Investigation of intensity fluctuations of $\lambda=10.6\mu$ laser radiation in the atmosphere

Measurements of the relative variance of the intensity fluctuations $\beta^2= \overline{(I-I)^2}/\bar{I}^2$ were carried out over paths $\chi=16.3$ and $13.5$ km long using a collimated $\lambda = 10.6$ $\mu$ laser beam. Saturation of the function $\beta(\beta_0)$ was observed in the range $\beta_0^2=1.23 C_n^2k^{7/6}\chi^{11/6}> 4$ ($C_n^2$ is the structure characteristic of the refractive index of air). A comparison of the results obtained at wavelengths of 10.6 and 0.63 $\mu$ indicated that the function $\beta(\beta_0)$ was the same at both wavelengths.