A full time-dependent kinetic study is presented for the main microscopic collisional and radiative processes underlying the optical flashes associated with an impulsive (τ = 5 µs) discharge in the form of a single sprite streamer passing through an air region of the mesosphere at three different altitudes (63, 68 and 78 km). The kinetic formalism developed includes the coupling of the rate equations of each of the different species considered (electrons, ions, atoms and molecules) with the Boltzmann transport equation so that, in this way, all the kinetics is self-consistent, although, in the present approach, the electrodynamics (no Poisson equation is considered) is not coupled. The chemical model set up for air plasmas includes more than 75 species and almost 500 reactions. In addition, a complete set of reactions (more than 110) has been considered to take into account the possible impact of including H2O (humid chemistry) in the generated air plasmas. This study also considers the vibrational kinetics of N2 and CO2 and explicitly evaluates the optical emissions associated with a number of excited states of N2 ,O 2, O in the visible, CO2 in the infrared (IR) and ultraviolet (UV) emissions of sprite streamers due to the N2 Lyman–Birge–Hopfield (LBH) and the NO-γ band systems. All the calculations are conducted for midnight conditions in mid-latitude regions (+38 ◦ N) and 0 ◦ longitude, using as initial values for the neutral species those provided by the latest version of the Whole Atmosphere Community Climate Model (WACCM). According to our calculations, the impact of 4 ppm of H2O is only slightly visible in O − at 68 and 78 km while it strongly affects the behaviour of the anion CO − at all the altitudes investigated. The local enhancement of NOx predicted by the present model varies with the altitude. At 68 km, the concentrations of NO and NO2 increase by about one order of magnitude while that of NO3 exhibits a remarkable growth of up to almost three orders of magnitude. The variation of the O3 density predicted by the model in the sprite streamer head is negligible in all the altitudes investigated. The analysis of the time dependence of the electron distribution function (EDF) in the sprite plasma during the pulse reveals that the EDF transient is quite fast, reaching its ‘steady’ values during the pulse in less than 100 ns (much shorter than streamer head lifetimes). In addition, the calculated EDF during the pulse and in the afterglow is far from being Maxwellian, especially for energetic electrons (with e> 30 eV). Finally, the evaluation of the mid-latitude nighttime electrical conductivity of air plasmas under the influence of a single sprite event reveals an increase of up to four orders of magnitude (at 68 km) above its measured background level of 10 −11 cm −1 at an altitude of ∼70 km. This sudden increase in the electrical conductivity lasts for 100 ms (at 68 km), being shorter (∼1 ms) and longer (1 s) at 63 km and 78 km, respectively. The total power delivered by the streamer head of a single sprite event has been estimated to be approximately 1677 W (at 78 km), 230 kW (at 68 km) and 78 MW (at 63 km). (Some figures in this article are in colour only in the electronic version)

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Air plasma kinetics under the influence of sprites

[1] We report the global transient luminous event (TLE) distributions and rates based on the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) experiment onboard the FORMOSAT-2 satellite. ISUAL observations cover 45°S to 25°N latitude during the northern summer and 25°S to 45°N latitude during the northern winter. From July 2004 to June 2007, ISUAL recorded 5,434 elves, 633 sprites, 657 halos, and 13 gigantic jets. Surprisingly, elve is the dominant type of TLEs, while sprites/halos are a distant second. Elve occurrence rate jumps as the sea surface temperature exceeds 26 degrees Celsius, manifesting an ocean-atmosphere-ionosphere coupling. In the ISUAL survey, elves concentrate over the Caribbean Sea, South China Sea, east Indian Ocean, central Pacific Ocean, west Atlantic Ocean, and southwest Pacific Ocean; while sprites congregate over central Africa, Japan Sea, and west Atlantic Ocean. The ISUAL experiment observed global rates of 3.23, 0.50, 0.39, and 0.01 events per minute for elves, sprites, halos, and gigantic jets, respectively. Taking the instrumental detection sensitivity and the restricted survey area into account, the corrected global occurrence rates for sprites and elves likely are a factor of two and an order of magnitude higher, respectively. ISUAL observations also indicate that the relative frequency of high peak current lightning (>80 kA) is 10 times higher over the oceans than over the land. On the basis of the corrected ISUAL elve global occurrence rate, the total electron content at the lower ionosphere above elve hot zones was computed to be elevated by more than 5%.

https://ir.nctu.edu.tw:443/bitstream/11536/8465/1/000258515200004.pdf

Global distributions and occurrence rates of transient luminous events

Air Plasma Kinetics Under the Influence of Sprites

This paper presents a literature survey on the recent developments related to experimental and modeling studies of transient luminous events (TLEs) in the middle atmosphere termed elves, sprites and jets that are produced in association with thunderstorm activity at tropospheric altitudes. The primary emphasis is placed on publications that appeared in refereed literature starting from year 2008 and up to the present date. The survey covers general phenomenology of TLEs and their relationships to characteristics of individual thunderstorms and lightning, physical mechanisms and modeling of TLEs, past, present and future orbital observations of TLEs, and their chemical, energetic and electric effects on local and global scales.

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Lightning Related Transient Luminous Events at High Altitude in the Earth’s Atmosphere: Phenomenology, Mechanisms and Effects

Contributing Authors. Preface.- Introduction to the Physics of Sprites, Elves and Intense Lightning Discharges M.J. Rycroft. 1.1 Basic Properties of the Atmosphere. 1.2 Risk Theory of Electrical Phenomena Occurring in the Atmosphere. 1.3 The Properties of Sprites, Elves and Intense Lightning Discharges. 1.4 Introduction to Theories and Numerical Modelling of Sprites. 1.5 Conclusions. Acknowledgements.- The Meteorology of Transient Luminous an Introduction and Overview W.A. Lyons. 2.1 Introduction. 2.2 Observations of Convective Phenomena. 2.3 A Brief History of TEE Observations. 2.4 Characteristics of TLE-Parent Lightning and Storms. 2.5 Research Frontiers Acknowledgments.- The Microphysical and Electrical Properties of Sprite-Producing Thunderstorms E.Williams and Y. Yair. 3.1 Introduction. 3.2 The Non-Inductive Charging Process in Thunderclouds. 3.3 Cloud Scale Charge Structure Possible with the Non-Inductive Mechanism. 3.4 The Electrical Structure Inside Sprite-Producing Storms in Summer-time. 3.5 The Electrical Structure inside Sprite-Producing Storms in Wintertime. 3.6 Gaps in Knowledge and Future Needs. Acknowledgments.- Global Thunderstorm Activity C. Price. 4.1 The Earth's Energy Balance. 4.2 The General Circulation of the Atmosphere. 4.3 Frontal Thunderstorms in Mid-Latitude Regions. 4.4 Global Observations of Lightning. 4.5 The Global Atmospheric Electric Circuit. 4.6 Future Directions.- Imaging Systems in the Research Thomas H. Allin et al. 5.1 Introduction to Low Light Imaging. 5.2 The Spritewatch Systems. 5.3 Conclusions.- Spacecraft Based Studies of Transient Luminous Events S.B. Mende et al. 6.1 Introduction. 6.2 FORMOSAT-2 Satellite and the ISUAL Instrument. 6.3 Initial Observations with ISUAL. 6.4 Summary. Acknowledgments.- Observations of Sprites From Space at the Nadir: The LSO (Lightning and Sprite Observations) Experiment on Board of the International Space Station E. Blanc et al. 7.1 Introduction. 7.2 Spectral Differentiation of Sprite and Lightning Emissions. 7.3 Experiment. 7.4 Observations. 7.5 Perspectives.- Remote Sensing of the Upper Atmosphere by VLF C.J. Rodger and R.J. McCormick. 8.1 Ionospheric Conductivity. 8.2 Sources of VLF Electromagnetic (EM) Waves. 8.3 VLF Propagation in the Earth-Ionosphere Waveguide. 8.4 Relaxation of High-Altitude Ionospheric Modifications. 8.5 Summary.- Measurements of Lightning Parameters from Remote Electromagnetic Fields S.A. Cummer. 9.1 Background and Motivation. 9.2 Remote Lightning Parameter Measurements. 9.3 Data Analysis Techniques. 9.4 Summary.- Location and Electrical Properties of Sprite-Producing Lightning from a Single Elf Site Y. Hobara et al. 10.1 Introduction. 10.2 Locating Distant ELF Sources and Quantifying their Electrical Properties. 10.3 Winter TLEs and Associated Electromagnetic Phenomena in Japan. 10.4 Conclusion. Acknowledgments.- Calibrated Radiance Measurements with an Air-Filled Glow Discharge Tube: Applicat

/pdf/sprites-elves-and-intense-lightning-discharges-53wiyd2pc1.pdf

"Sprites, Elves and Intense Lightning Discharges"

[1] The experiment LSO (Lightning and Sprite Observations) is dedicated to the optical study, from the International Space Station, of sprites occurring in the upper atmosphere above thunderstorms. The objectives were to study these phenomena and to validate a new measurement concept for future measurements of sprites from space at the nadir. The first measurements were performed in the frame of the flight of the French Astronaut Claudie Haignere (mission Andromede) in October 2001. Observations were performed by two microcameras, one in the visible and near-infrared and the other equipped with a moderately wide band filter at 761 nm. This filter includes the most intense N2 1P emission of the sprites and partly the oxygen absorption A band of the atmosphere. The light emissions from sprites occurring in the middle and upper atmosphere are then differentiated from the emissions from lightning, occurring more deeply in the atmosphere and then more absorbed. This paper presents the first observations of sprites from space at the nadir and statistics about the respective intensities of lightning and sprites emissions as observed with this experiment.

Nadir observations of sprites from the International Space Station

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003JA009972

The experiment LSO (Lightning and Sprite Observations), on board of the International Space Station, was the first experiment dedicated to nadir observations of sprites from space. Such observations are innovative as sprites are generally observed at the horizon. At the nadir, sprites are superimposed with lightning flashes and the observation concept is based on a spectral differentiation of sprites and lightning by using an adapted filter. The experiment is composed of two micro-cameras, fixed on a station window. One camera is equipped with a filter and measures the sprites in the N2 1P most intense sprite emission line, which coincides also to the atmospheric absorption band of the molecular oxygen. The second microcamera provides observations of lightning flashes in the visible. Measurements were performed during four ESA missions: Andromede, Odissea, Cervantes and Delta. During 19h of effective observations, 180 flashes were analyzed and several possible sprites were identified, demonstrating the interest of this differentiation method. In addition during sunset and sunrise conditions when the lower atmosphere is in the dark, LSO observed the airglow of the secondary ozone maximum at about 90 km modulated by gravity wave activity.

Main results of LSO (Lightning and sprite observations) on board of the international space station

The experiment LSO (Lightning and Sprite Observations) on board of the In- ternational Space Station is the first experiment dedicated to sprite observations at the nadir. Such observations are difficult because the luminous emissions of sprites and lightning can be superimposed when they are observed from space at the nadir. Such observations are however needed for measuring simultane- ously all possible emissions (radio, X-γ, high energy electrons) associated with sprites for a better understanding of the implied mechanisms. They are possible in specific spectral lines where sprites are differentiated from lightning. Absorp- tion bands of the atmosphere are well adapted for this differentiation because the light emissions from sprites occurring in the middle and upper atmosphere are less absorbed in these bands than lightning emissions occurring more deeply in the atmosphere. The most intense spectral emission band of the sprites, cor- responding to the N21P band at 761 nm, partly superimposed with the oxygen absorption A band of the atmosphere, is used by the LSO experiment. The ex- periment is composed of two micro-cameras, one in the visible and near infra red, the other equipped with an adapted filter. Only sprites, halos and super- bolts, which correspond to a class of rare very intense lightning, are transmitted through the filter. Sprites, halos and superbolts are identified by the ratio of the intensities received through the filter and in the whole spectrum. This ratio is lower for superbolts than for sprites and halos. The response of the sprites is also more complex and variable than the response of superbolts which is very flat and comparable from an event to another. Finally, LSO observed 17 sprites, 3 halos and 9 superbolts. Several examples of differentiation of sprite and super- bolts are given. The results of a first global statistical study are also presented.

A. Labarthe

Papers

Nadir observations of sprites from the International Space Station

Nadir observations of sprites from the International Space Station

Main results of LSO (Lightning and sprite observations) on board of the international space station

Observations of sprites from space at the nadir: the lso (lightning and sprite observations) experiment on board of the international space station