The interaction of intense subpicosecond laser pulses with underdense plasmas

Thesis/Dissertation · Thu May 11 04:00:00 EDT 1995

DOI:https://doi.org/10.2172/104490· OSTI ID:104490

Coverdale, Christine Ann ^[1]

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1. Univ. of California, Davis, CA (United States)

Laser-plasma interactions have been of interest for many years not only from a basic physics standpoint, but also for their relevance to numerous applications. Advances in laser technology in recent years have resulted in compact laser systems capable of generating (psec), 10¹⁶ W/cm² laser pulses. These lasers have provided a new regime in which to study laser-plasma interactions, a regime characterized by L_plasma ≥ 2L_Rayleigh > cτ. The goal of this dissertation is to experimentally characterize the interaction of a short pulse, high intensity laser with an underdense plasma (n_o ≤ 0.05n_cr). Specifically, the parametric instability known as stimulated Raman scatter (SRS) is investigated to determine its behavior when driven by a short, intense laser pulse. Both the forward Raman scatter instability and backscattered Raman instability are studied. The coupled partial differential equations which describe the growth of SRS are reviewed and solved for typical experimental laser and plasma parameters. This solution shows the growth of the waves (electron plasma and scattered light) generated via stimulated Raman scatter. The dispersion relation is also derived and solved for experimentally accessible parameters. The solution of the dispersion relation is used to predict where (in k-space) and at what frequency (in ω-space) the instability will grow. Both the nonrelativistic and relativistic regimes of the instability are considered.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 104490
• Report Number(s): UCRL-LR--120922; ON: DE95015238
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BACKSCATTERING
DISPERSION RELATIONS
INERTIAL CONFINEMENT
LASER-RADIATION HEATING
PARAMETRIC INSTABILITIES
PLASMA
PLASMA DENSITY
RAMAN EFFECT