Field Components Research Articles

Method for prediction and control by uncertain microsatellite magnetic cleanliness based on calculation and compensation magnetic field spatial harmonics

Aim. Development of method for prediction and control the microsatellite magnetic cleanliness taking into account the uncertainties of the magnetic characteristics of the microsatellite, based on calculation the magnetic field spatial spherical harmonics in the area of the onboard magnetometer installation and using compensating multipoles. Methodology. Spatial spherical harmonics of microsatellite magnetic field in the area of the onboard magnetometer installation calculated as solution of nonlinear minimax optimization problem based on near field measurements for prediction far spacecraft magnetic field magnitude. Nonlinear objective function calculated as the weighted sum of squared residuals between the measured and predicted magnetic field. Values of the compensating dipoles, quadrupoles and octupoles and coordinates of them placement inside the spaceship for compensation of the dipoles, quadrupoles and octupoles components of the microsatellite initial magnetic field also calculated as solution of nonlinear minimax optimization problem. Both solutions of this nonlinear minimax optimization problems calculated based on particle swarm nonlinear optimization algorithms. Results. Results of prediction spacecraft far magnetic field magnitude based on spacecraft spatial spherical harmonics of the magnetic field using near field measurements and compensation of the dipoles, quadrupoles and octupoles components of the initial magnetic field with consideration of spacecraft magnetic characteristics uncertainty for ensuring the microsatellite magnetic cleanliness. Originality. The method for prediction and control by spacecraft magnetic cleanliness based on calculation spatial spherical harmonics of the magnetic field in the area of the onboard magnetometer installation using compensation of the dipoles, quadrupoles and octupoles components of the initial magnetic field with consideration of magnetic characteristics uncertainty is developed. Practical value. The important practical problem of ensuring the magnetic cleanliness of the «Sich-2» microsatellite family based on the spatial spherical harmonics of the magnetic field model using the compensation of the dipole, quadrupole and octupole components of the output magnetic field of the sensor for the kinetic parameters of the neutral component of the space plasma at the point of installation of the on-board magnetometer LEMI-016 by setting the compensating dipole, quadrupole and octupole with consideration of spacecraft magnetic characteristics uncertainty solved.

Development of algorithms for assessing the regional distribution of respiratory activity parameters based on the analysis of EIT results

The paper is devoted to development of a method and algorithm for assessing regional ventilation and perfusion based on the analysis of the tomographic cross section obtained by the EIT method. The method consists of chest cavity change in the conductivity field reconstruction results spectral analysis. Based on the spectral analysis of the results of monitoring the ventilation and perfusion component of the field of change in the conductance of the chest cavity, it allows to evaluate the distribution of the respiratory volume and perfusion. An algorithm for assessing the thoracic cavity VPR based on the results of EIT has been developed. The algorithm consists in monitoring the ventilation and perfusion component of the chest cavity conductance change field, followed by spectral or regression analysis of the monitoring results to assess regional ventilation and perfusion, followed by the evaluation of the VPR based on the results monitoring of the ventilation and perfusion component of the field of changes in the conductivity of the chest cavity, to assess regional ventilation and perfusion, followed by an assessment of the VPR. The results of the work were used in the development of software for the EIT device.

Application of Internet of Things technology in teaching management system optimization

Abstract With the progress of science and technology and the in-depth development of the Internet, the technology of the Internet of Things has gradually penetrated every corner of our lives. The Internet of Things greatly improves the efficiency of data acquisition and processing through the interconnection and exchange of information between devices. The development of information and intelligence in physical education teaching management has received a lot of attention as an important component of the education field. The grey relational Internet of Things model is used in this article to optimize the application of sports management. On this basis, this article conducts a systematic testing and analysis of physical education teaching. By verifying and analyzing the effectiveness and correctness of the model, real-time data during the teaching process was obtained, such as student movement trajectories, exercise intensity, etc. Providing data support for optimizing the teaching process.

Assessing the Solar Activity and Geomagnetic Disturbance during Minimum Phase of Solar Cycle 24 across the Globe.

Understanding solar activity and its implications on the Earth’s environment has become necessary. Most importantly, events that characterized the minimum phase of solar cycle 24 (2019) and geomagnetic disturbance experienced during this period calls for an assessment. To assess this, the study has therefore used INTERMAGNET data from geomagnetic stations across the globe during the solar minimum year of solar cycle 24. A total of nine geomagnetic stations data of five disturbed days in a month were used, and were averaged in a minute interval for year 2019. The stations were selected with reference to their geomagnetic locations (latitudes and longitudes) as well as analyzing their horizontal magnetic field (H-Component) from the X and Y component of the geomagnetic field to reveal the variance in the global pattern of solar variations. The seasonal variations were studied across various latitudes and longitudes to understand the impact of solar activities on the earth surface as a result of geomagnetic field disturbance on Earth’s magnetosphere at the end of cycle 24 (2019). The results of stations revealed ABK and DRV with 350nT and 150nT of H component respectively which are the highest while other stations have 60nT below. This study shows that low geomagnetic disturbance was witnessed during the end of the cycle due to the minimum solar activity which was as a result of low number of sunspot during this period.

К вопросу о вербализации лингвокультурного концепта «Родство» в официально-деловом дискурсе

The article is devoted to the study of the peculiarities of the implementation of verbal representations of the linguocultural concept of “Kinship” as a component of the mental field of kinship. Based on the material of texts presenting official business discourse, the main verbal representatives of the mental formation under study are identified — these are the nominations kinship, relatives, close relatives, which receive an obvious terminological clarification from the position of the current field of communication.

Kinetic simulations comparing quasi-parallel and quasi-perpendicular piston-driven collisionless shock dynamics in magnetized laboratory plasmas

Magnetized collisionless shocks are common in astrophysical systems, and scaled versions can be created in laboratory experiments by utilizing laser-driven piston plasmas to create these shocks in a magnetized background plasma. A key parameter for these experiments is the angle θB between the shock propagation direction and the background magnetic field. We performed quasi-1D piston-driven shock simulations to explore shock formation, evolution, and key observables relevant to laboratory experiments for a range of shock angles between θB=90° to θB=30°. Our results show that the spatial and temporal scales of shock formation for all angles considered are similar when expressed in terms of the perpendicular component of the magnetic field. In a steady state, ion and electron temperatures become more isotropic, and the electron-to-ion temperature ratio is higher for smaller θB. At θB=30°, ion heating parallel to the magnetic field becomes dominant, associated with more ions being reflected at one discontinuity and subsequently trapped by the next discontinuity due to shock reformation.

Poloidal magnetic field in the dense plasma focus

Existence of an axial (poloidal) component of magnetic field in the dense plasma focus has been inferred using multiple diagnostics in many laboratories since 1979. It has not received much attention because its origin as well as role in plasma focus physics was unclear till recently. Recent discovery of long-lasting neutron emission perpendicular to the axis in PF-1000 and neutron fluence ratio (end/side) less than unity in Gemini shows that azimuthally accelerated and radially confined deuterons play an observable role in fusion reactions. A spontaneously generated poloidal magnetic field can provide both the azimuthal electric field necessary for acceleration and radial confinement of the ions being accelerated in the acceleration zone. A comprehensive survey of plasma focus research also confirms the role of spontaneously self-organized plasma objects in the fusion reaction process where their three-dimensional magnetic field structure provides a mechanism for accelerating and trapping ions making them repeatedly pass through a dense plasma target. With emerging appreciation of the likely role of the axial magnetic field in plasma focus neutron emission, it becomes imperative to consider models for its origin. This Letter proposes a partial theory of growth of the axial (poloidal) magnetic field via a simple dynamo, with the geomagnetic field as the seed, which converts the kinetic energy of the plasma into energy of the poloidal magnetic field. This theory leads to an experimentally testable proposition.

Magnetic Dipole Model and Experimental Analysis of Magnetic Signal Detection Based on Magnetic Memory

By assuming that the magnetic charge is evenly distributed in the defect groove, the linear magnetic dipole is integrated in the depth direction of the defect, and the numerical calculation is carried out by using MATLAB to establish a two-dimensional magnetic dipole theoretical analysis model of double-correlated defects, which is suitable for analyzing the influence of stress on magnetic signal in the magnetic memory detection of rectangular and V-shaped combined macroscopic crack defects. To explore the influence factors and change rules of magnetic memory signal. In order to verify the correctness of the model analysis results, tensile tests were carried out on Q235 steel plate with double associated defects with different morphological characteristics, and the Hp(y) value of the normal component of the leakage magnetic field on the surface of the member was measured. The results show that the model based on magnetic dipole theory can explain some experimental phenomena and rules in magnetic memory detection.

Magnetic Hump Associated with Electron Vortex at Dipolarization Front

As the plasma boundary between two distinct plasma populations, dipolarization fronts (DFs) host abundant kinetic-scale substructures that change their normal directions and thus cause their deformation. However, studies on such deformation caused by an electron vortex have been lacking. Here, we present novel observations of a subion-scale magnetic hump (MHu) associated with an oblique electron vortex at a DF through strengthening three components of the magnetic field. A radial electric field in the MHu, showing bipolar variation, is also associated with the electron vortex as it is mainly ascribed to the electron convection term. There is apparent energy conversion ( J→·E→ ∼−0.3 nw m−3) from the particles to the electromagnetic field in the MHu’s leading part, which is accompanied by inflow and outflow of electromagnetic energy (nonzero ∇·S→ ). The other regions of the DF host opposite energy conversion ( J→·E→ > 0). Broadband parallel electrostatic waves are also observed in the MHu. Our study provides insights into the kinetic-scale processes at DFs.

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.

3D Polarisation of a Structured Laser Beam and Prospects for its Application to Charged Particle Acceleration

A Structured Laser Beam (SLB) is a type of optical beam with spatially inhomogeneous 3D polarisation structures. Generating SLBs from vector beams allows the creation of Hollow Structured Laser Beams (HSLB) with a dark central core. In this way, atypical electric and magnetic field vectors, which are purely longitudinally polarized in the dark zones of the beam, are obtained. The SLB spatial distribution can also include regions with both the electric and magnetic fields longitudinally polarized and oriented in the same or opposite directions. The SLB has a transverse distribution similar to that of a Bessel beam but can theoretically propagate to infinity, therefore giving the potential to generate strong, longitudinally oriented electric fields over long distances, which could possibly allow the acceleration of charged particles. The results of the study of this phenomenon, including simulations of the spatial distribution of the electromagnetic field components, are presented in this paper.

The Leakage Field of the New High-Field Septum Magnets for Fast Extraction in Main Ring of J-PARC

As part of the effort to increase the beam power of the Main Ring (MR) for fast extraction (FX) in J-PARC to 750 kW, five new septum magnets for FX (FX-septa) were installed in the MR in 2022. The most significant goal for the magnets was to achieve an extremely low leakage field in the circulating line. To realize the low leakage field, new pure iron duct-type magnetic shields were mounted in the circulating ducts of the two high-field FX-septa in 2022. In July 2022, we verified that the impact of the leakage field of all of the FX-septa on the 3-GeV circulating beam was below 10% of that of the previous FX-septa. We also measured the leakage field in the circulating ducts of the two high-field FX-septa with new shields in October 2022, and confirmed that the quadrupole field component was reduced to ≈1% of that of the previous high-field FX-septa.

A Fokker–Planck Framework for Studying the Variability of the Magnetic Field Direction in the Alfvénic Streams of the Solar Wind

Turbulent rotations of the magnetic field vector are observed in the Alfvénic streams of the solar wind where the magnetic field strength remains close to a constant. They can lead to reversals of the radial magnetic field component or switchbacks. It is not ruled out from the data that the rotations are divisible into the sum of small random angular deflections. In this work, we develop tools aimed at the analysis of the one-point statistical properties of the directional fluctuations of the magnetic field vector in the solar wind. The angular fluctuations are modeled by a drift-diffusion process which admits the exponential distribution as steady-state solution. Realizations of the stochastic process are obtained by solving the corresponding Langevin equation. It is shown that the cumulative effects of consecutive small-angle deflections can yield frequent reversals of the magnetic field vector even when the concentration parameter of the directional data is large. The majority of the rotations are associated with nearly transverse magnetic field fluctuations in this case.

On the Role of Alfvénic Fluctuations as Mediators of Coherence within Interplanetary Coronal Mass Ejections: Investigation of Multi-spacecraft Measurements at 1 au

Interplanetary coronal mass ejections (ICMEs) are defined as “coherent” if they are capable of responding to external perturbations in a collective manner. This implies that information must be able to propagate across ICME structures, and if this is not the case, single-point in situ measurements cannot be considered as indicative of global ICME properties. Here, we investigate the role of Alfvénic fluctuations (AFs) as mediators of ICME coherence. We consider multipoint magnetic field and plasma measurements of 10 ICMEs observed by the ACE and Wind spacecraft at 1 au at longitudinal separations of 0.5°–0.7°. For each event, we analyze the Alfvénicity in terms of the residual energy and cross helicity of fluctuations, and the coherence in terms of the magnetic correlation between Wind and ACE. We find that ∼65% and 90% of ICME sheaths and magnetic ejecta (MEs), respectively, present extended AFs covering at least 20% of the structure. Cross helicity suggests AFs of solar and interplanetary origin may coexist in the ICME population at 1 au. AFs are mainly concentrated downstream of shocks and in the back of MEs. The magnetic field is poorly correlated within sheaths, while the correlation decreases from the front to the back of the MEs for most magnetic field components. AFs are also associated with lower magnetic field correlations. This suggests either that ICME coherence is not mediated by Alfvén waves, implying that the coherence scale may be smaller than previously predicted, or that the magnetic field correlation is not a measure of coherence.

Dispersion diagram reconstruction of effectively bianisotropic composite periodic media

A dispersion diagram reconstruction technique is proposed for arbitrarily bianisotropic composite periodic media, which utilizes a previously introduced parameter retrieval technique based on eigenvalue analysis and field averaging. We initially retrieve the effective electromagnetic parameters of a composite periodic medium consisting of Edge-Coupled Split-Ring Resonators (EC-SRRs) via this homogenization technique using alternative integration approaches for the averaging of the field components. Subsequently, we derive the analytical framework for the wave propagation in a homogeneous medium of arbitrary bianisotropy and extract the appropriate equations which solve for the complex propagation constants. We then involve the retrieved effective parameters in these equations and reconstruct the dispersion diagrams for all three orthogonal directions, thereby spanning the whole irreducible Brillouin zone. An excellent agreement is found between the original dispersion diagrams and the reconstructed ones; a result which further validates the utilized parameter retrieval technique. The reconstruction technique moreover allows one to interpret the slope differences observed in the dispersion diagrams for in-plane and normal incidence modes of the examined composite medium. It may also be used as a tool for the confirmation of the accuracy of other formerly proposed homogenization techniques existing in the literature.

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.

High-resolution imaging of 3D stray-field components with a Fe3O4 nanoparticle sensor.

Despite rapid advances in magnetic domain imaging techniques, high-resolution imaging of 3D magnetic field components remains a great challenge. Magnetic force microscopy has been utilized to observe the 1D magnetic field component from the sample surface; however, the 1D stray-field component lacks sufficient conditions to clarify the nature of nanomagnetism. Herein, we propose a method for the detection of 3D stray-field components by using a Fe3O4-nanoparticle sensor. We employed this Fe3O4-nanoparticle sensor to detect nanoscale magnetic domains, domain walls, and magnetic vortices (resolution ∼5 nm), and our findings demonstrate its potential in imaging both out-of-plane and in-plane magnetic-field components. Our technique overcomes the limitations of 3D stray-field detection and high-resolution imaging and provides the possibility of observing both out-of-plane and in-plane magnetic field components with a 5 nm resolution, thereby paving the way for the development of future spin-based devices.

Strongly curved super-conducting magnets: beam optics modeling and field quality

Superconducting (SC) dipoles with a strong curvature (radius smaller than 2 meters, for an aperture of about 100 mm and a length of 1-3 meters) are required for applications where compactness is key, such as the synchrotron and gantry for Carbon-ion therapy developed within the European program HITRIplus. Such magnets challenge several assumptions in the field description and put to the test the range of validity of beam optics codes. In particular, the equivalence that holds for the straight magnets between the transverse multipoles description obtained from the Fourier analysis (used for magnet design and measurements) and the Taylor expansion of the vertical field component along the horizontal axis (used in beam optics) is not valid any longer. Proper fringe field modelling also becomes important due to the curved geometry and the aperture being large compared to the magnetic length. We explore the feasibility and the limits of modelling such magnets with optics elements (such as sector bends and multipoles), which allows parametric optics studies for optimization, field quality definition and fast long-term multi-pass tracking.

Development of an X-band RF gun with four-feed coupler

With the high accelerating gradient, radiofrequency (rf) gun has a significant feature of suppressing the growth of transverse emittance caused by space charge. Field emission cathodes were first used in vac-uum electronic devices, which do not require the high electron beam intensity, but the compact geometry size of the cathode. A new X-band (11.424 GHz) rf electron gun has been proposed with the highlight of four-feed coupler, which can eliminate the quadrupole field component observed and analysed from the imagine experiment carried on, which have affected the resolu-tion of the imaging system to some content.

Earthquake forecast by imbalance machine learning using geophysical predictors

In the present paper we consider the earthquake forecast as a binary problem of machine learning on the imbalanced data base applied to five regions of Georgia. For the training we used geophysical data base collected in 2017-2021, namely, variations of statistical characteristics of geomagnetic field components, seismic activity, water level in deep boreholes and tides. In this version a new predictor – the weighted seismic activity for previous 5 days - – is added compared to the predictors’ list used in previous papers. Besides, the length of the used database is increased 3 times compared to the earlier results. As in the database the earthquakes of M > 3.5 are rare, the number of negative cases is large (there are many days without EQs of M > 3.5), meaning that there is a strong imbalance between positive and negative cases of the order of 1:20; we apply the specific methodology Matthews’ correlation coefficient (MCC) and F1 score to avoid the strong imbalance effect.