Processes in expanding and condensing gases

The evolution of a hot gas or a weakly ionised plasma—formed as a result of evaporation of the surfaces of a solid under the action of high energy fluxes or flow out of a nozzle—is considered. The expansion of a vapour or a plasma into the surrounding space leads to its cooling and is accompanied by a chain of processes involving both charged (electrons, ions, atoms, charged clusters) and neutral particles. The evolutionary regimes leading to the condensation of atoms, accompanied by the formation of large charged and neutral clusters, are discussed. The experimental aspects of the generation of intense cluster beams in such regimes and the applications of such beams are considered.