| Autor: |
M. Desselberger, O. Willi, T. Afshar-rad, Danilo Giulietti, A. Giulietti, Colin N. Danson, S. E. Coe |
| Rok vydání: |
1991 |
| Předmět: |
|
| Zdroj: |
Laser Interaction and Related Plasma Phenomena ISBN: 9781461366966 |
| Popis: |
Plasmas with scalelegths of the order of 1 mm were produced by focusing four green laser beams of the Rutherford Appleton Laboratory Vulcan laser onto thin foil targets in a line focus configuration. A delayed green laser beam was focused axially into the preformed plasma up to irradiances of 2×1015W/cm2. Delays were chosen that the preformed plasma was underdense and the electron temperatures ranged from 0.3 KeV to 1 KeV. Several beam plasma instabilities were investigated under those experimental conditions including laser filamentation and whole-beam self-focusing, stimulated Brillouin and Raman scattering. The interacting laser beam was smoothed by using a random phase plate and an induced spatial incoherece system. It was found that both these methods give rise to a virtual suppression of self-focusing and to a significant reduction in the level of the Raman and Brillouin instabilities. In addition, time resolved spectra of stimulated Raman and Brillouin scattering were recorded showing distinct differences when random phase plate and induced spatial incoherence system were used in comparison with the normal laser beam. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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