Wander of the short-term spreading filter for partially coherent Gaussian beams through the anisotropic turbulent ocean.

The models of the short-term spreading and wander of the short-term spreading filter for partially coherent Gaussian beams propagating in an anisotropic oceanic turbulence are established by considering the effect of irradiance fluctuations on beam wander. The results of beam wander based on our model are larger than Andrews and Phillips's model, which considers the effect of the beam wander twice and weakens the effect of irradiance fluctuations on the beam wander. The results of our model show that the short-term spreading and wander of beams increase as the rate of dissipation of kinetic energy per unit mass of fluid and the emitting beam radius decrease, but they increase as the dissipation rate of temperature variance increases. As the temperature fluctuation of the oceanic turbulence gets stronger, the beam wander rises first and then turns into the wander saturation. The larger inner scale of turbulence and larger spatial coherent radius will decrease the short-term spreading of the beam and increase the beam wander. It also indicates that the anisotropy can restrain the impact of the turbulence to some extent in the oceanic channel. The salinity fluctuation has a greater impact on both short-term spreading and wander of the beam than temperature fluctuation does in oceanic turbulence.