Atmospheric Electric Field Research Articles

Thunderstorm Ground Enhancements Measured on Aragats and Progress of High-Energy Physics in the Atmosphere

High-energy physics in the atmosphere (HEPA) has undergone an intense reformation in the last decade. Correlated measurements of particle fluxes modulated by strong atmospheric electric fields, simultaneous measurements of the disturbances of the near-surface electric fields and lightning location, and registration of various meteorological parameters on the Earth have led to a better understanding of the complex processes in the terrestrial atmosphere. The cooperation of cosmic rays and atmospheric physics has led to the development of models for the origin of particle bursts recorded on the Earth’s surface, estimation of vertical and horizontal profiles of electric fields in the lower atmosphere, recovery of electron and gamma ray energy spectra, the muon deceleration effect, etc. The main goal of this review is to demonstrate how the measurements performed at the Aragats cosmic ray observatory led to new results in atmospheric physics. We monitored particle fluxes around the clock using synchronized networks of advanced sensors that recorded and stored multidimensional data in databases with open, fast, and reliable access. Visualization and statistical analysis of particle data from hundreds of measurement channels disclosed the structure and strength of the atmospheric electric fields and explained observed particle bursts. Consequent solving of direct and inverse problems of cosmic rays revealed the modulation effects that the atmospheric electric field has on cosmic ray fluxes.

GEOPHYSICAL EFFECTS OF THE ACTIVE STAGE OF THE STROMBOLI VOLCANO ERUPTION ON OCTOBER 9, 2022

Using the results of instrumental observations carried out in the surface atmosphere, the response of the microbaric background, variations of the Earth’s magnetic and electric fields to the paroxysmal activity of the Stromboli volcano (October 9, 2022, Italy) is analyzed. It is shown that the active stage of a volcanic eruption was accompanied by the generation of an acoustic signal and pronounced variations in the geomagnetic and atmospheric electric fields at considerable distances both during the period of volcano activity and during the arrival of an infrasonic wave at the observation point. It was also noted that the volcanic eruption caused a response in the ionosphere in the form of a change in the critical frequency of the F2 layer.

Lightning Prediction Using Electric Field Measurements Associated with Convective Events at a Tropical Location

Nowcasting of lightning occurrences is essential in tropical locations as lightening causes severe damage to life and property. This study attempts to nowcast lightning events during convective phenomena using an electric field monitor (EFM) at a tropical urban location, Kolkata (22.65°N, 88.45°E). Before the onset of heavy lightning occurrences, definite changes in the atmospheric electric field (EF) are observed, which in turn are associated with high cloud liquid water content (LWC) and low cloud base height (CBH). A model has been proposed to nowcast lightning strikes within about 17.5 km radius of the present location based on the EF standard deviation (EFSD) values. The proposed technique is tested with the lightning data provided by a collocated lightning detector, which yields a prediction efficiency of ~ 0.91 (~ 0.86), a false alarm rate of ~ 0.23 (~ 0.18), and a critical success index of ~ 0.71 (~ 0.72) with an optimal range of other performance parameters during the monsoon (pre-monsoon) periods, thereby generating an alarm 45 min before lightning events.

Impact of Various Disturbance Sources on the Atmospheric Electric Field and Thunderstorm Activity of the Northern Tien-Shan

Features of the manifestations of various sources of disturbances in the atmospheric electric field at the Tien-Shan high-mountain station have been studied, and the statistical relationship between solar and thunderstorm activity has been established. Air currents arising over the ocean, having overcome the mountain gorges of the Himalayas, carry moisture to the Northern Tien-Shan and determine the weather features and thunderstorm activity at the Tien-Shan high-mountain station. It was established that the maximum and minimum thunderstorm activity at the Tien-Shan high-mountain station corresponds to the distribution curve of daily thunderstorm activity for the Asia–Australia region. The investigation showed that coronal mass ejections (CMEs) affect the atmospheric electric field by increasing or decreasing its level or causing its fluctuations, depending on the features of manifestations in the near-Earth space and in the Earth’s magnetosphere. In at least 70% of cases, thunderstorm activity was observed with a 1–2-day delay after impact on the Earth’s magnetosphere by CMEs and HSSs. A number of cases were studied when thunderstorm activity was observed in a quiet geomagnetic field. In these cases, an increase in the values of fmin (the minimum frequency of reflection from the ionosphere) and foEs (the critical frequency of the sporadic E layer) was observed, which indicated an increase in the level of radio wave absorption in the ionospheric D-region and the level of electron density at altitudes of 100–120 km.

Mathematical model of the global ionospheric electric field generated by thunderstorms

A model is created for the thunderstorm-related ionospheric part of the global electric circuit in January. This current system consists of both mid-latitude currents and equatorial electrojets, day-time and night-time, westward and eastward, up to 120 A. Data on the atmospheric fair weather electric field obtained during Carnegie cruise VII are plotted as a two dimensional map in Universal Time and month coordinates to show both time and seasonal variations.

ОПРЕДЕЛЕНИЕ КОЭФФИЦИЕНТА РЕДУКЦИИ АТМОСФЕРНОГО ЭЛЕКТРИЧЕСКОГО ПОЛЯ В ПРИЗЕМНОМ СЛОЕ

The article examines the problem of interpretation of atmospheric-electrical observationsconducted regularly on a network of ground stations that are an integral part of the general monitoringof the state of the atmosphere. To solve the general task of monitoring - obtaining regimedata on the electric field of the atmosphere and identifying trends in its changes, a comparativeanalysis of measurement data at various observation points is required. The electric field strength(potential gradient) is usually measured at a certain height from the earth's surface using variousmethods (geometry) of installing sensors near the earth's surface. The resulting values of the electricfield may differ greatly from the reference values, which are understood as measurements on aflat surface in plain conditions. The structure of the atmospheric electric field near a flat electrodewith spherical inhomogeneity investigates in the paper. For the joint analysis of data from variousobservation points, their unification is usually carried out by introducing a reduction coefficient:the ratio of the values of the electric field strength in geometrically distorted conditions to its referencevalue on the plain. It is shown that the values of the reduction coefficient strongly dependnot only on the geometry of the sensor installation, but also on the values of the measured electricfield. To correctly calculate the reduction coefficient of the electric field, it is proposed to use simultaneouslythe geometric distortion coefficient of the electric field and the coefficient taking intoaccount the influence of the electrode effect near the earth's surface. Calculations of the values ofthe reduction coefficient in the vicinity of the spherical inhomogeneity of the electrode surface forthe cases of classical and turbulent electrode effect in the surface layer are performed. The influenceof meteorological factors and the measured electric field on the values and spatial distributionof the reduction coefficient has been established. For the correct interpretation of the resultsof ground-based atmospheric-electrical observations, taking into account the reduction coefficient,it is necessary to take into account not only the geometry of the sensor installation, but also theeffect of the electrode effect on the obtained values of the electric field.

3DAEFA-Based Thunderstorm Prediction System With Higher Performance

This article presents a thunderstorm prediction system with a 3-D atmospheric electric field (AEF) apparatus (3DAEFA), wherein the data source is the high-resolution 3-D AEF (3DAEF) values. The system is mainly composed of 3DAEF sensor design and calibration, 3DAEF acquisition and processing, and thunderstorm prediction, localization, and imaging. First, a self-made single-axis rotary vane 3DAEFA is employed to measure 3DAEFs. Second, a calibration device is developed to calibrate 3DAEF directions while completing intensity calibration. Considering that the AEF signal (AEFS) is disturbed by low-frequency noises, full-frequency-domain AEFS denoising is conducted through Savitzky–Golay (SG) filtering, and baseline estimation and denoising with sparsity (BEADS). A prediction model is built based on the bidirectional long short-term memory (BiLSTM) network. After inputting denoised AEFS spatial features into the model, which is extracted by a convolutional neural network (CNN), a CNN-BiLSTM model is formed. The proposed system is assessed in different weathers. There is a significant improvement in AEFS’s signal-to-noise ratio (SNR) measured by this system, especially in thunderstorm weather, compared with the original AEFS (OAEFS). Meanwhile, determining coefficients are more than 95%, showing better prediction effects. The deviation between predicted values and real values is smaller than that of OAEFS, which makes it easier to analyze AEFS characteristics. Comparisons with radar charts demonstrate that the proposed system can effectively predict thunderstorms.

A new network of electric field mills at the Pierre Auger Observatory

The Pierre Auger Observatory is the largest ground-based experiment for the detection of ultra-high energy cosmic rays. In a hybrid approach, many detectors – including radio antennas – observe the extensive air showers induced by cosmic rays. As part of the AugerPrime upgrade, new antennas will be installed on each of the surface-detector stations covering a total area of around 3000 km2. This will allow us to study the mass composition of cosmic rays arriving with large inclination angles.The radio emission of air showers is heavily influenced in the presence of strong atmospheric electric fields during thunderstorm conditions. In that case measured data are difficult to interpret and therefore the atmospheric electric field over the array has to be monitored. We present the design and status of a new network of electric field mills (EFM) that will be used to take on this task. We show how we plan to perform the measurements with an absolute calibration. In addition, the electric-field data will be useful for other studies related to atmospheric electricity.

Sinergy of extra-terrestrial particle accelerators and accelerators operated in the terrestrial atmosphere

We performed simulations of the EAS particle transport initiated by ultra-high-energy gamma rays entering the terrestrial atmosphere. During thunderstorms, the electric fields above the LHAASO array efficiently modulate EAS particles. Because of this modulation, the possible bias on the energy estimation for primary energies up to 100 TeV can be up to ten-fold. Moreover, for the higher primary energies (≈1 PeV), the electric field modulation enlarges “genuine” primary gamma ray energy 2.5-3 times. This result is very important because observation of PEVatrons by LHAASO is based on rather small statistics, and the highest energy events can occasionally coincide with thunderstorms. We also demonstrate the existence of a threshold effect on the intracloud E-field strength needed to trigger the startup of a runaway process that exponentially multiplies the free electrons entering a strong atmospheric electric field.

On the vertical and horizontal profiles of the atmospheric electric field during thunderstorms

We present the first results of a new experiment on Mt. Aragats for measuring the horizontal profile of atmospheric electric fields during thunderstorms. Networks of advanced particle spectrometers operated on the slopes of Mt. Aragats continuously measure fluxes of charged and neutral particles, periodically registering impulsive enhancements, so-called Thunderstorm Ground Enhancements (TGEs). This gives the possibility to estimate the strength of the electric field in the lower atmosphere. Relativistic Runaway Electron Avalanches (RREAs) are registered by the particle detectors located on the Earth's surface as TGEs sometimes exceeding the fair-weather fluxes up to a hundred times. The strong accelerating electric field can reach 1.7-2.2 kV/cm at altitudes 3-6 km, and extend down to 50-150 m above the Earth's surface. The horizontal extent of the electric field can reach 10 km and more.

Diurnal variation of the fair-weather atmospheric electric field in Binchuan, China

With the purpose of understanding the variation of fair-weather atmospheric electric field, the vertical component of atmospheric electric field (recorded as Ez) has been measured in the town Binchuan (25°50′N, 100°34′E, 1438.7 m asl) of Dali city, Yunnan, China from June 14, 2017 to December 1, 2020. Automatic measured visual range is used as a proxy of aerosol concentration. The mean diurnal variation curve of the fair-weather Ez in Binchuan, having two peaks occurred at around 9LT and 20LT, shows little correlation with the well-known Carnegie Curve and other two high-latitude sites' Curves. While strong negative correlation between fair-weather Ez and visual range is found, indicating the variation of fair-weather is dominated by aerosol concentration. The main source of aerosol concentration variation probably sunrise and sunset effect. We support our findings by comparing Ez, visual range with sunrise and sunset times. The peaks (troughs) of Ez (visual range) are proved to have weak correlations with anthropogenic pollution through comparing the Ez, visual range under workdays and holidays.

Observations and Analysis of the Mid‐Latitude Atmospheric Electric Field During Geomagnetic Activity

AbstractIn this study, the diurnal and seasonal variation curves of atmospheric electric field () are obtained, based on the extensive observations at Mohe station (Geographical coordinates: 22.357°E, 53.482°N and geomagnetic coordinates: 195.5°E, 48.8°N) of the Chinese Meridian Project. The results show that the diurnal variation of conforms to the “Carnegie” pattern, and the value of in winter is higher than the summer. The coupling effect of the solar wind–magnetosphere with the atmospheric electric field is established. In total, 15 cases of magnetic storms are selected while Mohe is under fair weather condition throughout the storm period. The analyzed results reveal that exhibits the same characteristics during the 15 storms, that is, decreases sharply and changes simultaneously with the interplanetary magnetic field (IMF) component and solar wind proton number density. When the IMF– shifts to south, presents a large decrease with magnitudes of about 100 V/m–600 V/m.

Analog Sensor Interface for Field Mill Sensors in Atmospheric Applications

An overview of the electric field mill sensor specifications in applications related to the measurement of the atmospheric electric field was conducted. The different design approaches of the field mill sensor interface are presented and analyzed, while the sensitivity-related parameters of a field mill are discussed. The design of a non-complex analog sensor interface that can be employed for the measurement of the electric field in both fair and foul weather conditions, such as thunderstorms, is implemented using discrete components for experimental validation and is optimized in an integrated version in terms of noise and power consumption. Advanced noise simulations are conducted in a 180 nm CMOS process (XH018 XFAB). The energy-autonomous operation of the sensor for extended periods of time is made feasible due to the low power consumption of the front-end circuitry (165 μW at 3 V) as well as the proposed intermittent style of operation of the motor. The total sensing system is low power, and its realization is simple and cost-effective, while also offering adequate sensitivity (45 mV/kV/m), making it comparable to the existing works.

Observed electric charge of insect swarms and their contribution to atmospheric electricity

The atmosphere hosts multiple sources of electric charge that influence critical processes such as the aggregation of droplets and the removal of dust and aerosols. This is evident in the variability of the atmospheric electric field. Whereas these electric fields are known to respond to physical and geological processes, the effect of biotic sources of charge has not hitherto been considered. Here, we combine theoretical and empirical evidence to demonstrate that honeybee swarms directly contribute to atmospheric electricity, in proportion to the swarm density. We provide a quantitative assessment of this finding, by comparing the electrical contribution of various swarming insect species with common abiotic sources of charge. This reveals that the charge contribution of some insect swarms will be comparable with that of meteorologically induced variations. The observed transport of charge by insects therefore demonstrates an unexplored role of biogenic space charge for physical and ecological processes in the atmosphere.

Surface atmospheric electric field variability at a desert site

Measurements of atmospheric electrical variables in arid desert environments provide a route to assessing dust charging, which affects dust lofting; satellite remote sensing of dust particles; long range transport of elevated dust layers; and may also influence rain droplet size. This paper analyses a new dataset of atmospheric electric field (or Potential Gradient, PG) measurements from an arid site, at Al Ain in the United Arab Emirates (UAE), to investigate the influence of local meteorological and dust processes on the PG, and assess whether global atmospheric electric signals are detectable. With no data selection applied, the diurnal PG variation has a single maximum around 14UT (18LT), which is likely to be associated with the sea breeze, present on 77% of days in the central UAE. Despite the abundance of apparently fine days meteorologically, conventional atmospheric electricity fair weather selection criteria are not effective at removing all locally generated PG variability. Even applying much stricter selection criteria (10 m wind speed(U10 )between 1 and 5 m/s, visual range >25 km, and no present weather), a diurnal variation in PG with a single maximum at 07UT (11LT) remains, likely due to local convection at sunrise. Although the stricter criteria can remove the sea breeze effect – associated with a visual range change - the PG measurements remain dominated by local meteorological and dust processes. This obscures the usual behaviour of the Global Electric Circuit. Exceptionally large PG values (∼kV/m, even for U10 < 8 m/s when no dust events are detectable visually) indicate that such desert regions can be a highly electrified environment, at least during daytime and during the summer convective months. The regular generation of highly charged dust observed is relevant to evaluating charge effects on large range transport of dust, preferential scavenging of charged dust by water droplets and obtaining accurate satellite retrievals of dust concentration.

Ionic Charge Emission Into Fog From a Remotely Piloted Aircraft

AbstractCharge influences the properties of liquid droplets, such as evaporation rates, hydrodynamic stability, and sticking probabilities. Modifying droplet charge therefore provides a possible method of influencing fogs or clouds. An instrumented, remotely piloted aircraft has been equipped with positive and negative corona emitters to cause droplet charging. With the aircraft circling at 20 m altitude, effects of ion release were compared in clear air and natural fog. In clear air, the surface atmospheric electrical field changed whenever the emitters were activated, but without significant differences in the short‐wave radiation as the aircraft passed over previously ionized air. In fog, radiation fluctuations showed a Gaussian distribution before either emitter operated or when both emitters were operating, but with different distributions during unipolar ion emission. Introducing unipolar ions led to a maximum change in fog reflectivity of ∼2%, about 25 s later.

On the Spatio-Temporal Dependence of Anomalies in the Atmospheric Electric Field Just around the Time of Earthquakes

In this study, we report atmospheric electric field (AEF) anomalies observed around the time of earthquakes (EQs) in Japan. Using a newly developed AEF observation network with three spatially separated stations in Japan (Chofu, Kakioka, and Iwaki), we conducted a study for two EQs that occurred within a few 100 km from the EQ epicenter under relatively good local weather conditions as shown by a local all-sky camera and weather information. Time series and wavelet analyses of the AEF indicate that fluctuation anomalies in the AEF with periods of 10–60 min and larger than 70 min were observed from a few hours before up to a few hours after the occurrence of the EQs. The lag in the onset time increased with increasing distance from the EQ epicenter to the field site. The above-mentioned characteristics of these AEF fluctuation anomalies were similar among the three stations, and therefore the observed AEF anomalies were considered to be an imminent precursor of EQs. The observed AEF anomalies were likely to be caused by internal gravity waves (IGWs) generated around the EQ epicenter a few hours before the EQ, passing over the field site while changing the AEF by changing the space charge density in the surface layer of the atmosphere.

The horizontal profile of the atmospheric electric fields as measured during thunderstorms by the network of NaI spectrometers located on the slopes of Mt. Aragats

The shape and evolution of the energy spectra of the thunderstorm ground enhancement (TGE) electrons and gamma rays shed light on the origin of TGEs, on the relationship between modification of the cosmic ray electron energy spectra (MOS) and relativistic runaway electron avalanche (RREA) processes, on the energy of the seed electrons, and on the strength and elongation of an atmospheric electric field. The network of large NaI spectrometers on slopes of Mt. Aragats 24/7 monitored secondary particle fluxes from 2013 until now, highly contributed to the understanding of the ways how RREAs are developed in the atmosphere. In 2022 we enlarge the NaI network with 2 remote detectors located at altitudes 2000 and 1700 m, and 13 and 16 km apart from the Aragats station to investigate the horizontal profile of the atmospheric electric field. We found, that the previously estimated values of the regions in the atmosphere, where RREA emerges, were highly underestimated. In the present report, we describe the NaI particle detector's network and present the first results of the experiment demonstrating that the particle fluxes from the atmospheric electron accelerators can cover large areas on the earth's (up to tens of km2).

Flux variations of cosmic ray air showers detected by LHAASO-KM2A during a thunderstorm on June 10, 2021* *Supported in China by National Key R&D program of China (2018YFA0404201, 2018YFA0404202, 2018YFA0404203, 2018YFA0404204), NSFC (U2031101, 11475141, 12147208) and in Thailand by RTA6280002 from Thailand Science Research and Innovation

The Large High Altitude Air Shower Observatory (LHAASO) has three sub-arrays, KM2A, WCDA, and WFCTA. The flux variations of cosmic ray air showers were studied by analyzing the KM2A data during a thunderstorm on June 10, 2021. The number of shower events that meet the trigger conditions increases significantly in atmospheric electric fields, with a maximum fractional increase of 20%. The variations in trigger rates (increases or decreases) were found to be strongly dependent on the primary zenith angle. The flux of secondary particles increased significantly, following a trend similar to that of shower events. To better understand the observed behavior, Monte Carlo simulations were performed with CORSIKA and G4KM2A (a code based on GEANT4). We found that the experimental data (in saturated negative fields) were in good agreement with the simulations, assuming the presence of a uniform electric field of -700 V/cm with a thickness of 1500 m in the atmosphere above the observation level. Due to the acceleration/deceleration by the atmospheric electric field, the number of secondary particles with energy above the detector threshold was modified, resulting in the changes in shower detection rate.

Fair-Weather Near-Surface Atmospheric Electric Field Measurements at the Zhongshan Chinese Station in Antarctica

The variability in the atmospheric electric field is modulated by a combination of solar activities, meteorological activities, and geological conditions. A foundational dataset of the daily variations in the fair-weather atmospheric electric field is established in this study, and several examinations are conducted into the details of these variations in particular regions. This paper is organized as follows. First, the researchers count the datasets of daily variations to the atmospheric electric field on fair-weather days from 1 March–1 August 2022 at Zhongshan Chinese Station in Antarctica and Changping Station in Beijing. Then, the average daily variation in the atmospheric electric field on 40 fair-weather days in Antarctica is shown and the variations are compared with the average curve of 37 fair-weather days in Beijing during the same time period. Finally, the three main differences between these variations, their possible reasons, and a reasonable error analysis are clarified and discussed at the end of this paper.