Temporal evolution of stimulated Brillouin backscatter

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870539· OSTI ID:7130774

Hinkel, D E; Williams, E A; Berger, R L ^[1]

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1. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

A qualitative understanding of the time dependence of stimulated Brillouin scattering (SBS) provides estimates of the amount of temporal growth that occurs in current inertial confinement fusion and short laser pulse interaction experiments when the growth is limited by the length of the experiment or by motion of the hot spots'' of the laser intensity pattern induced by beam smoothing. In the weak coupling limit, the instantaneous growth rate depends upon the plasma initial conditions early in time, is proportional to [ital t][sup [minus]1/2] later in time, and asymptotically approaches the absolute growth rate (in the absence of damping). When the instability is strongly coupled, the growth rate depends upon the plasma initial conditions early in time but is proportional to [ital t][sup [minus]1/3] later in time. When the growth rate drops to a value comparable to that of the ion acoustic frequency, the instability becomes effectively weakly coupled. The effects of damping are also discussed.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7130774
• Journal Information: Physics of Plasmas; (United States), Journal Name: Physics of Plasmas; (United States) Vol. 1:9; ISSN 1070-664X; ISSN PHPAEN
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
700350 -- Plasma Production
Heating
Current Drive
& Interactions-- (1992-)
BEAM-PLASMA SYSTEMS
BRILLOUIN EFFECT
COHERENT SCATTERING
ELECTROMAGNETIC RADIATION
HOT SPOTS
ICF DEVICES
INSTABILITY
INSTABILITY GROWTH RATES
ION ACOUSTIC WAVES
ION WAVES
LASER RADIATION
LIGHT SCATTERING
PLASMA INSTABILITY
PLASMA WAVES
RADIATIONS
SCATTERING
THERMONUCLEAR DEVICES
TIME DEPENDENCE