Plasma focus devices (PFDs) are strong sources of fusion neutrons but the problem of which interactions are responsible for the fusion reactions is still open since neither of the proposed theoretical models has been confirmed experimentally. The authors propose a model for the trajectories of the deuteron ions in a configuration of self-consistent electromagnetic fields starting from an empirical plasma model which describes the plasma focus collapse and column phases. The proposed model is only electrodynamical under the assumption of a uniform current density and an infinite length of the plasma column, not taking into account the fluid characteristics of the plasma.