The model of collective acceleration of ions in the spark stage of vacuum discharge is proposed on the basis of the ectonic mechanism of the cathode spot functioning and the concept of a deep non-stationary pit. The proposed model belongs to the class of electrostatic models in which ions are accelerated by the electric field of the spatial charge of the electron beam. In particular, the own electric field of the virtual cathode, when conditions are created for its occurrence on the front of the cathode torch in the vacuum diode. The principal possibility of formation of a deep potential well in the event of a virtual cathode in an explosion-emission diode is shown. The unsteady problem of formation of a virtual cathode when a high-current electron beam enters a diode with an accelerating electric field is solved. As a result of numerical modeling, the possibility of formation of a deep non-stationary pit in the presence of an electric field in the diode gap is shown and a model of the process of current passage and formation of such a pit in a vacuum diode with explosive electron emission is proposed. The analysis of different modes of current collection from the cathode torch plasma is carried out. The connection of current bursts with the appearance of high potentials at the plasma front and collective acceleration of ions is established. The proposed model is in good agreement with the experimental results.