The dynamics of nonlinear atmospheric planetary waves is determined by a
small number of independent wave clusters consisting of a few connected
resonant triads. We classified the different types of connections between
neighboring triads that determine the general dynamics of a cluster. Each
connection type corresponds to substantially different scenarios of energy flux
among the modes. The general approach can be applied directly to various
mesoscopic systems with 3-mode interactions, encountered in hydrodynamics,
astronomy, plasma physics, chemistry, medicine, etc.Comment: 6 pages, 3 figs, EPL, publishe