Backscatter measurements for NIF ignition targets (invited).

Backscattered light via laser-plasma instabilities has been measured in early NIF hohlraum experiments on two beam quads using a suite of detectors. A full aperture backscatter system and near backscatter imager (NBI) instrument separately measure the stimulated Brillouin and stimulated Raman scattered light. Both instruments work in conjunction to determine the total backscattered power to an accuracy of ∼15%. In order to achieve the power accuracy we have added time-resolution to the NBI for the first time. This capability provides a temporally resolved spatial image of the backscatter which can be viewed as a movie.

[1]  Edward I. Moses,et al.  The National Ignition Facility: Laser Performance and First Experiments , 2005 .

[2]  K. Piston,et al.  Implementation of a near backscattering imaging system on the National Ignition Facility , 2004 .

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

[4]  F. D. Lee,et al.  Full aperture backscatter station measurement system on the National Ignition Facility , 2004 .

[5]  R. E. Bahr,et al.  A pulsed-laser calibration system for the laser backscatter diagnostics at the Omega laser. , 2008, The Review of scientific instruments.

[6]  Stephen D. Jacobs,et al.  Direct‐drive laser‐fusion experiments with the OMEGA, 60‐beam, >40 kJ, ultraviolet laser system , 1996 .

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

[8]  D. Montgomery,et al.  Design considerations for fiber-coupled streaked optical spectroscopy , 2000 .

[9]  R. Kirkwood,et al.  Full-aperture backscatter measurements on the National Ignition Facility , 2004 .

[10]  J. Moody,et al.  Calibration of initial measurements from the full aperture backscatter system on the National Ignition Facility , 2004 .

[11]  M. J. Edwards,et al.  Symmetric Inertial Confinement Fusion Implosions at Ultra-High Laser Energies , 2009, Science.

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