激光等离子体动量转换效率的实验研究

强激光与固体靶相互作用时，产生的高速喷射的等离子体对靶具有强烈的反冲作用，因此，激光等离子体可以作为一种新型的推进动力源.与传统的化学燃料推动相比，激光等离子体具有较高的比冲和有效载荷比等特点.对纳秒激光脉冲与铝、石墨、铅和碳氢靶相互作用时，等离子体对靶的冲量进行了实验测量，研究了大气与真空环境下的靶动量与激光聚焦面积的关系，并对部分实验结果与理论计算的数值进行了比较.实验结果显示，大气与真空环境下的靶动量有很大的差异，并且真空下的靶动量受材料性质的影响较大，与以往长脉冲激光的实验结果有很大的不同.关键词：激光等离子体动量动量耦合系数

Experimental study on the momentum coupling efficiency of laser plasma

During the interaction of laser with solid targets, the counteracting force is generated by the plasma, which can be used as a new type source of propulsion. Compared with the chemical propulsion, laser plasma has unique advantages such as high specific impulse and large load ratio. In this paper, the momentum generated by the laser plasma is measured during the interaction of nanosecond laser pulses with aluminum, graphite, lead and CH targets. The relation of target momentum with laser focal area in atmosphere and vacuum ambient pressure is obtained,and the comparison is performed between the experimental and analytical results. It is shown that the target momentum in vacuum is different from that in atmosphere. In vacuum, the target momentum shows a dependence on the target property. These results are different from those generated by long width pulses.