Relevant bibliographies by topics / Transient electromagnetic fields

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
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Academic literature on the topic 'Transient electromagnetic fields'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Transient electromagnetic fields"

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Zhdanov, M. S., M. A. Frenkel, and A. I. Katsevich. "Interpolation method for transient electromagnetic fields." Il Nuovo Cimento C 12, no. 5 (September 1989): 555–65. http://dx.doi.org/10.1007/bf02508015.

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Grcev, L. D., and F. E. Menter. "Transient electromagnetic fields near large earthing systems." IEEE Transactions on Magnetics 32, no. 3 (May 1996): 1525–28. http://dx.doi.org/10.1109/20.497540.

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Skotte, JH. "Exposure to high-frequency transient electromagnetic fields." Scandinavian Journal of Work, Environment & Health 22, no. 1 (February 1996): 39–44. http://dx.doi.org/10.5271/sjweh.107.

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Hoole, P. Ratnamahilan P., and S. Ratnajeevan H. Hoole. "Computing transient electromagnetic fields radiated from lightning." Journal of Applied Physics 61, no. 8 (April 15, 1987): 3473–75. http://dx.doi.org/10.1063/1.338760.

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Dariescu, Marina-Aura, Ciprian Dariescu, and Ovidiu Buhucianu. "Charged Scalars in Transient Stellar Electromagnetic Fields." Chinese Physics Letters 28, no. 1 (January 2011): 010303. http://dx.doi.org/10.1088/0256-307x/28/1/010303.

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de Hoop, Adrianus T., Michael L. Oristaglio, Tarek M. Habashy, and Carlos Torres-Verdin. "Asymptotic ray theory for transient diffusive electromagnetic fields." Radio Science 31, no. 1 (January 1996): 41–49. http://dx.doi.org/10.1029/95rs02593.

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Wait, James R., and I. R. Qureshi. "Transient Electromagnetic Fields for a Polarized Conductive Sheet." Exploration Geophysics 20, no. 4 (September 1989): 487–89. http://dx.doi.org/10.1071/eg989487.

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Tzeng, Jerome T., and Kou-Ta Hsieh. "Electromagnetic analysis of composite structures subjected to transient magnetic fields." Journal of Composite Materials 54, no. 6 (August 9, 2019): 745–52. http://dx.doi.org/10.1177/0021998319868005.

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When carbon composites are exposed to a transient electromagnetic field, a rapid temperature increase can be observed due to joule heating from magnetic induction. The electromagnetic induction heating and heat transfer in the composite are anisotropic and concentrated upon the carbon fiber orientation and distribution. In addition, the strength and frequency of transient electromagnetic fields have great influence on the final quality of the composite. A computational model has been developed by solving coupled Maxwell’s and heat transfer equations. The analysis accounts for the three-dimensional transient electromagnetic field and electrical conductivity of the composite material. This paper will illustrate the derived formulation and numerical solution based on finite element methods. The developed code is validated with a 2D closed-form solution. Numerical simulations of a cylinder and a flat laminated plate are conducted to illustrate the computational capability. The induction heating for composite manufacture is also discussed for current Army’s applications.
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Swidinsky, Andrei, and Misac Nabighian. "Transient electromagnetic fields of a buried horizontal magnetic dipole." GEOPHYSICS 81, no. 6 (November 1, 2016): E481—E491. http://dx.doi.org/10.1190/geo2016-0136.1.

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Electromagnetic surveys using a vertical transmitter loop are common in land, marine, and airborne geophysical exploration. Most of these horizontal magnetic dipole (HMD) systems operate in the frequency domain, measuring the time derivative of the induced magnetic fields, and therefore a majority of studies have focused on this subset of field measurements. We examine the time-domain electromagnetic response of a HMD including the electric fields and corresponding smoke rings produced in a conductive half-space. Cases of a dipole at the surface and buried within the earth are considered. Results indicate that when the current in the transmitter is rapidly switched off, a single smoke ring is produced within the plane of the vertical transmitter loop, which is then distorted by the air-earth interface. In this situation, the circular smoke ring, which would normally diffuse symmetrically away from the source in a whole space, is approximately transformed into an ellipse, with a vertical major axis at an early time and a horizontal major axis at a late time. As measured from the location of the transmitter, the depth of investigation and lateral footprint of such a system increases with burial depth. It is also observed that the electric field measured in the direction of the magnetic dipole only contains a secondary response related to the charge accumulation on any horizontal conductivity boundaries because the primary field is always absent. This field component can be expressed analytically in terms of a static and time-varying field, the latter term adding spatial complexity to the total horizontal electric field at the earth surface at early times. Applications of this theoretical study include the design of time-domain induction-logging tools, crossborehole electromagnetic surveys, underground mine expansion work, mine rescue procedures, and novel marine electromagnetic experiments.
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Ignetik, Rainer. "Asymptotic representation of transient electromagnetic fields in geophysical prospecting." Bulletin of the Australian Mathematical Society 47, no. 3 (June 1993): 523–24. http://dx.doi.org/10.1017/s0004972700015343.

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Dissertations / Theses on the topic "Transient electromagnetic fields"

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Barbieri, Nicholas. "MEASUREMENT AND CHARACTERIZATION OF MICROWAVE TRANSIENT ELECTROMAGNETIC FIELDS GENERATED FROM LASER/MATTER INTERACTION." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3417.

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From past experiments conducted with high intensity lasers, it has been known for some time that laser matter interactions result in the emission of short, transient electromagnetic pulses. Previous investigations into laser generated electromagnetic pulses provide basic information regarding frequencies where such pulses may be present, along with the time duration of the pulses. Such investigations have also demonstrated a number of measurement techniques in which basic information on the pulses may be obtained. The purpose of this current investigation is to obtain a more thorough description and understands of electromagnetic pulses generated for laser matter interaction. To this end, spatial radiation patterns emanating from various laser excited matter sources was predicted using antenna theory for far field radiators. Experimentally, it is the intention of this investigation to gather comprehensive time and frequency domain data on laser matter generated electromagnetic pulses using a number of specific laser targets. Radiation detection techniques using broadband, calibrated EMC horn antennas were devised. A unique measurement system known as an inverse superhetereodyne receiver was designed, tested and demonstrated. An experimental setup using such instrumentation was established. Using the above instrumentation and experimental setup should yield comprehensive time and frequency domain data over a spectra range of 1-40 GHz and with a time resolution of 50 ps. Because the experimental system employed is calibrated, measurements can be corresponded to incident electromagnetic fields. Several tests were conducted to ensure the proper operation of experimental apparatus. A modulation test was conducted on the inverse superhetereodyne receiver to ensure that the experimentally observed signals appeared when and where predicted within the receiver's bandwidth. The experimental setup was used to measure radiation emitted from an electrostatic discharge source of known distance and discharge voltage. Frequency domain data from the discharges were collected and compiled using a Matlab application ultimately intended to measure laser matter interaction generated electromagnetic pulses, resulting in a compiled frequency domain description comprising 1-17 GHz. The inverse Fourier transform was used to retrieve the time domain response from the compiled data. The discharge gaps characteristics where systematically altered as to allow a parametric study of the compiled data. The discharge measurements demonstrate the measurement system's ability to analyze unknown, short duration; broadband microwave signals.
M.S.
Department of Physics
Arts and Sciences
Physics
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Pao, Hsueh-yuan 1954. "ELECTROMAGNETIC SCATTERING FROM A BRANCH LINE IN A PARALLEL PLATE WAVEGUIDE (METHOD OF MOMENTS, TRANSIENT FIELDS)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276837.

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Malecki, Stephan, Ralph-Uwe Börner, and Klaus Spitzer. "Absolute Positionierung unter Tage mittels transientelektromagnetischer Felder." Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-206635.

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Die dreidimensionale Positionsbestimmung unter Tage ist eine in der bergbautechnischen Praxis häufig gestellte Aufgabe. Die derzeit gebräuchlichen Verfahren basieren überwiegend auf zahlreichen relativen Messungen zwischen Festpunkten an der Erdoberfläche und dem zu bestimmenden Punkt unter Tage. Das hier vorgestellte Verfahren ist ein im geodätischen Sinn absolutes Verfahren. Die Punktbestimmung erfolgt direkt mit Hilfe der Festpunkte über Tage und dem unbekannten Punkt unter Tage. Relative Messungen zu benachbarten Punkten sind nicht notwendig. Die Grundlage des Verfahrens bildet die zeitliche Erfassung transienter elektromagnetischer Felder an einem zu bestimmenden Punkt unter Tage. Die Quellen dieser Felder sind gleichstromdurchflossene Drahtschleifen an der Erdoberfläche, die näherungsweise magnetische Dipole darstellen. Nach Abschalten des Stromes zerfällt das statische Magnetfeld und induziert elektrische Ströme in der leitfähigen Erde. Das transiente Magnetfeld wird unter Tage an einem Punkt für verschiedene Senderpositionen aufgezeichnet. Mit Hilfe eines Inversionsalgorithmus werden letztlich die dreidimensionalen Koordinaten des Messpunktes bestimmt
Three-dimensional positioning in mines and caves is a common challenge. The methods currently used are based on numerous relative measurements. The method presented here is an absolute procedure in a geodesic sense. The coordinates of the unknown point are directly calculated using the surface points and the point underground. Relative measurements to neighboring points are not necessary. The localization procedure is based on recording transient electromagnetic fields under-ground. They are generated at the surface using direct-current carrying wire loops, which approximately represent magnetic dipoles. After shutoff the static magnetic field decays and induces electric currents in the conductive Earth. The transient electromagnetic field is recorded at an unknown point in the subsurface for different source positions. Finally, the three-dimensional coordinates of this point are reconstructed using an inversion algorithm
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Foteinopoulou, Stavroula. "Electromagnetic Wave Propagation in Two-Dimensional Photonic Crystals." Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/822058-9BqHHS/native/.

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Thesis (Ph.D.); Submitted to Iowa State Univ., Ames, IA (US); 12 Dec 2003.
Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2048" Stavroula Foteinopoulou. 12/12/2003. Report is also available in paper and microfiche from NTIS.
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Sun, Zhishen. "Application of Lorentz Force in Ultrasound-electromagnetic-field-coupled Electrical Impedance Tomography and Elastography." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1261.

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La première partie de la thèse étudie le balayage des gradients de conductivité électrique avec la force de Lorentz induite par ultrasons (SECG-UILF). Pour réduire la puissance de stimulation instantanée du transducteur émetteur et en même temps la pression acoustique maximale du transducteur, cette thèse propose d'appliquer l'excitation de l'impulsion ultrasonore à la modulation de fréquence linéaire ou l'excitation de l'impulsion ultrasonore à fréquence sinusoïdale dans SECG-UILF. Pour les gradients de conductivité électrique à balayage avec la force de Lorentz induite par l’ultrasons à la modulation de fréquence linéaire (SECG-LFM-UILF), un signal électrique de puissance instantanée maximale de 39,54 dBm est utilisé pour exciter le transducteur de transmission, ce qui est inférieur de 25,5 dB à la puissance instantanée maximale de l'impulsion étroite haute tension négative (65,05 dBm) adopté dans le SECG-UILF traditionnel. Et en temps, la pression acoustique d'émission maximale dans le SECG-LFM-UILF est inférieure de 0,44 MPa à celle du SECG-UILF traditionnel. Des expériences de SECG-LFM-UILF sont effectuées en utilisant des fantômes de conductivité à la gélose saline à plusieurs formes de conductivité allant de 0,2 S/m à 0,5 S/m, ce qui montre que: (1) le SECG-LFM-UILF peut détecter avec précision la distance longitudinale des gradients de conductivité électrique; (2) le rapport signal sur bruit des images de balayage B reconstituées de la distribution de gradient de conductivité électrique par le SECG-LFM-UILF est comparable à celui obtenu par le biais du SECG-UILF traditionnel; et (3) en utilisant une largeur de bande de fréquence de modulation de 2 MHz et une durée de modulation de 500 μs, une résolution longitudinale de 1 mm est obtenue. Pour balayer des gradients de conductivité électrique avec une force de Lorentz induite par ultrasons à fréquence fréquentielle (SECG-SF-UILF), le schéma de démodulation en phase présente une implémentation matérielle plus simple que le schéma de démodulation IQ, mais ne peut détecter que la moitié de la plage longitudinale. Des expériences de SECG-SF-UILF sont effectuées sur un échantillon de feuille de cuivre à deux couches, qui démontrent qu’en utilisant une largeur de bande de fréquences de 2 MHz et 64 fréquences discrètes, la plage longitudinale de l’échantillon peut être détectée avec précision. La deuxième partie de la thèse étudie l'élastographie à base d'approche de corrélation croisée. Pour élargir la largeur de bande de fréquence du champ de déplacement de l’onde de cisaillement afin d’améliorer la qualité de la carte de vitesse de l’onde de cisaillement, cette partie étudie l’application de la force de Lorentz pour la génération de champs d’onde de cisaillement. Tout d'abord, la génération des sources des ondes de cisaillement sur la surface du support souple à travers le mécanisme de la force de Lorentz est étudiée en stimulant un anneau ou un patch conducteur non ferromagnétique avec un champ magnétique transitoire. La mesure de déplacement à l'aide d'une sonde laser interférométrique confirme les caractéristiques d'origine, de fréquence et d'amplitude de la force de Lorentz. Sous un champ magnétique transitoire dont la vitesse de changement est de 10,44 kTs-1, le patch génère une source de champ des ondes de cisaillement d'amplitude de 100 µm à la surface de l'échantillon de fantôme d'alcool polyvinylique (PVA). Ensuite, le potentiel des champs d'ondes de cisaillement générés pour la reconstruction de la vitesse des ondes de cisaillement basée sur la corrélation croisée est exploré. Sur la base de l’approche de corrélation croisée, les cartes qualitatives de la vitesse des ondes de cisaillement sont reconstruites à partir de 100 cadres des champs de déplacement, à partir desquels les interfaces ou les limites entre des régions de rigidité différente peuvent être clairement reconnues, lesquelles sont complètement dissimulées dans les images ultrasonores
The first part of the thesis studies the scanning electric conductivity gradients with ultrasonically induced Lorentz force (SECG-UILF). To reduce the instantaneous stimulation power to the transmitting transducer and at the same time the peak acoustic pressure from the transducer, this thesis proposes to apply the linearly frequency-modulated ultrasound pulse excitation or the sinusoidal step-frequency ultrasound pulse excitation in SECG-UILF. For the scanning electric conductivity gradients with linearly frequency-modulated ultrasound-induced Lorentz force (SECG-LFM-UILF), electrical signal of peak instantaneous power of 39.54 dBm is used to excite the transmitting transducer, which is 25.5 dB lower than the peak instantaneous power of the negative high-voltage narrow pulse (65.05 dBm) adopted in traditional SECG-UILF; and at the same time, the peak transmitting acoustic pressure in SECG-LFM-UILF is 0.44 MPa lower than that in traditional SECG-UILF. Experiments of SECG-LFM-UILF are done using multi-shaped saline agar phantoms of conductivity ranging from 0.2 S/m to 0.5 S/m, which show that: (1) the SECG-LFM-UILF can detect precisely the longitudinal distance of the electric conductivity gradients; (2) the signal-to-noise ratio of the reconstructed B-scan images of the electrical conductivity gradient distribution by the SECG-LFM-UILF are comparable to that obtained through the traditional SECG-UILF; and (3) using modulation frequency bandwidth of 2 MHz and modulation duration of 500 μs, a longitudinal resolution of 1 mm is achieved. For the scanning electric conductivity gradients with step-frequency ultrasound induced Lorentz force (SECG-SF-UILF), the in-phase demodulation scheme is simpler in hardware implementation than the IQ demodulation scheme but can only detect half of the longitudinal range. Experiments of SECG-SF-UILF are done on a sample of two-layer copper foil, which demonstrate that, using a frequency bandwidth of 2 MHz and 64 discrete frequencies, the longitudinal range of the sample can be detected precisely. The second part of the thesis studies the cross-correlation approach based elastography. To expand the frequency bandwidth of the shear wave displacement field so as to improve the quality of the shear wave velocity map, this part studies application of the Lorentz force for generation of shear wave fields. First, generation of shear wave sources on the soft medium surface through the mechanism of the Lorentz force is investigated by stimulating a non-ferromagnetic conductive ring or patch with a transient magnetic field. The origin and the frequency and amplitude characteristics of the Lorentz force acting on the conductive ring are confirmed by the displacement measurement using an interferometric laser probe. Under a transient magnetic field of changing rate of 10.44 kTs-1, the patch generates a shear wave field source of amplitude of 100 μm at the surface of the sample of polyvinyl alcohol (PVA) phantom. The shear wave fields created and propagating in the PVA phantom by experiments agree qualitatively well with the theoretical shear wave fields calculated through the analytical Green function solution. Then, the potential of the generated shear wave fields for the cross-correlation based shear wave velocity reconstruction is explored. Based on the cross-correlation approach, the qualitative shear wave velocity maps are reconstructed from 100 frames of the displacement fields, from which the interfaces or boundaries between regions of different stiffness can be clearly recognized, which are completely concealed in the ultrasound images
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Gertrudes, João Bosco. "Influência da condutividade e permissividade do solo em função da frequência no cálculo da impedância longitudinal e admitância transversal de linhas aéreas de transmissão." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260993.

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Orientador: Maria Cristina Dias Tavares
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-16T03:57:35Z (GMT). No. of bitstreams: 1 Gertrudes_JoaoBosco_D.pdf: 5500576 bytes, checksum: ef85206048f845d1bff89f7c8948d288 (MD5) Previous issue date: 2010
Resumo: Esta tese tem como objetivo o desenvolvimento de modelos mais precisos para o cálculo de parâmetros elétricos de linhas aéreas de transmissão para estudos de transitórios na faixa de frequência 0 a 2 MHz. Esta faixa de frequência cobre a maioria das perturbações eletromagnéticas nos sistemas elétricos: energização, faltas simétricas e assimétricas, rejeições de carga, descargas atmosféricas, perturbações harmônicas, etc. Na faixa de frequência citada, em consequência da dependência dos parâmetros do solo com a frequência, a condutividade elétrica do solo (sg) tem a mesma ordem de grandeza que o produto entre a frequência angular do sinal incidente no solo (w) e a permissividade elétrica do solo (eg). Portanto, as suposições de baixa frequência tradicionalmente adotadas - sg constante e weg desprezível (sg >> weg) - podem levar a modelos que não representam de forma adequada a resposta da linha no caso de transitórios rápidos (com espectro de frequência acima de 1 kHz). O objetivo central desta tese é verificar a influência da dependência dos parâmetros do solo no cálculo da impedância longitudinal e admitância transversal por unidade de comprimento em comparação com os modelos tradicionais de cálculo. As análises são feitas inicialmente para o caso de um único condutor acima do solo e posteriormente através de um estudo para uma linha de transmissão trifásica, 440 kV, em operação no sistema elétrico brasileiro. As impedâncias longitudinais e as admitâncias transversais de retorno pelo solo são avaliadas através de métodos tradicionais de cálculo e através de integração numérica das formulações de Carson modificadas para inclusão do modelo de solo que considera a depêndencia de sg e weg em função da frequência
Abstract: This thesis aims to propose more accurate models for calculating the electrical parameters of overhead power transmission lines. The influence of earth's conductivity and permittivity frequency dependence is evaluated when calculating transversal and longitudinal transmission lines' parameters in the frequency range 0 to 2 MHz. This frequency range covers the majority of the electromagnetic transients in electrical systems (switching transients, faults' transients, load rejections, harmonic disturbances, etc). Between 1 kHz to 2 MHz, the product of the signal angular frequency (w) by the dielectric constant (eg) of the soil may have the same order of magnitude as the conductivity (sg), due to the variation of these parameters with frequency. Therefore, the assumptions of low frequency traditionally used - the soil conductivity (sg) considered as constant and weg that can be negligible (sg >> weg) - can lead to incorrect models that do not adequately represent the transmission line's response, in cases of fast transients phenomena (with frequency spectrum above 1 kHz). The importance of properly considering the frequency dependent soil model is presented for the one-conductor case and for a single three-phase transmission line (440 kV, considered ideally transposed). The aim is to compare the transmission line parameters calculated considering the conductivity and weg frequency dependence ground model in relation to the common ground representation, with constant conductivity and weg that may be neglected. It is also compared the results obtained from the complex plane method with those obtained from the Carson's modified expressions for longitudinal parameters and between Carson's modified potential-coefficient correction factors and from the most common approximated methods for transversal admittance parameters
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica
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Romero, Fabio. "Avaliação do Comportamento dos Campos Eletromagnéticos Gerados por Descargas Atmosféricas Nuvem-Terra." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-26032007-162159/.

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As descargas atmosféricas são reconhecidamente responsáveis por uma parcela expressiva das interrupções não programadas de fornecimento de energia em sistemas elétricos, contribuindo de forma significativa para a composição dos índices de qualidade de energia mesmo no caso de regiões com níveis ceráunicos moderados. No caso de sistemas de distribuição, grande parte dos problemas está relacionada às sobretensões induzidas por descargas próximas às linhas, as quais decorrem dos campos elétrico e magnético, associados à corrente que se propaga ao longo do canal da descarga. O conhecimento das características de tais campos é, portanto, fundamental para a determinação das sobretensões induzidas nas linhas aéreas de energia. Embora a importância do tema tenha propiciado nos últimos anos o desenvolvimento de um grande número de pesquisas a respeito dos campos eletromagnéticos e das tensões induzidas por descargas atmosféricas, na grande maioria dos trabalhos o solo é representado através de um plano condutor perfeito, portanto com condutividade infinita. Embora tal simplificação possa, em geral, ser considerada válida para a indução magnética e para o campo elétrico vertical, ela não é aplicável ao campo elétrico horizontal, em especial no caso de solos com alta resistividade. Este estudo visa avaliar o comportamento dos campos elétrico (vertical e horizontal) e indução magnética gerados por descargas atmosféricas nuvem-terra, levando em consideração os parâmetros da descarga (amplitude, forma de onda e velocidade de propagação da corrente) e os diferentes modelos para representação do canal da descarga. Além do caso de solo perfeitamente condutor, são consideradas situações mais realistas, isto é, verificando-se a influência, nos campos, de parâmetros como a resistividade e permissividade do solo.
The occurrence of lightning discharges causes a significant amount of unscheduled supply interruptions in overhead lines of electricity systems, contributing to decrease quality indicators of these systems, even in the case of regions with moderated ground flash density. Focusing on the distribution systems, great part of the problems are related to the induced voltages due to lightning discharges in the vicinity of overhead lines, which results from the electric and magnetic fields associated with the current propagation along the return stroke channel. The knowledge of the characteristics of lightning electromagnetic fields is, therefore, crutial for determining induced voltages on overhead lines. Although the importance of the assumption has propitiated in the last years the development of a great number of research concerning the lightning electromagnetic fields and induced voltages on overhead lines, in most of the studies the hypothesis of a perfect conducting ground is assumed. While such assumption can be considered valid for magnetic induction field and for the vertical component of the electric field, it doesn’t apply to the horizontal electric field, especially in the case of ground with high resistivity. The aim of this work is to present and to discuss the characteristics of the electric field (vertical and horizontal components) and magnetic induction generated by the cloud-to-ground lightning discharge, taking into account the lightning parameters (amplitude, waveform and propagation speed of the return stroke current) and the different return stroke models. Besides the case of perfect conducting ground, the influences of the ground permittivity and finite conductivity in the calculation of the electromagnetic fields are so considered.
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Daněk, Michal. "Simulace toroidních cívek v Ansoft Maxwell 3D." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218197.

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The master thesis is focused on the simulation of the toroid coils in Ansoft Maxwell 3D software, which uses finite element method for electromagnetic field simulation. Firstly the process creation of the geometric model toroid coil with seventy-five threaded is presented. It is necessary to debug this model and prepare it for the mesh generation. Physical properties are assign to this model and it gives rise to the physical model. We will set boundaries, excitation current, core material, winding material and the parameters for the mesh generations. New material Kashke K4000 will be created in the materials library and subsequently we will define its BH curve on the basis of datasheet. Analysis is made in two modes. Direct currents (7,5A; 10A; 15A; 20A; 25A) and (non)linear materials are used in magnetostatic solution. Toroid coil is excited by current pulse in transient solution. In Ansoft Maxwell Circuit editor a source which generates current pulse will be created. This excitation will be assigned to the toroid coil as an extern source through a terminal. Core material is linear in the case of transient analysis, because Ansoft Maxwell 3D doesn´t allow to use nonlinear material in this solution. Settings are different in transient and in magnetostatic analysis. End time and time step are entered to solve this task in transient analysis. Time points are entered too. Flux density and electromagnetic field strength are calculated in these time points and later it will be possible to view the results. Calculated fields are shown as the pictures in this thesis. The procedure how to use a field calculator in the postprocessing is given as well. The achievements are summarized in the conclusion.
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Camper, Antoine. "Spectroscopie de phase multi-dimensionnelle de l'émission attoseconde moléculaire." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112024/document.

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Une molécule soumise à un champ laser infra-rouge intense (dans la gamme des 10 14 W.cm−2) peut être ionisée par effet tunnel. Le paquet d’ondes électroniques (POE) ainsi libéré est alors accéléré par le champ laser et, lorsqu’il repasse à proximité de l’ion parent, il a une certaine probabilité de se recombiner dans son état fondamental. Lors de cette recombinaison, le POE libère son énergie sous la forme d’un flash attoseconde (1as=10 −18s) de rayons XUV. Cette émission cohérente est produite à chaque demi-cycle laser résultant en un train d’impulsions attosecondes. Dans le domaine spectral, ce train correspond à un spectre discret d’harmoniques de la fréquence lasers. L’étape de recombinaison de l’électron avec l’ion parent peut être considérée comme une sonde de la structure des orbitales de valence moléculaires participant à la génération d’harmoniques et de la dynamique ayant lieu dans l’ion pendant l’excursion de l’électron dans le continuum. En caractérisant en amplitude, phase et polarisation, l’émission harmonique associée à cette recombinaison, il est possible de remonter à ces informations structurales et dynamiques avec une précision de l’ordre de l’Ångström et une résolution attoseconde. En particulier, la phase de l’émission harmonique qui est difficile à caractériser, encode des informations indispensables à la bonne compréhension des processus ayant lieu dans le milieu de génération. Nous présentons les principes et testons de nouvelles techniques permet tant de caractériser la phase de l’émission attoseconde suivant plusieurs dimensions à la fois et dans un laps de temps optimisé. Dans une première partie, nous présentons une méthode permettant de caractériser rapidement la phase spectrale de l’émission harmonique, fondée sur un modèle en champ fort de la photoionisation à deux couleurs (RABBIT). Nous introduisons ensuite une nouveau dispositif interférométrique à deux sources, permettant de mesurer les variations de phase de l’émission attoseconde induites par l’excitation d’un paquet d’ondes rotationnelles ou vibrationnelles. Ce dispositif très stable, compact et sobre énergétiquement repose sur l’utilisation d’un élément optique de diffraction (DOE) binaire. Après avoir qualifié notre dispositif par des simulations numériques et des expériences préliminaires, nous montrons qu’il est si sensible qu’il permet de mesurer les variations de phase en fonction du paramètre d’excitation pour différentes trajectoires électroniques dans le continuum. Pour l’azote et le dioxyde de carbone, les mesures expérimentales montrent des variations de phase très différentes pour les deux premières trajectoires électroniques. Ce DOE est ensuite utilisé pour mesurer la phase de l’émission harmonique dans les molécules alignées dans les mêmes conditions expérimentales que le RABBIT. Les deux expériences menées successivement donnent des résultats compatibles que nous combinons par deux méthodes différentes : le CHASSEUR et le MAMMOTH. Enfin, nous proposons de combiner le DOE avec un réseau transitoire pour caractériser simultanément la phase de l'émission attoseconde moléculaire suivant deux axes de polarisation différents. Ces différentes techniques de mesure de phase nous ont permis d’étudier précisément l’émission harmonique suivant différentes dimensions (angle d’alignement, intensité de génération, trajectoire électronique) et d’en tirer de nouvelles informations sur le mécanisme de génération dans les molécules
When a low-frequency laser pulse is focused to a high intensity into a gas, the electric field of the laser light may become of comparable strength to that felt by the electrons bound in an atom or molecule. A valence electron can then be 'freed' by tunnel ionization, accelerated by the strong oscillating laser field and can eventually recollide and recombine with the ion. The gained kinetic energy is then released as a burst of coherent XUV light which is spectrally organized as harmonics of the fundamental driving field frequency.In high-harmonic molecular spectroscopy, the recombining electron wave-packet probes the structure of the molecule and the dynamics occurring in the ion left after tunnel ionization. The XUV burst is imprinted with this information which can be retrieved through an accurate characterization of the amplitude, phase and polarization of the harmonics. In the case of small molecules as nitrogen and carbon dioxide, impulsive alignment allows to change the direction of recombination of the electron wave-packet with respect to the molecular axis. The XUV burst from the molecular sample should then be characterized both along the spectral dimension and the alignment angle one, and this for the two polarization components. In this report, we present a new experimental scheme to perform two-source interferometry to measure the phase of the emission in aligned molecules along the alignment angle dimension. We how a refined spatio-spectral analysis of the fringe patterns obtained with this very stable interferometer allows one to extend high-harmonic spectroscopy from short to long trajectories. We then show how the combination of this setup together with RABBIT gives access to a bidimensionnal (spectrum and alignment angle) phase map with no arbitrary constant. Finally comparing two-source interferometry with transient grating spectroscopy leads to inconsistent results that can be interpreted taking into consideration polarization effects
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Gharagozloo, Pooya. "Power transmission lines transient electromagnetic fields-a study of scale modeling and the effects of ground loss." 2012. http://hdl.handle.net/1993/5267.

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In this thesis, the problem of calculating power transmission line induced or radiated electromagnetic fíelds is studied by decomposing the line into a large number of snall segments, k¡own as Hertzian dipoles. Since the presence of lossy ground makes the electromagnetic fìeld distribution very different from that of the same dipole over perfectly conducting ground, different approaches should be followed for the lossy and lossless ground assumptions. The contribution of each dipole on the total electric and magnetic field is calculated using three analytical techniques. Two of these methods are frequency-domain solutions for the problem of dipole radiation above lossy ground, while the third method is a time-domain exact solution for the same problem based on the assumption of perfectly conducting ground. The theoretical background and extent of validity of each technique are reviewed in this thesis. Tlie results derived by applying each method are compared with those obtained using a commercial software package. The time-domain solution for the problem of power transmission line electromagnetic fields is obtained using Fourier and inverse Fourier transforms, rvhich enables us to obtain the electromagnetic waveforms associated with power system transients. The effect of different parameters such as conductivity and relative permittivity of the ground, the line{o-observation point distance, height, and sag of the transmission line is studied. Further, the impact of downscaling of transmission line on different electromagnetic parameters is analyzed, and the appropriate scale factor for each parameter is derived.
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Books on the topic "Transient electromagnetic fields"

1

Shneerson, G. A. Fields and tra[n]sients in superhigh pulse current device. New York: Nova Science Publishers, 1997.

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Goldberg, Robert B. Safety of high speed guided ground transportation systems: An overview of biological effects and mechanisms relevant to EMF exposures from mass transit and electric rail systems. Washington, D.C: U.S. Dept. of Transportation, Federal Railroad Administration, Office of Research and Development, 1993.

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Felsen, L. B. Transient Electromagnetic Fields. Springer, 2013.

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Slob, E. C. Scattering of Transient Diffusive Electromagnetic Fields. Delft Univ Pr, 1994.

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Transient Electromagnetic Fields Produced by Pulsed Moving Conductors. Storming Media, 1999.

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Analysis of Transient Electromagnetic Fields in an Electrical Utility Substation Environment. Delft Univ Pr, 1994.

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Strong And Superstrong Pulsed Magnetic Fields Generation. Walter de Gruyter, 2012.

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M, Dietrich Fred, United States. Federal Railroad Administration. Office of Research and Development., Energy Research and Management, Inc., and John A. Volpe National Transportation Systems Center (U.S.), eds. Safety of high speed guided ground transportation systems: Magnetic and electric field testing of the Washington Metropolitan Area Transit Authority Metrorail system. Washington, D.C: U.S. Dept. of Transportation, Federal Railroad Administration, Office of Research and Development, 1993.

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M, Dietrich Fred, Jacobs William L, United States. Federal Railroad Administration. Office of Research and Development., Electric Research and Management, Inc., and John A. Volpe National Transportation Systems Center (U.S.), eds. Safety of high speed guided ground transportation systems: Magnetic and electric field testing of the Washington Metropolitan Area Transit Authority metrorail system. Washington, D.C: U.S. Dept. of Transportation, Federal Railroad Administration, Office of Research and Development, 1993.

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Book chapters on the topic "Transient electromagnetic fields"

1

Namkung, M., B. Wincheski, S. Nath, and J. P. Fulton. "Transient Electromagnetic Fields in Highly Conductive Media." In Review of Progress in Quantitative Nondestructive Evaluation, 523–29. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4791-4_66.

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Krawczyk, Andrzej. "The Use of the Boundary Element Method in Transient Open Boundary Problems." In Electromagnetic Fields in Electrical Engineering, 57–62. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0721-1_11.

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Campostrini, P. P., and A. Stella. "Computer - Aided Modelling and Simulation of Fast Transient Phenomena in Large Coils." In Electromagnetic Fields in Electrical Engineering, 251–56. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0721-1_46.

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Li, Kai. "Exact Transient Field of a Horizontal Electric Dipole on the Boundary Between Two Dielectrics." In Electromagnetic Fields in Stratified Media, 165–201. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-95964-9_8.

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Komçza, K., and S. Wiak. "Errors of Solution of Classical and Variational Finite Difference Method Applied to Transient Electromagnetic Field Analysis." In Electromagnetic Fields in Electrical Engineering, 45–50. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0721-1_9.

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Baum, Carl E. "Producing Large Transient Electromagnetic Fields in a Small Region: An Electromagnetic Implosion." In Ultra-Wideband Short-Pulse Electromagnetics 8, 97–104. New York, NY: Springer New York, 2007. http://dx.doi.org/10.1007/978-0-387-73046-2_14.

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Li, Kai. "Approximate Transient Field of Horizontal Electric Dipole on the Boundary Between a Homogeneous Isotropic Medium and One-Dimensionally Anisotropic Medium." In Electromagnetic Fields in Stratified Media, 203–20. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-95964-9_9.

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Savov, V. N., E. S. Bogdanov, and Zh D. Georgiev. "Analysis of Induction Motors by Coupling of Transient Electromagnetic Field Equations, Circuit Equations and Motion Equations Using Finite Elements Method." In Electric and Magnetic Fields, 147–50. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-1961-4_32.

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Weaver, James C. "Transient Aqueous Pores: A Mechanism for Coupling Electric Fields to Bilayer and Cell Membranes." In Mechanistic Approaches to Interactions of Electric and Electromagnetic Fields with Living Systems, 249–70. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4899-1968-7_15.

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Skulkin, Sergey P., and Victor I. Turchiu. "Transient Fields of Parabolic Reflector Antennas." In Ultra-Wideband, Short-Pulse Electromagnetics 3, 81–87. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4757-6896-1_11.

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Conference papers on the topic "Transient electromagnetic fields"

1

Tijhuis, Anton G. "Computational Techniques for Transient Electromagnetic Fields." In 28th European Microwave Conference, 1998. IEEE, 1998. http://dx.doi.org/10.1109/euma.1998.338058.

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Zhao, Zhibin, Xiang Cui, Tiebing Lu, and Changzheng Gao. "Calculation of the Transient Electromagnetic Fields in Substation." In 2007 International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications. IEEE, 2007. http://dx.doi.org/10.1109/mape.2007.4393772.

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"Transient magnetic fields and currents in residences." In Proceedings of 2001 International Symposium on Electromagnetic Compatibility (EMC 2001). IEEE, 2001. http://dx.doi.org/10.1109/isemc.2001.950611.

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Stuchly, M. A., and S. S. Stuchly. "Measurement techniques for steady-state and transient electromagnetic fields." In Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 1988. http://dx.doi.org/10.1109/iembs.1988.95249.

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Min Tang, Junfa Mao, Xiaochun Li, and Linsheng Wu. "Transient analysis of dispersive transmission lines with incident electromagnetic fields." In 2010 Asia-Pacific International Symposium on Electromagnetic Compatibility. IEEE, 2010. http://dx.doi.org/10.1109/apemc.2010.5475817.

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Ngoly, Adrian, and Steve McFee. "Sparse wavelet approximations to transient space-time electromagnetic wave fields." In 2010 14th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC 2010). IEEE, 2010. http://dx.doi.org/10.1109/cefc.2010.5481282.

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Vogel, M. H., and H. Songoro. "Simulation of transient electromagnetic fields on a finite-element mesh." In Propagation Conference (LAPC). IEEE, 2010. http://dx.doi.org/10.1109/lapc.2010.5666794.

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Celozzi, S., and M. Feliziani. "FEM Analysis of Transient Electromagnetic Fields Coupled to Multiconductor lines." In International Conference on Magnetics. IEEE, 1990. http://dx.doi.org/10.1109/intmag.1990.734356.

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Ametani, Akihiro, and Kazuo Yamamoto. "A study of transient magnetic fields in a wind turbine nacelle." In 2010 Asia-Pacific International Symposium on Electromagnetic Compatibility. IEEE, 2010. http://dx.doi.org/10.1109/apemc.2010.5475560.

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Dong, Xue-he, and Dong-lin Meng. "A Novel Pulse Sensor for Weak Fields of Transient Electromagnetic Pulse." In Proceedings of the 2019 International Conference on Modeling, Analysis, Simulation Technologies and Applications (MASTA 2019). Paris, France: Atlantis Press, 2019. http://dx.doi.org/10.2991/masta-19.2019.31.

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Reports on the topic "Transient electromagnetic fields"

1

Kohlberg, Ira, Alexander Zielinski, and Calvin D. Le. Transient Electromagnetic Fields Produced by Pulsed Moving Conductors. Fort Belvoir, VA: Defense Technical Information Center, April 1999. http://dx.doi.org/10.21236/ada361995.

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Baum, Carl E. A Figure of Merit for Transit-Time-Limited Time-Derivative Electromagnetic Field Sensors. Fort Belvoir, VA: Defense Technical Information Center, January 1993. http://dx.doi.org/10.21236/ada260016.

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