Measurements of laser-imprinted perturbations and Rayleigh–Taylor growth with the Nike KrF laser : The 38th annual meeting of the Division of Plasma Physics (DPP) of the American Physical Society
Pawley, C. J. ; Gerber, K. ; Lehmberg, R. H. ; McLean, E. A. ; Mostovych, A. N. ; Obenschain, S. P. ; Sethian, J. D. ; Serlin, V. ; Stamper, J. A. ; Sullivan, C. A. ; Bodner, S. E. ; Colombant, D. ; Dahlburg, J. P. ; Schmitt, A. J.
[S.l.] : American Institute of Physics (AIP)
Published 1997
[S.l.] : American Institute of Physics (AIP)
Published 1997
| ISSN: |
1089-7674
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| Source: |
AIP Digital Archive
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| Topics: |
Physics
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| Notes: |
Nike is a 56 beam Krypton Fluoride (KrF) laser system using Induced Spatial Incoherence (ISI) beam smoothing with a measured focal nonuniformity 〈ΔI/I〉 of 1% rms in a single beam [S. Obenschain et al., Phys. Plasmas 3, 1996 (2098)]. When 37 of these beams are overlapped on the target, we estimate that the beam nonuniformity is reduced by 37, to (ΔI/I)≅0.15% (excluding short-wavelength beam-to-beam interference). The extraordinary uniformity of the laser drive, along with a newly developed x-ray framing diagnostic, has provided a unique facility for the accurate measurements of Rayleigh–Taylor amplified laser-imprinted mass perturbations under conditions relevant to direct-drive laser fusion. Data from targets with smooth surfaces as well as those with impressed sine wave perturbations agree with our two-dimensional (2-D) radiation hydrodynamics code that includes the time-dependent ISI beam modulations. A 2-D simulation of a target with a 100 Å rms randomly rough surface finish driven by a completely uniform beam gives final perturbation amplitudes similar to the experimental data for the smoothest laser profile. These results are promising for direct-drive laser fusion.
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| Type of Medium: |
Electronic Resource
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| URL: |