Accession Number : ADA261384
Title : Start-Up Imprinting and Shock Dynamics in Laser-Target Interaction
Descriptive Note : Interim rept.
Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR COMPUTATIONAL PHYSICS DEVELOPMENTS
Personal Author(s) : Emergy, Mark H
Report Date : 10 Dec 1992
Pagination or Media Count : 27
Abstract : Improved uniformity of the laser for-al spot profile is a necessary criterion for the success of high intensity laser fusion and to improve the quality of data from moderate intensity laser driven shock experiments in solids. Recently developed laser smoothing techniques rely on both temporal smoothing and thermal smoothing to produce uniform ablation pressures on the target surface. Thermal smoothing is not effective during the low intensity portion of a laser pulse and the resultant shock structure mirrors the residual laser nonuniformities. The impact of the first (nonuniform) shock can be diminished by using foam layers, a precursor flash, shallow angles of incidence, and by adiabatically compressing the target with a temporally long, slowly rising laser pulse.
Descriptors : *SHOCK , *LASER TARGET INTERACTIONS , *LASER SPOTS , MIRRORS , ANGLES , ABLATION , IMPACT , LAYERS , PRECURSORS , STRUCTURES , INTENSITY , PULSED LASERS , SOLIDS , TARGETS , LASERS , SURFACES , INCOHERENCE , PROFILES , QUALITY , PULSES , LOW INTENSITY , FLASHES , NONUNIFORM , FOAM , UNIFORMS , FLUID DYNAMICS , HIGH INTENSITY , PRESSURE , RESIDUALS
Subject Categories : Directed Energy Weapons
Distribution Statement : APPROVED FOR PUBLIC RELEASE