Electromagnetic Hybrid Research Articles

Collective trajectory planning for satellite swarm using inter-satellite electromagnetic force

The inter-satellite electromagnetic force presents several significant advantages that help to expand its space applications to the multi-satellite missions gradually. For a satellite swarm, whether the electromagnetic force is applied to enable collective maneuver and how to provide a better performance and broader applications for such swarm highlight an important issue. Considering the trajectory planning problem of satellite swarm using inter-satellite electromagnetic force, a behavior-based collective planning scheme is developed by designing the desired velocity of each satellite as the sum of several different behavioral contributions, which are used to represent the internal and external interactions of the swarm. Therefore, the desired configuration is associated with the equilibrium points of the pre-designed kinematical field. Furthermore, the trajectory planning problem could be translated to a parameter optimization problem considering the swarm dynamics with inter-satellite electromagnetic force. Then based on the analysis of the applicability and advantages triggered by integrating the inter-satellite electromagnetic force into such behavior-based planning scheme, the collective trajectory planning problem with sole electromagnetic force actuation and hybrid actuation with thruster are studied respectively. Numerical simulations are carried out to verify the validity of the proposed algorithm, and the satellite swarm performance enhanced by inter-satellite electromagnetic force is discussed at last.

Cosimulation of Electromagnetics-Circuit Systems Exploiting DGTD and MNA

A hybrid electromagnetics (EM)-circuit simulator exploiting the discontinuous Galerkin time domain (DGTD) method and the modified nodal analysis (MNA) algorithm is developed for analyzing hybrid distributive and nonlinear multiport lumped circuit systems. The computational domain is split into two subsystems. One is the EM subsystem that is analyzed by DGTD, while the other is the circuit subsystem that is solved by the MNA method. The coupling between the EM and circuit subsystems is enforced at the lumped port where related field and circuit unknowns are coupled via the use of numerical flux, port voltages, and current sources. Since the spatial operations of DGTD are localized, thanks to the use of numerical flux, coupling matrices between EM and circuit subsystems are small and are directly inverted. To handle nonlinear devices within the circuit subsystem, the standard Newton-Raphson method is applied to the nonlinear coupling matrix system. In addition, a local time-stepping scheme is applied to improve the efficiency of the hybrid solver. Numerical examples including single and multiport linear/nonlinear circuit networks are presented to validate the proposed solver.

Electromagnetic properties of Si–C–N based ceramics and composites

Besides the excellent high-temperature mechanical properties, Si3N4 and SiC based ceramics containing insulating or electrically conductive phase are attractive for their tunable dielectric properties, which may vary from electromagnetic (EM) wave transparent to absorption and shielding. Consequently, SiC, Si3N4, SiON, SiBN, SiBC, SiCN and SiBCN ceramics have attracted extensive interest in recent years. SiO2, Si3N4, Si3N4–SiO2, Si3N4–BN, and Si3N4–SiO2–BN are promising EM wave transparent materials for applications in microelectronic packaging, microwave transparent reaction chamber, radome and antenna window. C, SiC, SiC–C, Si3N4–C and Si3N4–SiC are potential EM wave shielding materials, which can be used as electronic packaging of highly integrated circuits, and be used in wireless communication system, telecommunication base stations and the other electronic devices. Si3N4–SiBC, Si3N4–SiCN and Si3N4–SiBCN are attractive EM wave absorbing materials for potential applications in amplifier, accelerator, microwave heating, anechoic chambers, stealth aircraft and ship. Other potential harsh environment or high-temperature applications will also benefit from the Si–C–N ceramic system. The concept of hybrid structure and EM metamaterials (MMS) opens up new avenues in developing EM wave absorption materials. The key developments and future challenges in this field are summarised. The main issues regarding permittivity of high-temperature structural ceramics are discussed, with an emphasis on the EM wave transparent, shielding and absorbing mechanisms that are responsible for the EM wave properties.

The Transient Effectiveness Research of Ultra-High Voltage Short Tripping Fault to Large Region Grid Based on Hybrid Simulation

The paper build the large region grid model of ultra-high voltage in electro-magnetic and electro-mechanical hybrid simulation system, and researched the effectiveness of ultra-high voltage transmission line to large region grid, especially the N-1 short tripping fault caused transient stability problems.

Magnetosheath filamentary structures formed by ion acceleration at the quasi‐parallel bow shock

AbstractResults from 2.5‐D electromagnetic hybrid simulations show the formation of field‐aligned, filamentary plasma structures in the magnetosheath. They begin at the quasi‐parallel bow shock and extend far into the magnetosheath. These structures exhibit anticorrelated, spatial oscillations in plasma density and ion temperature. Closer to the bow shock, magnetic field variations associated with density and temperature oscillations may also be present. Magnetosheath filamentary structures (MFS) form primarily in the quasi‐parallel sheath; however, they may extend to the quasi‐perpendicular magnetosheath. They occur over a wide range of solar wind Alfvénic Mach numbers and interplanetary magnetic field directions. At lower Mach numbers with lower levels of magnetosheath turbulence, MFS remain highly coherent over large distances. At higher Mach numbers, magnetosheath turbulence decreases the level of coherence. Magnetosheath filamentary structures result from localized ion acceleration at the quasi‐parallel bow shock and the injection of energetic ions into the magnetosheath. The localized nature of ion acceleration is tied to the generation of fast magnetosonic waves at and upstream of the quasi‐parallel shock. The increased pressure in flux tubes containing the shock accelerated ions results in the depletion of the thermal plasma in these flux tubes and the enhancement of density in flux tubes void of energetic ions. This results in the observed anticorrelation between ion temperature and plasma density.

A Study on Design and Analysis of Hybrid Vibration Damper with Energy Harvesting and Optimal Damping Effect

The basic purpose of a damper is to reduce the vibration and to have a better ride comfort, road handling and safety to the rider. Recent developments show that an active vibration damper can effectively work much better than a passive damper. The effectiveness and reliability can be further enhanced by using hybrid dampers, which is a combination of active and passive dampers. But the need to have energy optimization in any field need not be stressed. Consequently, novel suspension concepts are required, not only to improve the vehicle’s dynamic performance, but also to see that the energy generated during vibration can be harvested by utilizing regeneration functions. Hence if a hybrid damper with energy harvesting capability be designed, it would serve both purposes. In the hybrid damper a combination of hydraulic damper to act as a passive damper and an electromagnetic (EM) damper to act as an active damper is considered. The hydraulic system has more reliability and is time tested and the EM system acts as a dynamic vibration system as well as energy harvester. In this study a hybrid EM damper is modeled, analyzed and validity is shown for frequency response functions and energy balance for its active use. It is also shown how the effectiveness of the suspension system can be enhanced by using a hybrid damper.

Design and Establishment of HIL Testing Bench for Electromagnetic and Hydraulic Hybrid Brake System

This paper discussed the brake performance and reviewed the research progress of the eddy current-hydraulic hybrid brake system. The paper mainly described the design principle of HIL testing bench, and presented a structure drawing of HIL testing bench. Based on the basic principle and structure of HIL testing bench, a real testing bench including hardware, software, interface, and virtual controller on PCs etc., is manufactured. Through two kinds of experiments on wet and dry road, the results indicates that the hybrid brake system has a perfect performance, the HIL testing bench of hybrid brake system is very convenient to study and simulate the braking system. Because the simulation on PCs cannot solve lots of actual problems, with the HIL testing bench, more actual research project can be done in the future.

Analysis of Static thrust characteristics and levitation force characteristics of the magnetic levitation system using the <i>X</i>-<i>Y</i> LSM armature.

We studied the magnetic levitation system for an X-Y Linear Synchronous Motor(LSM). This system was used an X-Y LSM armature as a primary side, and 4 pole type yoke hybrid electromagnet was used for a secondary side. There are some advantages in using the magnetic levitation system for an X-Y LSM. It will be decreases friction and abrasion by making it noncontacting. In this paper, for stable levitation the magnetic levitation system, we analyzed the levitation force and static thrust of the this system.

Integration of Arbitrary Lumped Multiport Circuit Networks Into the Discontinuous Galerkin Time-Domain Analysis

A hybrid electromagnetic (EM) circuit simulator is proposed for incorporating multiport lumped circuit networks through their admittance matrices into the discontinuous Galerkin time-domain (DGTD) method. The admittance matrix in the Laplace domain can be derived analytically or obtained from network parameters such as S-parameters in the frequency domain. To convert frequency-dependent S-parameters into the admittance matrix in the Laplace domain, the vector-fitting technique is employed to facilitate the mapping process. The computational domain of interest is split into two subdomains. One is the EM part solved by the DGTD, and another is the circuit part modeled by the basic I-V relationships in the time domain. The couplings between the EM and circuit parts happen at lumped ports where the port voltages and currents are solved via these coupled systems. Due to the local properties of DGTD operations, only small coupling matrix equation systems are involved. To further improve the efficiency, local time-stepping strategy is included. To show the validity of the proposed simulator, several numerical examples are presented and compared with results from other references.

Gyrokinetic turbulence simulations of high-beta tokamak and helical plasmas with full-kinetic and hybrid models

Turbulent transport in high-beta toroidal plasmas is investigated by means of an electromagnetic gyrokinetic model and a newly developed electromagnetic hybrid model consisting of the gyrokinetic equation for ions and drift-Landau-fluid equations for electrons. Full gyrokinetic simulation results for Cyclone base case tokamak and for Large Helical Device (LHD) plasmas are quickly and accurately reproduced by the hybrid simulation. In the kinetic ballooning mode (KBM)-driven turbulence the ion heat and particle fluxes are mainly caused by electrostatic perturbation, and the contribution of magnetic perturbation is small and negative. The electron heat flux is caused by both electrostatic and magnetic perturbations. The numerical solutions satisfy the entropy balance equation, and the entropy is transferred from ions to electrons through electrostatic and magnetic perturbations. An analysis based on the entropy balance equation shows that the zonal structure is produced by magnetic nonlinearity corresponding to the Maxwell stress in the fluid limit but is weakened by the electrostatic one related to the Reynolds stress. A linear analysis on the standard configuration of LHD plasmas shows the suppression of the ion temperature gradient mode by finite-beta effects and the destabilization of KBM at high beta.

A Hybrid Electromagnetics-Circuit Simulation Method Exploiting Discontinuous Galerkin Finite Element Time Domain Method

A hybrid electromagnetics (EM)-circuit simulation method employing the discontinuous Galerkin finite element time domain (DGFETD) method is developed to model single lumped port networks comprised of both linear and non-linear elements. The whole computational domain is split into two subsystems: one is the EM subsystem that is analyzed by DGFETD, while another is the circuit subsystem that is modeled by the Modified Nodal Analysis method to generate a circuit subsystem. The coupling between the EM and circuit subsystems is achieved through a lumped port. Due to the local properties of DGFETD operations, only small coupling matrix equation systems are involved. To handle non-linear devices, the standard Newton-Raphson method is applied to the established non-linear matrix equations. Numerical examples are presented to validate the proposed algorithm.

Verification of electromagnetic fluid-kinetic hybrid electron model in global gyrokinetic particle simulation

The fluid-kinetic hybrid electron model is verified in global gyrokinetic particle simulation of linear electromagnetic drift-Alfvenic instabilities in tokamak. In particular, we have recovered the β-stabilization of the ion temperature gradient mode, transition to collisionless trapped electron mode, and the onset of kinetic ballooning mode as βe (ratio of electron kinetic pressure to magnetic pressure) increases.

Electromagnetic waves and electron anisotropies downstream of supercritical interplanetary shocks

We present waveform observations of electromagnetic lower hybrid and whistler waves with fci ≪ f < fce downstream of four supercritical interplanetary shocks using the Wind search coil magnetometer. The whistler waves were observed to have a weak positive correlation between δB and normalized heat flux magnitude and an inverse correlation with Teh/Tec. All were observed simultaneous with electron distributions satisfying the whistler heat flux instability threshold and most with T⊥ h/T∥ h > 1.01. Thus, the whistler mode waves appear to be driven by a heat flux instability and cause perpendicular heating of the halo electrons. The lower hybrid waves show a much weaker correlation between δB and normalized heat flux magnitude and are often observed near magnetic field gradients. A third type of event shows fluctuations consistent with a mixture of both lower hybrid and whistler mode waves. These results suggest that whistler waves may indeed be regulating the electron heat flux and the halo temperature anisotropy, which is important for theories and simulations of electron distribution evolution from the Sun to the Earth.

Spontaneous hot flow anomalies at quasi‐parallel shocks: 2. Hybrid simulations

AbstractMotivated by recent THEMIS observations, this paper uses 2.5‐D electromagnetic hybrid simulations to investigate the formation of Spontaneous Hot Flow Anomalies (SHFAs) upstream of quasi‐parallel bow shocks during steady solar wind conditions and in the absence of discontinuities. The results show the formation of a large number of structures along and upstream of the quasi‐parallel bow shock. Their outer edges exhibit density and magnetic field enhancements, while their cores exhibit drops in density, magnetic field, solar wind velocity, and enhancements in ion temperature. Using virtual spacecraft in the simulation, we show that the signatures of these structures in the time series data are very similar to those of SHFAs seen in THEMIS data and conclude that they correspond to SHFAs. Examination of the simulation data shows that SHFAs form as the result of foreshock cavitons interacting with the bow shock. Foreshock cavitons in turn form due to the nonlinear evolution of ULF waves generated by the interaction of the solar wind with the backstreaming ions. Because foreshock cavitons are an inherent part of the shock dissipation process, the formation of SHFAs is also an inherent part of the dissipation process leading to a highly nonuniform plasma in the quasi‐parallel magnetosheath including large‐scale density and magnetic field cavities.

Microstructure and metal–dielectric transition behaviour in a percolative Al2O3–Fe composite via selective reduction

The electromagnetic (EM) medium plays a key role in many areas, such as communications, stealth technology, etc. Different EM properties are required for different applications. In this paper, we have obtained tunable EM properties in an Al2O3–Fe composite via selective reduction. By adjusting the content of one functional component, the composite shows totally different EM properties, in accordance with the predictions of effective medium theory. Hybrid EM behaviour is obtained near the percolation threshold, which has a close relationship with its microstructure.

Optimal control of an electromagnetic power-split hybrid electric vehicle

A new electromagnetic power-split hybrid electric vehicle is introduced in this paper. This system, which has a dual-rotor brush motor, was developed with the aim of combining all the advantages of an internal-combustion engine and two electric motors in an optimal way so as to improve the power performance and the fuel economy. This system can be used as an electromagnetic, continuously variable transmission. The architecture and analogy of the electromagnetic power-split hybrid electric vehicle are analysed; a control strategy is designed and explained in detail. The system’s optimal zone is designed. To evaluate the performance and the control strategy, the tests were performed on the chassis dynamometer under the New European Driving Cycle. The economic performance of the electromagnetic power-split hybrid electric vehicle is analysed. The operational zones of the engines of an electromagnetic power-split hybrid electric vehicle and of a conventional vehicle were compared. The results indicate that the designed vehicle control strategy of the electromagnetic power-split hybrid electric vehicle worked properly under the New European Driving Cycle and that the engine worked in the optimized zone. The average fuel consumption under the New European Driving Cycle is 4.75 l/100 km; the saved petrol ratio is 41.3% compared with that of the related prototype vehicle.

Design and test of an adaptive vibration absorber based on magnetorheological elastomers and a hybrid electromagnet

The focuses of this study are to design an adaptive-tuned vibration absorber based on a smart materials known as magnetorheological elastomers and to test its dynamic performance. A primary system replicating a miniature cryogenic cooler (i.e. mass and shape) was designed and fabricated in order to test the effectiveness of the vibration absorber. A hybrid magnetic system (electromagnet and permanent magnets) was also designed and fabricated in order to actuate the magnetorheological elastomers as an adaptive stiffness element in the vibration absorber. The vibration testing was conducted on both the primary system and vibration absorber individually in order to characterize the behavior and verify the design constraints. Further testing was performed on a 2-degrees-of-freedom system to measure and assess the feasibility of the magnetorheological elastomer material for use in an application requiring an adaptive vibration absorber. The results show that by using a hybrid design for the electromagnet within the vibration absorber, the stiffness of the magnetorheological elastomer material can be increased and decreased above its nominal value, therefore demonstrating the feasibility of this design as an alternative adaptive vibration absorber.

Flow stagnation at Enceladus: The effects of neutral gas and charged dust

Enceladus is one of Saturn's most active moons. It ejects neutral gas and dust particles from its southern plumes with velocities of hundreds of meters per second. The interaction between the ejected material and the corotating plasma in Saturn's magnetosphere leads to flow deceleration in ways that remain to be understood. The most effective mechanism for the interaction between the corotating plasma and the neutral gas is charge exchange which replaces the hotter corotating ions with nearly stationary cold ions that are subsequently accelerated by the motional electric field. Dust particles in the plume can become electrically charged through electron absorption and couple to the plasma through the motional electric field. The objective of this study is to determine the level of flow deceleration associated with each of these processes using Cassini RPWS dust impact rates, Cassini Plasma Spectrometer (CAPS) plasma data, and 3‐D electromagnetic hybrid (kinetic ions, fluid electrons) simulations. Hybrid simulations show that the degree of flow deceleration by charged dust varies considerably with the spatial distribution of dust particles. Based on the RPWS observations of dust impacts during the E7 Cassini flyby of Enceladus, we have constructed a dust model consisting of multiple plumes. Using this model in the hybrid simulation shows that when the dust density is high enough for complete absorption of electrons at the point of maximum dust density, the corotating flow is decelerated by only a few km/s. This is not sufficient to account for the CAPS observation of flow stagnation in the interaction region. On the other hand, charge exchange with neutral gas plumes similar to the modeled dust plumes but with base (plume opening) densities of ∼109 cm−3 result in flow deceleration similar to that observed by CAPS. The results indicate that charge exchange with neutral gas is the dominant mechanism for flow deceleration at Enceladus.

Application of a total variation diminishing scheme to electromagnetic hybrid particle-in-cell plasma simulation

A discretization procedure for a total variation diminishing (TVD) scheme is introduced to an electromagnetic hybrid particle-in-cell (PIC) plasma simulation code in order to improve the numerical stability and resolution when calculating the plasma flow field in which magnetic field discontinuities (for example, Rankine–Hugoniot jump conditions for shock waves) are generated. In the hybrid PIC code used in this study, ions are treated as particles and electrons are assumed to be an inertia-less (mass-less) fluid. In the numerical results of one-dimensional test simulations, the TVD scheme significantly prevents non-physical, numerical oscillations, which would ordinarily be produced in the solution when the convection term of the magnetic induction equation in the hybrid PIC code is discretized by central difference schemes at magnetic field discontinuities. Furthermore, a two-dimensional simulation of the global structure of a collision-less bow shock, which is suitable for practical use, makes it possible to clearly capture the bow shock by using the hybrid PIC code with the TVD scheme.

Dynamic Multiscale Quantum Mechanics/Electromagnetics Simulation Method.

A newly developed hybrid quantum mechanics and electromagnetics (QM/EM) method [Yam et al. Phys. Chem. Chem. Phys.2011, 13, 14365] is generalized to simulate the real time dynamics. Instead of the electric and magnetic fields, the scalar and vector potentials are used to integrate Maxwell's equations in the time domain. The TDDFT-NEGF-EOM method [Zheng et al. Phys. Rev. B2007, 75, 195127] is employed to simulate the electronic dynamics in the quantum mechanical region. By allowing the penetration of a classical electromagnetic wave into the quantum mechanical region, the electromagnetic wave for the entire simulating region can be determined consistently by solving Maxwell's equations. The transient potential distributions and current density at the interface between quantum mechanical and classical regions are employed as the boundary conditions for the quantum mechanical and electromagnetic simulations, respectively. Charge distribution, current density, and potentials at different temporal steps and spatial scales are integrated seamlessly within a unified computational framework.