Impulse Generation on Aluminum Target Irradiated with Nd:YAG Laser Pulse in Ambient Gas

摘要

Mechanisms of the impulse on an aluminum foil generated through laser ablation with the Nd:YAG laser with anwavelength of 1064 nm are studied by fitting computed results to the time-resolved impulse data measured by usingnthe Velocity Interferometer System for any reflector for different ambient pressures ranging from 10u00012nto 105nPa.nThe computational method used accounts for thermal conduction within the aluminum target, the vaporizationnprocess under equilibrium thermodynamics through the Clausius–Clapeyron equation, and the expansion ofnaluminum ablation jet described by compressible gas dynamics with the laser radiation energy transfer. A constantnreflectivity value on the aluminum target surface is used to replicate the time-resolved impulse data. The presentnstudy shows that the breakdown of ambient gas and the gas dynamic confinement of an ablation jet are attributed tonthe impulse generation at higher pressure cases after the laser power peak of the Nd:YAG laser. At lower ambientnpressures, the impulse is produced due to the momentum transfer of the aluminum vapor ejected by laser ablationnduring the laser power peak.