激光推进冲量耦合系数测量方法比较

 针对测量冲量耦合系数的水平导轨法和冲击摆法,分别进行了误差计算和实验研究。计算结果表明:水平导轨测量法的相对误差（4.6%）略小于冲击摆测量法的相对误差（6.1%）,其中位移参数和最大摆角的测量精度对于相对误差的影响最大。实验结果表明:两种方法的测量结果基本一致,冲量耦合系数均随着入射脉冲能量的增大而增大,且两组数据相差在6%以内,在入射脉冲能量为3~14 J时,冲量耦合系数最高可达260 N·MW^-1。     

Coupling coefficient for TEA CO2 laser propulsion with variable pulse repetition rate

Because pulse repetition rate affected directly the momentum coupling coefficient of transversely excited atmospheric (TEA) CO2 laser propulsion, a double pulse trigger, controlling high voltage switch of laser excitation circuit, was designed. The pulse interval ranged between 5 and 100 ms. The momentum coupling coefficient for air-breathing mode laser propulsion was studied experimentally. It was found that the momentum coupling coefficient decreased with the pulse repetition rate increasing.     

Experimental investigation of the effects of laser parameters on laser propulsion

The effects of main laser parameters,such as pulse energy,pulse duration,frequency,and work time on laser propulsion of "air-breathing mode",are investigated experimentally with a high power and high repetition frequency TEA-CO2 pulsed laser.The results show that the momentum coupling coefficient Cm decreases with increasing the pulse energy for single pulse tests and pulse duration of about 1μs.Either higher or lower frequency will reduce Cm in multi-pulse tests,which suggests an optimal frequency for the maximum Cm.As to the work time,the longer the work time is,the less the Cm will be.     

基于MATLAB的CO2 激光光斑质量鉴别技术

针对光栅调谐TEA CO2激光器，为了得到良好的光斑质量，利用红外热像仪、图像采集卡、直驱交流伺服电机和计算机建立了一套光斑鉴别系统，并通过实验成功地实现了对CO2激光光斑质量的鉴别。     

Experimental investigation of the effects of laser parameters on laser propulsion

The effects of main laser parameters, such as pulse energy, pulse duration, frequency, and work time on laser propulsion of "air-breathing mode", are investigated experimentally with a high power and high repetition frequency TEA-CO_2 pulsed laser. The results show that the momentum coupling coefficient C_m decreases with increasing the pulse energy for single pulse tests and pulse duration of about 1 μs. Either higher or lower frequency will reduce C_m in multi-pulse tests, which suggests an optimal frequency for the maximum C_m. As to the work time, the longer the work time is, the less the C_m will be.     

激光脉冲重复频率对冲量耦合系数的影响

 设计了触发间隔从100 ms到5 ms可调的双脉冲触发器驱动TEA CO₂激光器高压开关，用以模拟激光器不同的输出脉冲重复频率。用该装置精确控制的不同激光脉冲重复频率下，对抛物面型光船模型进行了大气模式激光推进中冲量耦合系数的实验研究。发现冲量耦合系数随着重复频率的增加而下降，而单位时间内光船获得的冲量耦合系数的增量则随着重复频率的增加而增大。初步分析认为，这是由于飞行器内的空气未得到充分的补充造成的。     

TEA CO2激光器预电离结构电极系统的电场研究

 高功率气体激光器的非对称复杂电极系统中,电极参数的变化以及预电离结构的引入将会使所设计的均匀电场发生具体的改变。采用高精度有限元方法,对这类复杂电极系统进行建模并且计算其电场分布,根据分析结果更合理地指导激光器设计。对一种典型的非对称复杂电极系统TEA CO₂激光器,应用该方法并结合了预电离过程,研究了引入预电离器导体和变化电极形状对电极表面的电场强度起伏和放电空间的均匀电场面积产生的影响。结果表明:通过这种预先模拟,合理选择电极构型参数和预电离结构安装位置,可以产生性质较好的均匀电场以及效率较高的激光输出。     

紧凑型双路TEA CO_(2)激光器谐振腔热稳定性及补偿EI北大核心CSCD

通过实验和仿真的方法,研究了多点分布的内部热源加热作用对紧凑型双路TEA CO_(2)激光器谐振腔热稳定性的影响。采用直流风扇热交换抑制了高压电源的局部加热效应,通过调整热交换的效率,可在13~22℃环境温度范围内,使前后谐振腔镜受到的局部加热形变作用和环境温度引起的热胀冷缩作用基本抵消。为实现更宽温度范围的谐振腔稳定性,在有效热交换措施的基础上,根据模拟预测的形变规律,提出了谐振腔变形的角度补偿方法。使用传感器获得环境温度与设定初始环境温度的偏差,通过调整伺服电机步数实现对方位角的补偿,补偿值约0.28 step/℃,通过PZT促动器调整悬臂调谐结构末端位移,实现对俯仰角的补偿,补偿值约0.79μm/℃。     

激光推进自由飞行实验

为了解决激光推进自由飞行演示中飞行器垂直飞行的稳定性问题,设计了旋转发射平台装置。在飞行器起飞前,给其施加一定的转速。当转速达到700 r/m时,质量为4.2 g,焦距为10 mm的抛物面型飞行器在单脉冲输出能量为13 J,重复频率50 Hz的TEA CO2激光器的推进下,成功实现了重复频率脉冲激光推进竖直自由飞行演示。飞行高度达到2.6 m,飞行持续时间为1.75 s。结果表明,在激光输出能量一定的情况下,通过提高飞行器的转速,可以提高激光推进自由飞行演示中飞行器的稳定性,从而适当地提高飞行高度。     

TEA CO2激光推进耦合系数的实验研究

报道了采用高重复频率TEA CO2激光器在不同气压下对冲击摆进行大气模式激光推进耦合系数测试的实验.结果发现,在气压为34.6×103 Pa左右可获得最大的冲量耦合系数.这与在不同气压下采用冲击摆进行固体靶激光推进实验中,在34.6×103 Pa左右存在最大的冲量耦合系数相似.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.