Laser interaction in long-scalelength plasmas. Interim report

Technical Report · Tue Dec 31 04:00:00 EST 1985

OSTI ID:5725515

Gardner, J H; Herbst, F C; Young, M J; Stamper, J A; Obenschain, S P

Absorption of a short-pulse, high-intensity Nd-laser beam (vacuum irradiance of 10/sup 14/ to 10/sup 15/ W/sq cm) by preformed plasmas of different density scalelengths is investigated. Increased effects of plasma instabilities are found at longer scalelengths. The amount of backscattered light increases with plasma scalelength and limits the absorption fraction at the longest scalelength. The onset of suprathermal electron production, deduced from observations of energetic (20- to 50-keV) x rays, occurs at lower laser irrradiance for longer scalelength 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: Naval Research Lab., Washington, DC (USA)
• OSTI ID: 5725515
• Report Number(s): AD-A-163604/2/XAB; NRL-MR-5651
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700208* -- Fusion Power Plant Technology-- Inertial Confinement Technology
ABSORPTION
BACKSCATTERING
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
ENERGY TRANSFER
FERMIONS
INTERACTIONS
LASER RADIATION
LASER-PRODUCED PLASMA
LEPTONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLASMA
PRODUCTION
RADIATIONS
SCATTERING
STABILITY