Laser interaction in long-scalelength plasmas. Interim report

Technical Report · Tue Dec 31 00:00:00 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
ELECTRONS
PRODUCTION
LASER RADIATION
INTERACTIONS
LASER-PRODUCED PLASMA
ABSORPTION
BACKSCATTERING
ENERGY TRANSFER
OPTICAL PROPERTIES
STABILITY
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
FERMIONS
LEPTONS
PHYSICAL PROPERTIES
PLASMA
RADIATIONS
SCATTERING
700208* - Fusion Power Plant Technology- Inertial Confinement Technology