Studies on Relaxation-Time-Difference Laser by Supersonic Nozzle Flow and the Superposition of Discharge

一种新研制的激波管在工作时不需要传统激波管中用来分隔高压区和低压区的膜片。采用这种新方案，可望获得几个有利的特性：在无膜片型激波管中，每次实验后不必更换膜片。因此，可以减少实验中杂质的流入。例如，在CO_2-N_2系统中，激波加热和超音速喷管流动（快速膨胀）系统中，即使少量的H_2O也对粒子数反转的程度相当敏感。因此，无膜片型激波管对于该方案中粒子数反转的详细研究至关重要。此外，实验的重复性和效率可望大大提高。无膜片激波管中的高压驱动活塞如图1所示。圆柱体部分C和D填充有 关于我们 其压力高于驾驶室的压力。由于活塞B中心钻有一个小针孔（ψ= 1 mm），因此C、D缸段的压力在初始阶段是相等的。当气体通过排气阀从C部分释放时，C部分的压力迅速下降。由于通过C和D之间的针孔的传导性低，压力不平衡迅速发展，这将导致活塞B向左手侧快速移动。当D段的气体通过侧孔流出时，D段与驱动室之间的压力不平衡导致活塞A快速向左侧移动，这使得驱动室中的高压气体流入从动室。因此，一种无膜片式激波管正在发展中，用于气动激光器的研究。就会产生冲击波为了使活塞快速运动，进行了一些改进，最终成功地获得了冲击波的传播。观察了冲击波到达引起的压力变化的动态行为，用压电计测量了冲击波速度，最后用CO_2-N_2混合气体获得了10.6μm波段的气动激光振荡。

A shock tube has been newly developed to be operated without a diaphragm which the conventional shock tube has in order to separate the high and low pressure regions. By this new scheme, several advantageous properties are expected to be obtained.In the non-diaphragm type shock tube, there is no necessity for replacing a diaphragm after each experiment. Thus, it will be possible to reduce influx of impurities in the experiment. For example, even a small amount of H_2O is anticipated to be quite sensitive for the extent of population inversion in CO_2-N_2 case with shock wave heating and supersonic nozzle flow (fast expansion) system. Consequently, a non-diaphragm type shock tube is very important for the detailed studies of population inversion in this scheme. In addition, the reproducibility and the efficiency of experiments may be expected to be largely improved.High pressure driven pistons in the non-diaphragm shock tube are shown in Fig.1. The cylinder sections C and D are filled w … More ith a higher pressure gas than that of the driver room. Since a small pinhole (ψ=1mm) is drilled at the center of the piston B, the pressures of cylinder sections C and D are equal at the initial stage. When the gas is released from the C part through exhaust valve, the pressure of section C quickly decreases. Because of a low conductance through the pinhole between C and D, a pressure imbalance quickly develops and this will lead the fast movement of the piston B toward left hand side. When the gas in the section D flows out through lateral holes, the pressure imbalance between the section D and the driver room causes a fast movement of the piston A to the left side, and this makes the high pressure gas in the driver room flows into the driven room. Consequently, A non-diaphragm type shock tube is being developed for the gas-dynamic laser research. a shock wave will occur. Several improvements have been carried out in order to have quick movement of pistons, and finally the shock wave propagation has been successfully obtained. The dynamic behaviors of pressure changes caused by the arrival of shock waves have been observed, and the shock wave velocity has been measured by using piezo electric gauges.Finally, the gas-dynamic laser oscillation of 10.6μm band with the CO_2-N_2 mixture has been obtained Less