Abstract
A rigorous asymptotic and numerical analysis is made of the spatial coherence function of the field of a laser beam propagating in a turbulent atmosphere. The form of the spatial coherence function is established and the maximum excess of the coherence radius of the field of a spatially bounded beam over the values of this radius for plane and spherical waves is determined under conditions of strong intensity fluctuations. The accuracy of approximations obtained earlier for the coherence radius of the field of a laser beam is estimated.