大气模式激光推进耦合系数的实验研究

Experimental Study of Coupling Coefficients for Air-Breathing Mode Laser Propulsion

为了研究大气压强对激光推进耦合系数的影响,设计了一座真空仓,利用真空泵系统控制仓内气压从4.6×103Pa到101.3×103Pa之间变化。采用单脉冲能量为20J的TEACO2激光器,对挂有光船模型的冲击摆进行大气模式激光推进耦合系数的测定。实验发现随着真空仓内气压的上升,冲量耦合系数逐渐增大,当气压值达到34.6×103Pa左右时,冲量耦合系数达到最大,随后伴同气压值的增加冲量耦合系数逐步下降。当入射激光单脉冲能量为10J时,冲量耦合系数的峰值处的气压值略有降低。从激光等离子体冲击波的角度对这一现象进行了初步的分析和解释,预测了能量对冲量耦合系数的峰值影响。

In order to study the effect of the air pressure on the coupling coefficients for laser propulsion, a vacuum chamber was designed in which the air pressure can be changed from 4.6 × 103 Pa to 101.3 × 103 Pa. The pendulum with light-craft model was propelled by TEA CO2 laser. It was found in the experiment that when the laser pulse energy was 20 J, the coupling coefficients increased gradually with the increase of air pressure, reached the summit at the air pressure of 34.6 kPa, then began to decrease. When the laser pulse energy was reduced to the 10 J, the air pressure value at which the coupling coefficients reached the summit fell. According to the theory of shockwave and laser plasma, the paper gives a preliminary analysis to this phenomenon and predicted the effect of the laser pulse energy on the peak value of coupling coefficients.