A numerical simulation of Trichel-pulse formation in a negative corona

Abstract

A new quasi-one-dimensional model for a negative corona in air is formulated allowing for the quantitative description of the mechanism of Trichel-pulse formation. Detailed analysis of the processes controlling pulse dynamics is made. Comparison with experiment for a short-gap corona demonstrates a reasonable agreement with the shape of the pulse and in the average characteristics of the negative corona.

Physical Mechanisms of Negative Corona Current Pulse With Secondary Oscillation

“…Evidently, just due to a small effect of this process at the low ion energy, it was not taken into consideration in most of the modellings, as the negative corona [8,22,23] and the positive corona [29,45]. However, taking into account that in the cathode region (the sheath playing a decisive role in forming the current pulse and its secondary structure [2]) the field intensity amounts to considerably higher values (in separate discharge stages -of the order of 10 5 -10 6 V/cm), in this work, as in [21], this electron detachment type was taken into account. The authors of [30] have investigated the electron separation from O − 2 at the collision with N 2 under extremely high ion energies (> 20 eV).…”

“…Because of very low current density of the negative corona it was assumed (as in all previous corona modellings [2,4,[20][21][22][23]), that during the pulsation period the room gas temperature is kept in all discharge points. Under this condition, the coefficients of kinetic processes including the neutral particles are constant in time, and those related to the ionized particles are dependent only on the local field intensity [22].…”

“…The pulsation of the negative corona in a pure electropositive nitrogen is indicated in the work [20]. However, the authors have linked their calculation of the corona pulsation in the air only with "a carrying-out of negative ions from drift region" [21]. Such an approach does not allow to explain the dependence of the double pulse frequency on the admixture concentration [2,4,5].…”

“…But a more complicated secondary oscillation has been measured for the first time, when an extremely low concentration of oxygen in argon and in nitrogen was used [2][3][4][5]9]. The numerical model simplifications [21][22][23] have resulted in the inconsistent interpretation of the initial pulse rise [11,16,17], since the secondary elements were qualitatively compared with the model results obtained under experimentally irrelevant conditions [22,23]. Besides, the corona SCO was not described [21].…”

“…The numerical model simplifications [21][22][23] have resulted in the inconsistent interpretation of the initial pulse rise [11,16,17], since the secondary elements were qualitatively compared with the model results obtained under experimentally irrelevant conditions [22,23]. Besides, the corona SCO was not described [21]. Thus the recently registered secondary oscillations [16,17] are explained phenomenologically by a "back and forth motion of the electric field" [22,24], a "turbulent beam-plasma interaction" [6,16], or is referred to the "non-Trichel" one and it is recognized that its "mechanism .…”