Saturation and damping of stimulated Raman scattering (SRS)

Conference · Sat Oct 01 04:00:00 EDT 1988

OSTI ID:6385708

Drake, R P; Young, P E; Williams, E A; Darrow, C B; Estabrook, K; Montgomery, D S; Kruer, W L; Baldis, H A; Johnston, T W

Three experiments are discussed that investigated the saturation and damping of the SRS instability. First, 3 ..mu..m thick CH targets were exploded by up to 2 kJ of 0.35 ..mu..m laser light in pulses of 1 to 4.4 ns at 10/sup 13/ to 4 x 10/sup 15/ W/cm/sup 2/. The laser intensity, pulse length, and spot size were systematically varied to study, in planar plasmas, the dependence of SRS on either laser intensity or density-gradient sale length. This produced evidence that SRS was as absolute instability under the conditions of these experiments. Second, 15 ..mu..m thick CH targets were exploded by about 18 kJ or 0.35 ..mu..m light to produce a reactor-scale, underdense plasma. This plasma was irradiated by an intense (10/sup 15/ W/cm/sup 2/), 0.35 ..mu..m laser beam and was measured to produce an SRS reflectivity of 15%. Third, thin Au targets were irradiated at intensities of 10/sup 14/ to 4 x 10/sup 15/ W/cm/sup 2/ with up to 2 kJ of 0.35 ..mu..m light. When the ratio of electron-ion collision rate to SRS growth rate reached unity, the emissions in the SRS frequency band abruptly dropped to thermal levels. 11 refs., 3 figs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6385708
• Report Number(s): UCRL-99821; CONF-881056-10; ON: DE89006235
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107 -- Fusion Energy-- Plasma Research-- Instabilities
700208* -- Fusion Power Plant Technology-- Inertial Confinement Technology
ANGULAR DISTRIBUTION
COLLISIONS
DAMPING
DISTRIBUTION
ELECTRON COLLISIONS
ELECTRON-ION COLLISIONS
INSTABILITY
ION COLLISIONS
LASER-PRODUCED PLASMA
PARAMETRIC INSTABILITIES
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
RAMAN EFFECT