On the dominant and subdominant behavior of stimulated Raman and Brillouin scattering driven by nonuniform laser beams

In a number of experiments, stimulated Brillouin (SBS) or Raman backscattering (SRS) has been observed to be much more vigorous than the other although the expectations based on linear gain exponents are that they should both be reflecting large amounts of incident light. Multidimensional fluid simulations of the growth and saturation of these two instabilities driven by a nonuniform incident laser beam are presented. On the fast time scale, the nonlinear saturation occurs via an anomalous damping inspired by fundamental studies of Langmuir turbulence [D. F. DuBois et al., Bull. Am. Phys. Soc. 41, 1531 (1996)] and acoustic wave turbulence [B. I. Cohen et al., Phys. Plasmas 4, 956 (1997)]. Over a longer time scale, SRS and SBS are limited by quasilinear processes such as flows induced by the transfer of momentum from the light to the plasma and ion temperature increases caused by a loss of light energy in SBS. The simulations show a reduction of the SBS reflectivity under conditions of strong SRS reflectiv...

[1]  J. M. Perlado,et al.  Advances in Laser Interaction with Matter and Inertial Fusion. , 1998 .

[2]  Rose,et al.  Laser hot spots and the breakdown of linear instability theory with application to stimulated Brillouin scattering. , 1994, Physical review letters.

[3]  E. Williams,et al.  Doppler shift of laser light reflected from expanding plasmas , 1981 .

[4]  D. Villeneuve,et al.  Electron Plasma-Wave Production by Stimulated Raman Scattering: Competition with Stimulated Brillouin Scattering , 1984 .

[5]  J. Moody,et al.  Evidence of plasma fluctuations and their effect on the growth of stimulated Brillouin and stimulated Raman scattering in laser plasmas , 1998 .

[6]  Rose,et al.  Observed Dependence of Stimulated Raman Scattering on Ion-Acoustic Damping in Hohlraum Plasmas. , 1996, Physical review letters.

[7]  J. Lindl.  Development of the indirect‐drive approach to inertial confinement fusion and the target physics basis for ignition and gain , 1995 .

[8]  A. A. Galeev,et al.  Nonlinear plasma theory , 1969 .

[9]  T. H. Stix.  Waves in plasmas , 1992 .

[10]  Rose,et al.  Saturation of stimulated Raman scattering by the excitation of strong Langmuir turbulence. , 1993, Physical review letters.

[11]  Donald W. Phillion,et al.  Laser ionization and heating of gas targets for long‐scale‐length instability experiments , 1994 .

[12]  V. Tikhonchuk,et al.  Effect of the speckle self-focusing on the stationary stimulated Brillouin scattering reflectivity from a randomized laser beam in an inhomogeneous plasma , 1997 .

[13]  Peter A. Amendt,et al.  Gas‐filled targets for large scale‐length plasma interaction experiments on Nova , 1995 .

[14]  H. Rose.  Saturation of Stimulated Brillouin Scatter by Self Consistent Flow Profile Modification , 1997 .

[15]  M. Goldman,et al.  Parametrically Excited Plasma Fluctuations , 1967 .

[16]  J. D. Moody,et al.  Laser–plasma interactions in ignition‐scale hohlraum plasmas , 1996 .

[17]  E. Epperlein.  Kinetic simulations of laser filamentation in plasmas , 1991 .

[18]  Michael D. Feit,et al.  Beam nonparaxiality, filament formation, and beam breakup in the self-focusing of optical beams , 1988 .

[19]  R. P. Drake,et al.  Observation of the Langmuir decay instability driven by stimulated Raman scattering , 1997 .

[20]  Y. Zel’dovich,et al.  Principles of phase conjugation , 1985 .

[21]  C. Labaune,et al.  Time-resolved measurements of secondary Langmuir waves produced by the Langmuir decay instability in a laser-produced plasma , 1998 .

[22]  W. Kruer,et al.  Nonlinear features of stimulated Brillouin and Raman scattering , 1989 .

[23]  W. Rozmus,et al.  Saturation of backward stimulated Raman scattering and enhancement of laser light scattering in plasmas , 1995 .

[24]  H. Rose,et al.  Statistical properties of laser hot spots produced by a random phase plate , 1993 .

[25]  A. C. Gaeris,et al.  The frequency and damping of ion acoustic waves in hydrocarbon (CH) and two‐ion‐species plasmas , 1995 .

[26]  Berger.  Suppression of parametric instability by weakly incoherent laser beams. , 1990, Physical review letters.

[27]  G. Bonnaud,et al.  Nonlinear Raman scattering behavior with Langmuir and sound waves coupling in a homogeneous plasma , 1990 .

[28]  R. Berger,et al.  Effect of plasma noise spectrum on stimulated scattering in inhomogeneous plasma , 1989 .

[29]  Rose,et al.  Nonlinear coupling of stimulated Raman and Brillouin scattering in laser-plasma interactions. , 1987, Physical review letters.

[30]  R. Berger.  Nonlinear competition between stimulated Brillouin-scattered light waves in plasmas , 1983 .

[31]  Harvey A. Rose.  Laser beam deflection by flow and nonlinear self‐focusing , 1996 .

[32]  A. Ramani,et al.  Stimulated Brillouin scattering in an inhomogeneous plasma with broad-bandwidth thermal noise , 1983 .

[33]  A. Langdon,et al.  Resonantly excited nonlinear ion waves , 1997 .

[34]  Peter A. Amendt,et al.  Design and modeling of ignition targets for the National Ignition Facility , 1995 .

[35]  R. S. Craxton,et al.  Convective stimulated Raman scattering instability in UV laser plasmas , 1984 .

[36]  J. Moody,et al.  Imaging backscattered and near to backscattered light in ignition scale plasmas (invited) , 1997 .

[37]  J. Heikkinen,et al.  Ion acoustic nonlinearities in stimulated Brillouin scattering , 1984 .

[38]  D. Villeneuve,et al.  Stimulated Brillouin scattering in picosecond time scales: Experiments and modeling , 1993 .

[39]  H. Rose,et al.  SATURATION OF RADIATION-INDUCED PARAMETRIC INSTABILITIES BY EXCITATION OF LANGMUIR TURBULENCE , 1995 .