“…As the medium is highly collisional, the dynamics of electron and ion densities is considered to evolve according to drift‐diffusion equations, as usual in discharge physics (e.g., Bourdon et al.,
2007) and also used in the context of RREAs to simulate the effects of low‐energy electrons and ions (e.g., Berge et al.,
2022; Liu & Dwyer,
2013):
where n e , n n , and n p are the electron, negative ion, and positive ion densities, respectively; ν i is the electron‐impact ionization frequency, and ν a is the electron attachment frequency considering dissociative attachment producing a negative oxygen atom
(two‐body attachment) and a three‐body attachment producing a negative oxygen molecular ion
; and v e , v n , and v p are the electron, negative ion, and positive ion drift velocities, respectively. Because of the magnitude of the densities and the timescales of interest in the present work, we neglect ion‐ion recombination, electron‐ion recombination, and the diffusion of ions (see Berge et al.,
2022, Section 2.1). Given the electron densities obtained in the present study, diffusive fluxes of electrons are much lower than drift fluxes over the smallest length scale consi...…”