Effects of density scale length on backward and forward stimulated Raman scattering in 0. 53 [mu]m laser--plasma interaction
- Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, 91128 Palaiseau Cedex (France)
Forward and backward stimulated Raman scattering (SRS) have been investigated in three different plasma geometries: in exponential density profile, in Gaussian density profile, and in quasihomogeneous preformed plasmas. The experiments were performed with the same irradiation setup at 0.53 [mu]m wavelength and at a laser intensity [similar to]10[sup 15] W/cm[sup 2]. Time-resolved spectra and energy rates of this instability have been measured in the three experiments. A strong increase of the backward SRS energy rate---up to 1%---with the increasing length of the plasma was observed. From data analysis, backward SRS is explained in terms of absolute instability. On the other hand, forward SRS can be interpreted by considering linear scattering of the incident laser light on the plasma wave driven by backward SRS. This assumption is adequately supported both by the spectral characteristics and by the energy rates of the forward emission light.
- OSTI ID:
- 6783765
- Journal Information:
- Physics of Fluids B; (United States), Vol. 5:3; ISSN 0899-8221
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LASER-PRODUCED PLASMA
RAMAN EFFECT
SCATTERING
ABSOLUTE INSTABILITIES
BACKSCATTERING
ELECTRON PLASMA WAVES
NEAR INFRARED RADIATION
PARAMETRIC INSTABILITIES
PLASMA DENSITY
ELECTROMAGNETIC RADIATION
INFRARED RADIATION
INSTABILITY
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA WAVES
RADIATIONS
700350* - Plasma Production
Heating
Current Drive
& Interactions- (1992-)