脉冲波形对冲量耦合系数的影响

为了研究TEA CO2激光输出的脉冲波形对激光推进中冲量耦合系数的影响,通过激光技术手段,改变激光混合气体比例及压强,控制激光器脉冲输出波形,将激光的脉冲宽度压缩近50%.在此基础上进行的激光推进冲量耦合系数的实验测量和数值计算结果表明,对于大气呼吸模式TEA CO2激光推进而言,在不影响工质击穿功率密度的情况下,减小脉冲前段起击穿工质作用的尖峰部分占整个脉冲能量的比例,有利于获得高的冲量耦合系数.脉冲宽度大于二维运动的特征时间时,获得的冲量耦合系数也高于脉冲宽度偏小时所获得的冲量耦合系数.

Effect of Pulse Waveform on Momentum Coupling Coefficient

To study the effect of transversely excited atmospheric(TEA) CO_2 laser pulse waveform on the momentum coupling coefficient,the waveform of laser pulse was changed,and the pulse duration was compressed about to 50% by controlling the pressure of the gas and proportion of components in gas mixture.According to that,some experiments and numerical calculation were done.Achieved results indicate that increasing the coupling coefficient is very favorable for decreasing the proportion of energy between the forepart and the whole pulse in TEA CO_2 laser propulsion.Also,the coupling coefficient can be effectively raised while pulse duration is bigger than characteristic time of two-dimensional movement.