Backscatter and beam refraction in underdense gas breakdown with nanosecond CO/sub 2/ laser

Journal Article · Thu Sep 01 04:00:00 EDT 1977 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.324289· OSTI ID:7096939

Burnett, N H; Baldis, H A; Enright, G D; Richardson, M C; Corkum, P B

A 50-J 2-ns FWHM CO/sub 2/ laser pulse focused to intensities in excess of 10/sup 14/ W/cm/sup 2/ has been used to induce breakdown in underdense He gas. The laser radiation scattered from these plasmas has been temporally and spectrally analyzed. It is observed that ion wave scattering can result in reflectivities in excess of 50% of the incident intensity. At filling pressures above 30 Torr the incident laser radiation is explosively refracted around the focal region by plasma formed a few mm upstream from focus thus quenching the high-intensity laser plasma interaction less than 1 ns subsequent to breakdown. A weak but well-defined line at 7.06 ..mu..m (..omega..=3/2 ..omega../sub 0/) was observed in the backscatter at filling pressures above 40 Torr.

• Research Organization: National Research Council of Canada, Division of Physics, Ottawa, K1A OR6, Canada
• OSTI ID: 7096939
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 48:9; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
BACKSCATTERING
BREAKDOWN
BRILLOUIN EFFECT
CARBON DIOXIDE LASERS
COHERENT SCATTERING
CRYOGENIC FLUIDS
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
ELEMENTS
FLUIDS
FOCUSING
GAS LASERS
HELIUM
IONIZATION
LASER-PRODUCED PLASMA
LASERS
NONMETALS
PLASMA
PRESSURE DEPENDENCE
RADIATIONS
RAMAN EFFECT
RARE GASES
REFRACTION
SCATTERING
WAVE PROPAGATION