Sprites are transient luminous events in the upper stratosphere and mesosphere, induced by cloud-to-ground lightning discharges (CGs). The upper and lower potions of sprites exhibit different spatial structures. The upper portion is characterized by a diffuse glow called sprite halo, lasting a few ms, centered at an altitude of 70-80 km with a vertical extent of 10-20 km and a horizontal extent of 50-100 km, while the lower portion is characterized by a cluster of streamers. Past studies using numerical simulations [1, 2] demonstrated that quasi-electrostatic (QE) field in the mesosphere induced by CGs is the source of both the sprite halo and the sprite streamer [Pasko et al., 1997; Barrington-Leigh et al., 2001]. We performed Monte Carlo simulation to obtain the energy distribution function of electrons accelerated by the lightning-induced QE field. The obtained electron energy distribution function shows a non-Maxwellian shape with a high energy component in the energy range above 2-3 eV. Using this energy distribution function, we calculated the rate coefficients of electron impact in the processes related to dissociation and ionization of N2 and O2. Then we calculated the production rates of excited states of N2, O2 and O. We also estimated the total production rate of metastable singlet D oxygen atoms (O(1D)) due to individual sprite events. It is found that the estimated peak production rate of O(1D) is comparable to, or even larger than the production rate by solar UV radiation. Consequently, it is suggested that sprite events significantly affect the chemistry of ozone and related minor species in the upper stratosphere and mesosphere.

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