Spreading and evolution behavior of coherent vortices of multi-Gaussian Schell-model vortex beams propagating through non-Kolmogorov turbulence

The explicit closed-form expressions for the beam width and angular spread of multi-Gaussian Schell-model vortex (MGSMV) beams propagating through atmospheric turbulence are derived in this paper. The spreading and evolution behavior of coherent vortices of MGSMV beams in non-Kolmogorov turbulence are investigated quantitatively by some typical numerical examples, where the evolution behavior of coherent vortices is stressed in particular. It is illustrated that MGSMV beams are more resistant to atmospheric turbulence than multi-Gaussian Schell-model (MGSM) non-vortex beams. By increasing the beam index of MGSMV beams, the deleterious turbulence effects can be reduced gradually. As MGSMV beams propagate in non-Kolmogorov turbulence, the position and number of coherent vortices are changeable. The impact of the beam index and fluctuations of atmospheric turbulence on the conservation distance of the topological charge is also explored in depth. •Closed-form expressions for the beam width and angular spread are derived.•Average intensity undergoes several stages of evolution in turbulence.•MGSMV beams spread more slowly than MGSM non-vortex beams in turbulence.•Position and number of coherent vortices change with MGSMV beams propagating.•Conservation distance of the topological charge is affected by the beam index M.