Numerical simulation of glow corona discharge in air based on a plasma chemical model

Glow corona is one of the major forms of positive DC corona discharge. In order to reveal the microscopic physical process of glow corona in air, a plasma chemical model of glow corona discharge in 1D coaxial wire was established based on COMSOL, considering 28 species and 127 chemical reactions (CKS, a comprehensive kinetic scheme), and the photoionization process. The temporal and spatial distribution and evolution of the major species during the glow corona discharge were obtained. The results show that the major positive ions in the gap are
$\mathbf{O}_{2}\ ^{+},$
which are distributed in a shell shape. Negative ions are O-
$,\mathbf{O}_{\boldsymbol{2}}\ ^{-}$
and
$\mathbf{O}_{\boldsymbol{3}}\ ^{-}$
, which mainly exist in the ionization layer.
$\mathbf{O}^{-}$
and
$\mathbf{O}_{\boldsymbol{2}}\ ^{-}$
participate in the detachment and provide seed electrons for the next pulse. The classical fluid model (FPM, a fully coupled physical model) fails to fully consider the detachment process of negative ions, resulting in the steepness and peak-to-peak value of current waves are too large. In order to accurately predict the current oscillation waveforms, in addition to
$\mathbf{O}_{\boldsymbol{2}}\ ^{-}$
, it is also necessary to consider
$\mathbf{O}^{-}$
in detachment process.