Coherent states, pion correlations, and skyrmions in the semiclassical models of nucleon-antinucleon annihilation

We do not want to provide a technical review but a cultural outlook about topics of general physical interest. While it is rather natural to consider NN-bar annihilation as a microscopic pion factory, less obvious perhaps is the fact that classical pion waves may be generated as from an antenna. What is a pion wave? What is the relation with pions detected by counters? Remember the duality between electromagnetic waves and the bright spots on a photographic plate !