Intensity fluctuation measurements in strong atmospheric scintillation: effect of the apparatus saturation on higher order moments

In laser atmospheric scintillation measurements, during evolving turbulence, a large range of intensity fluctuations can be spanned. Very strong fluctuations can reach the saturation region of the apparatus, giving rise to deterioration of the intensity statistics. The results of a theoretical and experimental investigation on the higher order moments of the intensity, up to five, due to the apparatus saturation, are presented. The intensity statistics is assumed to be described by an Ito-Furutsu distribution. For comparison the standard log-normal distribution is also examined. The final purpose is to provide criteria to evaluate the performance of a giving apparatus and to choose a suitable system when its saturation effect is to be reduced below given limits.