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Al2O3/ZrO2 (A/Z) layers with embedded Pt nanoparticles (Pt-nps) at the interface of A/Z have been used to create a dielectric film with an enhanced permittivity. The Pt-nps and dielectrics are both grown by the atomic layer deposition process, which is complementary metal–oxide–semiconductor compatible. In order to control the thickness ratio of Pt-nps in the overall dielectrics more easily, the thickness of the ZrO2 layer is changed from 12 to 30 nm with a fixed thickness of 12 nm for Al2O3 and constant growth cycles of 70 for Pt-nps. The results show that the introduction of Pt-nps is beneficial to the enhancement of the dielectric permittivity. As the thickness of ZrO2 is 30 nm, the capacitance density increases from 2.5 to 5.1 fF/μm2 with the addition of Pt-nps, i.e., a doubling of the capacitance density achieved. Additionally, the leakage current at 2 V increases from 1.1 × 10−8 to 1.5 × 10−7 A/cm2. Furthermore, the dielectric breakdown field decreases from 5.4 to 2.7 MV/cm. The electric field distribution simulation and charging–discharging test imply that interfacial polarization is built at the interface of Pt-nps and the dielectric films, which contributes to the dielectric permittivity enhancement, and local electric field increasing in the affinity of Pt-nps gives rise to the deterioration of the leakage current and breakdown electric field. [ABSTRACT FROM AUTHOR]

Polyurethanes have been extensively studied for their strong electromechanical response. Previous studies have mainly investigated the impact of electrical charges on these polymers' DC conductivity, which was measured on the order of 10−10 S/m. The movement of electric charges is responsible for the macroscopic deformation of polymer films under an electric field. However, this study focused primarily on electric fields below 107 V/m, where the electric current complies with Ohm's law. In this paper, we examine the electric current above this field value and observe a deviation in the current from linearity with the applied field, especially for a high electric field of 106–107 V/m. This change is known in polymers under high electric fields but has never been observed in polyurethane. This suggests the injection of electrode charges into the polymer material. This article provides the threshold at which the transition occurs from linear (Ohm's law) to nonlinear conduction as a result of injected electric charges. [ABSTRACT FROM AUTHOR]

A non-destructive method for detecting sub-micrometer-sized micropipes on an entire wafer surface is investigated. Since it is difficult to detect sub-micrometer-sized micropipes due to their small core size, a non-destructively and accurately detecting method is required. To solve the issue, we focus on a characteristic depression generated around micropipes, namely, line-shaped depressions. In this paper, the location of line-shaped depressions is identified by using optical inspection, and the line-shaped depressions are distinguished whether micropipes exhibit line-shaped depression or not by using mirror electron microscope observation as high-resolution inspection. The accuracy of the distinction results is confirmed by scanning electron microscope observation, and electrical characteristics of the P–N diode are fabricated using the inspected wafer. Furthermore, the sub-micrometer-sized micropipes are observed at the sites of leakage current identified by emission microscopy. Additionally, device simulation of the blocking-voltage characteristics of P–N diodes suggests that the increase in leakage current depends on the electric field at the sub-micrometer-sized micropipes, regardless of their core size. [ABSTRACT FROM AUTHOR]

The tailward high‐speed flows, in which various kinetic processes and magnetic structures can be embedded, are usually produced by the magnetic reconnection in the Earth's magnetotail. Here, using high‐resolution measurements from the Magnetospheric Multiscale (MMS) mission, we report an intense current in the tailward high‐speed flow. The current density can reach ∼180 nA/m2 and is primarily carried by electrons. Taking advantage of the First‐Order Taylor Expansion (FOTE) method, we reveal that such an intense current is associated with a ribbon‐like magnetic structure. A large electric field, reaching ∼90 mV/m, is also observed at the magnetic structure. The Hall term dominates the electric field, however, the contribution from the pressure gradient term and the electron inertial term is nonnegligible and can lead to strong energy conversion (E ⋅ J > 2 nW/m3) through the synergistic action with the intense current. This study improves the understanding of the current behaviors and energy conversion associated with magnetic structures in the Earth's magnetotail. Plain Language Summary: As products of the magnetotail magnetic reconnection, the earthward and tailward high‐speed flows can be usually observed as associated with a variety of kinetic processes and magnetic structures. Here, for the first time, we report an electron‐carried intense current associated with a ribbon‐like magnetic structure in the tailward high‐speed flow, by using high‐resolution MMS data and the First‐Order Taylor Expansion (FOTE) method. Encountering a large electric field with a nonnegligible contribution from the pressure gradient term and electron inertial term, such intense current leads to a strong energy conversion at the ribbon‐like magnetic structure. This study shed light on how the intense current is associated with the ribbon‐like magnetic structure and how the strong energy conversion is driven at such a structure, which complements the knowledge of the energy conversion process in the Earth's magnetotail. Key Points: An electron‐carried intense current (J > 180 nA/m2) is observed in association with a ribbon‐like structure in the tailward high‐speed flowA large electric field, with nonnegligible contribution from pressure gradient and electron inertial term, is observed at such a structureThe intense current and large electric field work together to drive a strong energy conversion (E ⋅ J > 2 nW/m3) at this structure [ABSTRACT FROM AUTHOR]

The electrical conductivity and volt–ampere characteristics (VAC) of the p-CuTlS2 single crystal with specific resistance ρ = 4 0 Ω ⋅ cm and irradiated by γ -quantum were studied in the range of 100–300 K temperature and 10–104 V/cm. It was determined that the cause of the conduction disorder observed in the CuTlS2 single crystal at low electric fields and high radiation doses is the formation of defect clusters dominated by cation vacancies. A sharp increase in current at high electric fields and temperatures occurs as a result of thermo-field ionization of the acceptor level with activation energy Δ E a = 0. 0 8 eV and the ionization voltage decreases with increasing radiation dose. Based on the determination of the parameters (λ , r m , n 0 , ε) that determine the mechanism of current flow, the dependence of the shape of the potential hole on the radiation dose was determined. [ABSTRACT FROM AUTHOR]

A one-dimensional charge-density wave (CDW) is driven to slide by a dc electric field, carrying an electric current. In an additional ac field with frequency ω ex , it is known that the sliding CDW can be synchronized to ω ex , leading to the occurrence of Shapiro steps in the I–V characteristics. Motivated by a recent experiment where ac fields with two frequencies ω ex and ω ex ′ are simultaneously applied, we theoretically investigate the effects of frequency mixing on the Shapiro-step formation. Based on the Fukuyama–Lee–Rice model, we show that in addition to the main steps induced by ω ex , satellite steps characterized by ω ex ′ emerge. It is also found that with increasing the ac-field strength for ω ex ′ , each step width first exhibits a damped oscillation as in the one-frequency case and then exhibits a non-monotonic behavior. The origin of these behaviors and the relevance to the associated experiment are also discussed. [ABSTRACT FROM AUTHOR]

Flash events, which are electric power spikes occurring under an electric field and temperature above the threshold, can significantly accelerate mass diffusion over short periods of time. This study investigated the surface structure of the (001) surface of strontium titanate single-crystal treated by flash events caused by direct current (DC) and alternating current (AC) electric fields from a viewpoint of surface-related mass diffusion. The surface structuring caused by flash events was significantly different among DC and AC electric fields. The DC-flash event destabilized surface steps, causing them to wander and form surface mounds with a height of several tens of nanometers. In addition, numerous two-dimensional (2D) nuclei with a size of several nanometers are formed on the terraces. In contrast, the AC-flash event stabilized surface steps without the formation of surface mounds, causing them nearly straight with uniform terrace width at approximately 500 nm. 2D nuclei with a size of a few 10 nm were formed at the step edges with round shapes. Both methods were confirmed as evidenced by the formation of two-dimensional nuclei on the surface after the flash events, to enhance surface-related mass diffusion. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion Various catheter designs are appearing for Pulsed Field Ablation (PFA). It is unclear if they differ in terms of safety and efficiency. PFA studies have reported hemolysis, kidney injury, high troponin, among other side effects.Using a CT‐derived computer model, we compared catheter designs using two metrics: (1) efficiency: power delivered to an atrial wall target, expressed as a percent of total generator power; and (2) safety: electric current to achieve 90% transmurality (since more energy causes more collateral effects), as well as the corresponding electrode current density (ECD), a heat and bubble metric. The following catheter designs were compared: penta‐spline basket, Nitinol spheres (focal 9 mm and large 1‐shot), circular, balloon, and flex‐circuit. Target was a 6 × 47 mm circumferential segment of atrial wall at LPV antrum. Transmurality was defined as percent of target having >600 volts per centimeter (V/cm) electric field needed for electroporation.Efficiency was 0.9, 1.4, 2.7, 5.9, 10, and 12% for the large 1‐shot and 9 mm Nitinol spheres, penta‐spline, circular, flex spline, and balloon catheters, respectively. Regarding safety, currents for 90% transmurality were 70, 39,36,12.5, 5.3, and 4 Amps for the same respective catheters, with less being safer. ECD was 124, 25, 74, 83, 41, and 31 A/cm2, respectively.Computer models demonstrated a remarkable range in efficiency among catheters studied. Those having less atrial blood exposure had the highest efficiencies, with factors of up to 13X more efficiency compared to exposed ones. Higher efficiency designs have less collateral current and are safer. Confirmatory in‐vivo studies are required. [ABSTRACT FROM AUTHOR]

When radon emanates, the conductivity in surface air increases, which causes variation in the electric field not only in the lower atmosphere, but also in the ionosphere. There have been proposals to use such ionospheric disturbances as earthquake precursors. The ionospheric electric fields are calculated using a quasi-stationary model of an atmospheric conductor including the ionosphere. Earlier, we showed that even with extreme radon emanation, electric field disturbances in the E- and F-regions of the ionosphere are several orders of magnitude smaller than the supposed earthquake precursors and smaller than the fields usually existing there, which are created by other generators. In this paper, we focus on the D-region. In the vertical component of the electric field strength, the main contribution to the D-region comes from the fair-weather field. It is shown that in the D-region, the vertical electric field component over the area of intense radon emanation can double in comparison with the fair-weather field. A detailed spatial pattern of disturbances of electric fields and currents in the atmosphere and ionosphere over the radon emanation region is constructed. [ABSTRACT FROM AUTHOR]

Electron transport characteristics were measured at room temperature applying nanosecond duration electrical pulses on two-dimensional electron gas (2DEG) channel in AlGaN/GaN heterostructures grown on SiC substrate. Crystal lattice self-heating effects were minimised by usage of nanosecond duration pulses being as short as 2 ns. We were able to reach highest current densities of 1.24 A/mm and 1.80 A/mm for different type of AlGaN/AlN/GaN and AlGaN/GaN heterostructures under the electric field of 57 kV/cm and 69 kV/cm, respectively. Even stronger electric field usage was allowed by the pulse source employed (up to 75 kV/cm for channel length of 12.5 μ m), however, that was not needed as the electric current near saturation was observed. The three-dimensional (3D) electron channels in GaN epilayer on GaN substrate were also investigated under pulsed electric field reaching up to 216 kV/cm. The electron drift velocity was found from experimental charge current density characteristics assuming that Hall electron density does not change in the sample under high electric fields. Maximum drift velocities for the 2DEG channels in AlGaN/GaN and AlGaN/AlN/GaN samples were found to be up to 1.2 × 10 7 cm/s at 69 kV/cm and 1.1 × 10 7 cm/s at 57 kV/cm, respectively, while, the highest value of ∼ 2.6 × 10 7 cm/s at 216 kV/cm was obtained for the 3D GaN channels. In the region of high electric fields the electron drift velocity in 2DEG channel was smaller than that in 3D channel as the result of stronger hot-phonon effect. [ABSTRACT FROM AUTHOR]

To date, new prototype device for directly converting chemical energy into electricity is still the most important pursuit although various types of fuel cells have been developed/commercialized. In this work, a novel (101¯0$10\bar{1}0$) orientated ZnO single crystal device is reported that generates electricity using the usual redox reactions. The principle of the device is similar to that of a photovoltaic device, known as a chem‐voltaic device. The air‐KBH4 chem‐voltaic device has an open‐circuit voltage (Voc) of 2.14 ± 0.007 mV and a short‐circuit current (Isc) of 1.44 ± 0.007 µA. The Voc and Isc increase to 2.24 mV and 2.81 µA, respectively, by preadding H2O2. A similar phenomenon is also observed when glucose is used to substitute KBH4. When KBH4 or glucose solution is added to the ZnO (101¯0$10\bar{1}0$) surface, it reacts with chemisorbed oxygen to produce free electrons. Due to the presence of the spontaneous electric field (Es) in the polar [0001] azimuth of ZnO, these free electrons move along the [0001] direction, producing an electric current. So chemical energy is converted into electricity. This finding opens up research on the chem‐voltaic cell. [ABSTRACT FROM AUTHOR]

Storm-time ionospheric electrodynamics effects have been the subject of extensive studies. The solar wind/magnetosphere/ionosphere and thermosphere disturbance wind dynamos have long been identified as the main drivers of low latitude storm-time electrodynamics. Extensive detailed studies showed that climatology of low latitude disturbance electric fields and currents is in good agreement with results from global theoretical and numerical models. Over the last decade, however, numerous studies have highlighted that the response of low latitude electrodynamics to enhanced geomagnetic activity is significantly more complex than previously considered. It is now clear that the electrodynamic disturbance processes are affected by a larger number of solar wind and magnetospheric parameters and that they also have more significant spatial dependence. This is especially pronounced during and after large geomagnetic storms when multiple simultaneous disturbance processes are also active. In this work, we briefly review the main past experimental and modeling studies of low latitude disturbance electric fields, highlight new results, discuss outstanding questions, and present suggestions for future studies. [ABSTRACT FROM AUTHOR]

The magnetotail plasma sheet boundary layer (PSBL) is a dynamic boundary layer between the hot‐denser plasma sheet and the cold‐tenuous tail lobes. It plays an important role in exchanging mass and energy in the magnetotail. In previous studies, the local current carried by the electron beams has been well understood. The strong energy conversion (E ⋅ J, E is electric field and J is current density), however, is barely reported at the PSBL. Here, using magnetospheric multiscale mission, we find a strong dawn‐dusk current with a magnitude of 80 nA/m2 at the magnetotail PSBL. The strong current appears during crossing the PSBL and is primarily contributed by the perpendicular electron currents. Cooperating with an intense fluctuating electric field (reaching ∼40 mV/m) carried by the lower‐hybrid drift waves, this dawn‐dusk current leads to a strong energy conversion with a magnitude larger than 3 nW/m3. This study enhances the understanding of local energy‐conversion processes at the PSBL. Plain Language Summary: As a spatial boundary layer between the plasma sheet and tail lobes, the magnetotail plasma sheet boundary layer (PSBL) has been widely thought of as an important channel for mass and energy exchanged in the magnetotail. In this study, we report a strong dawn‐dusk current (J > 80 nA/m2) at the PSBL by utilizing the magnetospheric multiscale mission. Such a strong current is contributed by electron currents in the perpendicular directions and leads to strong energy conversion (E ⋅ J > 3 nW/m3) at the PSBL through the interaction with the intense electric field (E > 40 mV/m) associated with the lower‐hybrid drift waves. Our results improve the understanding of the energy conversion at the PSBL. Key Points: A strong dawn‐dusk current with a magnitude of 80 nA/m2, primarily contributed by electron currents, is observed at the magnetotail plasma sheet boundary layer (PSBL)The lower‐hybrid drift waves are observed at the PSBL and carry an intense fluctuating electric field which can reach ∼40 mV/mSuch current and electric field leads to strong energy conversion at the PSBL, with a magnitude of larger than 3 nW/m3 [ABSTRACT FROM AUTHOR]

Lightning is the severest threaten to safe operation of wind turbines. In this letter, the authors present the first altitude‐triggered lightning experiment involving an elevated 12 m‐long wind turbine blade placed on the ground. A total of 50 precursors with amplitude over 62.9 A were observed through measurements of channel‐base current, fast electric field, and optical data. The air gap with around 3–5 m has been bridged between the wire's lower extremity and the metal blade tip during ascending of the rocket and it is observed to be luminous by slow framing rate camera. The precursors are classified into three groups, namely bipolar pulses, unipolar pulses, and group pulses. Excluding the precursors preceding the initial stage and M‐components at the late‐time of the initial stage, five stages are classified. In the first stage, the current remains limited at a relatively small value, while the electric field exhibited a slow rising behavior with positive polarity. In the second stage, the current starts to increase, and the electric field rapidly intensifies due to the accumulating charge, and the wire is assumed to experience an explosion. In the third stage, the reconnection process occurs. The current is characterized by a peak value of 1.45 kA with 10%–90% risetime of 10.4 μs. The electric fields suffer from notable decrease and are characterized by a microsecond‐scale V‐shape pulse. The current cutoff is quite short that almost not found. In the fourth step, the current is characterized by superimposed pulses. The final stage is the channel darkening. Plain Language Summary: Observation results are reported in detail about the altitude‐triggered lightning experiment involving an elevated 12 m‐long wind turbine blade placed on the ground. There are fruitful precursors prior to the beginning of the initial stage. The precursors demonstrate that the air gap with around 3–5 m has been bridged between the wire and the metal blade tip. The precursors are grouped into three groups, namely bipolar pulses, unipolar pulses, and group pulses. The initial stage is classified into five periods. The triggering wire is believed to be vapourized during the second stage. The so‐called initial current variation (ICV), also called reconnection process, occurs at the third stage. The superimposed pulses are found immediately after the reconnection process in the fourth stage. The late‐time of the initial stage is also characterized by superimposed pulses associated with M‐components. This work is potentially helpful to understand the physical process lightning strikes a wind turbine, and design lightning protection strategies for wind turbines. Key Points: First altitude‐triggered lightning experiment associated with an elevated 12 m‐long wind turbine blade has been conducted through simultaneous measurements of current, electric fields and optical dataThe 50 precursors over 62.9 A proceeding the initial stage are classified into three groups: (a) bipolar pulses with the notably initial positive peak and followed by the negative excursion; (b) unipolar pulses with the notably initial positive peak but with quite flat late‐time response; and (c) group pulsesFive stages associated with channel reestablishment are classified according to the measured current and electric field, in which the current cutoff is quite short that almost not found [ABSTRACT FROM AUTHOR]

X-rays have been observed in natural downward cloud-to-ground lightning for over 20 years and in rocket-triggered lightning for slightly less. In both cases, this energetic radiation has been detected during the stepped and dart leader phases of downward negative flashes. More recently, X-rays have also been reported during the dart leader phase of upward negative flashes. In this study, we present the observations of four upward positive lightning flashes from the Säntis Tower (2.5 km ASL) in Switzerland. These consist of the simultaneous records of electric current passing through the tower, and electric field strength and X-ray flux 20 m from the tower base. One of the flashes was captured by a high-speed camera operating at 24,000 frames per second, stills from which are also presented. We detected X-rays during the initial phase of upward negative leader propagation, which can be associated with the leader-stepping process from electric field and current waveforms. To the best of our knowledge, this is the first time that such measurements are reported in the literature. The obtained time-synchronised data confirm that the X-ray emissions detected are associated with the initial steps of the upward negative leader. The frequency and energy of X-ray pulses appear to decrease as functions of time, with pulses disappearing altogether within the first millisecond of the leader initiation. X-ray emission also appears to be correlated with the maximum current-derivative and the electric field change of leader steps, consistent with cold electron runaway. These observations contribute to improving our understanding of upward lightning, which is a primary source of damage to tall structures such as wind turbines and telecommunications towers, as well as aircraft during takeoff and landing. [ABSTRACT FROM AUTHOR]

Taste and odor (T&O) compounds have emerged as crucial parameters for assessing water quality. Therefore, identifying effective methodologies for the removal of these compounds is imperative. In this study, an effective approach utilizing laccase assisted by a micro-electric field was developed for the degradation of 2-methylisoborneol (2-MIB). For this purpose, the optimal conditions for the laccase-catalyzed degradation of 2-MIB were determined, and they were pH 4.0, 25 °C, 150 rpm, 0.1 U/mL of laccase, and 200 ng/L of 2-MIB. Under these specified conditions, the degradation efficiency of 2-MIB was approximately 78% after a 4 h reaction period. Subsequently, the introduction of an electric field yielded a synergistic effect with the enzyme for 2-MIB degradation. At an electric current intensity of 0.04 A over a 4 h duration, the degradation efficiency increased to 90.78%. An analysis using SPME-GC/MS provided information on the degradation intermediates of 2-MIB resulting from laccase-catalyzed degradation, electrocatalytic degradation, and micro-electric-assisted laccase degradation. The potential degradation pathways of 2-MIB illustrated that these three methods result in common degradation products, such as capric aldehyde, nonylaldehyde, and 2-ethylhexanol, and their final products include 3-pentanone, acetone, and 2-butanone. This study provides an enzyme–electrochemical method for the efficient and rapid degradation and removal of 2-MIB. The strategy of laccase catalysis assisted by a micro-electric field has good potential for the removal of pollutants from the natural environment. [ABSTRACT FROM AUTHOR]

A novel ultra-wideband (UWB) flexible metamaterial absorber (MA) is proposed and thoroughly examined both numerically and experimentally for microwave range applications. The design is based on a rectangular ring array of silver nanoparticles (SNP) inkjet-printed on an ultra-thin flexible Polyethylene terephthalate (PET) substrate. The finite integration technique (FIT) is employed to simulate the proposed design. The results demonstrate absorption performance surpassing 90% across a wide frequency span, ranging from 3 to 96.4 GHz, for both transverse electric (TE) and transverse magnetic (TM) polarizations under normal incidence. The surface current and electric field distributions at different frequencies reveal the underlying physical mechanisms responsible for the UWB absorption phenomenon. Perfect absorption is due to the intrinsic character of the metamaterial structure that can be confirmed from the extracted effective permittivity and effective permeability. The proposed design is fabricated and experimentally tested, demonstrating good agreement with the simulation outcomes. The metamaterial absorber's remarkable characteristics make it highly promising for various applications in communications and stealth, primarily due to its perfect absorptivity over the UWB frequency range. [ABSTRACT FROM AUTHOR]

A metasurface consisting of a 2D periodic square lattice of metallic square ring resonators is considered for supporting spoof surface plasmon polariton (SSPP) modes. First, SSPP modes are highlighted by simulated dispersion curves. The dispersion curves are analyzed by considering hybridization of modes in either a patch or an aperture array with frequency shifts. Hybridization of modes is also supported by means of surface current and electric field mappings showing consistent symmetric and anti-symmetric fields. Second, it is shown that a dipole antenna located near the metasurface is able to generate SSPP modes. The transmission spectra between two antennas located at each extremity of the metasurface show transmission enhancements compared with propagation in free space. The transmission enhancements are shown for different locations of the antennas either facing each other or positioned in diagonal. Finally, the transmission enhancement is connected to SSPP modes by comparing the transmission spectra and the measured dispersion curves with each other. Specifically, two transmission windows measured for an embroidered metasurface are related to the cutoff frequency of the two SSPP modes supported by the metasurface as evidenced by the measured dispersion curves. [ABSTRACT FROM AUTHOR]

Interfacial differences between the Hf0.5Zr0.5O2 (HZO) and the top/bottom electrodes caused by the process sequence could lead to the imprint effect of the TiN/HZO/TiN ferroelectric capacitor, which leads to serious reliability problems. In this article, a method of introducing a HfO2 protective layer is proposed to inhibit the imprint effect of the TiN/HZO/TiN ferroelectric capacitor. By introducing the HfO2 protective layer, the leakage current at the positive electric field is reduced by three orders of magnitude, the asymmetry of the coercive field is reduced from 1.5 to 0.1 MV/cm, and the endurance is improved by two orders of magnitude with no degradation in retention. The proposed method provides a feasible strategy to inhibit the imprint effect of TiN/HZO/TiN ferroelectric capacitors and is more compatible with complementary metal–oxide–semiconductor processes. [ABSTRACT FROM AUTHOR]

To study the current response to space charge in oil–paper insulation, a simultaneous space charge and external current measurement system are developed for a solid–liquid sample. The space charge and external current of oil-immersed paper are tested under different applied voltages. In the oil–paper sample, it accumulates heterocharge at 0.25 kV and homocharge at a higher voltage. The external currents first decrease and then increase with time. The changing timepoint decreases with the applied voltage. It shows that dynamic space charge evolution influences external current development. An unusual phenomenon is observed that the charge on both electrodes increases without heterocharge accumulation in a certain time range after voltage application, resulting in an increase in the average electric field. The transient electric field and displacement current at the cathode are calculated according to the amount of surface charge at the cathode. It indicates that displacement current takes up the main part of external current and decreases to zero when the surface charge amount stops increasing. After this stage, the conduction current is almost equal to the external current. The correlation between conduction current and electric field is analyzed. It reveals that when the electric field is lower than 5 kV/mm, the conduction current of oil–paper seems to be linear to the electric field strength, following Ohm's law. When the electric field is higher than 5 kV/mm, the conduction current of oil–paper follows the Fowler–Nordheim law that the ln(jc/E2) is linear to 1/E. The transient external current has great potential in diagnosing electrical equipment. [ABSTRACT FROM AUTHOR]

The mechanism of electrical interaction between subsystems in the Earth–atmosphere–ionosphere–magnetosphere system is currently the least studied and substantiated subject. Moreover, some experts doubt its existence. This study is devoted to investigating the mechanisms of generation and propagation of electric fields that vary in time under the influence of transient high-energy sources of various physical nature and atmospheric turbulence enhanced by these sources, which is an urgent problem. Four options of penetration of electric fields from the atmospheric surface layer into the ionosphere have been proposed. Electrical parameters that depend on disturbances in the electric charge density and the characteristics of atmospheric turbulence have been estimated and numerically calculated for a number of high-energy sources. It is shown that the disturbances arising in the atmospheric surface layer are capable of penetrating into the ionosphere and even into the magnetosphere. [ABSTRACT FROM AUTHOR]

The impact of interplanetary (IP) shocks on the Earth's magnetosphere can greatly disturb the geomagnetic field and electric currents in the magnetosphere-ionosphere system. At high latitudes, the current systems most affected by the shocks are the auroral electrojet currents. These currents then generate ground geomagnetically induced currents that couple with and are highly detrimental to ground artificial conductors including power transmission lines, oil/gas pipelines, railways, and submarine cables. Recent research has shown that the shock impact angle, the angle the shock normal vector performs with the Sun-Earth line, plays a major role in controlling the subsequent geomagnetic activity. More specifically, due to more symmetric magnetospheric compressions, nearly frontal shocks are usually more geoeffective than highly inclined shocks. In this study, we utilize a subset (332 events) of a shock list with more than 600 events to investigate, for the first time, shock impact angle effects on the subsequent GICs right after shock impact (compression effects) and several minutes after shock impact (substorm-like effects). We use GIC recordings from the Finnish natural gas pipeline performed near the Mäntsälä compression station in southern Finland. We find that GIC peaks ( > 5 A) occurring after shock impacts are mostly caused by nearly frontal shocks and occur in the post-noon/dusk magnetic local time sector. These GIC peaks are presumably triggered by partial ring current intensifications in the dusk sector. On the other hand, more intense GIC peaks ( > 20 A) generally occur several minutes after shock impacts and are located around the magnetic midnight terminator. These GIC peaks are most likely caused by intense energetic particle injections from the magnetotail which frequently occur during substorms. The results of this work are relevant to studies aiming at predicting GICs following solar wind driving under different levels of asymmetric solar wind forcing. [ABSTRACT FROM AUTHOR]

Dipolarization fronts (DFs), characterized by sharp increases in the northward magnetic field and usually preceded by magnetic dips, are suggested to play an important role in energy conversion and transport in the magnetotail. It has been documented that strong energy conversion typically develops right at the fronts. Here we present spacecraft observations of electron‐scale energy conversion (EEC) developed inside the dip region ahead of a DF, by using high‐cadence data from the Magnetospheric Multiscale Mission. The EEC, with magnitude comparable to that at the front, is primarily driven by ion current and electron‐scale electric field. The electric field inside the dip is provided by electrostatic waves fed by lower hybrid drift instability, which experiences temporal decaying. Such decaying leads to nonhomogeneity of EEC along the dawn‐dusk direction. These results, uncovering a new channel for DF‐driven energy conversion, can provide important insights into understanding energy transport in the magnetotail. Plain Language Summary: Space weather is determined by earthward transport of energy and mass in the magnetosphere. In the magnetotail, such transport is usually associated with dipolarization fronts embedded inside high‐speed plasma jets, which are characterized by a sharp enhancement of the northward component of the magnetic field and serve as the leading boundaries of plasma jets. Statistical studies reveal that a small decrease in the magnetic field often occurs ahead of the fronts, which is dubbed as a magnetic dip. Dipolarization fronts have been suggested to play a key role in the energy conversion chain in the magnetotail, and the energy conversion typically happens right in the front region where strong currents and electric fields usually develop. In this research, we find that in addition to the front region, the dip preceding the fronts can also host strong energy conversion. Our results help further understand energy conversion in the terrestrial magnetotail. Key Points: Electron‐scale energy conversion (EEC) is observed for the first time in the magnetic dip ahead of a dipolarization frontThe EEC, with magnitude comparable to that at the front, is primarily driven by ion current and electron‐scale motional electric fieldThe EEC electric field is induced by a decaying lower hybrid drift instability which may cause temporal damping of the EEC [ABSTRACT FROM AUTHOR]

To enhance the electrical safe operation area (eSOA) of laterally diffused metal oxide semiconductor (LDMOS) transistors, a novel reduced surface electric field (Resurf) structure in the n-drift region is proposed, which was fabricated by ion implantation at the surface of the LDMOS drift region and by drift region dimension optimization. Technology computer-aided design (TCAD) simulations show that the optimal value of Resurf ion implantation dose 1 × 1012 cm−2 can reduce the surface electric field in the n-drift region effectively, thereby improving the ON-state breakdown voltage of the device (BVon). In addition, the extended n-drift region length of the Ld design also improves device BVon significantly, and is aimed at reducing the current density and the electric field, and eventually suppressing the n-drift region impact ionization. The results show that the novel 60 V nLDMOS has a competitive BVon performance of 106.9 V, which is about 20% higher than that of the conventional one. Meanwhile, the OFF-state breakdown voltage of the device (BVoff) of 88.4 V and the specific ON-resistance (RON,sp) of 129.7 mΩ⋅mm2 exhibit only a slight sacrifice. [ABSTRACT FROM AUTHOR]

The ever-increasing needs of the working population have led to the development of various branches of industry, an increase in the number of employees, and a rise in the number of work-related accidents. The welder occupation is one of the most sought after occupations in Europe, according to the EURopean Employment Services (EURES) statistics. Taking into account the work system in which welders conduct their activity (uncomfortable working positions, splashes, high temperatures, mechanical factors, gases and fumes, magnetic fields due to electric current), the paper presents the risk factors identified for the welder occupation, based on the occupational injury and illness risk assessments. Following the analysis of 25 risk assessments, carried out by the assessment team that must include qualified evaluators, process specialists, the workers' representative, occupational health and safety responsible at various industrial economic agents, a total of 70 main risk factors of occupational accidents and diseases were identified for the welder occupation. Risk factors were classified according to four main work components: worker, workload, work environment, and means of production. To reflect the importance of the identified risk factor, the number of organizations that considered that the risk was likely to occur but also the possibility that the risk was above the acceptable limit, calculated using the National Institute for Research and Development for Labor Protection "Alexandru Darabont" (INCDPM) method, a method often used in Romania, was identified from the analyzed assessments. Finally, a prevention and protection plan was drawn up with regard to the risks identified for the welder occupation, the final aim of which was to respectively reduce the probability of occurrence with the severity of the risks identified. [ABSTRACT FROM AUTHOR]

Neuromodulation with transcranial direct current stimulation (tDCS) can transiently alter neural activity, but its spatial precision is low. High‐definition (HD) tDCS was introduced to increase spatial precision by placing additional electrodes over the scalp. Initial evaluations of HD tDCS indicated polarity‐specific neurophysiological effects—similar to conventional tDCS albeit with greater spatial precision. Here, we compared the effects of cathodal tDCS or HD tDCS in a 4 × 1 configuration over prefrontal cortex (PFC) regions on behavioural outcomes in a magnitude classification task. We report results on overall performance, on the numerical distance effect as a measure of numerical processing, and on the spatial‐numerical associations of response codes (SNARC) effect, which was previously affected by prefrontal tDCS. Healthy volunteers (n = 68) received sham or cathodal HD tDCS at 1 mA over the left dorsolateral prefrontal cortex (DLPFC) or the left inferior frontal gyrus (IFG). Results were compared to an identical protocol with conventional cathodal tDCS to the left PFC versus sham (n = 64). Mixed effects models showed performance gains relative to sham tDCS in all conditions after tDCS (i.e. 'offline'), whereas montages over PFC and DLPFC already showed performance gains during tDCS (i.e. 'online'). In contrast to conventional tDCS, HD tDCS did not reduce the SNARC effect. Neither condition affected numerical processing, as expected. The results suggest that HD tDCS with cathodal polarity might require further adjustments (i.e. regarding tDCS intensity) for effective modulations of cognitive‐behavioural performance, which could be achieved by individualised current density in electric field modelling. [ABSTRACT FROM AUTHOR]

Background: Transcranial electrical stimulation (tES) generates an electric field (or current density) in the brain through surface electrodes attached to the scalp. Clinical significance has been demonstrated, although with moderate and heterogeneous results partly due to a lack of control of the delivered electric currents. In the last decade, computational electric field analysis has allowed the estimation and optimization of the electric field using accurate anatomical head models. This review examines recent tES computational studies, providing a comprehensive background on the technical aspects of adopting computational electric field analysis as a standardized procedure in medical applications. Methods: Specific search strategies were designed to retrieve papers from the Web of Science database. The papers were initially screened based on the soundness of the title and abstract and then on their full contents, resulting in a total of 57 studies. Results: Recent trends were identified in individual- and population-level analysis of the electric field, including head models from non-neurotypical individuals. Advanced optimization techniques that allow a high degree of control with the required focality and direction of the electric field were also summarized. There is also growing evidence of a correlation between the computationally estimated electric field and the observed responses in real experiments. Conclusions: Computational pipelines and optimization algorithms have reached a degree of maturity that provides a rationale to improve tES experimental design and a posteriori analysis of the responses for supporting clinical studies. [ABSTRACT FROM AUTHOR]

The topological (anti)skyrmion configurations have presented promise for versatile spintronic applications in racetrack memory, logic gates, and bio-inspired computing due to the nontrivial spin topology and convenient current-driven dynamics. However, the precise control of (anti)skyrmion-based information unit transportation via electric current in conquer of skyrmion Hall effect remains challenging especially in ferromagnetic films, limiting their integration into spintronic devices. In this study, we demonstrate the density, velocity, and direction control of half-skyrmion, with a topological charge of 1/2, in a predictable and governable way under the stimuli of electric current in Pt/Co/Ta multilayers. The particular nonsymmetric configuration of half-skyrmion introduces variable competing forces under joint manipulation of magnetic field and electric current. Thereby, the half-skyrmion application with highly controllable dynamic behavior is further proposed in prototype devices such as half-skyrmionic racetrack memory device with parallelized operation, programmable logic devices, and neuromorphic computing artificial synapses. This work sheds light on the versatile spintronic applications of half-skyrmions through electromagnetic coordinated manipulation. [ABSTRACT FROM AUTHOR]

The potential application of conducting Scholte‐wave analysis using electroseismic pressure fields excited by an electric current source due to the electrokinetic effect in fluid‐saturated porous seabed sediments is investigated. First, we develop a numerical modelling algorithm by combining the Luco–Apsel–Chen generalized reflection and transmission method with the peak‐trough averaging method to simulate the electroseismic wave fields in stratified fluid/porous media. The modelling results show that the electroseismic pressure signals recorded on the seafloor are mainly composed of evanescent electroseismic waves, and Scholte waves are the dominant wave pattern. Their amplitudes are generally within the order of magnitudes capable of being detected by current seismic instruments. Then, the modified frequency–Bessel transform method is extended to extract the Scholte‐wave dispersion curves from electroseismic pressure fields. Results demonstrate that Scholte‐wave dispersion curves extracted from electroseismic records are superior to those extracted from conventional seismic wave fields excited by an airgun source under the same source–receiver geometry because they contain many overtones and are almost free from the interferences of dispersive guided waves. Furthermore, the Scholte‐wave dispersion inversion results obtained by employing the Levenberg–Marquardt method show that the shear‐wave velocity model inverted by Scholte‐wave dispersion curves extracted from the electroseismic pressure field is more accurate than those obtained by dispersion curves extracted from the seismic wave fields with the guided‐wave removal. The above results indicate that the electroseismic Scholte‐wave analysis method has the potential to evaluate the shear‐wave velocities of shallow‐water seabed sediments. [ABSTRACT FROM AUTHOR]

The ability to stimulate deep brain regions in a focal manner brings new opportunities for treating brain disorders. Temporal interference (TI) stimulation has been suggested as a method to achieve focused stimulation in deep brain targets. Individual-level knowledge of the interferential currents has permitted personalizing TI montage via subject-specific digital human head models, facilitating the estimation of interferential electric currents in the brain. While this individual approach offers a high degree of personalization, the significant intra-and inter-individual variability among specific head models poses challenges when comparing electric-field doses. Furthermore, MRI acquisition to develop a personalized head model, followed by precise methods for placing the optimized electrode positions, is complex and not always available in various clinical settings. Instead, the registration of individual electric fields into brain templates has offered insights into population-level effects and enabled montage optimization using common scalp landmarks. However, populationlevel knowledge of the interferential currents remains scarce. This work aimed to investigate the effectiveness of targeting deep brain areas using TI in different populations. The results showed a trade-off between deep stimulation and unwanted cortical neuromodulation, which is target-dependent at the group level. A consistent modulated electric field appeared in the deep brain target when the same montage was applied in different populations. However, the performance in terms of focality and variability varied when the same montage was used among populations. Also, group-level TI exhibited greater focality than tACS, reducing unwanted neuromodulation volume in the cortical part by at least 1.5 times, albeit with higher variability. These results provide valuable population-level insights when considering TI montage selection. [ABSTRACT FROM AUTHOR]

Observations of a regular pulse burst (RPB) at the end of a K‐event are analyzed utilizing a simple geometric model and particle swarm optimization (PSO) to estimate the currents and propagation speeds of successive pulses of the RPB. The results show that the current of successive pulses is strongly overlapped and, for typical speeds of continuously propagating K‐events, are unphysically large (88 kA), exceeding the currents of most strokes to ground. By default, the unphysical nature of the result, coupled with very high frequency interferometer observations of an RPB in Florida, shows that the propagation speed of the pulses is significantly faster than expected, namely ∼0.6–1.8 × 108 m/s. This reduces the inferred current from 88 kA down to 6–18 kA, typical of intracloud events. The fast propagation speed of the stepping is explained by successive pulses retracing much of the path of the preceding pulses due to the successive pulses being strongly overlapped. Plain Language Summary: Regular pulse bursts (RBP) are a spectacular phenomenon in lightning studies, in which rapidly propagating, conductive channels called K‐events transition from a smoothly and continually lengthening channel to an intermittent but regularly‐spaced stepping process, with each step producing a highly‐impulsive current and electric field change, or "sferic." Here we introduce a new approach for analyzing sferic observations that models the K‐event as a series of successive segments, with the parameters of the current and extent of each pulse being determined by searching the multi‐dimensional parameter space that best fits the corresponding pulse waveforms. This was done using a process called PSO, and indicated that the RBP pulses were caused by a succession of overlapping fast breakdown events, but having unphysically strong currents. For the distant measurements of the study, the sferic amplitudes can determine only the product of current and propagation speed of the pulses, causing their current and speed values to be ambiguous. However, for the currents to have reasonable values, we are able to conclude that the speeds needed to be faster than assumed maximum value of 1.5 × 107 m/s value in the analysis. This contention is supported by observations of similar RPBs being studied by the authors. Key Points: A new, innovative method is developed for estimating the currents and extents of fast electric field change pulsesThe method is applied to the study of a regular pulse burst, showing that it consisted of a succession of fast overlapping eventsThe speed of the pulses is inferred to be significantly higher than that of continuously‐developing K‐leader [ABSTRACT FROM AUTHOR]

It has been found that heat release in a homogenized composite model is described by the Joule–Lenz law for the averaged current strength and voltage. It has been shown that the local electric field strength and the local electric current in a real composite are usually significantly different from those in the homogenized model despite the fact that the electric field potentials in the homogenized model and the real composite are close. [ABSTRACT FROM AUTHOR]

A comparative analysis of various model representations of seismogenic quasi-stationary electric fields/currents from large-scale sources on the Earth's surface was carried out. It has been established that previously proposed analytical models of seismogenic quasi-stationary sources of electric field/current with field/current amplitudes continuously decreasing to zero at infinity are consistent with extreme values of electric field/current experimentally observed in epicentral zones before earthquakes. It is also shown that sharply spatially limited models of seismogenic sources of quasi-stationary electric fields/currents in the epicentral zones of future earthquakes on the Earth's surface lead to their values being an order of magnitude or more greater than those actually observed. [ABSTRACT FROM AUTHOR]

The study of evolution of magnetic field and electric currents in active regions of the Sun over a long-time interval is of interest for understanding the processes of energy accumulation and release in them, leading to various phenomena that affect space weather. In this study, based on the photospheric vector magnetograms of the helioseismic and magnetic imager instrument aboard the Solar Dynamics Observatory, the authors analyzed the evolution of a number of characteristics of the magnetic field and vertical electric current in three active regions, 11 158, 11 675, and 12 673, that produced M and X class flares, during the time from their origin in the eastern hemisphere, during passage through the solar disk, and until their disappearance near the western limb with a step of 2 h. The characteristics considered included: the power-law exponent of the probability density function of the absolute value of the vertical electric current density, the maximum absolute value of the vertical current density, the signed and unsigned total vertical currents and the unsigned total vertical and horizontal magnetic fluxes, the energy of the nonlinear force-free and potential magnetic fields, the free magnetic energy, and the number of islands with strong vertical current. Some regularities in the behavior of the characteristics considered are found, in particular, regarding the occurrence of solar flares. The correlation coefficients between pairs of these characteristics are calculated. Additionally, M. Aschwanden's approach is shown to be promising for predicting the maximum X-ray class of a flare by calculating the energy of the potential magnetic field in active regions. The results can be used to predict powerful solar flares. [ABSTRACT FROM AUTHOR]

We study the Schwinger pair creation of scalar charged particles by a homogeneous electric field in an expanding universe in the quantum kinetic approach. We introduce an adiabatic vacuum for the scalar field based on the Wentzel–Kramers–Brillouin solution to the mode equation in conformal time and apply the formalism of Bogolyubov coefficients to derive a system of quantum Vlasov equations for three real kinetic functions. Compared to the analogous system of equations previously reported in the literature, the new one has two advantages. First, its solutions exhibit a faster decrease at large momenta which makes it more suitable for numerical computations. Second, it predicts no particle creation in the case of conformally coupled massless scalar field in the vanishing electric field, i.e., it respects the conformal symmetry of the system. We identify the ultraviolet divergences in the electric current and energy–momentum tensor of produced particles and introduce the corresponding counterterms in order to cancel them. [ABSTRACT FROM AUTHOR]

Joule heating is one of the main energy inputs into the thermosphere‐ionosphere system. Precise modeling of this process is essential for any space weather application. Existing thermosphere‐ionosphere models tend to underestimate the actual Joule heating rate quite significantly. The Thermosphere‐Ionosphere‐Electrodynamics General‐Circulation‐Model applies an empirical scaling factor of 1.5 for compensation. We calculate vertical profiles of Joule heating rates from approximately 2,220 hr of measurements with the EISCAT incoherent scatter radar and the corresponding model runs. We investigate model runs with the plasma convection driven by both the Heelis and the Weimer model. The required scaling of the Joule heating profiles is determined with respect to the Kp index, the Kan‐Lee merging electric field EKL, and the magnetic local time. Though the default scaling factor of 1.5 appears to be adequate on average, we find that the required scaling varies strongly with all three parameters ranging from 0.46 to ∼20 at geomagnetically disturbed and quiet times, respectively. Furthermore, the required scaling is significantly different in runs driven by the Heelis and Weimer model. Adjusting the scaling factor with respect to the Kp index, EKL, the magnetic local time, and the choice of convection model would reduce the difference between Joule heating rates calculated from measurement and model plasma parameters. Plain Language Summary: The vast majority of the energy input to the Earth system originates from the sun. This includes the absorption of various types of radiation, for example, ultraviolet radiation in the ozone layer or visible light and infrared radiation at the surface. In the upper atmosphere above about 80 km altitude, the absorption of extreme ultraviolet radiation and soft X‐rays plays a major role. However, other processes also contribute significantly to the heating of this region, for example, the energy dissipation in the form of electric currents flowing along electric fields, also known as Joule heating. Joule heating is highly variable and can be drastically enhanced especially during solar storms, which can have potentially disastrous effects on satellites. Accurate modeling, and therefore also prediction, of Joule heating is not possible at the moment since thermosphere‐ionosphere models have to scale the Joule heating empirically to fit the actual values. We investigate how the required scaling changes under different geophysical conditions. Key Points: The constant Joule heating scaling factor in TIE‐GCM is inadequate to compensate for the underestimation under various geomagnetic conditionsJoule heating rates calculated from 2,220 hr of EISCAT measurements are compared to TIE‐GCM runs driven with the Heelis and Weimer convection modelsThe required scaling factor varies significantly with the Kp index, the Kan‐Lee merging electric field, and the magnetic local time [ABSTRACT FROM AUTHOR]

A model for the distribution of the ionospheric potential which drives the ionospheric currents closing the electric currents from/to the atmosphere is constructed. It is a part of the global electric circuit (GEC). Only the internal electric fields and currents generated by thunderstorms are studied, and without any magnetospheric or ionospheric generators. The atmospheric conductivity profiles with altitude are empirically determined, and the topography of the Earth's surface is taken into account. A two-dimensional approximation of the ionospheric conductor is based on high conductivity along the geomagnetic field. The model of the global distribution of thunderstorms obtained from the ground-based World Wide Lightning Location Network is used as a proxy for the electric currents to the ionosphere from the atmosphere above thunderstorm regions. The global distributions of the electric potential in the ionosphere are calculated for twelve months during a year with low solar activity. The designed models contain the equatorial electrojets. There are day-time electrojets, the strengths of which are up to 200 A, and night-time ones (which are up to only half this value), while the total current of the GEC is taken equal between 1.5 and 2.5 kA in our model to satisfy the Carnegie data for the simulated dates and UT. The results are presented as diagrams of the currents in the electrojets depending on the geomagnetic longitude and month for 04 and 18 UT. These times are chosen to be the times of minimum and maximum fair weather electric field in accordance with the Carnegie results. The diagrams could help us to choose optimal conditions for measurements of the magnetic perturbations observed on the ground or by satellites to find the electrojets of the GEC which are obtained in our simulations. [ABSTRACT FROM AUTHOR]

We describe a new class of the periodic banding of Ag2O precipitates through reaction-transport-reaction processes in an agarose-hydrogel column; the gel contains NaNO3 as an additive and is inserted between Ag and Ti rods with an applied constant voltage of 4.0-7.0 V. Submillimeter-scale periodic dark-brown precipitation bands were transiently generated with high reproducibility in this system, in which (i) electrochemical reactions at the metal rods to generate Ag+ and OH-, (ii) transportation of the reactant ions by the electric field, and (iii) reactions to produce Ag2O are expected to couple. The bands successively emerged mainly toward the cathode, accompanied by substantial changes in the electric current through the gel. The periodic banding depended on the applied voltage, duration of application, and concentration of NaNO3 initially loaded in the gel. The banding was most clearly observed in a 2.0 mass% agarose gel column containing 0.005 MNaNO3 under a constant applied voltage of ~5.5 V for ~3 h. This optimal condition resulted in more than ten periodic bands, of which the bandwidth (w) and the distance between the adjacent bands (d) were randomly distributed around the average values: for the bands formed up to 2 h, w = 0.25 ± 0.04mmand d = 0.42 ± 0.05 mm; for the bands formed after 2 h, w = 0.42 ± 0.11mmand d = 0.68 ± 0.07 mm. The generated periodic bands were gradually painted out with time to form an almost continuous broad band, even after the applied voltage was discontinued, although immersion of the gel in deionized water for 3 h could suppress this uniformization. Observations using optical and scanning electron microscopes with an energy-dispersive X-ray detector suggested that the periodic bands were composed of gelatinous Ag2O and micrometer-scale (1-50 μm) clusters, which comprised Ag-abundant nanoparticles with considerable size dispersion (10-500 nm). The relationship between the periodic banding and inhomogeneous distribution of the reactant ions and potential applications of the observed banding phenomena are discussed. [ABSTRACT FROM AUTHOR]

This study investigates the non-equilibrium dynamics of massive N = 2 supersymmetric gauge theory under pulse-like electric field quenches, utilizing holographic techniques within the AdS/CFT correspondence framework. Focusing on subcritical electric fields, our analysis reveals prolonged oscillations in the electric current as well as the quark condensate dynamics with no dissipation. Notably, through power spectrum analysis of the time-dependent electric current, we identify a dominant frequency in the oscillations, which remains the same within numerical precision across different parameter variations, serving as a universal feature of the system. [ABSTRACT FROM AUTHOR]

We developed a soft contact probe capable of making electrical contact with a specimen without causing damage. This probe is now commercially available. However, the contact area with the probe changes according to the pressure applied during electric contact, potentially affecting electric measurements when current density or electric field strength is critical. To address this, we developed methods to control the area of electric contact. This article reports on these methods, as well as variations in probe size, pressure for electric contact, probe materials, and attachment to commercial probers. [ABSTRACT FROM AUTHOR]

Since the 18th century, the use of electrical stimulation has been widely used to treat disease and control the development of cells, tissues, and organ growth. Electric fields and currents are used to mimic endogenous signals that regulate cell behavior to both better understand their mechanism of action and provide control for bio-engineering and therapeutics. While delivery of electric fields has proven useful, low frequency field delivery remains inaccessible with standard metal electrodes. This delivery of low frequency electric fields is limited by areal capacitance, resulting in low charge injection capacities or Faradaic reactions, which can generate cytotoxic by-products. Here, we demonstrate freestanding poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) electrodes, which conduct both ions and electrons, resulting in electrode capacitance that scales with volume rather than area. We show that these electrodes can be used to generate electric fields in an aqueous medium at frequencies as low as 0.1 Hz. Specifically, we demonstrate persistent electric fields in aqueous media without exceeding the electrochemical window of water, previously unattainable using standard electrodes. Finally, we show that thick PEDOT:PSS electrodes are not cytotoxic. This work opens the path toward delivery of low frequency stimulating electric fields to cells and tissues both in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Light-emission data were collected before, during, and after the occurrence of the flash event in pressureless electric-field-assisted (flash) sintering experiments on ZrO2: 8 mol% Y2O3 (8YSZ) and CeO2: 20 mol% Sm2O3 (20SDC) ceramic green pellets to analyze the luminescent emission from the samples. The experiments were performed at 800 °C with an applied electric field of 100 V·cm−1 at 1 kHz, limiting the electric current to 1 A. Luminescence data were obtained in the 200–1200 nm (ultraviolet–visible–near-infrared) range. The deconvolution of the optical spectra allowed for the identification of emission bands in the visible range due exclusively to the samples. The wavelength maxima of the emission bands in 8YSZ were found to be different from those in 20SDC. It is suggested that these bands might originate from the interaction of the electric current, resulting from the application of the electric field, with the depleted species located at the space-charge region at the grain boundaries of these ceramics. The main results represent a contribution to help to clarify the mechanisms responsible for the fast densification with inhibition of grain growth in electroceramics. [ABSTRACT FROM AUTHOR]

In the prevailing form of the generalized Ohm's law (GOL), −me/e(J/en)⋅∇(J/en) ${-}\left({m}_{e}/e\right)\left[(\boldsymbol{J}/en)\cdot \nabla \right](\boldsymbol{J}/en)$ is often neglected. Because of the resemblance to the magnetic tension, we refer to this term as the current tension electric field (ECT). Our theoretical analysis reveals that ECT with a characteristic length of mi/me1/6λe ${\left({m}_{i}/{m}_{e}\right)}^{1/6}{\lambda }_{e}$ dominates the electron inertia terms in the electron diffusion region (EDR) and is comparable to the electron pressure term in low‐βe conditions. Using particle‐in‐cell simulations, we demonstrate that ECT can contribute significantly to the reconnection electric field and energy dissipation at the boundaries of the inner EDR and in the outer EDR. Positive and negative J ⋅ ECT can be used to identify inner and outer electron diffusion regions, respectively. Plain Language Summary: Magnetic reconnection is a fundamental physical process which allows for the explosive release of magnetic energy into thermal and kinetic energy. It underlies many dynamic phenomena in the universe, including solar eruptions, geomagnetic substorms and tokamak disruptions. In collisionless plasma, the generalized Ohm's law (GOL) introduces collisionless effects which break the frozen‐in constraint and enable reconnection to occur. The term, −me/e(J/en)⋅∇(J/en) ${-}\left({m}_{e}/e\right)\left[(\boldsymbol{J}/en)\cdot \nabla \right](\boldsymbol{J}/en)$, which is one of the electron inertia terms of GOL, is referred to as the current tension electric field (ECT) by us due to its mathematical resemblance to magnetic tension. In many classic textbooks and review papers, ECT is considered as a small quantity and thus is ignored. In this study, we present solid evidence from both theoretical studies and particle‐in‐cell (PIC) simulations to demonstrate that ECT dominates the electron inertia terms and plays important roles in providing reconnection electric field and energy dissipation in reconnection. Therefore, it should not be ignored. Based on our results, many classic textbooks in which ECT has been ignored must be modified. Key Points: ECT dominates the electron inertia terms in the electron diffusion region (EDR) and thus cannot be ignored in the generalized Ohm's lawECT contribute significantly to the reconnection electric field and energy dissipation in the inner and outer EDRsPositive and negative J · ECT can be used to identify inner and outer EDRs, respectively [ABSTRACT FROM AUTHOR]

This paper is aimed at proposing a calculation model for the ground resistance of a grounding scheme servicing a high-voltage direct-current converter station. The method is based on the equivalence of current conduction and electric field from the grounding scheme through the surrounding medium. The grounding scheme is composed of three concentric ring electrodes supported by two horizontal conductors and eight vertical rods. The calculated ground resistance is 4.8   Ω against the experimental value of 5   Ω with an error of 4.2 % . The calculated ground resistance value agrees reasonably well with that of 4.7   Ω as obtained using CYMGRD software (version 7.0). The calculated surface-potential values over the ground surface agreed reasonably well with those measured experimentally, with an average deviation not exceeding 6.5 % . This study is designed to investigate how ground resistance is decreased by the increase in the scheme parameters, including the rods' diameter and length, as well as the radius of the inner and outer rings. The dependency of the ground resistance on the soil type is also investigated. [ABSTRACT FROM AUTHOR]

Plasmas have emerged as a promising technology for the utilization of NH3 as a carbon-free fuel for direct plasmas-assisted combustion and hydrogen production. This study aims to explore the electrical and optical emission characteristics of the rotating gliding arc (RGA) discharge in NH3 and air swirling flows over a wide range of nominal power inputs. The electrical characteristics were measured using voltage–current probes, while a spectrometer was employed to assess the spectral characteristics. Additionally, a synchronized high-speed camera equipped with a dual-scope objective was utilized to capture transient phenomena of the arc in the optical emission spectrum. Both the spark-type and glow-type discharges were observed in RGA. Interestingly, the spark-type discharge frequency exhibited a non-monotonic variation with increasing nominal power inputs for both NH3 and air, while the glow-type discharge frequency displayed a monotonous upward trend. Regarding the spectral emission characteristics in NH3, a dramatic transition of the arc emission spectrum from Hα to NH2* was observed as nominal power inputs increased. The Hα and NH2* emissions that are dominated in the spark-type and glow-type discharges, respectively, and the intensity ratio of Hα and NH2* emission shows evident correlations with discharge current and electric field strength. In summary, this study represents the first investigation into the electrical and spectral characteristics of RGA in NH3. [ABSTRACT FROM AUTHOR]

Importance of studying Brinkman–Navier–Stokes flow under the influence of electric and magnetic fields lies in its relevance to fundamental physical phenomena, its applications in various fields of science and engineering and its potential for technological advancements. The study of Brinkman–Navier–Stokes flow under the influence of electric and magnetic fields, along with additional factors such as Joule heating, fractional derivatives and convection, represents a multifaceted and challenging problem in fluid dynamics and applied mathematics. In this study, we explore the combined effects of Joule heating due to electric current passing through the fluid and fractional derivatives that describe nonlocal behaviors. The fractional formulation leads to a relaxation mechanism that exhibits delay and recollection of the fluid motion. The organization of direct temperature and concentration changes in MHD flow is made possible by this formalization. A finite difference/finite element method is used to calculate the flow dynamics issue and fractionally linked fields. The physical factors explain how the topic under examination is relevant. [ABSTRACT FROM AUTHOR]

Flow cytometry-based measurement techniques have been widely used for single-cell characterizations, such as impedance, size, and dielectric properties. However, in the measurement process, the reliability of the output measurement signal directly affects the ability of the microsystem to judge the characteristics of single cells. Here, we designed a multiple nonparallel electrode structure for single-cell 3D localization. The performance of the structures was studied by analyzing the changes in electric field strength and the output differential current. The effects of microchannel height, sensing electrode distance, electrode inclination angle, and electrode width on output signals are investigated by analyzing the current change and electric field strength of single cells passing from the center of the microchannel. The numerical simulation results indicate that, when the microchannel height is 20 µm, the distance of the sensing electrodes is 100 µm, the inclination angle is 30°, the electrode width is 20 µm, and the optimal signal quality can be obtained. Reducing the height of the flow channel and shortening the sensing electrode spacing can significantly improve the signal amplitude. When the channel height is 20 µm, the signal intensity increases by 80% than that of 30 µm. The signal intensity of induced current with the sensing electrode spacing of 100 µm is 42% higher than that with the spacing of 120 µm. We analyzed the presence of multiple independent cells and adherent cells in the detection area and demonstrated through simulation that the signal changes caused by multi-cells can be superimposed by multiple single-cell signals. The induced current signal intensity of the same volume of cells with an ellipticity of 1 is 49% lower than that of cells with an ellipticity of 4. Based on the numerical investigation, we expect that the optimal geometry structure design will aid in the development of better performance signal cell impedance cytometry microsystems. [ABSTRACT FROM AUTHOR]

Rapid connection at low temperatures is an urgent and continuous need for transparent ceramic applications, allowing for high-quality joints without compromising the strength of the base material. This study investigated the flash joining of yttrium oxide and Ti-6Al-4V in seconds with the assistance of a threshold electric field. The maximum shear strength reached 36 ± 2 MPa at 900 ℃ under a current density of 4 mA/mm2 for 180 s. During the flash joining, the applied electric field contributes to generating oxygen vacancies which combine with electrons from the cathode, and accumulate near the grain boundary to become micropores, reacting with atom/ionic rapidly due to the effect of Joule heating and electromigration. This work summarizes flash joining as a process in which electric field and current act together, and applies it to transparent ceramic and metal connections. This research provides important insights for ceramic-alloy flash joining, such as transparent ceramic to titanium alloy interconnects. [ABSTRACT FROM AUTHOR]

We present a unified approach to subauroral arcs within intense subauroral ion drifts (SAID), which explains the observed transition of a precursor Stable Auroral Red (SAR) arc into Strong Thermal Emission Velocity Enhancement (STEVE). This approach is based on the short‐circuiting concept of fasttime SAID as an integral part of a magnetospheric voltage generator between the innermost boundaries of the freshly injected plasma sheet electrons and ring current ions. Here, enhanced plasma turbulence rapidly heats the bulk plasma and accelerates suprathermal non‐Maxwellian "tails." Heat and suprathermal electron transport rapidly elevate the ionospheric electron temperature—the source of a bright SAR arc. Through a substorm, the density altitude profile within the evolving ionospheric SAID channel transforms into a "fresh" F‐region trough with the E‐region valley. The ionospheric feedback instability within the depleted‐density SAID channel generates small‐scale, field‐aligned currents with parallel electric fields sufficient to produce the suprathermal electron population, exciting the STEVE and Picket Fence emissions. This approach also explains the inner electromagnetic structure of intense SAID, which is consistent with fine optical structures in STEVE and Picket Fence. Key Points: Nightside Stable Auroral Red (SAR) arcs emerge and follow the evolution of the fasttime subauroral ion drifts (SAID) until the ensuing emergence of Strong Thermal Emission Velocity Enhancement (STEVE)Density trough formation with the E‐region valley initiates the emergence of STEVE and Picket Fence underneath of the precursor SAR arcSmall‐scale parallel electric fields created by the ionospheric feedback instability in the low‐density SAID channel make STEVE and Picket Fence [ABSTRACT FROM AUTHOR]