Chemistry of sprite discharges through ion-neutral reactions

Abstract

Abstract.We estimate the concentration changes, caused by streamer discharge in sprites, of ozone and related minor species as odd nitrogen (NO x ) and hydrogen (HO x ) families in the upper stratosphere and mesosphere. The streamer has an intense electric field and high electron density at its head, where a large number of chemically-radical ions and atoms are produced through electron impact on neutral molecules. After its propagation, densities of minor species can be perturbed through ion-neutral chemical reactions initiated by the relaxation of these radical products. We evaluate the production rates of ions and atoms using an electron kinetics model and by assuming that the electric field and electron density are in the head region. We calculate the density variations mainly for NO x , O x , and HO x species using a one-dimensional model of the neutral and ion composition of the middle atmosphere, including the effect of the sprite streamer. Results at the nighttime condition show that the densities of NO, O 3 , H, and OH increase suddenly through reactions triggered by the first atomic nitrogen and oxygen product, and electrons just after streamer initiation. It is shown that NO and NO 2 still remain for 1 h by a certain order of increase with their source-sink balance, predominantly around 60 km; for other species, increases in O 3 , OH, HO 2 , and H 2 O 2 still remain in the range of 40-70 km. From this affirmative result of long-time behavior previously not presented, we emphasize that sprites would have the power to impact local chemistry at night. We also discuss the consistency with previous theoretical and observational studies, along with future suggestions.

The effects of thunderstorm-generated atmospheric gravity waves on mid-latitude F-region drifts

“…Kazimirovsky et al (2003), Siingh et al (2005), and Rycroft (2006) reviewed the upward influences of the atmosphere on space. Cloud-to-ionosphere (CI) electrical discharges influence the temperature (Sharma et al, 2004), the ion density (Taranenko et al, 1993) and the chemical composition (Hiraki et al, 2008) of the ionosphere. There is a multitude of associated transient (millisecond) optical phenomena including sprites, elves, blue jets and blue starters, and other newly discovered phenomena (Lyons et al, 2003).…”

Evaluation of isotopic fractionation of oxygen ions escaping from terrestrial thermosphere

“…implicit scheme similar to what we did in our previous study (Hiraki et al, 2008a). For spatial integration of the diffusion term, we assume a fixed boundary condition at the bottom z ¼ 100 km of the system and the flux-controlled boundary condition (Ogawa and Shimazaki, 1975) at the top z ¼ 1500 km.…”

“…We used their cross section data for 16 O 17 O and 16 O 18 O at the right peak (%121.6 nm) of the Lyman-a solar spectrum with a background air temperature of 300 K; see Fig. 2 (Hiraki et al, 2008a), we defined the optical depth of O 2 at this wavelength as 10 À20 N O 2 þ 2:32Â 10 À18 N NO , where N i ðzÞ is the total column density above a height z in units of cm À2 , and the solar irradiance of Lyman-a is 3:0 Â 10 11 cm À2 s À1 . Fig.…”

Book of Proceedings: Seventh Workshop, Sunny Beach, Bulgaria, 1-5 June 2015

“…The problems is considered about ability of sprites to be a link between solar activity (SA) and the chemical state of stratomesosphere (at least, in specific regions on the Earth). Our arguments are: 1) In the sprite region from ~ 90 down to ~ 40 km, the factors for ionization and formation of conductivity are sensitive to the solar activity, hence, the post-lighting electric fields and sprite parameters can be also affected by SA; 2) A sprite consists of thousands of streamers which cause (especially below 60 km) chemical perturbations concerning NO x and O 3 for hours and another small constituents (Hiraki et al, 2008;Arnone et al, 2008); 3) The global frequency of visible sprites estimated from satellite data is 1 -3 per minute, and large part of sprites remain unobservable. In specific regions at middle geomagnetic latitudes where the GCR flux is the main ionization factor and the sprite activity is large (Great Plains in USA, South Africa, South America, etc.)…”

“…Below ~65 km (in its mature portion) a sprite is essentially a net of positive streamers which propagate downwards with velocity in the range ~2×10 6 -~2×10 7 m/s and are multiplied by branching. Sprites are widely studied as a factor of disturbances in chemical balance in stratomesosphere (Arnone et al, 2008;Hiraki et al, 2008). The problems is considered about ability of sprites to be a link between solar activity (SA) and the chemical state of stratomesosphere (at least, in specific regions on the Earth).…”