Active nitrogen and oxygen: Enhanced emissions and chemical reactions

Kamaratos, Efstathios

doi:10.1016/j.chemphys.2005.09.026

“…Another proposed source of nitrogen afterglow is the well known Lewis‐Rayleigh Afterglow [ Becker et al , 1972], but in the laboratory this process produces 1PN2 spectra different than observed in sprites so it is unlikely to be a dominant mechanism. Yet another source is proposed by Kamaratos [2006], who invokes complex interactions between vibrationally excited N 2 (A 3 Σ u + , v ) and O 2 ( a 1 Δ g ) to explain N 2 (B 3 Π g ) vibrational distributions with enhancements in the high‐ v level populations.…”

Section: Observational Basis Of Modelmentioning

confidence: 99%

Plasma chemistry of sprite streamers

Sentman¹,

Stenbaek‐Nielsen²,

McHarg³

et al. 2008

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[1] A study is conducted of the principal chemical effects induced by the passage of a single sprite streamer through the mesosphere at an altitude of 70 km. Recent high-speed imaging of sprite streamers has revealed them to comprise bright (1-100 GR), compact (decameter-scale) heads moving at $10 7 m s À1 . On the basis of these observations, a quantitative model of the chemical dynamics of the streamer head and trailing region is constructed using a nonlinear coupled kinetic scheme of 80+ species and 800+ reactions. In this initial study, chemical processes related to currents in the trailing column and to vibrational kinetics of N 2 and O 2 are not included. The descending streamer head impulsively (t $ 10 ms) ionizes the gas (fractional ionization density $10 À9 ), leaving in its trail a large population of ions, and dissociated and excited neutral byproducts. Electrons created by ionization within the head persist within the trailing column for about 1 s, with losses occurring approximately equally by dissociative attachment with ambient O 3 , and by dissociative recombination with the positive ion cluster N 2 O 2 + . The ion cluster is produced within the trailing channel by a three-step process involving ionization of N 2 , N 2 + charge exchange with O 2 , and finally three-body creation of N 2 O 2 + . On the basis of simulation results, it is concluded that the observed reignition of sprites most likely originates in remnant patches of cold electrons in the decaying streamer channels of a previous sprite. Relatively large populations (fractional densities $10 À9 -10 À8 ) of the metastable species

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“…The metastable oxygen molecules O 2 (a metastable species has recently been discussed in Kamaratos (2006). However, in a simulation of the plasma chemistry associated with sprite streamers at 70 km altitude Sentman et al (2008) found that this process is not a major contributor to sprite optical emissions.…”

Section: General Phenomenology Of Spritesmentioning

confidence: 99%

Physical Processes Related to Discharges in Planetary Atmospheres

Roussel-Dupré

¹

,

Colman

²

,

Symbalisty

³

et al. 2008

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This paper focuses on the rudimentary principles of discharge physics. The kinetic theory of electron transport in gases relevant to planetary atmospheres is examined and results of detailed Boltzmann kinetic calculations are presented for a range of applied electric fields. Comparisons against experimental swarm data are made. Both conventional breakdown and runaway breakdown are covered in detail. The phenomena of transient luminous events (TLEs), particularly sprites, and terrestrial gamma-ray flashes (TGFs) are discussed briefly as examples of discharges that occur in the terrestrial environment. The observations of terrestrial lightning that exist across the electromagnetic spectrum and presented throughout this volume fit well with the broader understanding of discharge physics that we present in this paper. We hope that this material provides the foundation on which explorations in search of discharge processes on other planets can be based and previous evidence confirmed or refuted.R. Roussel-Dupré ( ) · J.J. Colman · E. Symbalisty

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“…The metastable oxygen molecules O 2 (a 1 g ) are abundantly produced in streamer discharges (Lowke 1992; Naidis 1999), and a possible contribution to sprite N 2 (B 3 g ) emissions of energy transfer between O 2 (a 1 g ) and N 2 (A 3 + u ) metastable species has recently been discussed in Kamaratos (2006). However, in a simulation of the plasma chemistry associated with sprite streamers at 70 km altitude Sentman et al (2008) found that this process is not a major contributor to sprite optical emissions.…”

Section: General Phenomenology Of Spritesmentioning

confidence: 99%

Physical Processes Related to Discharges in Planetary Atmospheres

Roussel-Dupré

¹

,

Colman

²

,

Symbalisty

³

et al. 2008

Space Sciences Series of ISSI

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This paper focuses on the rudimentary principles of discharge physics. The kinetic theory of electron transport in gases relevant to planetary atmospheres is examined and results of detailed Boltzmann kinetic calculations are presented for a range of applied electric fields. Comparisons against experimental swarm data are made. Both conventional breakdown and runaway breakdown are covered in detail. The phenomena of transient luminous events (TLEs), particularly sprites, and terrestrial gamma-ray flashes (TGFs) are discussed briefly as examples of discharges that occur in the terrestrial environment. The observations of terrestrial lightning that exist across the electromagnetic spectrum and presented throughout this volume fit well with the broader understanding of discharge physics that we present in this paper. We hope that this material provides the foundation on which explorations in search of discharge processes on other planets can be based and previous evidence confirmed or refuted.R. Roussel-Dupré ( ) · J.J. Colman · E. Symbalisty

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Active nitrogen and oxygen: Enhanced emissions and chemical reactions

Cited by 13 publications

References 90 publications

Plasma chemistry of sprite streamers

Plasma chemistry of sprite streamers

Physical Processes Related to Discharges in Planetary Atmospheres

Physical Processes Related to Discharges in Planetary Atmospheres

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