Electric Field Components Research Articles

Evaluating the Electromagnetic Field Problem Generated by the Power Transmission Line Using High Order Compact Method

This paper compares a finite difference method-based computational scheme for evaluating electromagnetic field problems in power transmission lines in cases of on surface and in Ground. The scheme uses Maxwell's partial differential equations to represent electric and magnetic field components and approximate boundary conditions. The High Order Compact Method (HOC) is applied to estimate the electric field (Ez )in ground and compares it with the standard central difference scheme. The HOC produces more accurate results than the traditional central approximation at 99.7% for the electric field Ez. It also calculates both of Electric and magnetic intensity to evaluate the effect of Electric and magnetic intensities in ground and on surface respect to distance.

Generation of extremely strong accelerating electric field by focusing radially polarized THz pulses with a paraboloid ring

Efficient acceleration of electrically charged particles by focused electromagnetic pulses requires a strong accelerating electric field as well as a sufficiently large interaction region. Single-cycle terahertz pulses are promising candidates for such applications due to their advantageous wavelength and available peak electric field at the MV/cm level. We propose and characterize a focusing optics for a possible electron vacuum accelerator. This consists of a reflaxicon for beam shaping and a ring-like segment of an on-axis parabolic mirror for tight focusing of the radially polarized THz pulse in order to reach a strong accelerating electric field. The electric field distribution in the focal region was determined by the Stratton–Chu vector diffraction method. Semi-analytical and purely analytical formulae were also derived, simplifying the computation procedure. By focusing radially polarized single-cycle terahertz pulses with 3mJ pulse energy, calculations predict accelerating electric field component in the order of 100MV/cm, well suitable for particle acceleration.

Artificial excitation and propagation of ultra-low frequency signals in the polar ionosphere

This paper has established a relatively comprehensive model for ultra-low frequency (ULF) current induced by thermal pressure gradients and its propagation. In the ULF current excitation model, we decomposed the current into a constant term unaffected by altitude and a product with a function significantly influenced by altitude. Combining this with the EISCAT background, we determined that for modulation frequencies below 5 Hz, the optimal height for ULF current excitation corresponds to the critical frequency height. We calculated the ionospheric currents at heating altitudes of 332 km for modulation frequencies of 5 Hz; the corresponding maximum currents were 1.03 × 10−10 A·m−2. By incorporating the current into the ULF waves propagation model based on magnetoionic theory, we found that the electromagnetic field energy is mainly concentrated in the horizontal direction, indicating that the energy primarily propagates outward through magnetosonic waves. The dominant components are the electric field component Ey and the magnetic field component Bz, whose maximum values reached 1.1 μV·m−1 and 1.5 pT. Unfortunately, magnetosonic waves cannot propagate downward due to the sharp variation in the real part of the refractive index between 200 and 300 km. However, the shear Alfvén waves component By can propagate downward, and there is still an intensity of approximately 0.1 pT at the bottom of the ionosphere, which is because the refractive index of shear Alfvén waves is most uniform in the parallel magnetic field direction, allowing By to propagate parallel to the magnetic field effectively.

Existence of Local Solutions to a Free Boundary Problem for Incompressible Viscous Magnetohydrodynamics

We consider the motion of an incompressible magnetohydrodynamics with resistivity in a domain bounded by a free surface which is coupled through the free surface with an electromagnetic field generated by a magnetic field prescribed on an exterior fixed boundary. On the free surface, transmission conditions for the electromagnetic field are imposed. As transmission condition we assume jumps of tangent components of magnetic and electric fields on the free surface. We prove local existence of solutions such that velocity and magnetic fields belong to H2+α,1+α/2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$H^{2+\\alpha ,1+\\alpha /2}$$\\end{document}, α>5/8\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\alpha >5/8$$\\end{document}.

Effect of vertical electric field components on the local arc development along contaminated surfaces

During operation, a vertical-component electric field emerges on the surface of high-voltage AC bushings. This unique electric field structure renders the bushing more susceptible to discharge and flashover. However, limited attention has been paid to studying the flashover characteristics resulting from surface pollution in such electric fields. This investigation, involving four differently structured bushings as well as post insulators, delves into the impact of pollution, creepage distance, and electric field structure on bushing flashover characteristics. The study reveals that increasing the creepage length of heavily polluted bushings does not significantly enhance their flashover voltage. Moreover, the role of the vertical electric field in the local arc development was analysed. This research could provide valuable references for future bushing design in polluted areas.

Atmospheric pressure uniform dielectric barrier discharge (DBD) in a wide air gap initiated from a narrow starting point

Generating a uniform non-equilibrium plasma in atmospheric pressure air has always been a challenge. It is believed that the maximum spacing for generating a uniform non-equilibrium plasma in atmospheric pressure air, whether using AC or nanosecond pulse drive, is 4 mm. Discharges are always non-uniform when the spacing is greater than 4 mm. In this paper, we propose a new type of dielectric barrier discharge structure to address this challenge. The left end of the structure rapidly increases the discharge spacing from 0.5 mm to 6 mm, while the right side of the main discharge gap maintains a uniform spacing of 6 mm. Nanosecond pulse voltage is used to drive the plasma, an ICCD camera is used to capture the image of the plasma during a discharge pulse cycle, which indicates that a uniform plasma within the 6 mm spacing of the main discharge gap is generated. Upon further reducing the ICCD camera’s exposure time to 20 ns, it is revealed that the uniform plasma is formed due to the rapid propagation of the plasma from left to right at a speed of order of 105 m s−1. Due to the small transverse component of the external electric field, this rapid propagation behavior cannot be due to the external electric field. Therefore, this paper further proposes the hypothesis of electric dipole formation leading to this fast propagation. The hypothesis suggests that the charge separation on the surface of the anode forms an electric dipole, which generates a local discharge at its right end. This local discharge further triggers the discharge in the main gap, and the main gap discharge, in turn, forms a dipole due to charge separation again, by repeating this cycle, the plasma propagates rapidly to the right. Further analysis demonstrates that this dipole can indeed produce a strong electric field of up to 41 kV cm−1 at its right end, which is sufficient to induce a local discharge. Moreover, under such a strong electric field, the electron migration rate can indeed reach 105 m s−1. These findings support the plausibility of this hypothesis.

A new ER valve composed of multilayer mesh electrodes

In many cases, ER valves are required to be used at lower operating voltages. For example, to develop a two-dimensional Braille matrix display, it is necessary to lay out many ER valves and control each Braille dot independently. If the commonly used parallel plate electrodes are applied, a low voltage can only be used when the electrode gap is very small, which will make the ER valve flow resistance very large, thus making it difficult to achieve effective control. A new type of ER valve composed of multilayer mesh electrodes was designed, which are arranged vertically in the direction of ER fluid flow. The flow rate of the ER valve is determined by the opening ratio of the mesh electrodes. This type of mesh electrode results in a more complex electric field distribution, which has a different action pattern on ER fluid yield stress compared to parallel electrodes. The non-uniform electric field generated by mesh electrodes under different operating voltages was simulated using COMSOL software, and the pressure drops of ER valves with various sizes of mesh electrodes under different voltages were experimentally investigated. The results indicate that the longitudinal electric field component plays a dominant role, and the stress of the ER fluid exhibits a periodic and gradient distribution. This valve exhibits good ER performance when the applied voltage is much lower than that of parallel electrodes. At the same time, the flow rate of the ER valve can be increased by enlarging the opening ratio of the mesh electrodes. Even if the applied voltage is 180 V, the pressure drop of the ER valve is large enough and the operation stability is good. This new type of ER valve makes the device small in size, easy to control intelligently and low cost. Multilayer mesh electrodes also have universal application value in ER technology.

Broadband-tunable quarter wave plates based on paired metal nanowire grids

Ultrathin wave plates based on metallic and dielectric metasurfaces have attracted much attention for independently controlling the phase, amplitude, and polarization of incident light. However, the issues of narrow bandwidth and low polarization conversion need to be improved for their optical applications. In this study, we show that an array of paired metal nanowire grids (PMNG) covered with a dielectric layer controls the polarization state in a broadband of visible to mid-infrared wavelengths. By analyzing the phase difference and amplitude ratio of orthogonal electric-field components passing through the SiO2-covered PMNGs, it is observed that the wavelengths operating as a circular polarizer appear regularly in the range from 450 nm to 4.0 μm with a stable phase difference of π/2. Also, the array of PMNG continuously converts linear polarization into circular or elliptical polarization by rotating the polarization angle of the incident light. Then, we demonstrate experimentally accessible polarization control by investigating the change in polarization ellipse between input and output light for this PMNG structure. Moreover, the PMNG can play an effective role as a wire grid polarizer in the IR region. Therefore, the suggested PMNG platform can be variously applied to emerging fields requiring ultrathin, multifunctional, and high-performance planar polarization components.

Time-dependent model of temperature distribution in continuous flow pulsed electric field treatment chambers

A key component of a continuous flow pulsed electric field (PEF) system is the treatment chamber, where the product is exposed to electric pulses. Determination of the temperature distribution in the chamber during PEF treatment is important since high local increases in temperatures can affect the quality of the product. Coupled simulations of electric field, fluid flow, and heating in the existing literature do not model each individual electric pulse, but rather employ a “duty cycle” approach, which does not account for transient variations in treatment intensity and temperature changes in the medium. We present a time-dependent approach to modelling PEF treatment in continuous flow treatment chambers, which can model each pulse separately, and thus enables a more accurate study of temporal and spatial distributions of electric field and temperature. The model has been validated on laboratory scale treatment chambers of parallel plate or colinear design and using realistic protocols. Industrial relevance textThe paper is relevant to all pulsed electric field (PEF) applications either on laboratory or industrial scale that implement a continuous flow treatment chamber. It presents an improved modelling approach which allows for an analysis of the electrical current, electric field, and temperature distribution in the chamber during, at the end, and in between application of electrical pulses. The model can be used to predict the peak temperature at the end of each pulse in the hot spots, which if large enough could potentially lead to thermal damage of the product or in extreme cases even potential local boiling of the medium, resulting not only in degradation of the treated product, but also in accelerated electrode fouling, oxidation, and dissolution (etching), as well as arcing. This would not only affect the quality of the treated product but would also affect the wear and lifetime of electrodes/chambers, and of the pulse generator. The model can also be used to avoid expensive trial-and-error optimization of the PEF protocols and chamber geometries in situ.

Asymptotic evolution of speckle patterns to synthesize non-homogeneous string beams

We analyze the evolution of the speckle pattern subjected to a compression showing that the spatial evolution of the probability density function satisfies a non-linear diffusion equation. Its asymptotic solution corresponds to a non-homogeneous wave with string-shape. During the compression, an irradiance interaction is generated between the speckles. The interaction satisfies a type-logistic equation. The electric field components associated with the speckles present a random behavior, however, during the compression process, the transversal components cancel each other, and the resulting light presents a state of polarization parallel to the propagation coordinate, justifying the non-homogeneous behavior. Computer simulations are presented.

Realizing the diffraction coupling of silver nanodisk pair array for high-quality sensing

We report a novel approach to enhance the local electromagnetic fields of silver nanodisk pair arrays to achieve high-quality sensing. It is found that through lifting metallic nanodisk pair array by dielectric nanopillars to decrease the effects of substrates, the strong diffraction coupling of metallic nanodisk pair array can be achieved, which will result in a mixed localized surface plasmon resonance (LSPR) with huge electric field enhancement. More importantly, we also demonstrate that for such a diffraction coupling, the electric field component of the lattice resonance mode of periodic arrays must be parallel to the induced electric moment in the silver nanodisk pair array. Due to ultra-narrow linewidth and great electric field enhancement at the LSPR, the metallic nanodisk pair array performs high sensitivity (S = 760 nm RIU−1, S* = 89.5 RIU−1) and figure of merit (FOM = 492, FOM* = 6147), which holds important applications in high-efficiency biomedical sensing.

Polarization properties of E-FISH signals and optimization of simultaneous measurement of electric field vectors

Electric field measurements based on the electric field induced second harmonic (E-FISH) method have been employed in a wide range of studies. Most studies typically measure two components of the electric field separately. Although there have been proposals for the simultaneous measurement of electric field vectors, the imbalance of the two corresponding E-FISH signals has limited its application. Furthermore, the relationship between the polarization of the E-FISH signal and the direction of external electric field remains unclear. In this paper, the general expressions for the polarization and power of both components of E-FISH signals are derived, assuming arbitrary probe beam polarization and external electric field direction. The theoretical results indicate that the polarization of E-FISH signals varies along the interaction length. The final signal’s polarization is elliptically polarized for arbitrary electric field distribution and is correlated with the polarization of the probe beam, which deviates from what is commonly assumed to be consistent with the external electric field. If the polarization of the probe beam is not parallel to the axes, the power of each signal component is determined by both components of the external electric field, which lays the foundation for the simultaneous measurement of electric field vectors. This theoretical prediction is subsequently validated by experimental results. Finally, the power maps suggest that the optimal polarization angle of the probe beam is 45° or 135° to achieve a balanced signal power when measuring an unknown electric field vector. Both components of the electric field can be simultaneously obtained according to the theoretical relationship.

A 3D printed low‐profile wideband circularly polarised elliptical integrated lens antenna

AbstractThe authors presents a low‐profile wideband circularly polarised (CP) millimetre‐wave (mmWave) elliptical integrated lens antenna (ILA) fabricated by dielectric 3D printing technology. The proposed lens is integrated with a dielectric polariser and an air cavity for phase compensation, which can transfer incident waves from linearly polarised (LP) to planar CP waves over a wide bandwidth. Compared to the classic bifocal ILA, the proposed lens has a low profile. The phase compensation is performed by introducing a specifically shaped air cavity, which greatly reduces the length and weight of the lens. The polariser causes the two electric field components Ex and Ey to degenerate with an orthogonal phase difference, which results in the wideband characteristics of the antenna. The polariser, air cavity and lens can be conveniently and precisely fabricated by low‐cost 3D printing technology. Measurements show that the proposed ILA has a wide axial ratio (AR) bandwidth of 21.9–32.6 GHz, while the gain reaches 22.54 dBic with a 38% size reduction and a 60.7% weight reduction. Benefiting from the low profile, high gain, wide bandwidth and low cost, the proposed ILA has great potential to be the candidate antenna for 5G applications and satellite communications.

Machine learning assisted dual port metasurface loaded MIMO antenna with linearly polarized to circularly polarized conversion features for n257 band of 5G mm‐wave applications

SummaryIn this communication, a dual port printed multi‐input and multi‐output (MIMO) antenna with high isolation of dimension 12 × 8.5 × 0.8 mm3 is designed, analyzed, and investigated for 28‐GHz 5G mm‐wave applications. The metasurface layer is suspended over the MIMO antenna to convert the linearly polarized (LP) wave to a circularly polarized (CP) wave. The unit cell of the metasurface consists of a square‐shaped conducting strip with one side of diagonal points interconnected. The conducting strip and rectangular gap between the strips etched on the substrate are capable of generating the π/2 phase shifted electric field components (Ex and Ey) resulting in polarization conversion from LP to CP. The machine learning concept is used to characterize the dimensional configuration of the antenna to achieve the optimum throughput. The MIMO diversity performance parameters and antenna essential results are validated by the measured counterparts.

Experimental characterization of a fully polarimetric pulsed terahertz spectroscopy system

A terahertz time domain pulsed spectroscopy system is modified to provide fully polarimetric radiation and analysis. The operation of this polarimetry system is characterized using a birefringent, x-cut quartz crystal. The modification is based on rotating the photoconductive antennas such that both the emitted and detected polarizations are out of the plane of incidence. Subsequently, broadband wire grid polarizers are used to select the incident and detected direction of linear polarization to be either parallel with (vertical) or perpendicular to (horizontal) the plane of incidence with the sample surface. The experiments are conducted in both transmission and reflection. Depending on the frequency, the phase retardation of the incoming electric field components along the two perpendicular optical axes of the quartz crystal changes differently. This results in the polarization of the light exiting the crystal changing with frequency. As a result, multiple frequencies are identified where the crystal behaves as a near ideal quarter-, half-, or full-wave retarder. Additionally, due to the time-domain nature of the experiment, transmitted and reflected electric fields are measured after multiple consecutive reflections within the crystal. This leads to a further, complex control over the final polarization state of the signal. Finally, images of a resolution standard are obtained demonstrating the characteristics of the polarimetry system.

Real-time signal processing and data acquisition for the Electric Field Detector (EFD-02) on the CSES-02 satellite

The Electric Field Detector (EFD-02) on board the second China Seismo-Electromagnetic Satellite (CSES-02) will measure the electric field components at a Low Earth Orbit (LEO) over a wide frequency band (DC – 3.5 MHz) and with 1 μV/m sensitivity in the Low Frequency band. EFD-02 will measure the voltage differences between pairs of probes installed at the tips of four booms deployed from the satellite. In this article, we describe the Zynq System on Chip (SoC)-based digital hardware subsystem dedicated to signal processing, and the selected implementation strategy, which successfully complied to the specific requirements of the space mission. Furthermore, we present a comprehensive overview of the assessed instrument performance.

Mapping electric field components of superchiral field with photo-induced force.

Circular dichroism (CD) of materials, difference in absorbance of left- and right-circularly polarized light, is a standard measure of chirality. Detection of the chirality for individual molecules is a frontier in analytical chemistry and optical science. The usage of a superchiral electromagnetic field near metallic structure is one promising way because it boosts the molecular far-field CD signal. However, it is still elusive as to how such a field actually interacts with the molecules. The cause is that the distribution of the electric field vector is unclear in the vicinity of the metal surface. In particular, it is difficult to directly measure the localized field, e.g., using aperture-type scanning near-field optical microscope. Here, we calculate the three-dimensional (3D) electric field vector, including the longitudinal field, and reveal the whole figure of the near-field CD on a two-dimensional (2D) plane just above the metal surface. Moreover, we propose a method to measure the near-field CD of the whole superchiral field by photo-induced force microscopy (PiFM), where the optical force distribution is mapped in a scanning 2D plane. We numerically demonstrate that, although the presence of the metallic probe tip affects the 3D electric field distribution, the PiFM is sufficiently capable to evaluate the superchiral field. Unveiling the whole figure of near-field is significantly beneficial in obtaining rich information of single molecules with multiple orientations and in analyzing the boosted far-field CD signals.

Refining protein amide I spectrum simulations with simple yet effective electrostatic models for local wavenumbers and dipole derivative magnitudes.

Analysis of the amide I band of proteins is probably the most wide-spread application of bioanalytical infrared spectroscopy. Although highly desirable for a more detailed structural interpretation, a quantitative description of this absorption band is still difficult. This work optimized several electrostatic models with the aim to reproduce the effect of the protein environment on the intrinsic wavenumber of a local amide I oscillator. We considered the main secondary structures - α-helices, parallel and antiparallel β-sheets - with a maximum of 21 amide groups. The models were based on the electric potential and/or the electric field component along the CO bond at up to four atoms in an amide group. They were bench-marked by comparison to Hessian matrices reconstructed from density functional theory calculations at the BPW91, 6-31G** level. The performance of the electrostatic models depended on the charge set used to calculate the electric field and potential. Gromos and DSSP charge sets, used in common force fields, were not optimal for the better performing models. A good compromise between performance and the stability of model parameters was achieved by a model that considered the electric field at the positions of the oxygen, nitrogen, and hydrogen atoms of the considered amide group. The model describes also some aspects of the local conformation effect and performs similar on its own as in combination with an explicit implementation of the local conformation effect. It is better than a combination of a local hydrogen bonding model with the local conformation effect. Even though the short-range hydrogen bonding model performs worse, it captures important aspects of the local wavenumber sensitivity to the molecular surroundings. We improved also the description of the coupling between local amide I oscillators by developing an electrostatic model for the dependency of the dipole derivative magnitude on the protein environment.

Connection Between Gravity and Quantum World

Gravity is the most important force in cosmology. A lot of research deals with it, but we only know its perceptible properties. Two basic descriptions of gravity are accepted today. One is based on classical physics based on Newton\’s theory. The other is the theory of gravity described by Einstein. However, another description of gravity is also possible. Gravitation can also be described in other ways using the equations of Kepler, Newton, Coulomb, and Maxwell. Using their equations, it can be deduced that: The magnitude of the gravitational force field is not determined only by mass. It depends on the speed of the mass. It depends on the size of the gravitational field in which the mass moves Newton\’s and Coulomb\’s laws are equivalent. This has already been determined by several researchers. It was also conducted by Constantin Meis. Newton\’s, Coulomb\’s, Maxwell\’s law can be used to determine a new cosmic constant. It can be counted on in the Solar System, but also in the Milky Way. Denote by μ_2 and √ (μ_2) This constant connects the macro world and the micro or quantum world. This constant can also be calculated using Coulomb\’s and Maxwell\’s equations Maxwell\’s and Coulomb\’s equation can be used to determine the resultant of the associated vibrating charges for each mass and celestial body. Coulomb\’s law can also be used to accurately determine the force effect between masses. Even the force effect between celestial bodies can be determined with it. This is exactly the same as the force effect calculated by Newton\’s law. For a mass of 1 kg, we get exactly Cavendish\’s measurement result with Coulomb\’s law. Already in the 20th century, it was suggested that there is a connection between gravity and the electromagnetic field. This has already been conducted by Constantin Meis and Takaaki Musha and B. Ivanov. Gravitational constant can not only be measured, but also calculated in several ways. This has already been determined by several researchers. The gravitational constant can also be calculated using the mass and its speed. But it can also be calculated using the Coulomb constant and μ_2 The gravitational force field for a given mass or celestial body can be calculated using √(μ_2) and the charge of the mass. The speed of a given planet can be calculated using its charge and √ (μ_2) Based on the derivations, gravity is a force field that has an electric force field component. Therefore, it can be the carrier medium of electromagnetic waves. And so is the carrier of light If we assume that the gravitational force field is a very high frequency electromagnetic wave, then we also understand that gravity is unipolar.

Стационарная вращательно-симметричная конвекция при изотахофорезе в круговой цилиндрической области с недеформируемой свободной непроницаемой боковой поверхностью

The results of a study of the isotachophoresis process convective stability are presented. Isotachophoresis is the method of separation of a multicomponent mixture to individual components by an external electric field. It is assumed that the process of isotachophoresis occur in an infinite vertical circular cylinder with free side boundaries. The problem of the stationary (monotonic, neutral) concentration gravitational convection occurrence is transform to the study of the solution stability for the problem linearized on the solution of the original problem corresponding to the mechanical equilibrium of the final stage of the isotachophoresis process, in which the zones of the individual components of the mixture move with the identical constant velocity in a stationary flow. It is indicated that the main contribution to the stability/instability of the equilibrium is made by concentration gradients in the vicinity of the boundaries between the zones of individual components. Due to the complexity of constructing an exact solution corresponding to mechanical equilibrium, the exact solution replaced by an asymptotic solution (piecewise constant concentration distribution), which, in turn, is an exact solution of the asymptotic version of the transport under action of an electric field component equations (diffusion-free model). The choice of piecewise constant mechanical equilibrium leads to concentration gradients in the form of delta functions and a linear boundary value problem with delta-like coefficients to determine the critical parameters of instability. An exact solution of the problem (a system of ordinary differential equations with boundary conditions) and, using the method of one-dimensional perturbations, an exact dispersion relation for determining critical parameters (in the case of vanishingly small diffusion) is constructed.