Brillouin Backscatter Dependence Upon Pulse Amplitudes, Timing, Target Material and Geometry.
Abstract
The stimulated Brillouin backscatter instability plays an important role in the laser-plasma interaction for short (is less than 1 nsec), high-irradiance (is greater than 10 to the 13 power W/sq cm) Nd-laser pulses. Laser light is observed to be directly backscattered and the total absorption fraction reduced by this mechanism operating in the underdense region of plasma. Long underdense plasma scale lengths, which are conducive to large simulated backscatter, are set up, for example, in a plasma preformed by a small prepulse, longer incident pulses and larger plasmas, and by temporally structured pulses designed for laser fusion. The density gradient present when the high-intensity pulse strikes the target (and hence the degree of backscatter) is expected to be a function of several variables. Here we show the variation of backscatter with main pulse-prepulse timing and amplitudes, target material and geometry.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 15, 1979
- Accession Number
- ADA070300
Entities
People
- Barrett H. Ripin
- Edgar A. McLean
Organizations
- United States Naval Research Laboratory