Experimental Investigations of Optical Propagation in Atmospheric Turbulence

Experimental Investigations of Optical Propagation in Atmospheric Turbulence PDF Author: Michael W. Fitzmaurice
Publisher:
ISBN:
Category : Atmospheric chemistry
Languages : en
Pages : 196

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Book Description
The pertinent theoretical background and the results of a group of experiments conducted over 0.4- and 1.17-km near-ground horizontal ranges are presented. (1) The log-amplitude variances for HeNe (0.633 μm) and CO2 (10.6 μm) laser beams were found to have a ratio of 26.8, which is in close agreement with the predictions of Rytov-based spherical-wave theory. (2) Published measurements of the saturation level of the log-amplitude variance are reviewed and several inconsistencies noted. (3) The spatial correlation function of irradiance field was measured and found to agree with theory. The degree of correlation between different frequency beams which had traversed the same optical path was also measured and compared to theory. The data exhibited an unacceptably large scatter and did not show the wavelength dependence. (4) The log-normal, Rayleigh, and Rice probability distributions are discussed in terms of their applicability to irradiance statistics. Relatively weak 10.6 μm irradiance fluctuations were found to be equally well described by the log-normal and Rice distributions; strong fluctuations obtained at 0.488 μm were clearly best described by the log-normal distribution.

Experimental Investigations of Optical Propagation in Atmospheric Turbulence

Experimental Investigations of Optical Propagation in Atmospheric Turbulence PDF Author: Michael W. Fitzmaurice
Publisher:
ISBN:
Category : Atmospheric chemistry
Languages : en
Pages : 196

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Book Description
The pertinent theoretical background and the results of a group of experiments conducted over 0.4- and 1.17-km near-ground horizontal ranges are presented. (1) The log-amplitude variances for HeNe (0.633 μm) and CO2 (10.6 μm) laser beams were found to have a ratio of 26.8, which is in close agreement with the predictions of Rytov-based spherical-wave theory. (2) Published measurements of the saturation level of the log-amplitude variance are reviewed and several inconsistencies noted. (3) The spatial correlation function of irradiance field was measured and found to agree with theory. The degree of correlation between different frequency beams which had traversed the same optical path was also measured and compared to theory. The data exhibited an unacceptably large scatter and did not show the wavelength dependence. (4) The log-normal, Rayleigh, and Rice probability distributions are discussed in terms of their applicability to irradiance statistics. Relatively weak 10.6 μm irradiance fluctuations were found to be equally well described by the log-normal and Rice distributions; strong fluctuations obtained at 0.488 μm were clearly best described by the log-normal distribution.

Experimental Investigations of Optical Propagation in Atmospheric Turbulence

Experimental Investigations of Optical Propagation in Atmospheric Turbulence PDF Author: Michael W. Fitzmaurice
Publisher:
ISBN:
Category : Atmospheric chemistry
Languages : en
Pages : 196

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Book Description
The pertinent theoretical background and the results of a group of experiments conducted over 0.4- and 1.17-km near-ground horizontal ranges are presented. (1) The log-amplitude variances for HeNe (0.633 μm) and CO2 (10.6 μm) laser beams were found to have a ratio of 26.8, which is in close agreement with the predictions of Rytov-based spherical-wave theory. (2) Published measurements of the saturation level of the log-amplitude variance are reviewed and several inconsistencies noted. (3) The spatial correlation function of irradiance field was measured and found to agree with theory. The degree of correlation between different frequency beams which had traversed the same optical path was also measured and compared to theory. The data exhibited an unacceptably large scatter and did not show the wavelength dependence. (4) The log-normal, Rayleigh, and Rice probability distributions are discussed in terms of their applicability to irradiance statistics. Relatively weak 10.6 μm irradiance fluctuations were found to be equally well described by the log-normal and Rice distributions; strong fluctuations obtained at 0.488 μm were clearly best described by the log-normal distribution.

Electromagnetic Scintillation: Volume 2, Weak Scattering

Electromagnetic Scintillation: Volume 2, Weak Scattering PDF Author: Albert D. Wheelon
Publisher: Cambridge University Press
ISBN: 113943960X
Category : Science
Languages : en
Pages : 462

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Book Description
The first volume of this set of books on electromagnetic scintillation dealt with phase and angle-of-arrival measurement errors, which are accurately described by geometrical optics. This second volume concentrates on amplitude and intensity fluctuations of the received signal.

NASA Technical Report

NASA Technical Report PDF Author:
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 1054

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Book Description


Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 440

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Book Description


Experimental Study of Laser Propagation Through the Atmospheric Turbulence

Experimental Study of Laser Propagation Through the Atmospheric Turbulence PDF Author: Kirk Alan Lohnes
Publisher:
ISBN:
Category : Ionosphere
Languages : en
Pages : 198

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Book Description


Optical Waves and Laser Beams in the Irregular Atmosphere

Optical Waves and Laser Beams in the Irregular Atmosphere PDF Author: Nathan Blaunstein
Publisher: CRC Press
ISBN: 1351402684
Category : Computers
Languages : en
Pages : 334

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Book Description
The book introduces optical wave propagation in the irregular turbulent atmosphere and the relations to laser beam and LIDAR applications for both optical communication and imaging. It examines atmosphere fundamentals, structure, and content. It explains specific situations occurring in the irregular atmosphere and for specific natural phenomena that affect optical ray and laser beam propagation. It emphasizes how to use LIDAR to investigate atmospheric phenomena and predict primary parameters of the irregular turbulent atmosphere and suggests what kinds of optical devices to operate in different atmospheric situations to minimize the deleterious effects of natural atmospheric phenomena.

An Investigation of Atmospheric Turbulence by Stellar Observations

An Investigation of Atmospheric Turbulence by Stellar Observations PDF Author: Jack Lytle Bufton
Publisher:
ISBN:
Category : Astrophysics
Languages : en
Pages : 188

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Book Description
This study of the optical effects of atmospheric turbulence concentrates on the stellar observation problem. When an infinite plane wave from an incoherent stellar source is sampled by an earth-based telescope, the resultant stellar image exhibits random fluctuations in intensity, position, and size due to turbulence-induced scattering in the intervening atmosphere. One familiar aspect of this problem is the scintillation of starlight apparent to the naked eye. The central aim is to express optical statistics in terms of refractive-index structure constant which pertains to strength of turbulence along the optical path. Data is presented on stellar and meteorological observations made between fall 1968 and spring 1969 with a 0.152-meter diameter refracting telescope. Data was recorded simultaneously on the three parameters of image intensity, motion, and size. The data is interpreted in terms of the theory and used to estimate strength of turbulence. The central result is a series of profiles for refractive-index structure constant along the vertical path. These are constructed using stellar data to calculate parameters of a model.

Optical Beam Propagation in Turbulent Media

Optical Beam Propagation in Turbulent Media PDF Author: Ronald Louis Fante
Publisher:
ISBN:
Category : Atmospheric turbulence
Languages : en
Pages : 88

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Book Description
The most recent developments on the propagation of microwave and optical beams in turbulent media, such as the clear atmosphere are discussed. Among the phenomena considered are beam spreading, beam wander, loss of coherence, scintillations, angle-of-arrival variations, and short pulse effects. Also included is a discussion of methods of compensation of the effect of turbulence on communications and imaging systems.

Coherent Doppler Wind Lidars in a Turbulent Atmosphere

Coherent Doppler Wind Lidars in a Turbulent Atmosphere PDF Author: Viktor Banakh
Publisher: Artech House
ISBN: 1608076679
Category : Technology & Engineering
Languages : en
Pages : 277

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Book Description
Radiophysical tools for measuring atmospheric dynamics include sodars, Doppler radars, and Doppler lidars. Among these, coherent Doppler lidars (CDLs) have been considered the best for remote measurement of wind turbulence. This is important not only for understanding the exchange processes in the boundary layer, but also in the applied aspect, such as aviation safety. CDLs significantly extend possibilities of experimental investigation of not only wind turbulence, but also coherent structures such as aircraft wake vortices. The authors of this book conducted field tests of the developed methods of lidar measurements of the wind velocity, atmospheric turbulence parameters, and aircraft wake vortices. This valuable resource, containing over 500 equations based on original results from the authors’ work, gives professionals a comprehensive description of the operating principles of continuous wave and pulsed coherent Doppler lidars. This book studies the possibilities of obtaining information about wind turbulence from data measured by continuous wave and pulsed CDLs. The procedures for estimation are described, as well as algorithms for numerical simulation. Results on the vortex behavior and evolution are then presented.