Self‐similar solutions are given that represent an analytical theory of implosion and extension stages of a &THgr; pinch before the magnetic field lines reconnection in course of formation of field‐reversed configuration. Effects of Ohmic dissipation, thermal conductivity, and plasma turbulence are included. The self‐similar solutions, obtained in an explicit analytical form, demonstrate that magnetic flux is trapped during the implosion and expansion stages for a classical plasma, and that losses of magnetic flux are possible for a turbulent plasma during the expansion stage. The rate of flux trapping and diffusion is expressed in terms of experimental parameters.