Hot Air Atmospheric Turbulence Simulator

描述

The hot air convection type can simulate the main effect characteristics of atmospheric turbulence simulator laser transmission in the earth’s atmospheric environment, such as: light intensity flicker, arrival angle undulation and spot drift; The input parameters are configurable, the atmospheric coherence length parameters can be set, and the output results can be monitored and compared with theoretical values. It can be widely used for functional verification and performance testing of various types of atmospheric channel laser systems.

Hot air convection atmospheric turbulence simulation device

The principle of hot wind atmospheric turbulence simulation device is that when optical observation systems such as telescopes or observers observe through the hot air turbulence simulation device, obvious atmospheric turbulence effects can be observed, which is consistent with the phenomenon of the actual earth’s atmosphere passing through long distances. At the same time, the device can also change the intensity of turbulence and simulate different turbulent conditions in the Earth’s atmosphere. Based on actual wind speed and temperature measurements, simulated atmospheric turbulence with the same statistical regularity can be repeatedly generated. The device helps students majoring in meteorology and optics to understand the general laws of turbulence in the earth’s atmosphere. The device is equipped with detailed detection sensors, and can also be used as scientific research experimental equipment in optics, physics, environment and other disciplines, providing researchers with innovative ideas and methods.

When the beam propagates in the atmosphere and encounters atmospheric turbulence, due to the non-uniformity of the turbulent medium, the beam is irregularly refracted and turbulent effects such as beam drift, spot jitter, phase fluctuation and beam expansion are produced, which will seriously affect the beam propagation and imaging quality. Field trials, on the other hand, are time-consuming, laborious, and poorly reproducible.
In response to the above problems, the Ministry of Electronic Information urgently needs to design a turbulence simulation device that can produce stable turbulence, at present, the domestic and foreign atmospheric turbulence simulation scheme mostly adopts convective turbulence simulation device, because it has the advantages of wide inertial area, good uniformity, easy control and so on. Its basic principle is: relying on the temperature change of the upper and lower surfaces of the turbulent flow pool to cause random movement of air in the turbulent pool, thereby forming atmospheric turbulence.

Based on Kolmogorov’s local uniform isotropic turbulence theory, the R&D personnel designed a forced convective turbulence simulation device, and its main working mode is to control the temperature difference between the upper and lower plates of the turbulence cell in real time to produce stable turbulence.

The atmospheric turbulence simulation device mainly includes several cavities:

• Atmospheric transmission atmospheric turbulence simulation device, mainly simulation control r0 adjustment.
• Atmospheric aerosol simulation device, simulating the attenuation of light intensity, aerosol cavity simulation, mainly simulating the attenuation of light intensity (oily) caused by smoke.
• Atmospheric transmission attenuation simulation device, simulating the attenuation of light intensity, simulation of attenuation cavity, mainly simulating light intensity attenuation caused by fog (water solubility, simulated water vapor).

If particularly fine attenuation simulations are not required, a single-chamber type can be used. What we recommend is to choose a combination design of two cavities: atmospheric transmission atmospheric turbulence simulation device + laser atmospheric transmission attenuation simulation device.

Main technical indicators:

• Equivalent atmospheric refractive index structure constant: 10km:≥10-16m-2/3; 1km：≥10-14m-2/3
• Atmospheric coherence length: 1-40cm
• Inner scale: 5mm
• Outer scale: 20cm
• True channel length: 3M
• Intensity frequency range: 50-80Hz
• Phase frequency range: 50-100Hz
• Effective clear aperture: 30cm
• Transverse uniform area: 25cm
• Turbulence intensity error: 20%
• Scintillation factor: 0.5
• Angular of arrival variance: 10 μrad
• Beam spread variance: 10 μrad
• Beam drift variance: 10 μrad
• The optical window is an anti-reflection coating of sapphire material: 800nm-1200nm, reflectivity ≤0.5%
• The turbulence simulator comes with a stand

Scope of application:

1. Space laser communication

2. High-energy laser weapons

3. Lidar