Simulating long-range atmospheric turbulence in the laboratory with an artificial turbulence simulator

Atmospheric turbulence is the predominant propagation medium in random environments, significantly impacting beam propagation, particularly over long distances. In this study, we establish an equivalent experimental setup in the laboratory to simulate long-range atmospheric turbulence. The experiment employs a water tank, a wave maker, and a transparent perforated plate to generate turbulence with predetermined scales. We investigate the behavior of a laser beam propagating through a random environment induced by water flow from various directions. The scintillation index and RMS displacement of the beam's hot spot at the receiver are utilized to characterize the influence of water turbulence on light intensity fluctuations and beam wander, respectively. By inverting the intensity of water turbulence based on scintillation index and beam wander measurements, we observe an error magnitude less than one order of magnitude between them. Compared to atmospheric turbulence, our laboratory-generated water turbulence is four orders of magnitude stronger. This work establishes an equivalent connection between atmospheric turbulence and water turbulence, enabling realistic simulation of long-range laser propagation under actual atmospheric conditions.