A model of nonequilibrium freely localized (not bounded by the walls of the chamber) discharge in the field of a converging axisymmetric wave is investigated. Evolution of the system in time is studied under conditions where the built-up discharge plasma exerts strong influence on the wave field.It is shown that simple and complex (with several maxima) effectively localized dissipative structures in the distribution of electron concentration can emerge in the system at the developed stage.

The dynamics of a nonequilibrium high-frequency discharge under high pressure in a converging cylindrical wave under the condition of intensive gas heating is investigated. The gas dynamic processes are considered within the framework of the isobaric approximation. It is shown that the space-time evolution of the discharge depends essentially on the amplitude of the wave. At small amplitudes, where the field intensity is only slightly above break-down in the centre, at first the electron temperature Te and density rapidly (explosively) grow up to comparatively high values. The size of the arising plasma formation is much smaller than the wave-length and the skin layer (plasma cord). Later, due to the strong screening by the discharge plasma, the field weakens and ne, Te slowly get smaller (in fact it is the regime of dying plasma cord). At large amplitudes and average gas-heating speed the diminishing of the gas density occurs to be an accompanying factor and the dynamics of the discharge is the same as in the case of nonessential Joule heating.