Beam Wander Along Horizontal Paths

In this chapter we develop mathematical models of beam-wander effects on a conventional Gaussian beam with emphasis on horizontal paths. In particular, we compare the mathematical models displayed here with computer simulation data for both collimated and convergent Gaussian beams as a means of validating the theory. In addition, results from an outdoor experiment involving beam wander are also compared with this theory. We further examine the general behavior of focused beams in the vicinity of the region where Rytov theory for the scintillation index of an untracked beam fails and suggest a simple way to locate this region. In the last section we present computer simulation results for the scintillation index of a flattened Gaussian beam, with and without beam wander.