Blue Jets Research Articles

Implication of Subsequent Leaders in the Gigantic Jet

Most of the lightning appears below the cloud or inside the cloud. Unlike conventional lightning, blue jets and gigantic jets (GJ) produce upward discharge since electric discharge occurs as a form of cloud-to-air leader. We analyzed a gigantic jet recorded in the 2022 Taiwan campaign. For our color photograph recorded in the observation, high spatial resolution (150 m) at a close distance (140 km) resolves the important spatial features of the GJ phenomena. First, the GJ propagated upwardly as the fully developed jet with a maximum height of ~80 km above the cloud top ~17 km. After the fully developed stage, the subsequent leader reached its top height of ~30 km with a width of 0.5–1.0 km. The subsequent leader attempted but failed to develop from leader to fully developed jet. The subsequent leader may be interpreted as a negative stepped leader associated with cloud rebrightening, similar to the subsequent stroke in the multi-stroke lightning. Besides, the relatively higher IC flash rates associated with the rise of cloud tops benefit the required meteorological conditions for developing gigantic jets.

Detailed Modeling and Evaluation of the Potential Impact of Blue Jet on the Atmospheric Chemistry

AbstractTo evaluate the impact of a blue jet (BJ) discharge on the chemical system in the whole stratosphere as a function of altitude, we developed a detailed ion‐neutral chemistry model. The BJ discharge is formed as a streamer discharge up to 50 km with a leader part up to 28 km associated with high‐temperature chemistry. The simulations are performed in a 2‐day duration to investigate diurnal variations of chemical perturbations at the altitudes of every 2 km from 20 to 50 km. The specific chemistry processes during the leader (considering the molecular diffusion) and streamer discharges react with the whole stratospheric chemical families (oxygen, nitrogen, chlorine, and bromine). We systematically compare the simulations with and without the BJ discharge. The results obtained during the first 100 s indicate the ozone enhanced in the middle stratosphere, while no obvious change in the lower and close to the top of the stratosphere. After 2 days, simulations show that the entire neutral chemical stratospheric system is modified with the enhancement of nitrogen oxides, chlorine, and bromine reservoirs. As a consequence, ozone depletion appears in the middle and upper stratosphere due to the catalytic cycle associated with reactive NOx (=NO + NO2). Each chemical family results in a new equilibrium, and the ozone layer appears to be “shifted” to a lower altitude with its maximum less abundance. Due to the long lifetimes of the chlorine and bromine reservoirs in the stratosphere, the chemical perturbations caused by the BJ discharge at all studied altitudes are maintained.

On the Question of the Formation of the Lightning Current

The bipolar lightning development model was used to study the dependence of the potential that is transported to the earth by the downward leader channel. It was shown that this parameter strongly depends on the starting position of the lightning and on the trajectories of formation of its bipolar leaders. It was shown that the main reason for the change in potential is not the loss of voltage in the lightning channel with a finite conductivity but its polarization in the electric field of the storm cloud. An estimate was made of the range of potential variation in the channel with ideal conductivity depending on the starting position and trajectory of the lightning at a constant charge in the thunderstorm cell. It was shown that, for the variation of the lighting current within two orders of magnitude, a mere twofold change in the charge of the thunderstorm cell is sufficient. The preferable starting position is found for the lightning whose upward leader can penetrate into the upper layers of the troposphere, turning into a blue jet.

On the Question of the Formation of the Lightning Current

The bipolar lightning development model was used to study the dependence of the potential that is transported to the earth by the downward leader channel. It was shown that this parameter strongly depends on the starting position of the lightning and on the trajectories of formation of its bipolar leaders. It was shown that the main reason for the change in potential is not the loss of voltage in the lightning channel with a finite conductivity but its polarization in the electric field of the storm cloud. An estimate was made of the range of potential variation in the channel with ideal conductivity depending on the starting position and trajectory of the lightning at a constant charge in the thunderstorm cell. It was shown that, for the variation of the lighting current within two orders of magnitude, a mere twofold change in the charge of the thunderstorm cell is sufficient. The preferable starting position is found for the lightning whose upward leader can penetrate into the upper layers of the troposphere, turning into a blue jet.

The Perturbation of Ozone and Nitrogen Oxides Impacted by Blue Jet Considering the Molecular Diffusion

This study investigated the diffusion impact on the chemical perturbation of NOx and O3 caused by the streamer and leader parts of a blue jet in the low stratosphere (18–30 km), using the coupling of a detailed stratospheric chemistry model and a typical diffusion model. The study found that diffusion significantly impacted the evolution of chemical perturbations at both short-term and long-term time scales after the blue jet discharge, with changes in NOx and O3 concentrations observed at different altitudes (18–28 km). At 18 km, the concentrations of NOx and N2O that account for diffusion start to decrease after 1 s, whereas those without diffusion remain at their peak concentrations. Meanwhile, O3 is slowly destroyed with less NOx, rather than dropping to an unrealistic low value immediately after the discharge without diffusion. The perturbation caused by the blue jet discharge disappears within a few tens of seconds at 18 km when molecular diffusion is considered. At 30 km, the chemical perturbation from four point sources was observed through changes in NO2 concentrations. However, the total concentration of NO2 perturbed by the streamer part discharge at the given surface was negligible when considering diffusion. Overall, this study provided a useful model tool for a more accurate assessment of the chemical effects of individual blue jets.

Transient Luminous Events and Their Relationship to Lightning Strokes Over the Tibetan Plateau and Its Comparison Regions

AbstractThis study investigates the relationship between transient luminous events (TLEs) and lightning strokes, and the characteristics of TLE‐producing thunderstorms over the Tibetan Plateau (TP), and compares them to those over the Yangtze‐River Delta (YRD) and East China Sea (ECS) where at the same latitude during 2005–2015. The data were collected using the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) and the World Wide Lightning Location Network (WWLLN) observations. Elves, sprites and halo (abbreviated as ESHs) were dominantly detected over the southeastern TP (∼88%), mostly in August and September (∼81%). Different from the southeastern TP, the detected sprites and sprite‐to‐lightning stroke ratios over the YRD were larger in spring than those in summer and autumn. Halos were frequently observed in August over all study regions. Blue jets were only detected over the YRD. The density of TLEs over the southeastern TP was three times smaller than those over the YRD and ECS, while the density of elves over the southeastern TP was slightly larger than that over the YRD. The average energy of TLE‐related lightning strokes based on WWLLN was found to be larger over the southeastern TP compared to the YRD and ECS. The ESH‐producing clouds over the southeastern TP had a larger scale with a lower lightning frequency than those over the YRD.

Blue as an Abstraction of Carmel

Blue as an Abstraction of Carmel Robert Dorsett A man who looked for the worldbeneath the blue, without blue . . . —Wallace Stevens The blue of the sea, the shadowsthat fall beneath the skirts of water,the larkspur, lupine of the valleys,gnat-like flocks of thyme.The blue gas jets of rosemary,the lichen upon the sea break boulders,fly wing panes, tide-pools, theirshallows blended with gentian, plum gray fogsabove the cliff wash, and noon sky’s blaze,purpura of the evenings . . . And beyond the land spit—in theclarity of those waters—the blue beneaththe blue unworkable in metaphor. [End Page 112] The Woman Who Speaks My Words If you doubt the woman whospeaks my words, hesitate before heras before a rhetorical device, not knowing whether sheaccompanies me or I’m alone, then listen: She speaks,yet I have my say, and now it’s me, and yet again she, untilout of the fragments of our contradictory play, asingle voice devolves, and you know it’s not only she who speaksnor I who love alone. [End Page 113] Robert Dorsett Berkeley, California Copyright © 2023 Johns Hopkins University Press

First Flight of the EUV Snapshot Imaging Spectrograph (ESIS)

The Extreme-ultraviolet Snapshot Imaging Spectrograph (ESIS) launched on a sounding rocket from White Sands Missile Range on 2019 September 30. ESIS is a computed tomography imaging spectrograph (CTIS) designed to map emission line profiles across a wide field of view, revealing the structure and dynamics of small-scale transient events that are prevalent at transition region temperatures. In this paper, we review the ESIS instrument, mission, and data captured. We demonstrate how this unique data set can be interpreted qualitatively and further present some initial quantitative inversions of the data. Using a multiplicative algebraic reconstruction technique, we combine information from all four ESIS channels into a single spatial–spectral cube at every exposure. We analyze two small explosive events in the O v 629.7 Å spectral line with jets near ±100 km s−1 that evolve on 10 s timescales and vary significantly over small spatial scales. Intriguingly, each of these events turns out to be a bimodal (red+blue) jet with outflows that are asymmetric and unsynchronized. We also present a qualitative analysis of a small jetlike eruption captured by ESIS and draw comparisons to previously observed mini-filament eruptions. In 5 minutes of observing time, ESIS captured the spatial and temporal evolution of tens of these small events across the ∼11.′5 field of view, as well as several larger extended eruptions, demonstrating the advantage of CTIS instruments over traditional slit spectrographs in capturing the spatial and spectral information of dynamic solar features across large fields of view.

Influence of Nanoparticles and Metal Vapors on the Color of Laboratory and Atmospheric Discharges.

Currently, electrical discharges occurring at altitudes of tens to hundreds of kilometers from the Earth’s surface attract considerable attention from researchers from all over the world. A significant number of (nano)particles coming from outer space burn up at these altitudes. As a result, vapors of various substances, including metals, are formed at different altitudes. This paper deals with the influence of vapors and particles released from metal electrodes on the color and shape of pulse-periodic discharge in air, nitrogen, argon, and hydrogen. It presents the results of experimental studies. The discharge was implemented under an inhomogeneous electric field and was accompanied by the generation of runaway electrons and the formation of mini-jets. It was established that regardless of the voltage pulse polarity, the electrode material significantly affects the color of spherical- and cylindrical-shaped mini jets formed when bright spots appear on electrodes. Similar jets are observed when the discharge is transformed into a spark. It was shown that the color of the plasma of mini-jets is similar to that of atmospheric discharges (red sprites, blue jets, and ghosts) at altitudes of dozens of kilometers and differs from the color of plasma of pulsed diffuse discharges in air and nitrogen at the same pressure. It was revealed that to observe the red, blue and green mini-jets, it is necessary to use aluminum, iron, and copper electrodes, respectively.

An Abnormal Echocardiogram and Telemetry Tracing in a Late Preterm Infant.

An Abnormal Echocardiogram and Telemetry Tracing in a Late Preterm Infant.

On the Problem of Critical Electric Field of Atmospheric Air

It is traditionally accepted to define the dielectric strength of air as an electric field corresponding to the balance between the rates of impact ionization and electrons’ attachment to neutrals. Its reduced value is known to be about 110 Td regardless of the altitude above the mean sea level. In this study, the altitude profile of the critical electric field of atmospheric air in the 0–40 km altitude range is specified. Unlike the conventional approach, a wide range of additional plasma-chemical processes occurring in atmospheric air, such as electron detachment from negative ions and ion-ion conversion is taken into account. Atmospheric air is considered to be a mixture of N2:O2 = 4:1 containing a small amount of chemically active small gas components, such as water vapor, atomic oxygen, ozone, and several types of nitrogen oxides. It is shown that the dielectric strength of air falls noticeably compared to its conventional value. The results of the study can be important to solve the problems of initiation and propagation of lightning discharges, blue starters, and blue jets.

Resolving Elve, Halo and Sprite Halo Images at 10,000 Fps in the Taiwan 2020 Campaign

After almost thirty years’ efforts on studying transient luminous events (TLEs), ground-based observation has confirmed the TLE family, including elves, halos, sprites, and blue jets, etc. The typical elve has the shortest emission time (<1 ms) in comparison with other TLEs. The second shortest is the halo emission. Although elves and halos are supposed to be more frequent than sprites, ground campaigns still have less probability of recording their images due to their fleeting and short emission. Additionally, the submillisecond imaging of elves, halos, and sprite halos helps us resolve their electro-optic dynamics and morphological features, but few have been reported in the literature. Our study presents the 10,000 fps imaging frames on elves, halos and sprite halos, compares their similarity and disparity, and analyzes their parent lightning properties with associated VLF and ELF data.

Observation of the onset of a blue jet into the stratosphere.

Blue jets are lightning-like, atmospheric electric discharges of several hundred millisecond duration that fan into cones as they propagate from the top of thunderclouds into the stratosphere1. They are thought to initiate in an electric breakdown between the positively charged upper region of a cloud and a layer of negative charge at the cloud boundary and in the air above. The breakdown forms a leader that transitions into streamers2 when propagating upwards3. However, the properties of the leader, and the altitude to which it extends above the clouds, are not well characterized4. Blue millisecond flashes in cloud tops5,6 have previously been associated with narrow bipolar events7,8, which are 10- to 30-microsecond pulses in wideband electric field records, accompanied by bursts of intense radiation at 3 to 300 megahertz from discharges with short (inferred) channel lengths (less than one kilometre)9-11. Here we report spectral measurements from the International Space Station, which offers an unimpeded view of thunderclouds, with 10-microsecond temporal resolution. We observe five intense, approximately 10-microsecond blue flashes from a thunderstorm cell. One flash initiates a pulsating blue jet to the stratopause (the interface between the stratosphere and the ionosphere). The observed flashes were accompanied by 'elves'12 in the ionosphere. Emissions from lightning leaders in the red spectral band are faint and localized, suggesting that the flashes and the jet are streamer ionization waves, and that the leader elements at their origin are short and localized. We propose that the microsecond flashes are the optical equivalent of negative narrow bipolar events observed in radio waves. These are known to initiate lightning within the cloud and to the ground, and blue lightning into the stratosphere, as reported here.

Laboratory Simulation of the Effect of Volcanic Material on the Formation of Transient Phenomena Near the Boundary between the Middle and Lower Atmosphere

It is ascertained that heating of volcanic material from the Etna volcano (Italy) by an apokampic discharge reduces the voltage at which a positive streamer (apokamp) starts from the discharge channel and increases its propagation speed. The luminescence spectra show these processes to be accompanied by the emission of easily ionizable K and Na, which is consistent with data on the elemental composition of Etna samples. A hypothesis is suggested about an increase in the appearance probability of blue jets and starters over sites of high volcanic activity at altitudes of 10–18 km (at the level of the troposphere).

Progress in the Study of Transient Luminous and Atmospheric Events: A Review

Transient luminous events (TLEs) such as sprites, blue jets (BJs) and elves have been studied intensively during the last three decades, and much is now known of their properties. This progress is caused by several factors including satellite optical observations, ground-based measurements of sprite-produced electromagnetic fields, the use of high-speed video observations and telescopic cameras with high resolution that enables one to trace the dynamics of sprite and BJ development. In this paper, we review various types of TLEs, including recently discovered dancing sprites, gnomes, ultraviolet (UV) atmospheric flashes and other effects. The sprite initiation, visible evolution, streamer structure, and their relationship with intra-cloud (IC) process are discussed. Considerable study has been given to ULF/ELF measurements which can provide us with important information on the delayed sprite generation and the role played by IC processes in the perturbation of the lower ionosphere above the sprite. A set of electrodynamic and transport kinetic equations describing the TLEs are complicated because the number densities, mobilities of electrons and ions, reaction constants and other parameters are strongly dependent on altitude. Because of this, the majority of theoretical study of TLEs and other large-scale optical phenomena at high altitude are based on numerical modeling of the basic kinetic, transport and electrodynamic equations describing TLEs evolution, whereas the analytical theory remains a formidable task to be accomplished. In this paper, we review a few analytical results, which have been recently derived from simple physical models of the TLEs phenomena. In the remainder of this paper, we focus our attention on the properties of UV flashes in the mesosphere, which have been observed onboard Russian microsatellites “Universitetsky-Tanyana” and “Vernov.” Such a kind of optical flash is referred to as a transient atmospheric event, which differs from the TLEs in optical energy, duration and other parameters.

A New Detailed Plasma‐Chemistry Model for the Potential Impact of Blue Jet Streamers on Atmospheric Chemistry

AbstractA detailed ion‐neutral chemistry model named MiPO‐Streamer model has been developed to simulate the impact of blue jet streamers on stratospheric chemistry. It is based on the MiPLaSMO model (Microphysical and Photochemical Lagrangian Stratospheric Model of Ozone) widely used over the last 20 years to interpret balloon and satellite measurements associated with stratospheric ozone. In this study, instead of using a reduced electric field with constant value during blue jet streamer discharge process, we used a time‐dependent reduced electric field coming from an explicit streamer model. The simulations are performed on daytime/nighttime and in 2‐day long‐term duration at 27 km where the catalytic cycle of NOx is the most efficient to destroy ozone. Among 117 species considered, we put the focus on nitrogen, oxygen, chlorine, and bromine species, and ozone perturbation. The model results indicate that the densities of neutral species through an electrodynamic streamer simulation show an impact of a factor 2 as compared to the pulse‐based simulation at 27 km.

Emerging and expanding streamer head in low-pressure air

The emergence of a streamer from an ionisation wave and its expansion are ultra-fast processes shaping the very first moments of the streamer development, and are usually accessible only by complex numerical models. In this Letter, we report experimental evidence of the emergence of a streamer from an ionisation wave in 1.3 kPa air, a laboratory analogue of early-stage streamers emerging in geophysical Blue Starters and Jets. The radially and temporally resolved electric field patterns of an expanding streamer are determined by sub-nanosecond optical emission spectroscopy. As the emerged streamer expands, the electric field decreases by a factor of 1.4 in 1 ns. We quantify the radial expansion of the streamer head and its axial acceleration, reaching the velocity of 107 m s−1. In combination with electrical measurements, the transferred charge, electron density, and mean electron energy are quantified, enabling detailed insight into this ultra-fast phenomenon at its characteristic time-scale.

Experimental modelling of apokamp discharge formation under outer electric field

A laboratory setup has been created for modeling certain aspects of the initiation process of blue jets in the Earth’s atmosphere. With its help, the influence of an electric field on the apokamp discharge in air at pressures of 180-260 Torr was established. It is shown that the formation of a negatively charged zone located above the channel of a pulse-periodic discharge with a positive potential leads to both initiation and lengthening of the apokamps starting from the channel, and also reduces the voltage amplitude necessary for their formation.

Terrestrial gamma-ray flashes as the high-energy effect of tropospheric thunderstorms in near-Earth space

<p indent="0mm">Thunderstorms in the troposphere produce lightning flashes and cause charge transfer of different strength at varying spatial and temporal scales, leading to various forms of transient electromagnetic effects in the vast space above thunderstorms. In particular, normal intra-cloud (IC) lightning can generate ionizing hard X-rays and gamma rays, forming Terrestrial Gamma-ray Flashes (TGFs). We briefly summarize the progress in TGF studies that has been achieved in the past decade based on multiple space-borne platforms: (1) TGFs are usually associated with the upward negative leader during the initial stage of IC flashes and are often accompanied by relatively strong IC discharge with high peak current and large charge transfer, which is called the energetic IC pulse (EIP); (2) based on the characteristics of TGF-related radio-frequency signals, we can develop a remote sensing approach with ground-based measurements of lightning signals, thereby greatly enriching the investigation dataset of TGFs and parent thunderstorms; (3) till date, no unified mechanism for TGF production has been developed due to a lack of effective observation with respect to the source region. Thermal runaway breakdown and relativistic runaway electron breakdown are the two mainstream theories to explain TGF production. Compared with transient luminous events (TLEs; e.g., red sprites, gigantic jets, and blue jets) as the lightning-induced dielectric breakdown in the mesosphere, studies on TGFs, in terms of both observations and theoretical interpretation, lag behind the research in Europe and the USA. However, along with China’s latest progress in space detection technology (particularly the implementation of the <italic>Insight</italic> Hard X-ray Modulation Telescope (<italic>Insight</italic>-HXMT) and the Gravitational-wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM)), researchers in China desire to make steady progress in the field of TGF studies through continuous efforts in developing ground-based lightning detection techniques.

Formation of nitrogen oxides in a laboratory discharge simulating blue jets

Formation of nitrogen oxides in a laboratory discharge simulating blue jets