摘要
大气中折射率起伏主要由温度的随机变化引起,因此可通过调节气流的温度和速度来人工地产生湍流并控制其强度,基于此原理设计并研制了一种用于光传输实验研究的大气湍流箱。通过同时测量传输光波的到达角起伏和闪烁,得到了箱内光传输路径上大气折射率结构常数Cn2和湍流内尺度l0。实验结果显示,Cn2和l0分别受箱内温度和风速的影响。Cn2在温度45℃、风速0.48 m/s时达到1.58×10-11 m-2/3,l0在温度25℃、风速1.04 m/s情况下为2.33 mm。对对数光强时间功率谱的分析表明,此湍流箱所产生的湍流适合用于光波大气传输湍流效应的实验研究。
Since the refractive index fluctuations in the atmosphere are caused mainly by random variations in temperature,turbulence can be artificially generated and its strength can be controlled via changing the temperature and velocity of air flow.Based on this principle,a turbulence chamber was designed and built for performing optical propagation experiments.The refractive index structure constant Cn^2 of atmosphere and inner scale l0 of turbulence along the optical propagation path inside the chamber were obtained from the simultaneous measurement of angle-of-arrival fluctuations and scintillation of the propagating light-wave.The experimental results show that the Cn^2 and l0 of the generated turbulence are mainly influenced by the temperature and wind velocity inside the chamber,respectively.Cn^2=1.58×10^-11 m^-2/3 is obtained at 45 ℃ with wind velocity 0.48 m/s and l0=2.33 mm at 25 ℃ with wind velocity 1.04 m/s.And the temporal power spectrum analysis of log-intensity indicates that the generated turbulence is suitable for performing optical propagation experiments.
出处
《红外与激光工程》
EI
CSCD
北大核心
2010年第5期920-923,共4页
Infrared and Laser Engineering
基金
国防预研基金项目
关键词
大气光学
光传输
大气湍流模拟
折射率结构常数
内尺度
湍流折射率谱
Atmospheric optics
Optical propagation
Atmospheric turbulence simulation
Refractive index structure constant
Inner scale
Turbulence refractive index spectrum
