Determination of Atmospherically Induced Phase Fluctuations by Long–Distance Interferometry at 6328 Å*

Experimental values of atmospherically induced phase fluctuations have been obtained for various path lengths, using a near-ground horizontal Mach–Zehnder setup at 6328 Å. Independent determination of the structure–function constant of the refractive index Cn and other relevant parameters permitted a clear definition of prevailing meteorological conditions. For low turbulence, or strong turbulence and short path length, Tatarski’s theory generally underestimates the values of the observed rms phase fluctuations. For higher turbulence, no continuous phase information is directly obtainable, and the concept of phase structure function becomes experimentally undefined.