Positive Charge Region Research Articles

Radiation electric field produced by the lightning leader formation in a thundercloud: Observations and modeling

Recently for a number of thunderstorm systems in different regions of the planet there have been reports of observations of high frequency radio emission with duration varying from several to more than one hundred of milliseconds which may both be isolated or precede the lightning initiation. There is a consensus that this radiation originates from continuous sequences of short-duration discharges that randomly fill the areas of strong electric field between the main negative and the upper positive charge regions. But the concrete physical mechanism of discharge activity evolution and its contribution to the lightning leader formation remain unclear. To answer these questions several hypotheses were proposed, among which the runaway breakdown and fast positive discharge can be accentuated. In this study, we present another explanation which is based on comparison of experimental data of thundercloud radio activity obtained in the Nizhny Novgorod region of the Russian Federation on May 15, 2019 with the use of a wide band radio interferometer with the results of our numerical simulation of the lightning leader formation in the active part of a thundercloud. It is shown that the observed intense electric field bursts can originate from mergers of two or more streamer systems or bipolar leaders with lengths ranging from several to several tens of meters. In the framework of our approach, the sequence of such mergers can, under certain conditions, result in the self-sustaining leader channel formation finishing the lightning initiation process.

Characteristic Features of the Clouds Producing Thunderstorm Ground Enhancements

AbstractThunderstorm ground enhancements (TGEs) are fluxes of energetic particles multiplied in thunderclouds, which may be registered by ground‐based detectors. Using the Weather Research and Forecasting (WRF) Model, the state of the atmosphere with a 1‐km horizontal resolution is modeled for convective events accompanied by TGEs observed at the high altitude Aragats Research Station in Armenia (40.47 N, 44.18 E, 3,200 m above sea level). By comparing the data obtained in observations with the results of simulations using a microphysical parameterization for WRF, a technique is developed for estimating charge distribution parameters. A typical charge distribution in a TGE‐producing cloud is found to be well approximated by a two‐layered charge structure with a lower positive charge region formed by graupel particles and an upper negative charge region formed by snow particles. The characteristic charge density is 0.01 nC/m3 for the graupel cluster and −0.02 nC/m3 for the snow cluster. A vertical distance of about 1–2 km between the lower positive and upper negative layers is sufficient for the development of an energetic particle avalanche.

A positive charge region of Salmonella FliI is required for ATPase formation and efficient flagellar protein export

The FliH2FliI complex is thought to pilot flagellar subunit proteins from the cytoplasm to the transmembrane export gate complex for flagellar assembly in Salmonella enterica. FliI also forms a homo-hexamer to hydrolyze ATP, thereby activating the export gate complex to become an active protein transporter. However, it remains unknown how this activation occurs. Here we report the role of a positively charged cluster formed by Arg-26, Arg-27, Arg-33, Arg-76 and Arg-93 of FliI in flagellar protein export. We show that Arg-33 and Arg-76 are involved in FliI ring formation and that the fliI(R26A/R27A/R33A/R76A/R93A) mutant requires the presence of FliH to fully exert its export function. We observed that gain-of-function mutations in FlhB increased the probability of substrate entry into the export gate complex, thereby restoring the export function of the ∆fliH fliI(R26A/R27A/R33A/R76A/R93A) mutant. We suggest that the positive charge cluster of FliI is responsible not only for well-regulated hexamer assembly but also for substrate entry into the gate complex.

Thunderstorm charge structures favouring cloud-to-ground lightning

Thunderstorm electrical structures favouring cloud-to-ground lightning were investigated through a Lightning Mapping Array (LMA), an accurate three-dimensional lightning location system that allows inferring the heights of the regions of charge. The present study focused on classical, convective-scale thunderstorms, aiming to shed new light on how the charge structure affects lightning production, especially the cloud-to-ground fraction, including flash rate and polarity. Results showed that lightning flashes mainly initiate at two levels, around −41 °C (9,150 m MSL) and around −7 °C height (4,730 m MSL). These initiation levels, located between the dominant positive and negative charge regions, allowed to define three main charge structures: an upper dipole (positive above negative), a classical tripole and a lower dipole (negative above positive). Several differences were found between the three categories in terms of the cloud-to-ground lightning production: (i) the classical tripole structure is the one presenting a higher cloud-to-ground flash rate (5.2 flashes·min−1); (ii) in terms of intensity, the presence of an upper positive charge region is more relevant than a lower positive below the main mid negative; (iii) conversely, the lower positive favours higher cloud-to-ground peak currents; (iv) A higher upper positive charge region favours a higher cloud-to-ground rate.

Vertical electrical field during decay stage of local thunderstorm near coastline in tropical island

In order to directly observe the electric field characteristics and study the charge structure in thunderstorms occurring in tropical regions, a balloon-borne strong electric field sounding is used to measure the vertical component of the electric field, temperature within the cloud and real-time location information of the sounding. Based on the principle of corona discharge, two 1-m-long metal probes are used as the sensors to detect the vertical electric field. In the summer of 2019, a result of electric field sounding within a local thunderstorm was obtained in the northeastern coastal area of Hainan Island, China. With the combination of an S-band weather radar, atmospheric electric field instrument and lightning locating network, the charge structure of the thunderstorm is analyzed in detail. The results show that the thunderstorm is a small-scaled local thunderstorm occurring in the afternoon, the sounding starting to be observed at the decay stage of the thunderstorm. In this period, lightning activities is rare, and the variation of ground electric field is similar to that of conventional summer thunderstorms. The whole sounding process lasts 34 min, during which the vertical airflow in the cloud is relatively stable, basically keeping 4–6 m/s. It can be seen from the electric field profile that the charge distribution in the thunderstorm cloud shows a complex charge structure which is composed of six charge regions. A negative charge region is lowermost, and above this the polarity alternates successively from bottom to up, where all charge regions are located above the melting-layer. Due to data interruption, it is impossible to accurately judge the upper boundary of the upper negative charge region and the information about the positive charge region above. The remaining charge regions are located in an altitude range of 6.0–6.3 km, 6.3–6.6 km, 6.9–7.3 km and 7.3–8.3 km, respectively. The charge densities in these four regions are –1.84 nC/m<sup>3</sup>, 1.80 nC/m<sup>3</sup>, –1.46 nC/m<sup>3</sup>, and 1.04 nC/m<sup>3</sup>, respectively. According to the existing data, the charge density of the uppermost negative charge area should be greater than –0.51 nC/m<sup>3</sup>. Moreover, the upper positive charge region (the fourth from bottom up) has the largest strength, followed by the negative charge region above it, both of which are more than 1 km in thickness. The electric field intensities in the other charge regions are relatively small. The pairs of positive and negative charge regions at the bottom are slightly different in strength and thickness.

Sounding observation of vertical electric field in eyewall of Typhoon Wipha (No. 1907) during landing period

In the summer of 2019, one case of electric field sounding in eyewall of No.1907 typhoon named Wipha was obtained in Wenchang, Hainan Island, China. Up to now, it has been the first case of electric field sounding results obtained in a typhoon system. In this paper, based on the observations of satellite, meteorological radar, ground electric field and cloud-to-ground flash location data of Hainan province, China, the basic characteristics of the typhoon are analyzed in detail. Owing to the limitation of cloud-to-ground flash location system, only flash activities of the typhoon before and after landing period are analyzed and the result does not show obvious features as reported by other researches. Referring to the radar reflectivity and sounding path, we confirm that the sounding penetrates through the eyewall region of the typhoon from cloud base to top. The electric field profile and the charge region distribution in the sounding path area are analyzed, and the results show that four positive and three negative charge regions exist between 5.74 and 9.10 km above sea level and the corresponding temperatures range from –2.4 to –16.7 ℃ of the seven charge regions. The mean charge densities of each charge region from bottom to top are 0.63 nC/m<sup>3</sup>, –0.33 nC/m<sup>3</sup>, 0.31 nC/m<sup>3</sup>, –1.03 nC/m<sup>3</sup>, 1.70 nC/m<sup>3</sup>, 1.57 nC/m<sup>3</sup> and –1.20 nC/m<sup>3</sup>, respectively. According to the preliminary analysis, we consider that the two positive charge layers at the top should be in the same charge region. Under the comprehensive consideration of the thickness of charge regions, the intensities of these six charge regions are 0.33 nC/m<sup>2</sup>, –0.07 nC/m<sup>2</sup>, 0.06 nC/m<sup>2</sup>, –0.87 nC/m<sup>2</sup>, 0.73 nC/m<sup>2</sup>, and –0.18 nC/m<sup>2</sup>, respectively. We can find that there are three dominant charge regions with largest intensity and they are the lowest positive charge region, the middle main negative region, and upper main positive charge region. And these vertical distributions of the three dominant charge regions are characterized by a tripole charge structure. These results are basically consistent with some simulation results. In addition, a negative screen charge region with a shallow depth in a range of 15–20 dBZ of the upper cloud boundary can be found. Combining the popular charging mechanisms, the similarity of tripole charge structure between our sounding and normal thunderstorm are discussed, and we preliminary consider that the non-inductive charging mechanism and the inductive charging mechanism, which originate from normal convection, are also suitable for eyewall region of typhoon.

In Situ Observations of Microphysics, Electric Fields, and Lightning in the Trailing Stratiform Region of a Mesoscale Convective System

AbstractWe use in situ airborne observations to extend a previous analysis by Lang and Rutledge (2008; https://doi.org/10.1029/2006JD007709) of remotely sensed radar and lightning mapping array observations of the 11 June 2000 asymmetric mesoscale convective system (MCS) that moved through the primary observation region of the Severe Thunderstorm Electrification/Precipitation Study in northeastern Colorado and northwestern Kansas. We analyze in detail in situ aircraft observations, radar, and remotely mapped lightning discharges from a portion of the MCS that was starting to produce a bow echo during the time of the aircraft mission. The observations are interpreted to indicate the presence of a rearward and downward‐sloping positive charge layer detraining from a mature cell near the leading convective region. In the convective cell the positive charge region was at an altitude of ~10 km MSL. It then descended rearward, crossing the 6 km MSL altitude plane ~40 km to the rear of the leading convective region. During an 8‐min period, three major lightning discharges initiated in the convective region and propagated rearward into the trailing stratiform region in association with this positive charge layer. Airborne in situ microphysical and electrical observations suggest that the charge layer in the stratiform region of the storm during this period resulted from charge separation in the convective region and transport from there into the stratiform region. Microphysical and meteorological conditions in the stratiform region were not supportive of significant in situ charge separation in this portion of the stratiform region during this time period.

Identification of organic species with “double-sided tape” characteristics on the surface of carbonate reservoir rock

Carbonate reservoir rocks are normally mixed-wet or oil-wet, leading to low oil recovery efficiency using water-based oil recovery methods. It is critical to understand the molecular composition of the organic material coating the surface of carbonate reservoir rock in order to design better enhanced oil recovery (EOR) methods. Herein, we extracted organic compounds from a carbonate reservoir rock and characterized their composition using high resolution mass spectrometry (HRMS). In contrast to conventional interpretation that the mixed-wet or oil-wet nature of carbonate reservoir rocks arises from the adsorption of carboxylic acids, our results demonstrated that the organic species strongly bound to carbonate reservoir rock surface are dominated by N-containing species, including a group of “sticky molecules”. Each of these molecules can form multiple hydrogen-bonds, therefore they might act as a “double-sided tape” which binds crude oil strongly to the carbonate rock surface. Furthermore, we applied atomic force microscopy (AFM) techniques to a model mineral surface with regions of positive change and negative charge which was contacted with the crude oil produced from the formation where the rock was sampled. It was found that only the organic molecules with positive charge in the oil were adsorbed onto the mineral. This supports HRMS results which suggest that the organic materials strongly bound to the carbonate reservoir rock surface are dominated by basic N-containing molecules. Overall, these findings suggest that, beside fatty acids, these “sticky molecules” might also play an important role in controlling the wetting state of carbonate reservoir rock.

A Comparison on the E‐Change Pulses Occurring in the Bi‐Level Polarity‐Opposite Charge Regions of the Intracloud Lightning Flashes

AbstractWe have compared the E‐change pulses occurring in the upper positive charge region (UPCR) and the middle negative charge region (MNCR) of 41 normal intracloud (IC) flashes. E‐change pulses can be roughly grouped into isolated pulses and pulse trains with both positive and negative polarities. Although isolated pulses occurred about equally in UPCR and MNCR, there were much more pulse trains in MNCR than UPCR. Overall, the average amplitude, rise time, half‐peak width, and fall time of isolated pulses (pulse trains) are 56% larger (115% larger), 31% faster (43% slower), 25% narrower (46% wider), and 26% shorter (62% longer) in UPCR than in MNCR. Interestingly, in the same charge region, positive and negative pulses share similar characteristics. Based on a typical well‐structured IC, it was found that the majority of isolated pulses in both UPCR and MNCR occurred at or close to the leader tips. In contrast, about 30% UPCR pulse trains occurred at or close to the tip, while the remaining 70% pulse trains occurred in the leader channel retracing along the leader channel away from the flash origin; for MNCR pulse trains, about 60% occurred close to the tip, and 40% occurred in the channel with a backward extension to the flash origin. Based on these characteristics, we have discussed the physical nature of various types of pulses and pointed out that a leader is likely to progress with a fluctuating behavior when it is neutralizing space charge distributed in a region with sufficient thickness and width.

Electrical evolution of a rapidly developing MCS during its vigorous vertical growth phase

This study examined the coevolution of storm structure and electrical behavior of a rapidly developing mesoscale convective system (MCS) over Beijing metropolitan region during its vigorous growth phase based on observations and model simulations. When the isolated convection grew upscale and developed into a larger and organized MCS, it is found that the lightning production increased much faster than storm volume growth. Although the overall MCS went through rapid intensification, large differences exist in the radar reflectivity pattern of its convective cell members indicating their differential convective states. Several distribution peaks of lightning radiation pulses are also observed in the vertical direction, suggesting the overall complicated charge distribution inside the MCS. Given the decreased distances among cells during the upscale growth, it is hypothesized that such complicated charge distributions are more conducive to local high electric fields for lightning initiations and hence increased lightning production rates. The electrification-coupled WRF simulations support this proposed hypothesis, which clearly show that the MCS evolves from two layered charge regions to more complicated charge distributions. When some convective cells consisting of the MCS develop toward maturity, the precipitation particles descend to low levels and give rise to a lower positive charge region that is embedded inside a deep-layer negative charge region. In combination with enhanced interactions among the cells, a peak of electric field magnitude is generated at lower levels due to the approaching charge regions with opposite polarities, such that more lightning flashes are produced.

Variation of Velocity of Ions in a Magnetized Plasma Sheath for Different Magnetic Field

The kinetic trajectory simulation method has been used to study ion velocity profile in a plasma sheath for varying magnetic field at fixed obliqueness. As the electrons have higher velocity compared to that of ions the wall is charged up negatively with respect to the core plasma. The negative potential then attracts the ions and repels electrons forming a thin positive space charge region in front of the wall. This positive space charge region, known as the ‘sheath’ separates the negatively charged wall from the quasineutral ‘presheath’ plasma. The ions moving towards the wall have to satisfy the Bohm criterion to ensure the stability of the overall plasma. The mean value as well as oscillation frequency of velocity of ions change as the magnetic field is varied from 1.5 to 10.5 mT. The maximum amplitude of normal component of velocity is almost independent of the magnetic field but the maximum amplitude of other components of velocity change and shows oscillating nature as the magnetic field changes.

Aerosol Effects on Lightning Characteristics: A Comparison of Polluted and Clean Regimes

AbstractOceanic lightning can be a sensitive indicator of aerosol effects on lightning characteristics as thermodynamic contrast is indistinct over adjacent oceanic regions. The study presents discernable aerosol impacts on lightning characteristics by analyzing 2 years (2017–2018) of intracloud (IC) and cloud‐to‐ground (CG) lightning data from Earth Networks Total Lightning Network over two key regions in southern South China Sea. Mean stroke density, IC/CG ratio, +IC fraction, and +CG fraction in polluted conditions are respectively 3.7, 2, 1.2, and 5.8‐fold larger than unpolluted counterparts. Total stroke contrast is further confirmed with the GLD360 network. Thermodynamic parameters conversely support slightly stronger convection over clean ocean. Clear evidence shows cloud droplet size diminishes with added aerosol. Aerosol invigorates more frequent and robust mixed‐phase development, endowing maritime convection with continental characteristics. Modifications in the charge reversal temperature and lower and upper positive charge regions are speculated on as means for stimulating more positive ICs and CGs.

Evolution of the Charge Structure and Lightning Discharge Characteristics of a Qinghai‐Tibet Plateau Thunderstorm Dominated by Negative Cloud‐to‐Ground Flashes

AbstractThe correlation between the charge structure evolution and lightning type and frequency for a multicell thunderstorm dominated by negative cloud‐to‐ground (CG) flash on the Qinghai‐Tibet Plateau was analyzed using observations from a three‐dimensional lightning very high frequency radiation source location system. The analysis results showed the following. (1) In the initial developing stage of the thunderstorm, each cell developed independently and presented an inverted dipole charge structure. As the thunderstorm developed into its mature stage, multiple cells merged, and the charge structure changed to a tripole structure. In the dissipation stage of each thunderstorm region, the charge structure reverted to an inverted dipole or a normal dipole. (2) When the extent of the charge region expanded, the upper and lower charge regions became uneven and asymmetric. (3) In the inverted dipole charge structure, negative CG flashes accounted for 77.2% of the total number of lightning flashes, whereas negative intracloud flashes accounted for only 22.8%. In the tripole charge structure, negative CG flashes, positive intracloud flashes, and negative intracloud flashes accounted for 62%, 21%, and 16%, respectively, of all lightning flashes. These results indicate that the middle negative charge region was the strongest layer of the thunderstorm, while the upper positive charge region was slightly stronger, and the lower positive charge region was the weakest. These findings also indicate that the relative intensity of the charge layers directly determined the lightning quantity and frequency.

Termination of thunderstorm-related bursts of energetic radiation and particles by inverted intracloud and hybrid lightning discharges

Abstract Recent studies of thunderstorm-related enhancements of fluxes of energetic radiation and particles at ground level suggest that removal of mid-level negative charge from the cloud by negative cloud-to-ground (-CG) lightning flashes or normal intracloud (IC) flashes serves to abruptly terminate those enhancements. However, it was not clear if the electron-accelerating electric field responsible for flux enhancements at ground was primarily between the main negative charge region and ground (produced due to the dominant effect of negative cloud charge) or between the mid-level negative and lower positive charge regions inside the thundercloud. Here, we report that these flux enhancements can be also abruptly terminated by inverted intracloud flashes and hybrid lightning flashes (inverted IC followed by negative CG). Based on the analysis of 13 events of these two types, we provide first evidence that the electric field between the mid-level negative and lower positive charge regions in the thundercloud can be responsible for the flux enhancements at ground level.

Correlation Between the First Return Stroke of Negative CG Lightning and Its Preceding Discharge Processes

AbstractUsing the negative cloud‐to‐ground lightning cases well located by the Fast Antenna Lightning Mapping Array, we have examined the general characteristics of the preliminary breakdown (PB) and stepped leader (SL) processes, and further studied the correlation between the first return stroke (RS1st) intensity and its preceding discharge processes. The RS1st intensity is measured from the range‐normalized radiation field. The parameters used to characterize PB/SL include PB altitude, PB/SL vertical speed, PB/SL pulse rate, and SL duration. The arithmetic mean PB altitude is about 5.6 km and exhibits a weak inverse correlation with the RS1st intensity. As the PB develops into the SL, the arithmetic mean vertical speed decreases from 4.7 × 105 to 1.7 × 105 m/s and the arithmetic mean pulse rate reduces from 5.1 to 2.4 ms−1. In the PB/SL processes, the average vertical speed and pulse rate have positive correlations with the RS1st intensity while the corresponding Spearman's correlation coefficient for SL is considerably larger than that for PB. The average SL duration is 34 ms and has a negative relation to the RS1st intensity, with the coefficient of −0.71. These results demonstrate that on average, lower initiation altitude, faster PB/SL vertical speed, higher PB/SL pulse rate, and shorter SL duration tend to be followed by stronger RS1st. According to the above correlations, we speculate that the combination of a middle negative charge region with a uniform and wide horizontal distribution and a small lower positive charge region is a favorable condition for an intense RS1st.

Intracloud Lightning Flashes Initiated at High Altitudes and Dominated by Downward Positive Leaders

AbstractIntracloud (IC) lightning flashes are normally initiated below 10 km and start with upward negative leaders. In this paper, we report a special type of IC flash called “downward positive IC (+IC) flash” which is initiated at high altitudes (mainly above 12 km) and whose initial negative leaders do not propagate upward. Three‐dimensional location results of three downward +IC flashes are described in detail. It is demonstrated that downward +IC flashes start with positive leaders propagating downward with speeds on the order of 104 m/s and negative leaders propagating horizontally for only a short distance. Downward +IC flashes are produced in thunderstorms with deep convective updrafts (radar echoes of cloud tops typically higher than 14 km). The charge structure responsible for downward +IC flashes is inferred to be a positive dipole including a negative charge region at a normal altitude (near the −10 °C isotherm) and an upper positive charge region at a relatively high altitude (usually above the −50 °C isotherm), with downward +IC flashes likely initiated from the upper positive charge region. Further, lightning flashes in a thunderstorm producing a large number of downward +IC flashes are analyzed. Results show that normal IC flashes in this thunderstorm are also initiated at altitudes closer to the upper positive charge region and usually consist of downward positive leaders propagating for longer distances than upward negative leaders. Based on these results, we propose a relationship between the altitude of the upper positive charge region and initiation locations of IC flashes.

The heme-sensitive regulator SbnI has a bifunctional role in staphyloferrin B production by Staphylococcus aureus

Staphylococcus aureus infection relies on iron acquisition from its host. S. aureus takes up iron through heme uptake by the iron-responsive surface determinant (Isd) system and by the production of iron-scavenging siderophores. Staphyloferrin B (SB) is a siderophore produced by the 9-gene sbn gene cluster for SB biosynthesis and efflux. Recently, the ninth gene product, SbnI, was determined to be a free l-serine kinase that produces O-phospho-l-serine (OPS), a substrate for SB biosynthesis. Previous studies have also characterized SbnI as a DNA-binding regulatory protein that senses heme to control sbn gene expression for SB synthesis. Here, we present crystal structures at 1.9-2.1 Å resolution of a SbnI homolog from Staphylococcus pseudintermedius (SpSbnI) in both apo form and in complex with ADP, a product of the kinase reaction; the latter confirmed the active-site location. The structures revealed that SpSbnI forms a dimer through C-terminal domain swapping and a dimer of dimers through intermolecular disulfide formation. Heme binding had only a modest effect on SbnI enzymatic activity, suggesting that its two functions are independent and structurally distinct. We identified a heme-binding site and observed catalytic heme transfer between a heme-degrading protein of the Isd system, IsdI, and SbnI. These findings support the notion that SbnI has a bifunctional role contributing precursor OPS to SB synthesis and directly sensing heme to control expression of the sbn locus. We propose that heme transfer from IsdI to SbnI enables S. aureus to control iron source preference according to the sources available in the environment.

Analysis of the first positive polarity gigantic jet recorded near the Yellow Sea in mainland China

At 12:16:22 UTC on 12 August 2010, a gigantic jet (GJ) was recorded over a thunderstorm near the Yellow Sea in China. The extremely low-frequency (ELF) magnetic field recorded at the Onagawa Observatory indicates that this GJ transferred positive charge from the thundercloud to the ionosphere (namely a +GJ event), which is the first observation of a +GJ reported in mainland China. The top altitude of this GJ was estimated to be about 89 km. The parent thunderstorm formed in a very moist environment (precipitable water of 75.4 mm) with moderate convective available potential energy (1294 J/kg) and lifted index (−3.19), and strong 0–6 km wind speed shear (16.3 m/s). The meteorological parameters are not much different from typical summer thunderstorms. The area of cloud top brightness temperature colder than −60 °C (altitudes above 14 km) increased significantly after 10:00 UTC and reached the maximum at 12:00 UTC (16 min before the GJ), suggesting the occurrence of the GJ was related to the strong vertical development of the thunderstorm. Around the time of the GJ, the south cell of the storm featured overshooting top as indicated by radar data. Additionally, the storm was dominated by negative cloud-to-ground (-CG) flashes with an increase in -CG flash rate around the time of the GJ occurrence, indicating the storm appeared to be of normal polarity (the main positive charge region located above the main negative charge region). The + GJ was probably produced by a normally electrified thunderstorm, and a possible explanation for this unexpected behavior and different lightning activity of GJ-producing storms were discussed.

Mathematical Modelling of RF Plasma Flow at Low Pressures with 3D Electromagnetic Field

In this study, a hybrid mathematical model of a low-pressure RF plasma jet in transition mode between continuum and free molecular flow at a Knudsen number of 8·10−3 ≤ Kn ≤ 7·10−2 for a carrying gas is described. The model takes electrons, ions, metastable atoms, and potential and curl electromagnetic fields into account. The model is based on both a statistical approach for the atoms in the ground state and a continuum model for other components. The results of plasma flow calculations in an undisturbed jet are described. The distributions of the electrodynamic and electrostatic parts of the electric field are given. It has been observed that the plasma jet has a layered structure along the stream: a positive charge region is formed at the beginning of the jet, followed by a negative charge region, and then a positive one again. The reason for the formation of a layered structure is the fast flow expansion when the plasma inflows into the vacuum and the difference in electron and ion pulse.

Variation of Atmospheric Temperature with Height in the Phenomena of Lightning Waveforms

The temperature at different height at different places is different, it may depend on various factors. The variation of atmospheric temperature varies as a function of height taken from the sea level. The temperature decreases with height in the troposphere. The location of the charge centre appears to be determined by temperature and not by the height of the cloud above the ground. The main negative charge centre is generally located between the -10°C and -25°C isotherms with the main positive charges some km higher up. Due to the variation of temperature, the ice crystal, super cooled water droplet etc. move updraft and downdraft, forms the charge in the cloud due to which the lightning phenomena occurs. In the cloud, the negative charge lies in the central part of the cloud, positive charge remains on above the negative charge centre in the cloud and small amount of positive charge as a pocket charge remains on the bottom part of the cloud. The positive ground flashes are initiated from the upper positive charge region and the negative ground flashes are initiated from the negative charge region in the thunder-cloud. The lower positive charge also play an important role for determining the different types of lightning.