Minimization of the angular divergence of a partially coherent light beam on a vertical atmospheric path

The possibility of optimizing laser-beam energy transfer along a vertical path through the atmosphere and into the far diffraction zone is addressed. On the basis of numerical solutions of the small-angle radiation transfer equation for a wide range of energy parameters of the beam, including focusing in two perpendicular directions, the regions of these parameters that provide optimal transfer of the laser beam energy are determined. This approach and the results obtained make it possible to evaluate the feasibility of specific laser systems which transport energy through the atmosphere.