Electromagnetic Field In Space Research Articles

Multi‐Material Aerosol Jet Printing of Al/Cuo Nanothermites for Versatile Fabrication of Energetic Antennas

AbstractIn the present study, a nanoscale Al/CuO thermite system is patterned using a multi‐material aerosol jet printing technology. Morphological analysis of samples manufactured with different printing configurations reveal a strong effect of the printhead design on microstructure and degree of mixing between the constituent materials, providing insight on fundamental mechanisms of inline aerosol‐phase mixing during printing. The high‐resolution patterning capability of aerosol jet printing is leveraged to fabricate both blended nanoscale Al/CuO thermites and antennas containing the nanothermite, which exhibit rapid and low‐energy ignition upon exposure to a 2.45 GHz free space electromagnetic field, characterized by an ignition delay of ≈130 ms and ignition energy of ≈216 J. Moreover, the versatility of this approach is demonstrated by manufacturing compositionally graded samples, establishing multi‐material aerosol jet printing as a compelling and versatile platform for microscale energetic device fabrication with broader utility for graded materials. This work shows promise for use of the technique for in situ manufacturing of standalone and integrated energetics and electromagnetic devices.

Simulation and Experimental Study on Coupling Effect of Fuze under Ultra-wide Spectrum Strong Electromagnetic Pulse

The lack of anti-strong electromagnetic interference ability of fuze has become an important aspect restricting the effectiveness of weapon system. Taking a certain type of fuze as an example, this paper analyzes the coupling mechanism of ultra-wide spectrum transient strong electromagnetic pulse to the fuze, analyzes the action mode of aperture coupling and field line coupling, establishes the mathematical model of space electromagnetic field, and then simulates the effect of aperture coupling and field line coupling of the fuze by using CST Microwave Studio software. It is concluded that the strongest coupling state is when the polarization direction of the electromagnetic field is parallel to the axis of the fuze. Combined with the theory and simulation, the ultra-wide spectrum transient strong electromagnetic pulse simulation system is used to conduct the strong electromagnetic pulse irradiation test, and the electromagnetic pulse effect threshold is obtained. It is concluded that the effect threshold leading to communication failure is about 27~40kV/m, which provides a certain theoretical and experimental basis for fuse strong electromagnetic protection.

Calibrating instruments to analyze energetic neutral atoms in space

Neutrals are unaffected by electromagnetic fields in space, providing important information about their sources, but are difficult to characterize at low energies.

Задача Трикоми для одного класса многомерных смешанно гиперболо-параболических уравнений

It is known that in the mathematical modeling of electromagnetic fields in space, the nature of the electromagnetic process is determined by the properties of the medium. If the medium is non-conducting, we obtain degenerate multidimensional hyperbolic equations. If the medium has a high conductivity, then we come to degenerate multidimensional parabolic equations. Consequently, the analysis of electromagnetic fields in complex media (for example, if the conductivity of the medium changes) is reduced to degenerate multidimensional hyperbolic-parabolic equations. It is also known that the oscillations of elastic membranes in space can be modeled according to the Hamilton principle by degenerate multidimensional hyperbolic equations. The study of the process of heat propagation in a medium filled with mass leads to degenerate multidimensional parabolic equations. Therefore, by studying the mathematical modeling of the heat propagation process in oscillating elastic membranes, we also arrive at degenerate multidimensional hyperbolic-parabolic equations. When studying these applications, it becomes necessary to obtain an explicit representation of the solutions to the problems under study. Boundary value problems for hyperbolicparabolic equations on the plane are well studied, and their multidimensional analogues are little studied. The Tricomi problem for these equations was previously investigated. As far as we know, this problem has not been studied in space. In this paper, the Tricomi problem is shown to be ambiguously solvable for a class of multidimensional mixed hyperbolic-parabolic equations.

Spatio-temporal properties of pulse propagation in a graphene quantum system

In this paper we have theoretically studied the spatial-temporal evolution of electromagnetic light propagation through a four-level graphene quantum system by using density matrix method and perturbation theory. The four-level graphene quantum medium interacted by an elliptical polarized coupling and a weak probe lights, respectively. We present the analytical solution for solving the Maxwell–Bloch equations for graphene and electromagnetic field in space and time domains. Then, we have analyzed the dynamic control of pulse propagation and optical dual switching in such a laser-driven quantum system. Our theoretical findings show that by adjusting the optical parameters such as elliptical angle i.e. phase difference between right-and-left circularly polarized, one can easily control the absorption spectrum and pulse propagation of the probe light in graphene medium. Our results may have potential applications in designing the new quantum devices for usage in quantum information processing.

КОМПОЗИЦИЯЛЫҚ МАТЕРИАЛДАР ҚҰРЫЛЫМЫ ЖӘНЕ КОМПОЗИТТЕР МЕХАНИКАСЫНЫҢ ЕСЕПТЕРІ

It is known that in space during mathematical modeling of electromagnetic fields in space, the nature of the electromagnetic process is determined by the properties of the medium. If the medium is non-conductive, then we get degenerating multidimensional hyperbolic equations. Therefore, the analysis of electromagnetic fields in complex environments (for example, if the conductivity of the medium changes) is reduced to degenerating multidimensional hyperbolic equations. It is also known that oscillations of elastic membranes in space according to the Hamilton principle can be modeled by degenerating multidimensional hyperbolic equations. Therefore, by studying mathematical modeling of the process of heat propagation in oscillating elastic membranes, we also come to degenerating multidimensional hyperbolic equations. When studying these applications, it becomes necessary to obtain a clear representation of the solutions to the investigated problems. The mixed problem for degenerating multidimensional hyperbolic equations in generalized spaces is well researched. This task is also studied in the works of S. A. Aldashev, where it is shown that its correctness significantly depends on the height of the cylindrical region under consideration. A.V. Bitsadze drew attention to the importance of studies of multidimensional hyperbolic equations with degeneration of type and order. Mixed problems for these equations have not previously been studied. In this work, the solvability of a mixed problem is shown and a clear form of a classical solution for three-dimensional hyperbolic equations with degeneration of type and order is obtained.

MODERN METHODS FOR EVALUATING BUSINESS PROCESSES OF AN ENTERPRISE USING A BALANCED SCORECARD

It is known that in mathematical modeling of electromagnetic fields in space, the nature of the electromagnetic process is determined by the properties of the medium. If the medium is non-conductive, we get degenerate multi-dimensional hyperbolic equations. If the medium has a high conductivity, then we go to degenerate multidimensional parabolic equations. Consequently, the analysis of electromagnetic fields in complex media (for example, if the conductivity of the medium changes) reduces to degenerate multidimensional hyperbolic-parabolic equations. Also, it is known that the oscillations of elastic membranes in space according to the Hamilton principle can be modeled by degenerating multidimensional hyperbolic equations. Studying the process of heat propagation in a medium filled with mass leads to degenerate multidimensional parabolic equations. Consequently, by studying the mathematical modeling of the process of heat propagation in oscillating elastic membranes, we also come to degenerate multidimensional hyperbolic-parabolic equations. When studying these applications, it is necessary to obtain an explicit representation of the solutions of the studied problems. The mixed problem for degenerate multidimensional hyperbolic equations was previously considered. As far as is known, these questions for degenerate multidimensional hyperbolic-parabolic equations have not been studied. In this paper, unique solvability is shown and an explicit form of the classical solution of the mixed problem for one class of degenerate multidimensional hyperbolic-parabolic equations is obtained.

TRICOMI PROBLEM FOR MULTIDIMENSIONAL MIXED HYPERBOLIC-PARABOLIC EQUATION

It is known that in mathematical modeling of electromagnetic fields in space, the nature of the electromagnetic process is determined by the properties of the media. If the medium is non-conducting, then we obtain multidimensional hyperbolic equations. If the mediums conductivity is higher, then we arrive at multidimensional parabolic equations. Consequently, the analysis of electromagnetic fields in complex media (for example, if the conductivity of the medium changes) reduces to multidimensional hyperbolic-parabolic equations. When studying these applications, one needs to obtain an explicit representation of solutions to the problems under study. Boundary-value problems for hyperbolic-parabolic equations on a plane are well studied; however, their multidimensional analogs have been analyzed very little. The Tricomi problem for the above equations has been previously investigated, but this problem in space has not been studied earlier. This article shows that the Tricomi problem is not uniquely solvable for a multidimensional mixed hyperbolic-parabolic equation. An explicit form of these solutions is given.

Quasi-geometric integration of guiding-center orbits in piecewise linear toroidal fields

A numerical integration method for guiding-center orbits of charged particles in toroidal fusion devices with three-dimensional field geometry is described. Here, high order interpolation of electromagnetic fields in space is replaced by a special linear interpolation, leading to locally linear Hamiltonian equations of motion with piecewise constant coefficients. This approach reduces computational effort and noise sensitivity, while the conservation of total energy, magnetic moment and phase space volume is retained. The underlying formulation treats motion in piecewise linear fields exactly and, thus, preserves the non-canonical symplectic form. The algorithm itself is only quasi-geometric due to a series expansion in the orbit parameter. For practical purposes, an expansion to the fourth order retains geometric properties down to computer accuracy in typical examples. When applied to collisionless guiding-center orbits in an axisymmetric tokamak and a realistic three-dimensional stellarator configuration, the method demonstrates stable long-term orbit dynamics conserving invariants. In Monte Carlo evaluation of transport coefficients, the computational efficiency of quasi-geometric integration is an order of magnitude higher than with a standard fourth order Runge–Kutta integrator.

Calculation of electromagnetic field for very fast transient process in GIS

The calculation method of electromagnetic field generated by very fast transient process in GIS is studied. The VFTC is calculated, and the mathematical model of direct wire electromagnetic radiation is established according to the structure of GIS. The space electromagnetic field is calculated with VFTC as excitation source. The non-stationary VFTC simulation waveform is decomposed in combination with Hilbert yellow method. The electromagnetic field intensity of each decomposed waveform is calculated on the basis of mathematical model of direct wire electromagnetic radiation. Then the electromagnetic field intensity of fast transient process is reconstructed. The results show that the intensity of electromagnetic field decreases exponentially with the increase of distance. The method proposed solves the theoretical calculation of complex electromagnetic field for unsteady VFTC waveform that contains complex frequency components with transient characteristics in very fast transient process. That has theoretical guiding significance for the electromagnetic field calculation of very fast transient phenomenon in GIS.

Coupling analysis of transmission lines excited by space electromagnetic fields based on time domain hybrid method using parallel technique**Project supported by the National Natural Science Foundation of China (Grant No. 61701057) and the Chongqing Research Program of Basic Research and Frontier Technology, China (Grant No. cstc2017jcyjAX0345).

We present a time domain hybrid method to realize the fast coupling analysis of transmission lines excited by space electromagnetic fields, in which parallel finite-difference time-domain (FDTD) method, interpolation scheme, and Agrawal model-based transmission line (TL) equations are organically integrated together. Specifically, the Agrawal model is employed to establish the TL equations to describe the coupling effects of space electromagnetic fields on transmission lines. Then, the excitation fields functioning as distribution sources in TL equations are calculated by the parallel FDTD method through using the message passing interface (MPI) library scheme and interpolation scheme. Finally, the TL equations are discretized by the central difference scheme of FDTD and assigned to multiple processors to obtain the transient responses on the terminal loads of these lines. The significant feature of the presented method is embodied in its parallel and synchronous calculations of the space electromagnetic fields and transient responses on the lines. Numerical simulations of ambient wave acting on multi-conductor transmission lines (MTLs), which are located on the PEC ground and in the shielded cavity respectively, are implemented to verify the accuracy and efficiency of the presented method.

Electromagnetic Fields As An Element of Spacecraft Construction

The article suggests the best option for designing a spacecraft. The process of activity of proposed structure of a spacecraft in outer space must be based on the acceleration due to the electromagnetic fields of the Solar System and the Milky Way Galaxy. Purpose of the study. Suggest a design solution to create a model of a spacecraft that is accelerated in motion using space electromagnetic fields. The relevance of the chosen topic is based on the need to address issues related to the limited resources of the planet, significant levels of overpopulation, problems of demography, ecology, sociology and political life. Novelty. It is determined that in order to obtain calculations of the acceleration of 1 g of spatial arbitrary direction, it is necessary to make measurements along the chain and to deduce the amount of charge on the useful surface of the object. Methodology. Magnetic field strength measurement method, electromagnetic measurement method. Results and conclusions. The article presents a scheme of creating a modified magnetic type engine, the result its process of activity will be an acceleration of 0.05 g. It will be achieved by free movement in outer space with the appropriate current.

CORRECTNESS OF A MIXED PROBLEM FOR DEGENERATE THREE-DIMENSIONAL HYPERBOLIC-PARABOLIC EQUATIONS

In mathematical modeling of electromagnetic fields in space, the nature of electromagnetic process is determined by the properties of the medium. If the medium is non-conducting, we obtain degenerate three-dimensional hyperbolic equations. If the medium has a high conductivity, then we come to degeneratethree-dimensional parabolic equations. Consequently, the analysis of electromagnetic fields in complex media (for example, if the mediums conductivity changes) is reduced to degenerate three-dimensional hyperbolic-parabolic equations. The mixed problem for multidimensional hyperbolic equations is well studied and has been previously considered in the works of various authors. In the articles of Professor S.A. Aldashev, the unique solvability of the mixed problem for degenerate multidimensional hyperbolic equations is proved. It is known that mixed problems for multidimensional hyperbolic-parabolic equations have not been studied much. The paper finds a new class of degenerate three-dimensional hyperbolic-parabolic equations for which the mixed problem has a unique solution and gives an explicit representation of its classical solution.

Finite element solution to 3-D airborne time-domain electromagnetic problems in complex geological media using non-conforming hexahedral meshes

We propose the approach to 3-D modeling of the electromagnetic (EM) field in time-domain airborne EM problems in complex media including rugged topography and curved borders between the geological layers, target objects of different shapes, lateral inhomogeneity within subhorizontal layers. For discretization of the electromagnetic field in space, the vector finite element method is used. We propose the approach to generating the optimized non-conforming finite element meshes with hexahedral cells in which several finite elements can be attached to the face of the other finite element which allows achieving the significant reduction of computational costs in comparison with the regular meshes on which the numerical solution has the same accuracy. The optimized non-conforming finite element mesh in a complex medium with the topography and curved borders of layers is generated with the use of special transformations. The method of constructing the finite element approximations on these non-conforming hexahedral meshes is proposed. For discretization of the electromagnetic field in time, the implicit three-point scheme “with backward overstepping” is proposed. For solving the finite element SLAE, we use the direct solver PARDISO the effectiveness of which is achieved due to the use of time stepping with a piecewise constant step and grouping the calculations of the electromagnetic field in time steps and transmitter positions. In order to increase the accuracy of calculating the signal in the receiver, a special procedure of smoothing the magnetic field B in space and special scheme of approximating the derivative of B in time are proposed. The verification of the proposed approaches is performed using the solution for the 1-D model and solutions for 3-D models obtained by other authors. We present the results of the comparative analysis of different time schemes in finite element calculating the electromagnetic field and in calculating the signal (in the form of EMF) in the receiver and choose the optimal step and the number of subintervals with the constant steps into which the entire modeling time interval is divided. We perform the comparative analysis of stair-like approximation of curved surfaces with the use of rectangular parallelepipeds and approximation with the use of the hexahedral elements and choose the optimal parameters of generating the finite element meshes. We present the results of the analysis of the possibility of replacing the model with topography with the “flat” 3-D model in which the topography is taken into account by correcting the airborne system height. For the “flat” 3-D model, we present the results of the analysis of the computational effectiveness through the use of the primary-secondary field approach with automatic choice of a horizontally-layered medium for calculating the primary field. For the complex geolelectrical model with topography, laterally-inhomogeneous overburden with curved boundaries, target objects under overburden and for a great number of airborne system positions, the computational costs are presented for sequential and parallel modes for modeling time from 0.01 ms to 1 ms and 10 ms. We present the analysis of the topography effect, the influence of the inhomogeneities in the overburden and target objects in the complex media and show that in this conditions, to discover the target objects using the form of the signal is practically impossible, i.e. in order to discover the target objects in these complex media, it is required to perform a very fine 3-D interpretation for carrying out of which fast and high accuracy forward 3-D modeling is of great importance. We obtain that for calculating the field for one transmitter and the entire modeling time interval in the sequential mode on one core of PC with processor Intel i7-8700K CPU of 3.7 GHz and 32 GB of DRAM, the required computational time is about 4–6 s. The required computational time in the parallel mode with the use of six cores of this PC is about 0.65–1 s.

Research on mechanism and key technology of mechanical antenna for a low-frequency transmission

Unlike conventional electrically small antennas (ESAs) that rely on the electromagnetic wave excited by the oscillated current in a conductor, the mechanical antennas (MAs) use a novel low-frequency (LF) transmission technique that utilizes the mechanical motion of electric charge or magnetic to generate the electromagnetic wave directly. This transmission technique is a promising solution for overcoming the physical limit of ESAs, and solving the problems of a large volume, complicated facilities, low radiation efficiency, and large transmission loss of current LF transmission systems. Accordingly, it can improve the motility and flexibility of the LF communication, and thus has a wide prospect in the underwater and underground communication and navigation and location applications. First, the definition and research status of the MA are introduced. Next, the realization and physical model investigation of the MA are provided. Then, the distribution model and attenuation characteristic of the time-varying electromagnetic field in space are explained in detail. According to the comparison of different types, a general structure of the MA is proposed. The main challenges regarding the high-efficiency utilization are introduced, and the application mode and prospect are described. A rotating-magnet based MA prototype composed of a NdFeB high-speed permanent magnetic servo electrical machine is developed using the proposed MA structure. The time-varying magnetic field characteristic of the prototype is preliminarily verified by the near-field measurement, as well as the possibility and effectiveness of the FSK modulation.

Simulation, Design, and Test of a Dual-Differential D-Dot Overvoltage Sensor Based on the Field-Circuit Coupling Method.

Accurate measurement of overvoltage in power grids is of great significance to study the characteristics of overvoltage and design of insulation coordination. Based on the research of D-dot voltage sensor, we designed a Dual-Differential D-dot overvoltage sensor. In order to quantify the structural parameters of the sensor, improve the performance and measurement accuracy of the sensor. The Field-Circuit Coupling method was proposed to be used in the parameter design of D-dot overvoltage sensor. The joint simulation of space electromagnetic field model and equivalent circuit model of the Dual-Differential D-dot overvoltage sensor was established with the finite element simulation software Ansoft Maxwell and circuit simulation software Simplorer. Finally, the actual sensor was manufactured. A test platform was built to verify the steady-state and transient performance of the sensor. The results show that the Dual-Differential D-dot sensor has excellent steady-state and transient performance, the error of phase and amplitude are small, and the sensor can achieve the non-contact measurement of power transmission line. Simultaneously, the rationality of the Field-Circuit Coupling method was further verified.

Research on Suppression Technology of Electromagnetic Interference in CAN Communication

CAN communication is a relatively common communication method used in the industrial and automotive fields. It analyses the main cause of communication interference in the electromagnetic interference phenomenon of CAN communication in industry. Due to factors such as circuit imbalance and space electromagnetic field, the CAN bus will cause common mode interference due to radiation. The strong interference generated in the field may cause the relay to malfunction and cause the wrong signal. Therefore, this paper proposes protection measures against the malfunction of the relay from the perspective of signal input and relay triggering, and has strong anti-interference ability after testing in actual projects.

The high-energy particle package onboard CSES

The China Seismo-Electromagnetic Satellite (CSES) aims to monitor space electromagnetic fields, ionospheric plasma, high-energy charged particles and other features of the global space environment. The high-energy particle package (HEPP), which can effectively detect the energy spectrum, flux and pitch angle distribution of space electrons and protons, and soft X-ray emission from solar flares, is one of the main payloads of CSES. In this study, we designed, developed and calibrated the high-energy particle package and launched it into orbit with CSES. HEPP consists of the high-energy detector (HEPP-H), the low-energy detector (HEPP-L), and the solar X-ray monitor (HEPP-X). The three sub-detectors mainly use silicon detector and crystal calorimeter detection technology. Before launching, we calibrated the three sub-detectors in detail by using radiation source and accelerator beam. All the three sub-detectors have good energy linearity. After launching into orbit, the space energetic particles and X-ray distribution detected by HEPP are consistent with expectations. The performance indices of the detector reach the advanced level of the same kind of detector in the world. HEPP has a wide energy detection range, good energy resolution and high angular resolution ability for electrons and protons. It will play an important role in the study of space particle response and space physics of seismic activity.

Regulation of spatial fields in wireless power transfer with artificial magnetic conductor

In order to improve the efficiency of wireless power transfer (WPT) system, the spatial fields are regulated on a two-non-resonant-coil WPT system by hexagon artificial magnetic conductors (AMC). In our configuration, the AMC is located by the side of the two-non-resonant-coil WPT system and close to the transmitter coil. The AMC structure consists of small hexagon copper patches periodically arranged on the dielectric substrate. Each patch is grounded by a via passing through its center hole. Chip capacitors are soldered in the gaps between the adjacent patches. We can design the working frequency of WPT system through the capacitance of these chip capacitors. The results show that the electromagnetic fields are changed between the transmitter coil and the receiver coil in WPT system due to the introducing of the AMC structure. There are two main reasons. First, many resonant modes are excited by near magnetic fields on the AMC structure. Second, near magnetic fields are shielded by the AMC structure. The variation of space electromagnetic field improves the transmission efficiency of WPT system. When the working frequency is 27 MHz and the transmission distance is 3 cm, the experiment verifies that the transmission efficiency increases by 22% in the WPT system with the AMC structure compared with the WPT system without the AMC structure. Simultaneously, the transmission efficiency is raised by 25% at different transmission distances. The simulation results are almost consistent with the experimental results. There is a little difference that the number of resonant modes is different between the simulation and the experiment due to the resistance loss of the chip capacitors in experiment. Therefore, we correct the simulation results under consideration of resistive loss. In addition, the excited multiple resonant modes can supply multiple and adjustable working frequencies in the WPT system with the AMC structure. In practical applications, AMC is low in cost and easy to implement.

A Technology for Protection from Environmental Electromagnetic Fields

Cellular telephones, Wi-Fi, and electricity have revolutionized our communications and lifestyles. Wireless technologies have become one of the fastest growing industries, with billions of users around the world. While many of us enjoy and depend on these modern conveniences, an increasing number of people are becoming sensitive or allergic to the electromagnetic fields used to operate our modern technologies. Research in this area indicates that those who have no observable ill effects may still be compromised at a subtle level. Sensitive individuals may have one or more ailments, such as stomach aches, headaches, muscle pains, poor sleep, or “mystery symptoms” that are difficult to diagnose and treat because few physicians are familiar with the real cause. The growth of coverage of Wi Fi will probably increase rather than slow, so it is essential that people be able to protect themselves. Many devices are available that claim to protect against electromagnetic pollution. One of the most thoroughly tested is the PRANAN family of devices. Various laboratory tests have documented the effectiveness of these systems in stabilizing various physiological processes. This article explores the possible mechanisms by which these effects are achieved. The surfaces of the devices have interesting geometrical patterns corresponding to ancient images found throughout nature, art and architecture. The well-known mathematics behind the symbols is referred to as the Golden ratio, Golden mean, Golden section, or Phi. Some of the greatest mathematical minds of all ages have spent endless hours contemplating this simple ratio and its properties. Biologists, artists, musicians, historians, architects, psychologists, and even mystics have pondered and debated the basis of its ubiquity and appeal. Because of the well-documented physiological effects of the PRANAN devices, we explore the possibility that the geometrical patterns on the surfaces of the devices reveal physical relationships between the geometry of electromagnetic fields in space (the quantum vacuum) and living tissues. This concept, remarkable is it may seem, is supported by recent developments in quantum physics that have demonstrated the underlying mathematics of Phi in relation to magnetic fields.