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AIOFM proposes an equivalent method of non-Kolmogorov atmospheric turbulent refractive-index structure constant TEXT SIZE: A A A
Date:2015.12.07 Author:LI yujie Clicks:

 

Recently, an equivalent method of non-Kolmogorov turbulent refractive-index structure constant was proposed by prof. Wenyue ZHU group from the Key Laboratory of Atmospheric Composition and Optical Radiation (LACOR) of Anhui Institute of Optics and Fine Mechanics (AIOFM). This method established the equivalent relationship between the Kolmogorov turbulence refractive-index structure constant and the non- Kolmogorov turbulence refractive-index structure constant. The result has been reported recently in the journal of Optics Express (23, 2015 (18), 23004-23012).

 

The random fluctuations of atmospheric refractive-index caused by turbulence can result in the wave front distortion and damage the optical coherence, which limit the applications of optical communication, optical remote sensing, optical imaging and so on. Refractive-index structure constant is often used to describe the strength of turbulent fluctuations. It has the obvious characteristics of the diurnal variation and the height variation. At present, existing measurement data and models of turbulent refractive-index structure constant are based on the Kolmogorov statistical theory. However, with the development of researching in atmospheric turbulence, it was found that atmospheric turbulence has not always obeyed the Kolmogorov statistical characteristic. The concept of non-Kolmogorov turbulence is proposed. As before, the refractive index structure constant is still used to describe the turbulence fluctuations strength in non-Kolmogorov turbulence, but it has a variational dimension “m3-α” rather than “m-2/3”, where α is the spectral power law, which leads to many difficulties in describing the non-Kolmogorov turbulence strength and analyzing the light propagation effects in the non-Kolmogorov atmospheric turbulence. In addition, the relationship between the Kolmogorov and the non Kolmogorov turbulence is also an urgent problem to be solved in the study of optical atmospheric propagation.

 

In the paper, based on the turbulent structure function and the refractive-index fluctuations variance, the relation between the non-Kolmogorov turbulent refractive-index structure constant and the Kolmogorov turbulent refractive-index structure constant is established and the correctness of results is verified by experiments. The equivalent relation shows that the non-Kolmogorov refractive-index structure constant can be expressed as a function of the Kolmogorov refractive-index structure constant, the outer scale and the power law. On the one hand, it can avoid many difficulties in using the non-Kolmogorov refractive-index structure constant because of its variation dimension. On the other hand, the equivalent relationship can be used to connect the light propagation properties in Kolmogorov turbulent atmosphere and non-Kolmogorov turbulent atmosphere. In addition, by combining the out scale models, the spectral power law models and the existing Kolmogorov structure constant models, the models of non-Kolmogorov structure constant also can be established.

Comparison of non-Kolmogorov structure constant between measurement results and equivalent results (Image by Li Yujie)

The full text link: https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-23-18-23004

Title: Equivalent refractive-index structure constant of non-Kolmogorov turbulence

Key words: Atmospheric optics; Atmospheric propagation; Atmospheric turbulence; Wave propagation

Prof. Wenyue ZHU, Ph.D Principal investigator

Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences

Hefei, Anhui 230000, China

Tel: 0551-5591004

E-mail: zhuwenyue@aiofm.ac.cn

Drafter: Li Yujie



 
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