Beam wander in moderate to strong turbulence

Based on the Rytov approximation which is modified with a filter function, expressions are derived for the variance associated with the beam wander in moderate to strong turbulence regimes. The effects of the diameter of the effective scattering region and beam waist on the beam wander are analyzed, and the derived variance expression is compared with experimental data. The results show that the calculated value from the derived displacement variance extending into all regimes is in better agreement with experimental data, compared with the variance based on the exponential model. When the beam waist is larger than the diameter of the effective scattering region, the effects of the saturation don't occur. When the diameter of the effective scattering region is larger than the beam waist, the effects of the saturation do occur.