Observation of the Density Threshold Behavior for the Onset of Stimulated Raman Scattering in High-Temperature Hohlraum Plasmas
- L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)
We show that the measured stimulated Raman scattering (SRS) in a large-scale high-temperature plasma scales strongly with the plasma density, increasing by an order of magnitude when the electron density is increased by 20%. This is consistent with linear theory, including pump depletion, in a uniform plasma and, as the density is typically constrained by other processes, this effect will set a limit on drive laser beam intensity for forthcoming ignition experiments at the National Ignition Facility. Control of SRS at laser intensities consistent with 285 eV ignition hohlraums is achieved by using polarization smoothing which increases the intensity threshold for the onset of SRS by 1.6+-0.2. These results were quantitatively predicted by full beam three-dimensional numerical laser-plasma interaction simulations.
- OSTI ID:
- 21347091
- Journal Information:
- Physical Review Letters, Vol. 103, Issue 4; Other Information: DOI: 10.1103/PhysRevLett.103.045006; (c) 2009 The American Physical Society; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
Similar Records
Trapping induced nonlinear behavior of backward stimulated Raman scattering in multi-speckled laser beams
Inflation threshold: A nonlinear trapping-induced threshold for the rapid onset of stimulated Raman scattering from a single laser speckle