Abstract
For pt.III, see ibid, vol.26, p.6667 (1993). This paper is a continuation of a series of papers (1993 J. Phys. A: Math. Gen. 26, 6635, 6649, 6667), and makes use of the same assumptions. The paper presents a model of the first stage of the spatial scale splitting of hydrodynamic vortex structures. It is shown that this model is one of a first-order non-equilibrium phase transition, which leads to the forming of a heterogeneous low-conducting current state of the exploding conductor. As this takes place, its dynamics are determined by three interacting order parameters. As a result the exploding conductor is broken down into metallic particles with the size of the conductor diameter. It is shown that the transition from a high- to low-conducting state by the splitting of the spatial scale is energetically more profitable than the transition by excitation of current vortex structures. Parameters of the model, which describe the formation stage of hydrodynamic and current vortex structures, are identified by experimental results for the electrical explosion of conductors. The problems which emerged while bringing together the models describing these stages are also discussed.