Description and measurement of the strength of an optical turbulence

Abstract

In the theory of light wave propagation in turbulence the refractive index structure constant is taken as a measure of the strength of the turbulence. A lot of efforts have been made to measure this parameter at different regions and seasons. However, this parameter doesn't indicate the fluctuation strength directly and for a non-Kolmogorov turbulence its unit is not fixed. Such a unit-varying parameter shouldn't be a suitable measure of a physical quantity. It is found that the strength of an optical turbulence is the variance of the refractive index. In the inertial subrange the structure function of refractive index generally depends on both the variance and the turbulence outer scale. The light propagation effects could be interpreted more clearly through these turbulence parameters. Instead of the structure constant the variance, the outer scale, the scaling power and the inner scale should be measured in the study of light propagation.