Positive Charge Layer Research Articles

A 3D Numerical Model to Estimate Lightning Types for PyroCb Thundercloud

Pyrocumulonimbus (pyroCb) thunderclouds, produced from extreme bushfires, can initiate frequent cloud-to-ground (CG) lightning strikes containing extended continuing currents. This, in turn, can ignite new spot fires and inflict massive harm on the environment and infrastructures. This study presents a 3D numerical thundercloud model for estimating the lightning of different types and its striking zone for the conceptual tripole thundercloud structure which is theorized to produce the lightning phenomenon in pyroCb storms. More emphasis is given to the lower positive charge layer, and the impacts of strong wind shear are also explored to thoroughly examine various electrical parameters including the longitudinal electric field, electric potential, and surface charge density. The simulation outcomes on pyroCb thunderclouds with a tripole structure confirm the presence of negative longitudinal electric field initiation at the cloud’s lower region. This initiation is accompanied by enhancing the lower positive charge region, resulting in an overall positive electric potential increase. Consequently, negative surface charge density appears underneath the pyroCb thundercloud which has the potential to induce positive (+CG) lightning flashes. With wind shear extension of upper charge layers in pyroCb, the lightning initiation potential becomes negative to reduce the absolute field value and would generate negative (−CG) lightning flashes. A subsequent parametric study is carried out considering a positive correlation between aerosol concentration and charge density to investigate the sensitivity of pyroCb electrification under the influence of high aerosol conditions. The suggested model would establish the basis for identifying the potential area impacted by lightning and could also be expanded to analyze the dangerous conditions that may arise in wind energy farms or power substations in times of severe pyroCb events.

Особенности формирования слоя положительного заряда при модификации изделий в струе высокочастотного ёмкостного разряда в условиях динамического вакуума

The paper presents a physical description of the formation of a layer of positive charge around the body, during processing in a high-frequency capacitive (HF) discharge, due to which a directed flow of ions arises that bombard the surface of the body being processed. With the help of holographic measurements, the presence of a layer, which differs from the plasma of an RF discharge, is demonstrated around a body placed in an RF plasma. The theoretical substantiation of holographic measurements, plasma potentials, measurements of ion energy and ion current density on the surface of the treated body is presented.

Temporal evolution and mechanism of secondary streamers in N2/O2 mixtures at atmospheric pressure under DC voltage

In this work, the temporal evolution of secondary streamers in N2/O2 mixtures at atmospheric pressure under DC voltage were investigated using a two-dimensional axisymmetric fluid model. The effects of voltage amplitude, polarity and oxygen concentration were analyzed. The propagation of secondary streamers is divided into two stages: fast propagation followed by slow propagation. The interior of secondary streamers is filled with positive space charges, while the exterior contains negative space charges. The reduced electric field in the secondary streamer is initially linearly proportional to the applied voltage and decreases linearly with the length of secondary streamers. The length of secondary streamers is primarily determined by the applied voltage, regardless of the oxygen concentration. A reversed propagation direction is simulated under negative applied voltage. We propose a different mechanism for secondary streamers. The high-density positive charge layer near the electrode initiates the propagation of secondary streamers, and the extension of positive charge region dominates the propagation. The distribution of electric field along the channel is mainly determined by the distribution of net space charge. The propagation direction is opposite to the direction of electron drift. The secondary streamer eventually stagnates due to the decrease in electron density in high oxygen concentration, while it is caused by the uniform current density at the front of the secondary streamer in low oxygen concentration.

Negative Excursion of Surface Electric Fields During Gamma‐Ray Glows in Winter Thunderstorms

AbstractDuring the 2020–2021 winter season, we detected 6 gamma‐ray glows at Kanazawa University, Japan. Negative surface electric fields (E‐fields; in the sign convention of atmospheric electricity) were observed by a field mill during all the glow cases. In five of the six cases, the peak E‐field reached around −12 kV m−1, and the E‐field during the glow detection was the strongest in the interval including 3 hr before and after the detection time. Therefore, negative charges should have been dominant in the thunderclouds that produced the gamma‐ray glows, and electrons were probably accelerated and multiplied by the E‐fields between a predominantly negative charge layer and a localized positive charge layer below. In addition, we extracted 8 non‐detection cases in the 2020–2021 winter season, in which surface E‐fields were stronger than −12 kV m−1. In 5 of the 8 cases, radar echoes were inadequately developed, suggesting insufficient charge accumulation. On the other hand, the remaining 3 cases had well‐developed radar echoes, and there was no significant difference from the detection cases.

Comparative study of the microspot splitting characteristics of direct-current and pulsed cathodic vacuum arc

Ejection of macroparticles is an inherent and unavoidable characteristic of cold cathode arc discharges. The size of the cathode arc spot's melt pool is closely related to the emitted particle size, and existing studies mostly indicate that motion velocity of arc spots can be heightened primarily by magnetic fields, thereby reducing the ejection of macroparticles. However, scant consideration has been given to avoid the fundamental nature of arc spot current concentration discharge by exploring the phenomenon of arc spot splitting. In this paper, microspot splitting characteristics of direct current and pulsed cathodic vacuum arc were compared and analyzed to investigate the effect of pulsed discharges on the arc spot's internal structure, splitting, and kinematic characteristics. The results showed that pulsed arc discharges emit a dense, highly ionized plasma flow which impacts the relatively thin positive charge layer instantaneously during the peak pulsed period. This then produces a highly ionized plasma region, while also promoting an effect by which the arc spot is split into multiple microspots. Additionally, the degree of dispersion resulting from microspot splitting is positively correlated with the ratio of the plasma flow density to the concentration of the positive charge layer at the moment of microexplosion. Therefore, the microspot splitting effect of a second-order pulsed arc is weaker than that of a first-order pulsed arc. Moreover, the splitting characteristics indicated a trend toward the progressive splitting state of the direct current cathode arc. When the peak current of the single-order pulsed arc was increased from 100 to 400 A, the particle refinement effect on the surface of the CrN coating became much more evident compared to the effect of a 200 A arc in the direct current mode. And upon reaching a peak current of 500 A (and up to 600 A), the number of splits did not increase linearly due to the continuous increase in the discrete degree of microspot splitting and concurrent decrease in microspot stability. This resulted in relatively high individual microspot currents, while some relative macroparticles still appeared on the coating surface.

FORTE Measurements of Global Lightning Altitudes

AbstractWhile multiple lightning detection systems provide geographical locations of lightning events across the globe, robust lightning altitude measurements on a global scale have proven elusive. Space‐based platforms have an advantageous viewing geometry for making these measurements, but prior studies with the Fast On‐orbit Recording of Transient Events (FORTE) satellite were limited to a few thousand events. In this study, we apply the same technique for calculating source altitude from the previous efforts to a large catalog of hundreds of thousands of global FORTE in‐cloud lightning events that were coincident with flashes geolocated by its lightning imager between 1997 and 2003. We use this new data set to document global variations in lightning altitude. As in previous studies, we find that FORTE primarily resolves sources from the upper (positive) charge layer at ∼11 km altitude in normal thunderstorms. However, sources are also recorded from other charge layers in the storm and from leaders developing between layers. In particular, we note a pronounced increase in source altitude in the first 20 ms of FORTE flashes from the negative leader developing upward into the upper positive charge layer. Regions known for wintertime and/or stratiform lightning have increased contributions from low‐altitude sources, while tropical regions particularly around Panama and the Maritime Continent have the greatest concentrations of high‐altitude sources.

Microphysical and Kinematic Characteristics of Anomalous Charge Structure Thunderstorms in Cordoba, Argentina

Some thunderstorms in Cordoba, Argentina, present a charge structure with an enhanced low-level positive charge layer, and practically nonexistent upper-level positive charge. Storms with these characteristics are uncommon in the United States, even when considering regions with a high frequency of anomalous charge structure storms such as Colorado. In this study, we explored the microphysical and kinematic conditions inferred by radar that led to storms with this unique low-level anomalous charge structure in Argentina, and compared them to conditions conducive for anomalous and normal charge structures. As high liquid water contents in the mixed-phase layer lead to positive charging of graupel and anomalous storms through the non-inductive charging mechanism, we explored radar parameters hypothesized to be associated with large cloud supercooled liquid water contents in the mixed-phase layer and anomalous storms, such as mass and volume of hail and high-density graupel, large reflectivity associated with the growth of rimed precipitation to hail size, and parameters that are proxies for strong updrafts such as echo-top and Zdr column heights. We found that anomalous storms had higher values of mass and volume of hail in multiple sub-layers of the mixed-phase zone and higher frequency of high reflectivity values. Low-level anomalous events had higher hail mass in the lower portion of the mixed-phase zone when compared to normal events. Weaker updraft proxies were found for low-level anomalous events due to the shallow nature of these events while there was no distinction between the updraft proxies of normal and anomalous storms.

Separators Based on the Dynamic Tip‐Occupying Electrostatic Shield Effect for Dendrite‐Free Lithium‐Metal Batteries

AbstractLithium‐metal batteries (LMBs) have long been considered the “holy grail” of next‐generation energy storage systems due to the unique advantages of Li metal, such as having a high specific capacity and the lowest potential. Unfortunately, the practical application of LMBs is seriously hindered by the uncontrollable growth of dendritic Li. To address this issue, a positively charged layer (PCL) with freely moving multication sidechains is successfully polymerized on a commercial polypropylene (PP) separator. The cationic groups on the sidechains of the polymer realize dendrite‐free Li deposition based on the “dynamic tip‐occupying electrostatic shield” effect. LMBs with improved cycling stability and rate performance can be achieved by using a PP‐N,N,N,N”,N”‐pentamethyldiethylenetriamine (PP‐PMDT) separator. All the results demonstrate that this strategy for constructing a flexible “electrostatic shield layer” can successfully eliminate the formation of Li dendrites while retaining the desired performance.

Self-pulsing discharge in hollow cathode simulated by a fluid model

A fluid model without an external circuit is used in simulating self-pulses in hollow cathode discharge under a He-Ar gas at 10 Torr. The average discharge current increases with anode potential, and three types of self-pulsing discharge modes are obtained: (a) regular self-pulse, (b) low amplitude self-pulse, and (c) damped oscillating pulses modes. The temporal and spatial distributions of plasma parameters in the self-pulsing discharge mode are studied. Results show that the electron density, electric potential, electric field, total net electron production rates integrated over the entire discharge cell and net positive charge density change periodically in a self-pulsing period. Self-pulsing frequency ranges from tens of kHz to more than 100 kHz, and increases linearly with the average discharge current approximately. In the present average discharge current range, the peak value and current amplitude of pulsing current increases and then decreases with the increasing average current, whereas the minimum pulsing current consistently increases. The change trend of extreme self-pulsing discharge current is consistent with the change trends of total net electron production rate and net positive charge density in the discharge space. Finally, the mechanism of self-pulse in a hollow cathode discharge is proposed. Simulated results show that the phases of different plasma parameters are different in different discharge regions in a self-pulsing period. Non-equilibrium fluctuation of plasma parameters in different discharge regions is one of important factors in the formation of self-pulse. Self-pulse does not depend on an external circuit and originates from the internal microcosmic mechanism of discharge: the enhancement and weakening of the positive charge layer.

Meteorological and Electrical Conditions of Two Mid‐latitude Thunderstorms Producing Blue Discharges

AbstractBlue discharges are one type of rarely observed upward discharge emerging from the top of thunderstorms. The favorable meteorological conditions and charge structures needed to produce this marvelous phenomenon are still poorly understood. In this study, we report on two midlatitude thunderstorms producing 13 blue discharges observed simultaneously by the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) and ground‐based lightning detection array. In these two thunderstorms, blue discharges always occurred in the vicinity of the coldest cloud top (∼195 K) and clustered within a bounded area near the convective surge, leading to the overshooting thundercloud top (reaching about 18 km) into the stratosphere. The parent thunderstorms were normally electrified with a main midlevel negative and an upper positive charge layer centered at about 15 km as inferred from source heights of narrow bipolar events (NBEs). The associated negative NBEs near the tropopause indicated that they are upward positive discharges initiated between the upper positive charge layer and the negative screening layer at the cloud top. In addition, the outbreak of negative NBEs in the altitude range of 16–18 km was observed in conjunction with blue discharges observed from space. This suggests that there exists a strong upper positive layer with an intense convection at this altitude of the thunderstorm. It is inferred that an overshooting thundercloud top with intense convective updraft could lead to a strong and high upper positive charge layer and therefore create favorable charge structures for initiating upward positive blue discharges.

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.

How Does the Melting Impact Charge Separation in Squall Line? A Bin Microphysics Simulation Study

AbstractA new electrification and discharge model was developed based on a two‐moment bin microphysical scheme coupled with the Weather Research and Forecasting (WRF) model. Based on the electrical model, the role of the noninductive charging mechanism associated with the melting processes of both snow and graupel (rimed particles) in the charge structure formation in the stratiform region of an organized convective system was examined. Our results showed that the snow melting charging mechanism forms a substantial positive charge layer near and below 0°C isotherm in the stratiform region of a squall line. It was also found that the graupel melting charging process mostly enhanced the positive charge layer in the convective region with little impact in the stratiform region. The in situ charging of noninductive collisional and melting processes and the charge transportation from the convective core all contribute to the charge structure formation in the stratiform region of a squall line.

Observations of Anomalous Charge Structures in Supercell Thunderstorms in the Southeastern United States

AbstractAnomalous thunderstorm charge structures (ACSs), characterized by a dominant layer of positive charge in the lower mixed‐phase region, are uncommon and rarely reported outside of the Great Plains region of the United States. This study documents the kinematics, precipitation microphysics, and charge structures of two supercell thunderstorms exhibiting ACSs that were observed in the Southeastern United States. Ground‐based three‐dimensional total lightning observations, polarimetric Doppler radar observations, and environmental model analysis of these supercells presented the opportunity to evaluate conceptual models of ACS development and characteristics in an atypical parameter space. In both anomalous storms, prominent layers of positive charge were located in lower to middle mixed‐phase regions (−10°C to −30°C) of updrafts and were spatially associated with riming hydrometeor types. Simultaneously, negative charge regions were identified above the primary positive charge layers in the upper mixed‐phase and glaciated region of updrafts, collocated with graupel and small ice hydrometeors. While coarse charge structure observations were consistent with noninductive charging‐based models of anomalous storms, charge structure complexities were also observed that suggested variability in cloud microphysical conditions. Analysis of the environments in which these storms formed indicated that several parameters thought to increase mixed‐phase liquid water content in favor of anomalous charging were inconsistent with those documented in the Great Plains region. However, environmental humidity metrics were most comparable. Comparisons between these and other documented anomalous storms identified similarities in kinematic structure and microphysical conditions while motivating ongoing study of the environmental parameter space supportive of ACSs.

Evaluating Geostationary Lightning Mapper Flash Rates Within Intense Convective Storms

AbstractThe Geostationary Lightning Mapper (GLM) marks the first time that lightning observations at storm‐scale resolution are operationally available from geostationary orbit. We evaluate GLM detection efficiency (DE) for a special class of convective storms characterized by anomalous charge structures. These storms are anomalous as their internal layered charge structure departs from the tripole charge structure model, where midlevel negative charge is situated between upper and lower positive charge layers. Anomalous storms are characterized by extreme flash rates, low median flash heights, and intense precipitation. Ground truth information on lightning flash rates is provided by Lightning Mapping Arrays (LMA), which measure VHF radio frequency emissions produced by electrical breakdown. This study contrasts two regions: Colorado, where electrically “anomalous” storms are numerous, and Alabama, where they are rare. This study analyzes GLM DE as a function of the precipitation water path, cloud water path, and lightning properties from LMA. The GLM DE is found to vary with the geometric size of the flash and with cloud water path, the latter depending on flash height and cloud water content. Optical scattering (attenuation) by precipitation‐sized particles does not appear to be a factor since precipitation particles contain much less surface area than cloud particles. The size of the flash is correlated with its optical brightness, and the cloud water path is correlated with optical extinction. Regional differences in GLM DE remain that appear to be related to sensor viewing geometry and day versus night sensitivity differences.

The Impact of Salinity on the Interfacial Structuring of an Aromatic Acid at the Calcite/Brine Interface: An Atomistic View on Low Salinity Effect.

This study aims to elucidate the impact of salinity on the interactions governing the adsorption of polar aromatic oil compounds onto calcite. To this end, molecular dynamics simulations were employed to assess adsorption of a model polar organic molecule (deprotonated benzoic acid, benzoate) on the calcite surface in NaCl brines of different concentration levels, namely, deionized water (DW), low-salinity water (LS, 5000 ppm), and sea water (SW; 45,000 ppm). Calcite was found to be completely covered by several well-ordered water layers. The top hydration layer is very compact and prevents direct adsorption of benzoates onto the substrate. Instead, Na+ ions form a distinct positively charged layer by adhering on the calcite substrate through inner-sphere complexion mode. Cl- ions mostly lodge on top of the adsorbed sodium cations, forming a negatively charged layer. The distribution of ions at the calcite/brine interface thus exhibits the features of an electrical double layer, composed of a Stern-like positive layer followed by a negative one. The positive charged layer attracts benzoates toward the surface. As such, the sodium ions attached onto the calcite can act as adsorption sites to connect benzoates to the surface. By increasing the salinity, more Na+ ions adsorb onto the calcite surface, and the density of benzoate molecules at the interface is enhanced as a result of more Na+ bridging ions. The monotonic salinity-dependent adsorption of benzoate molecules on calcite offers a mechanism driving additional oil recovery upon injection of diluted brine into subsurface carbonate reservoirs.

Enhanced monovalent selectivity of cation exchange membranes via adjustable charge density on functional layers

Electrodialysis (ED) technique is a typical and promising membrane process, for applications like water treatment and ion separation. Especially, the separation between monovalent and multivalent cations is a current central issue in many industries and academic researches. Herein, a series of novel cation exchange membranes were prepared from quaternized polyaniline modified sulfonated polyphenyl sulfone (SPPSU) by in-situ polymerization-deposited polyaniline followed by quaternizing with methyl iodide. Restricted divalent cation penetration and regulated monovalent cation transport were achieved by elevating the kinetic effect of electrostatic repulsion and narrowing water channel. Importantly, positive charge density of modification layer could be adjusted by controlling the degree of quaternization, which was accompanied by the change of water channel. When evaluated in a simulated mixed salt system (Mg2+/Na+ and Mg2+/Li+), the optimal quaternized polyaniline membrane exhibited a higher perm-selectivity (PNaMg=4.1, PLiMg=1.75) than initial polyaniline modified cation exchange membrane (PNaMg=0.8, PLiMg=0.75), and commercial monovalent-selective cations exchange membrane CIMS (PNaMg=3.56, PLiMg=1.11). This presented strategy is straightforward and effective, demonstrating the effect of surface positive charge layer on perm-selectivity.

Gamma Ray Glow Observations at 20-km Altitude.

In the spring of 2017 an ER‐2 aircraft campaign was undertaken over continental United States to observe energetic radiation from thunderstorms and lightning. The payload consisted of a suite of instruments designed to detect optical signals, electric fields, and gamma rays from lightning. Starting from Georgia, USA, 16 flights were performed, for a total of about 70 flight hours at a cruise altitude of 20 km. Of these, 45 flight hours were over thunderstorm regions. An analysis of two gamma ray glow events that were observed over Colorado at 21:47 UT on 8 May 2017 is presented. We explore the charge structure of the cloud system, as well as possible mechanisms that can produce the gamma ray glows. The thundercloud system we passed during the gamma ray glow observation had strong convection in the core of the cloud system. Electric field measurements combined with radar and radio measurements suggest an inverted charge structure, with an upper negative charge layer and a lower positive charge layer. Based on modeling results, we were not able to unambiguously determine the production mechanism. Possible mechanisms are either an enhancement of cosmic background locally (above or below 20 km) by an electric field below the local threshold or an enhancement of the cosmic background inside the cloud but then with normal polarity and an electric field well above the Relativistic Runaway Electron Avalanche threshold.

Selective-area ALD for positively and negatively charged layers into the ion-beam track-etched conical pores in polyethylene terephthalate

This paper presents the strategy of selective-area growing of a positively-charged layer of Al2O3 and the negatively-charged layer of HfO2 on ion beam track-etched polyethylene terephthalate (PET) nanotubes through the thermal atomic layer deposition (T-ALD) technique. We used the self-assembled monolayer of octadecyl trichlorosilane (OTS-SAMs) on the surface to serve as a passivation layer and then selectively deposited the Al2O3 and HfO2 in the nanotubes. The influence of the dipping time of the substrates in the OTS solution and the experimental conditions on the roughness and the thickness of the OTS monolayer have been investigated. X-ray photoelectron spectroscopy (XPS) was used to analyze the composition of the ALD Al2O3 and HfO2 films. Atomic force microscope (AFM) and scanning electron microscope (SEM) were employed to study the morphologies before and after the ALD of Al2O3 and HfO2. The I-V characteristics of the film confirmed the surface charge polarities in the nanotubes, i.e. the positively-charged Al2O3 and negatively-charged HfO2, in the electrically-neutral solution. The results will aid surface modification and functionalization of PET by nanotubes.

Modeling of fast neutral atoms flow generation in channel rays of glow discharge

A physical-kinetic approach has been used for modeling of fast neutral atoms flow generation in the channel rays of abnormal glow discharge. The fast atoms are generated due to charge exchange of ions accelerated by voltage drop on the cathode layer of positive space charge. The limits of applicability of the created model and the range of operating parameters of the fast atom source are established for the Ar (gas) – Ta (cathode) pair. The work is directed towards implementation of the beam processing of dielectric optical nanostructured metamaterials with help of fast neutral atoms.