Experimental observations and simulations on relativistic self-guiding of an ultra-intense laser pulse in underdense plasmas
- Commissariat a lEnergie Atomique, Centre dEtudes de Limeil--Valenton, 94195 Villeneuve-Saint-Georges (France)
- Commissariat a lEnergie Atomique, Centre dEtudes de Saclay, SPAM, 91191 Gif-sur-Yvette Cedex (France)
The experimental images of the sidescattered light from a plasma, created by the multiterawatt laser pulse propagating in a hydrogen gas jet, exhibit clear dependence on both gas jet pressure and laser power. Two- and three-dimensional simulations of wave propagation, in presence of the relativistic electron mass increase and the ponderomotive expel of electrons, have been performed to reproduce the Thomson radiation from the plasma electrons. They show electron cavitation induced by the beam focusing, self-focusing, self-guiding, smoothing of the beam nonuniformities and, at larger power, beam filamentation. A bremsstrahlung model with account of the ionization, heating, expansion, and recombination dynamics of the gas, provides the plasma emission background. Both Thomson emission and bremsstrahlung are required to recover the experimental emission patterns. Among the interpretations, a scenario of laser self-guiding over five Rayleigh lengths can be found for 10 TW laser power and 5{times}10{sup 18} cm{sup {minus}3} electron density, which surprisingly disappears at larger powers and densities. {copyright} {ital 1996 American Institute of Physics.}
- OSTI ID:
- 279766
- Journal Information:
- Physics of Plasmas, Vol. 3, Issue 4; Other Information: PBD: Apr 1996
- Country of Publication:
- United States
- Language:
- English
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