Asymptotics of the Localized Bessel Beams and Lagrangian Manifolds

The Bessel beam-type asymptotic solutions of the three-dimensional Helmholtz equation, i.e., the solutions that have maxima in the vicinity of the -axis and are described by Bessel functions in the planes normal to it, are discussed. Since the Bessel functions slowly decrease at infinity, the energy of such solutions appears unlimited. Approaches to localizing such solutions by representing them in the form of the Maslov canonical operator on proper Lagrangian manifolds with simple caustics in the form of degenerate and nondegenerate folds are described. Efficient formulas for these solutions in the form of Bessel and Airy functions of a complex argument are obtained.