The detailed modelling of the negative corona current pulses including the secondary oscillation (SCO) has been realized, using the continuity differential equations for the fluxes of positive and negative ions and electrons, supplemented by the Poisson's equation for an electrical field in a quasione-dimensional space, as the basis for the numerical computation. The analysis of the basic plasma functions behaviour applicable to the pulsing corona in Ar+O 2 and N 2 +O 2 mixtures in the concentration region of O 2 from 2 · 10 −3 % to 0.04% has been carried out and the physical mechanisms of the secondary current oscillation have been grounded for the first time. Moreover, an effect of the photoprocesses on the parameters of the strikingly different pulses in Ar+O 2 and N 2 +O 2 mixtures is estimated for the first time. It has been determined that the SCO is caused by the field intensity oscillation in the antiphase in the surface region and in the end of the sheath. The SCO pulse can transfer into the full modes of the Trichel's pulse. Characteristics of the "precursor" and the "step" in the leading pulse front are determined by the dynamics of the volumetric charges in the sheath, whereas the SCO shape is determined by the variable flow of the positive ions to the cathode. In N 2 +O 2 the ionization of O 2 molecules by the N * 2 emitted photons leads to the adequate current rise. Pulse trailing part duration and current value are operated by the O − 2 ions collisions with the N * 2 metastables. Such processes are slowed in Ar+O 2 .

The method of determining an existence region of the non-equilibrium plasma of the pulsating negative corona and breakdown is developed. The low-temperature non-equilibrium pulsing plasma of the point-to-plane negative corona and a transition form to the breakdown in nitrogen-oxygen mixture are numerically simulated. It is shown that plasma parameters are pulsing in time as well as in space. In the phase of corona pulse peak, its position adjoins the cathode surface, no further than 0.01 cm. In the initial phase of breakdown, it extends far beyond the surface, within the distance of 0.03 cm. At the same time, the electron temperature changes in almost full anti-phase to the current: from 9100 K to 19000 K during the corona pulse peak and from 6000 K to 20000 K in initial phases of the breakdown. The average plasma density changes in the range 7 × 10 11 − 8 × 10 12 cm −3 in the first case and 1 × 10 13 − 5 × 10 13 cm −3 in the case of breakdown.