Effects of laser beam smoothing on stimulated Raman scattering in exploding foil plasmas

Journal Article · Wed May 01 04:00:00 EDT 1996 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.871682· OSTI ID:282892

Montgomery, D S; Moody, J D; Baldis, H A; Afeyan, B B; Berger, R L; Estabrook, K G; Lasinski, B F; Williams, E A ^[1]; Labaune, C ^[2]

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1. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
2. Ecole Polytechnique, 91128 Palaiseau Cedex (France)

Time-resolved spectra of backward stimulated Raman scattering (SRS) were measured from the interaction of a 527 nm laser with a preformed plasma. The effect of laser smoothing by spectral dispersion (SSD) was studied using laser bandwidth ({Delta}{lambda}/{lambda}=0.1{percent}) and varying the laser intensity (2{endash}20{times}10{sup 14} W/cm{sup 2}). A broad SRS spectrum extending to short wavelengths was observed for the high-intensity, {Delta}{lambda}/{lambda}=0 case. Narrow spectra corresponding to the peak plasma density were observed for cases with either high intensity and {Delta}{lambda}/{lambda}{approximately}0.1{percent}, or with low intensity and {Delta}{lambda}/{lambda}=0. Simulations of the filamentation process were performed for the conditions of these experiments. The simulations show that laser smoothing stabilizes filamentation for high-intensity interactions, and that filaments are stable without smoothing for low intensity. The predicted onset of filamentation without smoothing correlates with the growth of short wavelength SRS. These experimental results are presented and models are discussed that may help explain the data. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: Lawrence Livermore National Laboratory
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 282892
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 3; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM-PLASMA SYSTEMS
FILAMENTATION INSTABILITIES
FOILS
LASER RADIATION
LASER SPECTROSCOPY
LASER-PRODUCED PLASMA
LIGHT SCATTERING
PARAMETRIC INSTABILITIES
RAMAN SPECTRA