激光在不同环境下烧蚀铝靶冲量耦合系数研究

ABSRTACTHigh energy impulse laser irradiation of solid metal target can make the target get a certainmomentum.By studying the relationship between laser energy density and impulse coupling coefficient oftarget,the influence of environmental conditions on the impulse coupling coefficient can be analyzed.Laser ablation of target can present differently in gas and liquid.Firstly,the interaction between laser and target under different conditions was theoreticallystudied in this paper,and then the shock wave model in gas and liquid was analyzed.Then the impulsecoupling coefficient of aluminum target was measured.The measurement of this experiment is by usingpiezoelectric sensor which was designed dependently with the material of aluminum.Experiments wereundertook separately in both gas and liquid.In a gas environment,the research content are as follows:(1)Under the standard air pressure,the relationship between laser energy density and the impulse couplingcoefficient of aluminum target was researched;(2)Changing air pressure,the impulse coupling coefficientof aluminum target was measured under the same energy density,then the effect of air pressure on thealuminum target's ablation was studied;(3)When the laser energy density was changed,the effects on theradius of ablation aluminum target was studied.In the liquid,the main researches include as follows:(4)The relationship between laser energy density and the impulse coupling coefficient of aluminum targetwas researched under a certain layer thickness of water;(5)The influence of laser focus position in thewater on the impulse coupling coefficient of aluminum target was studied:(6)The effect of different liquid'scharacteristics on the impulse coupling coefficient of aluminum target was analyzed.The experiment results show that:When the ablation of aluminum target occurs under thecondition of gas,the ablation rate and the laser plasma shock wave pressure may have influence on theimpulse coupling coefficient of aluminum target in different laser energy density,at the same time,theablation threshold would affect the value of the impulse coupling coefficient.When ablation of aluminumis in liquid,the trend of laser ablation variation under different energy density is closed to the trend in gas,but the value of the impulse coupling coefficient in liquid is greatly higher than in the air.It was found that