Transmission characteristics of linear Gaussian array beams propagating through seawater to air

Abstract

We examine the transmission characteristics of linear Gaussian array beams (LGABs) propagating through seawater to air considering oceanic and atmospheric turbulences. We derive the expressions of the mean-squared beam width and Rayleigh range of LGABs for the case of both coherent and incoherent combinations using stochastic wave theory and the extended Huygens–Fresnel principle. In addition, the properties of mean-squared beam width versus propagation distance are studied. Furthermore, the characteristics of the Rayleigh range versus the ocean turbulence parameters and beam number as well as the interval distance are investigated. In the seawater–air interface, the Rayleigh range of LGABs is up to three times higher than that of the underwater circumstance. Moreover, the Rayleigh range increases linearly with the increase of interval distance in a turbulent ocean and turbulent atmosphere. It can be concluded that the Rayleigh range is more affected by the rate of dissipation of turbulent kinetic energy and the rate of dissipation of mean-square temperature than by the parameter related to temperature and salinity.