Laser interaction in long-scale-length plasmas

Journal Article · Tue Apr 01 04:00:00 EST 1986 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.865880· OSTI ID:6092364

Gardner, J H; Herbst, M J; Young, F C; Stamper, J A; Obenschain, S P; Manka, C K; Kearney, K J; Grun, J; Duston, D; Burkhalter, P G

Absorption of a short-pulse, high-intensity Nd-laser beam (vacuum irradiance of 10/sup 14/ to 10/sup 15/ W/cm/sup 2/) by preformed plasmas of different density scale lengths is investigated. Increased effects of plasma instabilities are found at longer scale lengths. The amount of backscattered light increases with plasma scale length and limits the absorption fraction at the longest scale length. The onset of suprathermal electron production, deduced from observations of energetic (20 to 50 keV) x rays, occurs at lower laser irradiance for longer-scale-length plasmas. A correlation between energetic x rays and 3..omega../sub 0//2 emission suggests that the suprathermal electrons are produced by a plasma instability at quarter-critical density. At higher intensities there is evidence for severe perturbations of the preformed plasma and for self-focusing of the incident beam.

• Research Organization: U. S. Naval Research Laboratory, Washington, D.C. 20375
• OSTI ID: 6092364
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:4; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
ABSORPTION
BACKSCATTERING
COLLISIONAL PLASMA
ELECTROMAGNETIC RADIATION
ENERGY ABSORPTION
ENERGY RANGE
HOT PLASMA
INSTABILITY
INTERFEROMETRY
IONIZING RADIATIONS
KEV RANGE
KEV RANGE 10-100
LASER RADIATION
LASER-PRODUCED PLASMA
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA INSTABILITY
POWER
PULSES
RADIATIONS
SCATTERING
X RADIATION