore National Lab., CA (United States)
2. Rochester Univ., NY (United States). Lab. for Laser Energetics

We have performed a series of experiments on hydrodynamic (Rayleigh-Taylor) instabilities in planar foils in the Nova laser at LLNL. For these experiments, we have implemented laser beam smoothing by means of a random phase plate and spectral dispersion of a high bandwidth (0.22%) beam on one beam of Nova, providing us with a flat-topped beam profile with a residual modulation of {sigma}/{mu} = 0.07. The center 600 {mu}m is flat to within {plus minus}10%. The foils (polyethylene samples 20 {mu}m thick and 600 {mu}m in diameter with varying imposed initial perturbations) are driven with {approximately}1*10{sup 14} W/cm{sup 2} of 0.53 {mu}m laser light for 3 ns. The targets are radiographed during acceleration using a multiple frame gated x-ray pinhole camera (gate time {approximately}100 ps). The x-ray backlighter target is uranium and is illuminated by a second laser beam. We have used targets with wavelengths of 20, 30, 50, and 70 {mu}m. These experiments have been simulated with the computer code LASNEX; in general, we see good agreement between simulation and experiment. In addition, targets with no initial perturbation have been measured. LASNEX simulations of flat targets with the time dependent drive modulations predicted for our smoothed beam show the development of amplitude modulation of the target from residual intensity nonuniformities; measured modulations of the target agree with the simulations. 7 refs.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5499370
• Report Number(s): UCRL-ID-107775; ON: DE91016504
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
LASER-PRODUCED PLASMA
RAYLEIGH-TAYLOR INSTABILITY
COMPUTERIZED SIMULATION
L CODES
LASER RADIATION
LASER TARGETS
NOVA FACILITY
PLASMA DIAGNOSTICS
STREAK CAMERAS
CAMERAS
COMPUTER CODES
ELECTROMAGNETIC RADIATION
INSTABILITY
MEASURING INSTRUMENTS
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RADIATION DETECTORS
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TARGETS
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