Non-linear reflexion of laser radiation by a plasma layer in a coherent wave description

Abstract

The paper presents a theoretical analysis of the problem of anomalous reflexion of laser radiation by a plasma due to stimulated scattering by ion-acoustic or electron plasma waves (stimulated Brillouin or Raman scattering). A coherent wave (or well-defined phase) description is used to investigate the case of perpendicular incidence on a plasma layer. The reflexion coefficient as found from the analysis is studied as a function of the power of the laser radiation and of the plasma parameters. The results are compared with those obtained from other investigations. Finally, numerical estimates are given for situations of interest for laser fusion.

Radiation penetration in plasma on the assumption of stochastically varying laser frequency

“…We have previously [5], shown that the fraction of the incident laser radiation, which is transmitted through a plasma slab, is equal to 1-Ro-The growth-rate in regions 1 and 2 are…”

“…[l], (see Eq. ( 5)) have previously derived the following expression for the reflection coefficient R o for stimulated scattered radiation in a lossless and homogeneous plasma slab [5]:…”

Production of Volume Wave Plasma with Internally Mounted Cylindrical Planar Microwave Launcher and Two-Dimensional Field Analysis Using Finite Difference Time Domain Method

“…(5)) have previously derived the following expression for the reflection coefficient R o for stimulated scattered radiation in a lossless and homogeneous plasma slab [5]: (7) where L o is the length of the plasma slab and L c is the non-linear interaction length. Let R e ff denote the effective value of R.…”

“…We have previously [5], shown that the fraction of the incident laser radiation, which is transmitted through a plasma slab, is equal to 1-Ro-The growth-rate in regions 1 and 2 are For large values of R o , i.e. a high-reflexivity situation in the unperturbed state, we obtain large values of r^ 2-This is physically very plausible since in this case there is, loosely speaking, much to gain from the scattering process.…”

Anomalous Reflexion of Laser Radiation due to the Build-up of Ion-sound Waves in a Plasma

“…The processes have been studied in computer simulation experiments [6, 71. A theoretical analysis using a well-defined phase description and assuming steady state conditions has been made in [5]. A numerical study of the steady state situation (in the case of Brillouin scattering) has been made in [l] using a random phase description.…”