New model of Raman spectra in laser produced plasma

Conference · Fri Mar 30 04:00:00 EST 1984

OSTI ID:7044792

Simon, A; Short, R W

Some experimental observations of Raman scattering in laser produced plasma have been previously attributed to the onset of the convective Stimulated Raman Instability (SRS-C). This interpretation has had a number of difficulties, associated with the calculated threshold for onset of the SRS-C, the existence of gaps in the frequency spectrum near the incident frequency ..omega../sub 0/ and near ..omega../sub 0//2, and with the angular distribution. We now propose a new explanation based on ordinary incoherent Thompson scattering, with a greatly enhanced plasma line. Transient local reversed-slope velocity distributions in the underdense region can be produced by pulses of hot electrons arising from the two-plasmon (2..omega../sub p/) or absolute stimulated Raman instabilities (SRS-A) occurring near the quarter critical surface. A simple model yields the observed spectral gaps near ..omega../sub 0/ and near ..omega../sub 0//2. It also explains the correlation of onset of this scattering with onset of the SRS-A, its transient localization in frequency and time, and the weak azimuthal angular variation. The existence of upscattered light is also predicted.

• Research Organization: Rochester Univ., NY (USA). Lab. for Laser Energetics
• DOE Contract Number: AC08-80DP40124
• OSTI ID: 7044792
• Report Number(s): DOE/DP/40124-34; CONF-8405163-5; ON: DE84012487
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700208* -- Fusion Power Plant Technology-- Inertial Confinement Technology
ELECTROMAGNETIC RADIATION
INELASTIC SCATTERING
LASER RADIATION
LASER-PRODUCED PLASMA
MATHEMATICAL MODELS
PLASMA
PLASMONS
QUASI PARTICLES
RADIATIONS
RAMAN EFFECT
SCATTERING
THOMSON SCATTERING