Impact of ground profile on scintillation: 50km and 200km slant paths from airplane to Antelope Peak

The interest for free space laser beam propagation has recently increased due to several experiments. These experiments have shown that optical links through the atmosphere can be effectively established, regardless of the several deleterious negative effects of refractive index fluctuations. The most deleterious effect is the scintillation which, consequently, has been widely investigated. However, it has not been reported yet what influence a ground profile has on scintillation values. In this paper we show theoretical results of the ground impact on scintillation, for a laser link between aircraft and mountain top; Antelope peak Nevada. The link was investigated for a specific mountainous profile of the ground for path lengths of 50 km and 200 km. The theoretical analysis shows that, if a low value is assumed for the Rytov variance (weak turbulence condition), then the presence of high peaks or mountains along the propagation path could have a remarkable impact on scintillation because the scintillation saturation effects do not occur; if the Rytov variance assumes medium-high values (moderate-to-strong turbulence conditions), then the scintillation index will be close to the saturation regime. Therefore the scintillation will be slightly affected by the mountains along the path, both for the plane wave model and the Gaussian beam wave model.