Electromagnetic Field Energy Research Articles

Enigmatic factor of 4/3 in electromagnetic momentum of a moving spherical capacitor

The electromagnetic energy–momentum of a moving charged spherical capacitor may be calculated by a 4-vector Lorentz transformation from the energy in the rest frame. However, energy–momentum of the moving system computed directly from electromagnetic fields yields extra terms; in particular a factor of 4/3 in momentum appears, similar to that encountered in the classical electron model, where this enigmatic factor has been a source of confusion for more than a century. There have been many attempts to eliminate this ‘unwanted’ factor, noteworthy among them is a modification in electromagnetic field energy–momentum definition that has entered even standard textbooks. Here it is shown that in a moving charged spherical capacitor, such a factor of 4/3 in the electromagnetic momentum arises naturally from electromagnetic forces in system or equivalently from terms in the Maxwell stress tensor; contributions that do not otherwise show up in 4-vector transformations. A similar factor of 4/3 in the momentum of a perfect fluid comprising a randomly moving ultra-relativistic gas molecules or an isotropic photon gas, filling an uncharged spherical capacitor in motion, appears owing to the contribution of pressure. Thus, genesis of the ‘enigmatic’ factor of 4/3 can be traced to pressure or stress whose presence in the system may even be of non-electromagnetic origin and where the proposed modifications in energy–momentum definition do not even come into picture, implying there is no justification in modifying the standard definition of electromagnetic energy–momentum.

Near-infrared multi-band small-angle TE-polarization nonreciprocal thermal emitter

Multi-band small-angle irreversible radiation is significantly demanded in applications of high-resolution infrared sensing and infrared filtering. However, current nonreciprocal thermal radiation is either multichannel radiating with large incident angles or radiating at small angles within one single band. To address this issue, a multi-band nonreciprocal thermal emitter operated by exciting multiple resonances within the near-infrared band is proposed. The adopted microstructure arrays consist of periodic silicon square-ring arrays that are supported by magneto-optical medium and metal layer. With the physical mechanisms study through electromagnetic field energy distribution, the TE-polarized multi-band nonreciprocity of thermal radiation is over 70 % at small incident angle of 4°. Equally important, this strategy is effective and generalizable for dual-polarized small-angle multi-band nonreciprocal radiation with adopted microstructure arrays. It is believed that this scheme can promote the development of nonreciprocal thermal photonics.

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.

Fast ultrasonic ablation monitoring: An innovative approach using ultrasound RF signals and singular value decomposition

Microwave ablation (MWA) can rapidly lead to tumor cell necrosis by heating local tissues using electromagnetic field energy, making it a highly efficient modality widely utilized in clinical ablation surgeries. However, the lack of timely and accurate intraoperative monitoring methods is a critical issue that urgently needs to be addressed in MWA. This article introduces an innovative approach for real-time monitoring of ablation therapies by the combination of ultrasound radio frequency (RF) signal acquisition and singular value decomposition (SVD), which breaks through the limitations of current monitoring techniques during MWA procedures. Due to the difference in acoustic scattering properties between the gas generated in high-temperature ablated region and the non-ablated tissues, the current new method aimed to apply SVD analyses to ultrasound RF signals scattered from the tissues, through which the range of gas generation could be determined and then the ablation area could be estimated. Eventually, high-precision differentiation between ablated and non-ablated tissues could be achieved, enabling real-time adjustment and improvement of MWA strategies. Validated through ex vivo experiments on pig liver, this technique demonstrated a relative error in monitoring the size of ablation region of approximately 7%, indicating a strong correlation with actual ablation outcomes. The study indicated the proposed method should have great potential to improve the precision and safety of MWA therapy.

Theoretical profiling of chloroperovskite compounds GaXCl3 (X = Ba, Sr) using density functional theory

This study employs the TB-mBJ exchange potential within the WIEN2k code and DFT to comprehensively analyze GaXCl3 compounds (X = Sr, Ba). The investigation includes verifying perovskite structure and determining structural, elastic, electronic, and optical properties. Upon optimization with the Birch Murnaghan equation of state, GaScCl3 and GaBaCl3 exhibit a cubic crystal structure with lattice constants of 5.675 Å and 5.978 Å, respectively. The contribution of elemental states to valence and conduction bands is assessed using TDOS and PDOS features. GaSrCl3 and GaBaCl3 display indirect band gaps of 3.260 eV and 4.365 eV, respectively. Mechanical properties are explored with IRelast software. Optical features, including dielectric function, optical conductivity, reflectivity, refractive index, absorption coefficient, and energy loss function, show significant dependence on electromagnetic field energy. GaSrCl3 and GaBaCl3 exhibit static field refractive index values of 2 and 1.5, with maximum refractive indices of 2.4 at 3.7 eV and 2.2 at 7 eV, respectively. Both compounds record a maximum optical conductivity of 5000 S/cm in the upper-UV region, while reflectivity remains below 30 % in the energy range of 0–12 eV. The study suggests potential applications for these compounds in UV light emitters, sensors, photodetectors, and thermal producers.

Electromagnetic field simulation modeling method and distribution characteristics of electric vehicle wireless charging system

In recent years, wireless charging technology for electric vehicles has gained significant attention. To accurately analyze the distribution characteristics of the electromagnetic field during the wireless charging process of electric vehicles, a finite element-based electromagnetic analysis method was employed. Applied in the commercial simulation software, the electromagnetic environment of the resonant coil and electric vehicle model was simulated under high-power charging conditions, resulting in an overall electromagnetic field distribution for the electric vehicle. The results indicated that within the coil region, the magnetic induction intensity in the central area of the coil was zero, and it increased as the distance from the center of the coil grew. Outside the coil region, the magnetic induction intensity gradually decreased. The electric field intensity of the resonant coil was maximum in the central area of the coil, and it weakened as the distance from the center of the coil increased. When a magnetic shielding resonant coil was used, the electromagnetic field was confined between the shielding materials, and the magnetic field rapidly attenuated on both sides of the magnetic shield. The electromagnetic field energy of the electric vehicle body was mainly concentrated at the bottom of the vehicle near the coil. When the coil was located in the front of the car body, the maximum electric field intensity distribution in the car body was 8.50 V/m, and the maximum magnetic induction intensity was 0.024 μT. When the coil was located in the middle of the car body, the maximum electric field intensity was 2.31 V/m, the maximum magnetic induction intensity was 0.019 μT. As the distance from the coil position increased, the energy weakened.

Enhanced second harmonic generation from supercavity mode and magnetic resonance in dumbbell-shaped silicon nanoblock

Abstract Electromagnetic multipole resonance can be excited by dielectric nanostructures of appropriate size to effectively promote light-matter interaction. The interactions between light and nanostructures have the capability to enhance the electromagnetic field in the near field, thereby improving the nonlinear effect of nanostructures. We illustrate that the supercavity mode and magnetic dipole resonance are activated by a single dumbbell-shaped silicon nanoblock (DS-SiNB), to trap the near-field electromagnetic field energy. Enhanced second harmonic generation is achieved by exploiting the localized electromagnetic field at the surface of the nanostructure. Numerical simulations reveal that magnetic quadrupole (MQ) and total electric dipole (TED) can be coupled to the same radiation channel by adjusting continuously the aspect ratio Lout/Ly (the outer edge length to the length of DS-SiNB) of the nanoblock. When the aspect ratio Lout/Ly = 1, the supercavity mode formed by the interference of MQ and TED is excited at λ1 = 1124 nm. And, the strong magnetic resonance mode formed by the coupling of two magnetic dipoles (MD) in the same direction is also excited at λ2 = 1124 nm. Supercavity mode and strong magnetic dipole resonance can effectively capture electromagnetic fields on the surface of nanostructures to attain enhanced second harmonic generation (SHG). Our study presents a novel approach to enhance the nonlinear optical effect of a single silicon nanostructure, which can lead to the development of more efficient nonlinear optical devices.

Application of a Surface Waveguide in Microwave Drying Units of the Agribusiness Industry

In the last two decades, the electromagnetic field of the microwave range has been successfully introduced into various branches of the agribusiness industry as one of the most promising and advanced technologies for drying manufactured products. In this regard, the article proposes a new microwave irradiation technique for drying various objects based on a surface waveguide’s properties. The paper analyses the main links that make up the surface waveguide as a microwave irradiation system and shows the ways of their implementation. The article describes the advantages of applying a vibratory device for exciting a surface wave, using a re-emitting antenna array, and operating a single conductor with a dielectric coating as a surface waveguide. Such advantages make it possible to introduce microwave drying units with the required distribution of electromagnetic field energy along the irradiated material, small dimensions, high drying quality, and low price.

Corrosion and heat-resistant SiCN/C as lightweight fibers for microwave absorption and electromagnetic field shielding in Ku-band

SiCN fibers are usually combined with metals to increase the magnetic loss in electromagnetic field (EMF) shielding, but this results in high weight density, easy corrosion, difficult treatment, and high cost of the material. This study proposes the manufacturing of corrosion and heat-resistant ceramic lightweight fibers containing in-situ synthesized carbon nanostructures (SiCN/C) with excellent EMF shielding in Ku-band (12.4–18 GHz). The samples showed differential trends of EMF shielding effectiveness in terms of reflectance, transmittance, and absorption behavior. Compared to SiCN fibers, the EMF absorption was two times greater when carbon was added to the SiCN matrix. A minimum reflection coefficient (S11) of −12 dB was observed for SiCN/C fibers, meaning a high shielding efficiency with >90 % of the EMF energy shielded. On the other hand, SiCN fibers showed a minimum S11 of −7 dB, resulting in a protection of 80 % against EMF energy. Computational simulations clarified the better features of SiCN/C in electromagnetic shielding compared to SiCN, which was ascribed to enhanced conduction loss derived from conductive free carbon, and dipole and interfacial polarization loss generated by defects. The fibers were resistant to acidic and basic environments and oxidation of up to 600 °C. Moreover, the addition of carbon precursor represented a weight decrease of 17 % for SiCN/C compared to SiCN fibers. This research will afford an alternative solution for the manufacturing of SiCN/C fibers with EMF absorption properties that can be used as lightweight materials in harsh environments.

Cilia-Like Observer for Tumor Recurrence in Active Soft Matter

Cilia-like sensitivity observer, at an adaptive treatment of a tumor recurrence in active soft matter, is built. Therefore, the activity of soft matter is shown as active colloidal chains with a cilia-like and flagella-like motility; the tumor recurrence, in active soft matter, is considered as run-away/quantum aging of soft matter; the adaptive treatment energy is defined as electromagnetic field energy, stabilizing or destabilizing life, and as energy of a force dipole. Information recovery at an adaptive treatment is fulfilled via two cilia-like quantum extremal islands. Information recovery is obtained for a mean maximum-tolerated dose of the adaptive treatment and cilia-like tumor growth in active soft matter. There are introduced four strategies for an adaptive treatment for run-away/quantum aging active soft matter with a mean maximum-tolerated dose at stabilized tumor/tumor diffusion. It is graphically determined, for each of these four strategies, the mean sensitivity of the adaptive treatment for three tumor types in 27 patients, according to a maximum-tolerated treatment dose and cilia-like tumor growth in active soft matter.

Periodic Folded Gold Nanostructures with a Sub-10 nm Nanogap for Surface-Enhanced Raman Spectroscopy.

Surface-enhanced Raman spectroscopy has emerged as a powerful spectroscopy technique for detection with its capacity for label-free, nondestructive analysis, and ultrasensitive characterization. High-performance surface-enhanced Raman scattering (SERS) substrates with homogeneity and low cost are the key factors in chemical and biomedical analysis. In this study, we propose the technique of atomic force microscopy (AFM) scratching and nanoskiving to prepare periodic folded gold (Au) nanostructures as SERS substrates. Initially, folded Au nanostructures with tunable nanogaps and periodic structures are created through the scratching of Au films by AFM, the deposition of Ag/Au films, and the cutting of epoxy resin, reducing fabrication cost and operational complexity. Periodic folded Au nanostructures show the three-dimensional nanofocusing effect, hotspot effect, and standing wave effect to generate an extremely high electromagnetic field. As a typical molecule to be tested, p-aminothiophenol has the lowest detection limit of up to 10-9 M, owing to the balance between the electromagnetic field energy concentration and the transmission loss in periodic folded Au nanostructures. Finally, by precisely controlling the periods and nanogap widths of the folded Au nanostructures, the synergistic effect of surface plasmon resonance is optimized and shows good SERS properties, providing a new strategy for the preparation of plasmonic nanostructures.

ARKADIEV-MARKS CIRCUIT WITH RESONANT CHARGING OF CAPACITIVE ENERGY STORAGE IN MAGNETIC-PULSE INSTALLATIONS

The effective use of Arkadiev-Marx scheme with a resonant charging of capacitive storages in magnetic-pulse installa-tions, as power sources, in technologies using the electromagnetic field energy is proposed and substantiated. It is found that during charging the maximum voltage amplitude at capacitor increases by number times equal to the quality factor of the charging circuit at the fundamental frequency of the harmonic expansion of exciting signal, but by ~34% less than possible maximum. The calculations of the characteristics of magnetic-pulse complex intended for the repair of damaged car bodies show the high efficiency of using the Arkadiev-Marx circuit with the resonant charging of ca-pacitive storage. It is found that during the time of ~0.45 s the battery of 10 capacitors connected in parallel with total capacitance of ~100 μF can be charged up to voltage of ~7500 V with stored energy of ~2.8 kJ. The results of the work allow us to give recommendations on the practical increase in the efficiency of magnetic-pulse metal processing. Refer-ences 16, figures 4.

Unmanned aerial vehicle for monitoring transport infrastructure

We consider the unmanned aerial vehicle of a multicopter type, in which the on-board battery is recharged using the energy of an external electromagnetic field created by the currents flowing through the wires of the contact network of an electrified railway transport or an overhead power line. This process is carried out without interrupting the flight of the aerial vehicle. The process of transferring this energy to the board of the multicopter is carried out by inductive method using an electric winding placed on it. This winding is connected to the battery. We constructed the finite element mathematical model. We performed the calculations of the EMF induced in the winding at the different trajectories of the aerial vehicle near the contact wire of the railway. It is revealed that the highest EMF values in the winding are induced when flying under the alternating current contact wire. When the winding moves under the direct current wire the frequency and amplitude of the induced EMF depend on the period of deviations of the aerial vehicle from the direction of the axis of its straightline movement. The EMF curve is non-sinusoidal. The degree of distortion of the EMF curve depends on the amplitude of the deviation of the winding from the axis of the direction of movement. At the alternating current through the contact wire the amplitude of the induced EMF mainly depends on the amplitude and frequency of the external magnetic field created by this current. The movement parameters of the aerial vehicle have a negligible effect on the EMF value.

Influence of tachyonic instability on the Schwinger effect in Higgs inflation model

We investigate the influence of the tachyonic instability on the Schwinger effect in Higgs inflation model. In this work we identify the standard horizon scale and the tachyonic instability . This is the horizon scale in which the given Fourier begins to become tachyonically unstable. Influence of this scale appears by vanishing electromagnetic field energy density and energy density of created charged particles due to the Schwinger effect at the very beginning of inflation but does not alter conclusions of our previous work in Kamarpour (2022 Gen. Relativ. Gravit. 54 32; 2023 Int. J. Mod. Phys.D 32 2350025). We use two coupling functions to break conformal invariance of Maxwell action. The simplest coupling function and a curvature based coupling function where is the potential of Higgs inflation in Kamarpour (2022 Gen. Relativ. Gravit. 54 32; 2023 Int. J. Mod. Phys.D 32 2350025). In fact, we find that only at the very beginning of inflation both energy densities of electromagnetic field and created charged particles vanish due to effect of tachyoinc instability.

A Surface Enhanced Raman Scattering (SERS) Sensing Method Enhanced by All-metal Metasurface

In this study, we developed a simple surface-enhanced Raman Scattering (SERS) composite substrate, composed of an all-metal metasurface and on-surface random distributing silver nanoparticles (AgNPs), to enhance the performance of SERS sensing. The metasurface is made up of gold (Au) nanopillars array on aluminum (Al), it can localize the electromagnetic field energy with a resonant absorption peak near the 630 nm wavelength, which contributes to the SERS performance of AgNPs deposited into the structure. The composite substrate can significantly improve the sensing performance, and the SERS Enhancement Factor (EF) reaches 2.81 × 106. The substrate also has good stability and reproducibility. The research is based on the combination of Localized Surface Plasmon Resonance (LSPR) and SERS effects, providing a method and idea for improving the sensitivity of SERS detection, and achieving the trace detection of Rhodamine 6G (R6G) and Thiram at 10−10 M, respectively.

Electromagnetic technologies in the system of oil production innovative methods at the fields of the Republic of Bashkortostan

An increase in the share of hard-to-recover oil in the total balance of its reserves, which is particularly important for the Republic of Bashkortostan, inevitably makes it necessary to search for and commercially introduce new ways to extract it. Among the many methods of increasing oil recovery and intensifying the inflow, the method of influencing the bottomhole zone of the formation with a high-frequency electromagnetic field is distinguished, which, despite many years of research, is still considered experimental in Russia and is limited to evaluating the production and technical characteristics of use. At the same time, financial and economic indicators are overlooked, the identification of which will justify the relative low cost and high profitability of the innovative method.The purpose of the study is to determine the feasibility of introducing methods of oil field development based on the use of electromagnetic field energy. The main research methods are the analysis of scientific literature on the research topic, systematization and generalization of specialized state statistics data. The calculation part uses methods of economic analysis and business analytics.The existing technologies for oil field development in the Republic of Bashkortostan are considered, a conclusion is made about their obsolescence and the need to replace them with technologies based on new physical principles. The prospects of electromagnetic technologies and the degree of development of this topic in the scientific environment of Russia and the Republic of Bashkortostan are indicated. With the help of modelling, the economic effect of the introduction of technology for influencing the bottomhole zone of the formation with a high-frequency electromagnetic field has been established, the possibilities of covering the deposits of the Republic of Bashkortostan suitable for development have been determined.The results of the study can be used in the analysis of the prospects of regions with the predominant development of the oil production and oil refining complex, on the territory of which there are large areas of depleted fields that require the use of innovative technologies for additional production. Further research may be devoted to assessing the economic and technological efficiency of using electromagnetic and other innovative technologies for influencing the reservoir directly in fields with different properties of residual oil and geological and geophysical parameters of the host reservoirs.

Research on liquid-phase catalytic thermolysis of high-viscosity oil samples being stimulated by microwave radiation in dynamic mode (in the order of discussion)

A significant part of Azerbaijan’s oil reserves are fields of high high-viscosity oil, being at younger stage of development, in conditions of low permeable reservoirs. Technogenic complications arising from the exploitation of such fields, create new requirements for oil production technologies, capable to increase the oil recovery of the already existing layers. This paper presents the results of a study of liquid-phase catalytic thermolysis stimulated by microwave radiation of samples of high-viscosity oil from the Balakhani-Sabunchu-Ramany (VI and XI horizons) and Kyurovdag fields, characterized by averaged values of density, respectively, 885 kg/m3, 908 kg/m3 and 923 kg/m3 at 20 oC. In dynamic mode in the presence of synthesized heterogeneous catalysts that intensively absorb the energy of the microwave electromagnetic field.

Energy flow and stochastic resonance in a memristive neuron

Static distribution of intracellular ions including calcium, sodium and potassium activates spatial distribution of electric field and energy is kept in the biological neurons. Continuous propagation of the intracellular and extracellular ions across the membrane channels can induce magnetic field accompanying with diffusion of field energy as well. In this paper, two kinds of memristors are connected in parallel and they are used as memristive channels for building a new neural circuit, which can perceive external magnetic field and electric field synchronously. The memristive channel developed from the charge-controlled memristor (CCM) can discern the changes of external electric field, and another memristive channel based on the magnetic flux-controlled memristor (MFCM) can detect the fluctuation of external magnetic field. The inner electromagnetic field energy is shunted between the capacitor, inductor and two memristors, and the inner field energy is described by an equivalent Hamilton energy H for this neuron including a sum for four terms (H C , H L , H M , H W ). The energy proportion of memristive channel to total energy is controlled to realize mode selection and transition in the firing patterns. Noisy disturbance is applied to discern the occurrence of stochastic resonance in this memristive neuron.

Faraday rotation enhancement due to proximity effect of surface plasmon resonance in magnetoplasmonic colloidal mixtures

The modification of Magneto-optic Faraday Rotation (MFR) based on Surface Plasmon Resonance (SPR) of noble metal nanoparticles (NP) has been an exciting field of research. The underlying physical mechanisms are intriguing and correspond to various observation patterns in composite magnetoplasmonic systems. Exploiting the immense potential of SPR phenomenon for excellent electromagnetic field confinement and energy transfer to a wide variety of dimensionally different nanostructures, we report MFR measurements in typical magnetoplasmonic colloidal mixtures of separately synthesized cobalt ferrite (CoFe2O4) and gold (Au) NP at wavelength of 532 nm where we have observed a spectacular possibility for “proximity effect” based plasmonic enhancement of MFR, for the very first time. The Langevin-type MFR patterns show a strong dependence on the concentrations of participating systems, where a typical optimum concentration produced a significant enhancement in MFR. For both the entities present in the liquid, a mutually dependent optimum concentration was necessary to obtain the Langevin pattern as well as MFR enhancement, confirming the influence from SPR due to the proximity effect. The observations open up exciting possibilities to apply SPR to discover novel magnetoplasmonic phenomena underlined by proximity effects, in addition to eluding constrained procedures to synthesize composite magnetoplasmonic systems.

Successive Energy Conversion at a Stepwise Dipolarization Front

Dipolarization fronts (DFs), ion-scale magnetic structures characterized by sharp enhancement of northward magnetic field developed within plasma jets, have been suggested to play a crucial role in the energy transfer chain in the terrestrial magnetotail. Here we present the first observation of successive energy conversion driven by multiple current layers at a stepwise DF, using high-cadence measurements from NASA’s Magnetospheric Multiscale mission. The multiple current layers are adjacent and cause gradual variations of particles and electromagnetic fields, leading to an intense, successive increase of energy conversion rates at the DF in the satellite frame, with electromagnetic field energy being transformed into particle energy. The energy conversion is contributed by both ion and electron currents. The motional electric field drives the energy conversion, while the wave electric field fed by lower hybrid drift instability modulates the energy partition. These results provide new insights into understanding energy transfer in the terrestrial magnetotail.