Amplification of a high-frequency electromagnetic wave by a relativistic plasma

NASA Technical Reports Server (NTRS)

Yoon, Peter H.

1990-01-01

The amplification of a high-frequency transverse electromagnetic wave by a relativistic plasma component, via the synchrotron maser process, is studied. The background plasma that supports the transverse wave is considered to be cold, and the energetic component whose density is much smaller than that of the background component has a loss-cone feature in the perpendicular momentum space and a finite field-aligned drift speed. The ratio of the background plasma frequency squared to the electron gyrofrequency squared is taken to be sufficiently larger than unity. Such a parameter regime is relevant to many space and astrophysical situations. A detailed study of the amplification process is carried out over a wide range of physical parameters including the loss-cone index, the ratio of the electron mass energy to the temperature of the energetic component, the field-aligned drift speed, the normalized density, and the wave propagation angle.

Electromagnetic fields with vanishing quantum corrections

NASA Astrophysics Data System (ADS)

Ortaggio, Marcello; Pravda, Vojtěch

2018-04-01

We show that a large class of null electromagnetic fields are immune to any modifications of Maxwell's equations in the form of arbitrary powers and derivatives of the field strength. These are thus exact solutions to virtually any generalized classical electrodynamics containing both non-linear terms and higher derivatives, including, e.g., non-linear electrodynamics as well as QED- and string-motivated effective theories. This result holds not only in a flat or (anti-)de Sitter background, but also in a larger subset of Kundt spacetimes, which allow for the presence of aligned gravitational waves and pure radiation.

A gyrofluid description of Alfvenic turbulence and its parallel electric field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bian, N. H.; Kontar, E. P.

2010-06-15

Anisotropic Alfvenic fluctuations with k{sub ||}/k{sub perpendicular}<<1 remain at frequencies much smaller than the ion cyclotron frequency in the presence of a strong background magnetic field. Based on the simplest truncation of the electromagnetic gyrofluid equations in a homogeneous plasma, a model for the energy cascade produced by Alfvenic turbulence is constructed, which smoothly connects the large magnetohydrodynamics scales and the small 'kinetic' scales. Scaling relations are obtained for the electromagnetic fluctuations, as a function of k{sub perpendicular} and k{sub ||}. Moreover, a particular attention is paid to the spectral structure of the parallel electric field which is produced bymore » Alfvenic turbulence. The reason is the potential implication of this parallel electric field in turbulent acceleration and transport of particles. For electromagnetic turbulence, this issue was raised some time ago in Hasegawa and Mima [J. Geophys. Res. 83, 1117 (1978)].« less

Hadron electric polarizability from lattice QCD

NASA Astrophysics Data System (ADS)

Alexandru, Andrei

2017-09-01

Electromagnetic polarizabilities are important parameters for hadron structure, describing the response of the charge and current distributions inside the hadron to an external electromagnetic field. For most hadrons these quantities are poorly constrained experimentally since they can only be measured indirectly. Lattice QCD can be used to compute these quantities directly in terms of quark and gluons degrees of freedom, using the background field method. We present results for the neutron electric polarizability for two different quark masses, light enough to connect to chiral perturbation theory. These are currently the lightest quark masses used in polarizability studies. For each pion mass we compute the polarizability at four different volumes and perform an infinite volume extrapolation. We also discuss the effect of turning on the coupling between the background field and the sea quarks. A.A. is supported in part by the National Science Foundation CAREER Grant PHY-1151648 and by U.S. DOE Grant No. DE-FG02-95ER40907.

Covariant effective action for a Galilean invariant quantum Hall system

NASA Astrophysics Data System (ADS)

Geracie, Michael; Prabhu, Kartik; Roberts, Matthew M.

2016-09-01

We construct effective field theories for gapped quantum Hall systems coupled to background geometries with local Galilean invariance i.e. Bargmann spacetimes. Along with an electromagnetic field, these backgrounds include the effects of curved Galilean spacetimes, including torsion and a gravitational field, allowing us to study charge, energy, stress and mass currents within a unified framework. A shift symmetry specific to single constituent theories constraints the effective action to couple to an effective background gauge field and spin connection that is solved for by a self-consistent equation, providing a manifestly covariant extension of Hoyos and Son's improvement terms to arbitrary order in m.

Dark energy, non-minimal couplings and the origin of cosmic magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiménez, Jose Beltrán; Maroto, Antonio L., E-mail: jobeltra@fis.ucm.es, E-mail: maroto@fis.ucm.es

2010-12-01

In this work we consider the most general electromagnetic theory in curved space-time leading to linear second order differential equations, including non-minimal couplings to the space-time curvature. We assume the presence of a temporal electromagnetic background whose energy density plays the role of dark energy, as has been recently suggested. Imposing the consistency of the theory in the weak-field limit, we show that it reduces to standard electromagnetism in the presence of an effective electromagnetic current which is generated by the momentum density of the matter/energy distribution, even for neutral sources. This implies that in the presence of dark energy,more » the motion of large-scale structures generates magnetic fields. Estimates of the present amplitude of the generated seed fields for typical spiral galaxies could reach 10{sup −9} G without any amplification. In the case of compact rotating objects, the theory predicts their magnetic moments to be related to their angular momenta in the way suggested by the so called Schuster-Blackett conjecture.« less

[Electormagnetic field of the mobile phone base station: case study].

PubMed

Bieńkowski, Paweł; Zubrzak, Bartłomiej; Surma, Robert

2011-01-01

The paper presents changes in the electromagnetic field intensity in a school building and its surrounding after the mobile phone base station installation on the roof of the school. The comparison of EMF intensity measured before the base station was launched (electromagnetic background measurement) and after starting its operation (two independent control measurements) is discussed. Analyses of measurements are presented and the authors also propose the method of the electromagnetic field distribution adjustment in the area of radiation antennas side lobe to reduce the intensity of the EMF level in the base station proximity. The presented method involves the regulation of the inclination. On the basis of the measurements, it was found that the EMF intensity increased in the building and its surroundings, but the values measured with wide margins meet the requirements of the Polish law on environmental protection.

Cluster: A fleet of four spacecraft to study plasma structures in three dimensions

NASA Technical Reports Server (NTRS)

Schmidt, R.; Goldstein, M. L.

1988-01-01

The four Cluster spacecraft are spin stabilized spacecraft which are designed and built under stringent requirements as far as electromagnetic cleanliness is concerned. Conductive surfaces and low electromagnetic background noise are mandatory for accurate electric field and cold plasma measurements. The mission is implemented in collaboration between ESA and NASA. A Russian mission will be closely coordinated with Cluster.

Nondestructive testing of delaminated interfaces between two materials using electromagnetic interrogation

NASA Astrophysics Data System (ADS)

Cakoni, Fioralba; de Teresa, Irene; Monk, Peter

2018-06-01

We consider the problem of detecting whether two materials that should be in contact have separated or delaminated using electromagnetic radiation. The interface damage is modeled as a thin opening between two materials of different electromagnetic properties. To derive a reconstruction algorithm that focuses on testing for the delamination at the interface between the two materials, we use the approximate asymptotic model for the forward problem derived in de Teresa (2017 PhD Thesis University of Delaware). In this model, the differential equations in the small opening are replaced by approximate transmission conditions for the electromagnetic fields across the interface. We also assume that the undamaged or background state is known and it is desired to find where the delamination has opened. We adapt the linear sampling method to this configuration in order to locate the damaged part of the interface from a knowledge of the scattered field and the undamaged configuration, but without needing to know the electromagnetic properties of the opening. Numerical examples are presented to validate our algorithm.

Survey of the Effects of Exposure to 900 MHz Radiofrequency Radiation Emitted by a GSM Mobile Phone on the Pattern of Muscle Contractions in an Animal Model

PubMed Central

Mortazavi, S. M. J.; Rahimi, S.; Talebi, A.; Soleimani, A.; Rafati, A.

2015-01-01

Background: The rapid development of wireless telecommunication technologies over the past decades, has led to significant changes in the exposure of the general public to electromagnetic fields. Nowadays, people are continuously exposed to different sources of electromagnetic fields such as mobile phones, mobile base stations, cordless phones, Wi-Fi routers, and power lines. Therefore, the last decade witnessed a rapidly growing concern about the possible health effects of exposure to electromagnetic fields emitted by these sources. Materials and Methods: In this study that was aimed at investigating the effects of exposure to radiofrequency (RF) radiation emitted by a GSM mobile phone on the pattern of contraction in frog’s isolated gastrocnemius muscle after stimulation with single square pulses of 1V (1 Hz), pulse height of contractions, the time interval between two subsequent contractions and the latency period were measured. Results: Our findings showed that the pulse height of contractions muscle could be affected by the exposure to electromagnetic fields. Especially, the latency period was effectively altered in RF-exposed samples. However, none of the experiments could show an alteration in the time interval between two subsequent contractions after exposure to electromagnetic fields. Conclusion: These findings support early reports which indicated a wide variety of non-thermal effects of electromagnetic radiation on amphibians including the effects on the pattern of muscle extractions. PMID:26396968

No effects of GSM-modulated 900 MHz electromagnetic fields on survival rate and spontaneous development of lymphoma in female AKR/J mice

PubMed Central

Sommer, Angela M; Streckert, Joachim; Bitz, Andreas K; Hansen, Volkert W; Lerchl, Alexander

2004-01-01

Background Several reports indicated that non-thermal electromagnetic radiation such as from mobile phones and base stations may promote cancer. Therefore, it was investigated experimentally, whether 900 MHz electromagnetic field exposure influences lymphoma development in a mouse strain that is genetically predisposed to this disease. The AKR/J mice genome carries the AK-virus, which leads within one year to spontaneous development of thymic lymphoblastic lymphoma. Methods 320 unrestrained female mice were sham-exposed or exposed (each n = 160 animals) to GSM like 900 MHz electromagnetic fields for 24 hours per day, 7 days per week, at an average whole body specific absorption rate (SAR) value of 0.4 W/kg. Animals were visually checked daily and were weighed and palpated weekly. Starting with an age of 6 months, blood samples were taken monthly from the tail. Animals with signs of disease or with an age of about 46 weeks were sacrificed and a gross necropsy was performed. Results Electromagnetic field exposure had a significant effect on body weight gain, with higher values in exposed than in sham-exposed animals. However, survival rate and lymphoma incidence did not differ between exposed and sham-exposed mice. Conclusion These data do not support the hypothesis that exposure to 900 MHz electromagnetic fields is a significant risk factor for developing lymphoma in a genetically predisposed species, even at a relatively high exposure level. PMID:15538947

A laboratory study of the electromagnetic bias of rough surface scattering by water waves

NASA Technical Reports Server (NTRS)

Parsons, Chester L.; Miller, Lee S.

1990-01-01

The design, development, and use of a focused-beam radar to measure the electromagnetic bias introduced by the scattering of radar waves by a roughened water surface are discussed. The bias measurements were made over wide ranges of environmental conditions in a wavetank laboratory. Wave-elevation data were provided by standard laboratory capacitance probes. Backscattered radar power measurements coincident in time and space with the elevation data were produced by the radar. The two data sets are histogrammed to produce probability density functions for elevation and radar reflectivity, from which the electromagnetic bias is computed. The experimental results demonstrate that the electromagnetic bias is quite variable over the wide range of environmental conditions that can be produced in the laboratory. The data suggest that the bias is dependent upon the local wind field and on the amplitude and frequency of any background wave field that is present.

Anthropogenic electromagnetic noise disrupts magnetic compass orientation in a migratory bird.

PubMed

Engels, Svenja; Schneider, Nils-Lasse; Lefeldt, Nele; Hein, Christine Maira; Zapka, Manuela; Michalik, Andreas; Elbers, Dana; Kittel, Achim; Hore, P J; Mouritsen, Henrik

2014-05-15

Electromagnetic noise is emitted everywhere humans use electronic devices. For decades, it has been hotly debated whether man-made electric and magnetic fields affect biological processes, including human health. So far, no putative effect of anthropogenic electromagnetic noise at intensities below the guidelines adopted by the World Health Organization has withstood the test of independent replication under truly blinded experimental conditions. No effect has therefore been widely accepted as scientifically proven. Here we show that migratory birds are unable to use their magnetic compass in the presence of urban electromagnetic noise. When European robins, Erithacus rubecula, were exposed to the background electromagnetic noise present in unscreened wooden huts at the University of Oldenburg campus, they could not orient using their magnetic compass. Their magnetic orientation capabilities reappeared in electrically grounded, aluminium-screened huts, which attenuated electromagnetic noise in the frequency range from 50 kHz to 5 MHz by approximately two orders of magnitude. When the grounding was removed or when broadband electromagnetic noise was deliberately generated inside the screened and grounded huts, the birds again lost their magnetic orientation capabilities. The disruptive effect of radiofrequency electromagnetic fields is not confined to a narrow frequency band and birds tested far from sources of electromagnetic noise required no screening to orient with their magnetic compass. These fully double-blinded tests document a reproducible effect of anthropogenic electromagnetic noise on the behaviour of an intact vertebrate.

Covariant effective action for a Galilean invariant quantum Hall system

DOE PAGES

Geracie, Michael; Prabhu, Kartik; Roberts, Matthew M.

2016-09-16

Here, we construct effective field theories for gapped quantum Hall systems coupled to background geometries with local Galilean invariance i.e. Bargmann spacetimes. Along with an electromagnetic field, these backgrounds include the effects of curved Galilean spacetimes, including torsion and a gravitational field, allowing us to study charge, energy, stress and mass currents within a unified framework. A shift symmetry specific to single constituent theories constraints the effective action to couple to an effective background gauge field and spin connection that is solved for by a self-consistent equation, providing a manifestly covariant extension of Hoyos and Son’s improvement terms to arbitrarymore » order in m.« less

Mars SubsurfAce Sounding by Time-Domain Electromagnetic MeasuRements

NASA Astrophysics Data System (ADS)

Tacconi, G.; Minna, L.; Pagnan, S.; Tacconi, M.

1999-09-01

MASTER (Mars subsurfAce Sounding by Time-domain Electromagnetic measuRements) is an experimental project proposed to fly aboard the Italian Drill (DEEDRI) payload for the Mars Surveyor Program 2003. MASTER will offer the scientific community the first opportunity to scan Mars subsurface structure by means of the technique employing time-domain electromagnetic measurements TDEM. Up today proposed experiments for scanning the Martian subsurface have focused on exploring the crust of the planet Mars up to few meters, while MASTER will explore electrical structures and related soil characteristics and processes at depths up to hundreds meters at least. TDEM represents an active remote sensing system and will be used likely a ULF/ELF/VLF ``radar." If a certain volumetric zone has different electrical conductivity, the current in the sample will vary generating a secondary scattered electromagnetic field containing the information about the explored volume. The volumetric mean value of the conductivity will be estimated according to the implicit near field e.m. propagation conditions, considering the skin depth (d) and the apparent resistivity (ra) as the most representative and critical parameters. As any active remotely sensed measurements the TDEM system behaves like a ``bistatic" communication channel and is mandatory to investigate the characteristics of the background noise at the receiver site. The MASTER system, can operate also as a passive listening device of the possible electromagnetic background noise on the Mars surface at ULF/ELF/VLF bands. Present paper will describe in details the application of the TDEM method as well as the approaches to the detection and estimation of the e.m. BGN on Mars surface, in terms of man made, natural BGN and intrinsic noise of the sensors and electronic systems. The electromagnetic background noise detection/estimation represents by itself a no cost experiment and the first experiment of this type on Mars.

Effect on cosmic microwave background polarization of coupling of quintessence to pseudoscalar formed from the electromagnetic field and its dual.

PubMed

Liu, Guo-Chin; Lee, Seokcheon; Ng, Kin-Wang

2006-10-20

We present the full set of power spectra of cosmic microwave background (CMB) temperature and polarization anisotropies due to the coupling between quintessence and pseudoscalar of electromagnetism. This coupling induces a rotation of the polarization plane of the CMB, thus resulting in a nonvanishing B mode and parity-violating TB and EB modes. Using the BOOMERANG data from the flight of 2003, we derive the most stringent constraint on the coupling strength. We find that in some cases the rotation-induced B mode can confuse the hunting for the gravitational lensing-induced B mode.

Electromagnetic plasma particle simulations on Solar Probe Plus spacecraft interaction with near-Sun plasma environment

NASA Astrophysics Data System (ADS)

Miyake, Yohei; Usui, Hideyuki

It is necessary to predict the nature of spacecraft-plasma interactions in extreme plasma conditions such as in the near-Sun environment. The spacecraft environment immersed in the solar corona is characterized by the small Debye length due to dense (7000 mathrm{/cc}) plasmas and a large photo-/secondary electron emission current emitted from the spacecraft surfaces, which lead to distinctive nature of spacecraft-plasma interactions [1,2,3]. In the present study, electromagnetic field perturbation around the Solar Probe Plus (SPP) spacecraft is examined by using our original EM-PIC (electromagnetic particle-in-cell) plasma simulation code called EMSES. In the simulations, we consider the SPP spacecraft at perihelion (0.04 mathrm{AU} from the Sun) and important physical effects such as spacecraft charging, photoelectron and secondary electron emission, solar wind plasma flow including the effect of spacecraft orbital velocity, and the presence of a background magnetic field. Our preliminary results show that both photoelectrons and secondary electrons from the spacecraft are magnetized in a spatial scale of several meters, and make drift motion due the presence of the background convection electric field. This effect leads to non-axisymmetric distributions of the electron density and the resultant electric potential near the spacecraft. Our simulations predict that a strong (˜ 100 mathrm{mV/m}) spurious electric field can be observed by the probe measurement on the spacecraft due to such a non-axisymmetric effect. We also confirm that the large photo-/secondary electron current alters magnetic field intensity around the spacecraft, but the field variation is much smaller than the background magnetic field magnitude (a few mathrm{nT} compared to a few mathrm{mu T}). [1] Ergun et al., textit{Phys. Plasmas}, textbf{17}, 072903, 2010. [2] Guillemant et al., textit{Ann. Geophys.}, textbf{30}, 1075-1092, 2012. [3] Guillemant et al., textit{IEEE Trans. Plasma Sci.}, textbf{41}, 3338-3348, 2013.

A Challenging Issue in the Etiology of Speech Problems: The Effect of Maternal Exposure to Electromagnetic Fields on Speech Problems in the Offspring

PubMed Central

Zarei, S.; Mortazavi, S. M. J.; Mehdizadeh, A. R.; Jalalipour, M.; Borzou, S.; Taeb, S.; Haghani, M.; Mortazavi, S. A. R.; Shojaei-fard, M. B.; Nematollahi, S.; Alighanbari, N.; Jarideh, S.

2015-01-01

Background Nowadays, mothers are continuously exposed to different sources of electromagnetic fields before and even during pregnancy.  It has recently been shown that exposure to mobile phone radiation during pregnancy may lead to adverse effects on the brain development in offspring and cause hyperactivity. Researchers have shown that behavioral problems in laboratory animals which have a similar appearance to ADHD are caused by intrauterine exposure to mobile phones. Objective The purpose of this study was to investigate whether the maternal exposure to different sources of electromagnetic fields affect on the rate and severity of speech problems in their offspring. Methods In this study, mothers of 35 healthy 3-5 year old children (control group) and 77 children and diagnosed with speech problems who had been referred to a speech treatment center in Shiraz, Iran were interviewed. These mothers were asked whether they had exposure to different sources of electromagnetic fields such as mobile phones, mobile base stations, Wi-Fi, cordless phones, laptops and power lines. Results We found a significant association between either the call time (P=0.002) or history of mobile phone use (months used) and speech problems in the offspring (P=0.003). However, other exposures had no effect on the occurrence of speech problems. To the best of our knowledge, this is the first study to investigate a possible association between maternal exposure to electromagnetic field and speech problems in the offspring. Although a major limitation in our study is the relatively small sample size, this study indicates that the maternal exposure to common sources of electromagnetic fields such as mobile phones can affect the occurrence of speech problems in the offspring. PMID:26396971

Prequantum classical statistical field theory: background field as a source of everything?

NASA Astrophysics Data System (ADS)

Khrennikov, Andrei

2011-07-01

Prequantum classical statistical field theory (PCSFT) is a new attempt to consider quantum mechanics (QM) as an emergent phenomenon, cf. with De Broglie's "double solution" approach, Bohmian mechanics, stochastic electrodynamics (SED), Nelson's stochastic QM and its generalization by Davidson, 't Hooft's models and their development by Elze. PCSFT is a comeback to a purely wave viewpoint on QM, cf. with early Schrodinger. There is no quantum particles at all, only waves. In particular, photons are simply wave-pulses of the classical electromagnetic field, cf. SED. Moreover, even massive particles are special "prequantum fields": the electron field, the neutron field, and so on. PCSFT claims that (sooner or later) people will be able to measure components of these fields: components of the "photonic field" (the classical electromagnetic field of low intensity), electronic field, neutronic field, and so on. At the moment we are able to produce quantum correlations as correlations of classical Gaussian random fields. In this paper we are interested in mathematical and physical reasons of usage of Gaussian fields. We consider prequantum signals (corresponding to quantum systems) as composed of a huge number of wave-pulses (on very fine prequantum time scale). We speculate that the prequantum background field (the field of "vacuum fluctuations") might play the role of a source of such pulses, i.e., the source of everything.

Extremely low-frequency electromagnetic fields cause DNA strand breaks in normal cells

PubMed Central

2014-01-01

Background Extremely low frequency electromagnetic fields aren’t considered as a real carcinogenic agent despite the fact that some studies have showed impairment of the DNA integrity in different cells lines. The aim of this study was evaluation of the late effects of a 100 Hz and 5.6 mT electromagnetic field, applied continuously or discontinuously, on the DNA integrity of Vero cells assessed by alkaline Comet assay and by cell cycle analysis. Normal Vero cells were exposed to extremely low frequency electromagnetic fields (100 Hz, 5.6 mT) for 45 minutes. The Comet assay and cell cycle analysis were performed 48 hours after the treatment. Results Exposed samples presented an increase of the number of cells with high damaged DNA as compared with non-exposed cells. Quantitative evaluation of the comet assay showed a significantly (<0.001) increase of the tail lengths, of the quantity of DNA in tail and of Olive tail moments, respectively. Cell cycle analysis showed an increase of the frequency of the cells in S phase, proving the occurrence of single strand breaks. The most probable mechanism of induction of the registered effects is the production of different types of reactive oxygen species. Conclusions The analysis of the registered comet indices and of cell cycle showed that extremely low frequency electromagnetic field of 100 Hz and 5.6 mT had a genotoxic impact on Vero cells. PMID:24401758

Position sensitive detection of neutrons in high radiation background field.

PubMed

Vavrik, D; Jakubek, J; Pospisil, S; Vacik, J

2014-01-01

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e(-) radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm(2)) spectroscopic Timepix detector adapted for neutron detection utilizing very thin (10)B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10(-4).

Position sensitive detection of neutrons in high radiation background field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vavrik, D., E-mail: vavrik@itam.cas.cz; Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9; Jakubek, J.

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e{sup −} radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm{sup 2}) spectroscopic Timepix detector adapted for neutron detection utilizing very thin {sup 10}B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane)more » and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10{sup −4}.« less

Electromagnetic analysis of a superconducting transformer for high current characterization of cable in conduit conductors in background magnetic field

NASA Astrophysics Data System (ADS)

Wu, Xiangyang; Tan, Yunfei; Fang, Zhen; Jiang, Donghui; Chen, Zhiyou; Chen, Wenge; Kuang, Guangli

2017-10-01

A large cable-in-conduit-conductor (CICC) test facility has been designed and fabricated at the High Magnetic Field Laboratory of the Chinese Academy of Sciences (CHMFL) in order to meet the test requirement of the conductors which are applied to the future fusion reactor. The critical component of the test facility is an 80 kA superconducting transformer which consists of a multi-turn primary coil and a minor-turn secondary coil. As the current source of the conductor samples, the electromagnetic performance of the superconducting transformer determines the stability and safety of the test facility. In this paper, the key factors and parameters, which have much impact on the performance of the transformer, are analyzed in detail. The conceptual design and optimizing principles of the transformer are discussed. An Electromagnetic-Circuit coupled model built in ANSYS Multiphysics is successfully used to investigate the electromagnetic characterization of the transformer under the dynamic operation condition.

TORO II: A finite element computer program for nonlinear quasi-static problems in electromagnetics: Part 1, Theoretical background

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gartling, D.K.

The theoretical and numerical background for the finite element computer program, TORO II, is presented in detail. TORO II is designed for the multi-dimensional analysis of nonlinear, electromagnetic field problems described by the quasi-static form of Maxwell`s equations. A general description of the boundary value problems treated by the program is presented. The finite element formulation and the associated numerical methods used in TORO II are also outlined. Instructions for the use of the code are documented in SAND96-0903; examples of problems analyzed with the code are also provided in the user`s manual. 24 refs., 8 figs.

The treatment of tendon injury with electromagnetic fields evidenced by advanced ultrasound image processing.

PubMed

Parker, Richard; Markov, Marko

2015-09-01

This article presents a novel modality for accelerating the repair of tendon and ligament lesions by means of a specifically designed electromagnetic field in an equine model. This novel therapeutic approach employs a delivery system that induces a specific electrical signal from an external magnetic field derived from Superconductive QUantum Interference Device (SQUID) measurements of injured vs. healthy tissue. Evaluation of this therapy technique is enabled by a proposed new technology described as Predictive Analytical Imagery (PAI™). This technique examines an ultrasound grayscale image and seeks to evaluate it by means of look-ahead predictive algorithms and digital signal processing. The net result is a significant reduction in background noise and the production of a high-resolution grayscale or digital image.

Pulsed magnetic field excitation sensitivity of match-type electric blasting caps

NASA Astrophysics Data System (ADS)

Parson, Jonathan; Dickens, James; Walter, John; Neuber, Andreas A.

2010-10-01

This paper presents a study on energy deposition and electromagnetic compatibility of match-type electroexplosive devices (EEDs), which recently have found more usage in pulsed power environments with high electromagnetic interference (EMI) background. The sensitivity of these devices makes them dangerous to intended and unintended radiation produced by devices commonly used in pulsed power environments. Match-type EEDs have been found to be susceptible to such low levels of energy (7-8 mJ) that safe operation of these EEDs is vital when in use near devices that produce high levels of pulsed EMI. The scope of this paper is to provide an investigation that incorporates results of similar studies to provide detonation characteristics of these EEDs. The three topics included in this study are sensitivity testing, modeling of the thermodynamic heat propagation, and electromagnetic compatibility from pulsed electromagnetic radiation. The thermodynamic joule heating of the primary explosive has been modeled by a solution to the 1D heat equation. A simple pulsed generator, Marx generator with an inductive load, was used for the electromagnetic compatibility assessment of the coupled field between the pulse generator and shorted EED. The results of the electromagnetic compatibility assessment relate the resistive, inductive, and capacitive components of the pulse generator to the area of the shorted EED.

Pulsed magnetic field excitation sensitivity of match-type electric blasting caps.

PubMed

Parson, Jonathan; Dickens, James; Walter, John; Neuber, Andreas A

2010-10-01

This paper presents a study on energy deposition and electromagnetic compatibility of match-type electroexplosive devices (EEDs), which recently have found more usage in pulsed power environments with high electromagnetic interference (EMI) background. The sensitivity of these devices makes them dangerous to intended and unintended radiation produced by devices commonly used in pulsed power environments. Match-type EEDs have been found to be susceptible to such low levels of energy (7-8 mJ) that safe operation of these EEDs is vital when in use near devices that produce high levels of pulsed EMI. The scope of this paper is to provide an investigation that incorporates results of similar studies to provide detonation characteristics of these EEDs. The three topics included in this study are sensitivity testing, modeling of the thermodynamic heat propagation, and electromagnetic compatibility from pulsed electromagnetic radiation. The thermodynamic joule heating of the primary explosive has been modeled by a solution to the 1D heat equation. A simple pulsed generator, Marx generator with an inductive load, was used for the electromagnetic compatibility assessment of the coupled field between the pulse generator and shorted EED. The results of the electromagnetic compatibility assessment relate the resistive, inductive, and capacitive components of the pulse generator to the area of the shorted EED.

Objects of Maximum Electromagnetic Chirality

NASA Astrophysics Data System (ADS)

Fernandez-Corbaton, Ivan; Fruhnert, Martin; Rockstuhl, Carsten

2016-07-01

We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. Reciprocal objects attain the upper bound if and only if they are transparent for all the fields of one polarization handedness (helicity). Additionally, electromagnetic duality symmetry, i.e., helicity preservation upon interaction, turns out to be a necessary condition for reciprocal objects to attain the upper bound. We use these results to provide requirements for the design of such extremal objects. The requirements can be formulated as constraints on the polarizability tensors for dipolar objects or on the material constitutive relations for continuous media. We also outline two applications for objects of maximum electromagnetic chirality: a twofold resonantly enhanced and background-free circular dichroism measurement setup, and angle-independent helicity filtering glasses. Finally, we use the theoretically obtained requirements to guide the design of a specific structure, which we then analyze numerically and discuss its performance with respect to maximal electromagnetic chirality.

Electromagnetically induced grating with Rydberg atoms

NASA Astrophysics Data System (ADS)

Asghar, Sobia; Ziauddin, Qamar, Shahid; Qamar, Sajid

2016-09-01

We present a scheme to realize electromagnetically induced grating in an ensemble of strongly interacting Rydberg atoms, which act as superatoms due to the dipole blockade mechanism. The ensemble of three-level cold Rydberg-dressed (87Rb) atoms follows a cascade configuration where a strong standing-wave control field and a weak probe pulse are employed. The diffraction intensity is influenced by the strength of the probe intensity, the control field strength, and the van der Waals (vdW) interaction. It is noticed that relatively large first-order diffraction can be obtained for low-input intensity with a small vdW shift and a strong control field. The scheme can be considered as an amicable solution to realize the atomic grating at the microscopic level, which can provide background- and dark-current-free diffraction.

Magnetic fields over active tectonic zones in ocean

USGS Publications Warehouse

Kopytenko, Yu. A.; Serebrianaya, P.M.; Nikitina, L.V.; Green, A.W.

2002-01-01

The aim of our work is to estimate the electromagnetic effects that can be detected in the submarine zones with hydrothermal activity. It is known that meso-scale flows appear in the regions over underwater volcanoes or hot rocks. Their origin is connected with heat flux and hot jets released from underwater volcanoes or faults in a sea bottom. Values of mean velocities and turbulent velocities in plumes were estimated. Quasiconstant magnetic fields induced by a hot jet and a vortex over a plume top are about 1-40 nT. Variable magnetic fields are about 0.1-1 nT. These magnetic disturbances in the sea medium create an additional natural electromagnetic background that must be considered when making detailed magnetic surveys. ?? 2002 Elsevier Science Ltd. All rights reserved.

Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-ray Background

NASA Technical Reports Server (NTRS)

Venters, T. M.; Pavlidou, V.

2013-01-01

The intergalactic magnetic field (IGMF) may leave an imprint on the angular anisotropy of the extragalactic gamma-ray background through its effect on electromagnetic cascades triggered by interactions between very high energy photons and the extragalactic background light. A strong IGMF will deflect secondary particles produced in these cascades and will thus tend to isotropize lower energy cascade photons, thereby inducing a modulation in the anisotropy energy spectrum of the gamma-ray background. Here we present a simple, proof-of-concept calculation of the magnitude of this effect and demonstrate that current Fermi data already seem to prefer nonnegligible IGMF values. The anisotropy energy spectrum of the Fermi gamma-ray background could thus be used as a probe of the IGMF strength.

New aspects of whistler waves driven by an electron beam studied by a 3-D electromagnetic code

NASA Technical Reports Server (NTRS)

Nishikawa, Ken-Ichi; Buneman, Oscar; Neubert, Torsten

1994-01-01

We have restudied electron beam driven whistler waves with a 3-D electromagnetic particle code. The simulation results show electromagnetic whistler wave emissions and electrostatic beam modes like those observed in the Spacelab 2 electron beam experiment. It has been suggested in the past that the spatial bunching of beam electrons associated with the beam mode may directly generate whistler waves. However, the simulation results indicate several inconsistencies with this picture: (1) whistler waves continue to be generated even after the beam mode space charge modulation looses its coherence, (2) the parallel (to the background magnetic field) wavelength of the whistler wave is longer than that of the beam instability, and (3) the parallel phase velocity of the whistler wave is smaller than that of the beam mode. The complex structure of the whistler waves in the vicinity of the beam suggest that the transverse motion (gyration) of the beam and background electrons is also involved in the generation of whistler waves.

Charged string loops in Reissner-Nordström black hole background

NASA Astrophysics Data System (ADS)

Oteev, Tursinbay; Kološ, Martin; Stuchlík, Zdeněk

2018-03-01

We study the motion of current carrying charged string loops in the Reissner-Nordström black hole background combining the gravitational and electromagnetic field. Introducing new electromagnetic interaction between central charge and charged string loop makes the string loop equations of motion to be non-integrable even in the flat spacetime limit, but it can be governed by an effective potential even in the black hole background. We classify different types of the string loop trajectories using effective potential approach, and we compare the innermost stable string loop positions with loci of the charged particle innermost stable orbits. We examine string loop small oscillations around minima of the string loop effective potential, and we plot radial profiles of the string loop oscillation frequencies for both the radial and vertical modes. We construct charged string loop quasi-periodic oscillations model and we compare it with observed data from microquasars GRO 1655-40, XTE 1550-564, and GRS 1915+105. We also study the acceleration of current carrying string loops along the vertical axis and the string loop ejection from RN black hole neighbourhood, taking also into account the electromagnetic interaction.

Propagation of monochromatic light in a hot and dense medium

NASA Astrophysics Data System (ADS)

Masood, Samina S.

2017-12-01

Photons, as quanta of electromagnetic fields, determine the electromagnetic properties of an extremely hot and dense medium. Considering the properties of the photons in the interacting medium of charged particles, we explicitly calculate the electromagnetic properties such as the electric permittivity, magnetic permeability, refractive index and the propagation speed of electromagnetic signals in an extremely hot and dense background. Photons acquire a dynamically generated mass in such a medium. The screening mass of the photon, the Debye shielding length and the plasma frequency are calculated as functions of the statistical parameters of the medium. We study the properties of the propagating particles in astrophysical systems of distinct statistical conditions. The modifications in the properties of the medium lead to the equation of state of the system. We mainly calculate all these parameters for extremely high temperatures of the early universe.

Near-field electromagnetic holography for high-resolution analysis of network interactions in neuronal tissue

PubMed Central

Kjeldsen, Henrik D.; Kaiser, Marcus; Whittington, Miles A.

2015-01-01

Background Brain function is dependent upon the concerted, dynamical interactions between a great many neurons distributed over many cortical subregions. Current methods of quantifying such interactions are limited by consideration only of single direct or indirect measures of a subsample of all neuronal population activity. New method Here we present a new derivation of the electromagnetic analogy to near-field acoustic holography allowing high-resolution, vectored estimates of interactions between sources of electromagnetic activity that significantly improves this situation. In vitro voltage potential recordings were used to estimate pseudo-electromagnetic energy flow vector fields, current and energy source densities and energy dissipation in reconstruction planes at depth into the neural tissue parallel to the recording plane of the microelectrode array. Results The properties of the reconstructed near-field estimate allowed both the utilization of super-resolution techniques to increase the imaging resolution beyond that of the microelectrode array, and facilitated a novel approach to estimating causal relationships between activity in neocortical subregions. Comparison with existing methods The holographic nature of the reconstruction method allowed significantly better estimation of the fine spatiotemporal detail of neuronal population activity, compared with interpolation alone, beyond the spatial resolution of the electrode arrays used. Pseudo-energy flow vector mapping was possible with high temporal precision, allowing a near-realtime estimate of causal interaction dynamics. Conclusions Basic near-field electromagnetic holography provides a powerful means to increase spatial resolution from electrode array data with careful choice of spatial filters and distance to reconstruction plane. More detailed approaches may provide the ability to volumetrically reconstruct activity patterns on neuronal tissue, but the ability to extract vectored data with the method presented already permits the study of dynamic causal interactions without bias from any prior assumptions on anatomical connectivity. PMID:26026581

Low-frequency pulsed electromagnetic fields significantly improve time of closure and proliferation of human tendon fibroblasts

PubMed Central

2014-01-01

Background The promotion of the healing process following musculoskeletal injuries comprises growth factor signalling, migration, proliferation and apoptosis of cells. If these processes could be modulated, the healing of tendon tissue may be markedly enhanced. Here, we report the use of the Somagen™ device, which is certified for medical use according to European laws. It generates low-frequency pulsed electromagnetic fields that trigger effects of a nature that are yet to be determined. Methods A 1.5-cm wide, linear scrape was introduced into patellar tendon fibroblast cultures (N = 5 donors). Treatment was carried out every second day. The regimen was applied three times in total with 30 minutes comprising pulsed electromagnetic field packages with two fundamental frequencies (10 minutes of 33 Hz, 20 minutes of 7.8 Hz). Control cells remained untreated. All samples were analyzed for gap closure time, proliferation and apoptosis one week after induction of the scrape wound. Results The mean time for bridging the gap in the nontreated cells was 5.05 ± 0.33 days, and in treated cells, it took 3.35 ± 0.38 days (P <0.001). For cell cultures with scrape wounds, a mean value for BrdU incorporation of OD = 0.70 ± 0.16 was found. Whereas low-frequency pulsed electromagnetic fields treated samples showed OD = 1.58 ± 0.24 (P <0.001). However, the percentage of apoptotic cells did not differ between the two groups. Conclusions Our data demonstrate that low-frequency pulsed electromagnetic fields emitted by the Somagen™ device influences the in vitro wound healing of patellar tendon fibroblasts and, therefore, possibly increases wound healing potential. PMID:24996421

Background Noise Analysis in a Few-Photon-Level Qubit Memory

NASA Astrophysics Data System (ADS)

Mittiga, Thomas; Kupchak, Connor; Jordaan, Bertus; Namazi, Mehdi; Nolleke, Christian; Figeroa, Eden

2014-05-01

We have developed an Electromagnetically Induced Transparency based polarization qubit memory. The device is composed of a dual-rail probe field polarization setup colinear with an intense control field to store and retrieve any arbitrary polarization state by addressing a Λ-type energy level scheme in a 87Rb vapor cell. To achieve a signal-to-background ratio at the few photon level sufficient for polarization tomography of the retrieved state, the intense control field is filtered out through an etalon filtrating system. We have developed an analytical model predicting the influence of the signal-to-background ratio on the fidelities and compared it to experimental data. Experimentally measured global fidelities have been found to follow closely the theoretical prediction as signal-to-background decreases. These results suggest the plausibility of employing room temperature memories to store photonic qubits at the single photon level and for future applications in long distance quantum communication schemes.

New Model for Ionospheric Irregularities at Mars

NASA Astrophysics Data System (ADS)

Keskinen, M. J.

2018-03-01

A new model for ionospheric irregularities at Mars is presented. It is shown that wind-driven currents in the dynamo region of the Martian ionosphere can be unstable to the electromagnetic gradient drift instability. This plasma instability can generate ionospheric density and magnetic field irregularities with scale sizes of approximately 15-20 km down to a few kilometers. We show that the instability-driven magnetic field fluctuation amplitudes relative to background are correlated with the ionospheric density fluctuation amplitudes relative to background. Our results can explain recent observations made by the Mars Atmosphere and Volatile EvolutioN spacecraft in the Martian ionosphere dynamo region.

Far-field detection of sub-wavelength Tetris without extra near-field metal parts based on phase prints of time-reversed fields with intensive background interference.

PubMed

Chen, Yingming; Wang, Bing-Zhong

2014-07-14

Time-reversal (TR) phase prints are first used in far-field (FF) detection of sub-wavelength (SW) deformable scatterers without any extra metal structure positioned in the vicinity of the target. The 2D prints derive from discrete short-time Fourier transform of 1D TR electromagnetic (EM) signals. Because the time-invariant intensive background interference is effectively centralized by TR technique, the time-variant weak indication from FF SW scatterers can be highlighted. This method shows a different use of TR technique in which the focus peak of TR EM waves is unusually removed and the most useful information is conveyed by the other part.

Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-Ray Background

NASA Technical Reports Server (NTRS)

Venters, T. M.; Pavlidou, V.

2012-01-01

The intergalactic magnetic field (IGMF) may leave an imprint on the anisotropy properties of the extragalactic gamma-ray background, through its effect on electromagnetic cascades triggered by interactions between very high energy photons and the extragalactic background light. A strong IGMF will deflect secondary particles produced in these cascades and will thus tend to isotropize lower energy cascade photons, thus inducing a modulation in the anisotropy energy spectrum of the gamma-ray background. Here we present a simple, proof-of-concept calculation of the magnitude of this effect and demonstrate that the two extreme cases (zero IGMF and IGMF strong enough to completely isotropize cascade photons) would be separable by ten years of Fermi observations and reasonable model parameters for the gamma-ray background. The anisotropy energy spectrum of the Fermi gamma-ray background could thus be used as a probe of the IGMF strength.

Geometric model of topological insulators from the Maxwell algebra

NASA Astrophysics Data System (ADS)

Palumbo, Giandomenico

2017-11-01

We propose a novel geometric model of time-reversal-invariant topological insulators in three dimensions in presence of an external electromagnetic field. Their gapped boundary supports relativistic quantum Hall states and is described by a Chern-Simons theory, where the gauge connection takes values in the Maxwell algebra. This represents a non-central extension of the Poincaré algebra and takes into account both the Lorentz and magnetic-translation symmetries of the surface states. In this way, we derive a relativistic version of the Wen-Zee term and we show that the non-minimal coupling between the background geometry and the electromagnetic field in the model is in agreement with the main properties of the relativistic quantum Hall states in the flat space.

Electromagnetic fields and their impacts

NASA Astrophysics Data System (ADS)

Prša, M. A.; Kasaš-Lažetić, K. K.

2018-01-01

The main goal of this paper is to briefly recall some different electromagnetic field definitions, some macroscopic sources of electromagnetic fields, electromagnetic fields classification regarding time dependences, and the ways of field determination in concrete cases. After that, all the mechanisms of interaction between electromagnetic field and substance, on atomic level, are described in details. Interaction between substance and electric field is investigated separately from the substance and magnetic field interaction. It is demonstrated that, in all cases of the unique electromagnetic field, total interaction can be treated as a superposition of two separated interactions. Finally, the main electromagnetic fields surrounding us is cited and discussed.

Electromagnetic Ion Cyclotron Waves Detected by Kaguya and Geotail in the Earth's Magnetotail

NASA Astrophysics Data System (ADS)

Nakagawa, Tomoko; Nishino, Masaki N.; Tsunakawa, Hideo; Takahashi, Futoshi; Shibuya, Hidetoshi; Shimizu, Hisayoshi; Matsushima, Masaki; Saito, Yoshifumi

2018-02-01

Narrowband electromagnetic ion cyclotron waves first discovered by the Apollo 15 and 16 Lunar Surface Magnetometers were surveyed in the magnetic field data obtained by the Kaguya satellite at an altitude of ˜100 km above the Moon in the tail lobe and plasma sheet boundary layer of the Earth's magnetosphere. The frequencies of the waves were typically 0.7 times the local proton cyclotron frequency, and 75% of the waves were left hand polarized with respect to the background magnetic field. They had a significant compressional component and comprised several discrete packets. They were detected on the dayside, nightside, and above the terminator of the Moon, irrespective of the lunar magnetic anomaly, or the magnetic connection to the lunar surface. The waves with the same characteristics were detected by Geotail in the absence of the Moon in the magnetotail. The most likely energy source of the electromagnetic ion cyclotron waves is the ring beam ions in the plasma sheet boundary layer.

Electromagnetic Fields of a Uniform Sphere in a Uniform Conducting Medium with Application to Dipole Sources

DTIC Science & Technology

1991-09-01

12b. DISTRIBUTION CODE Approved for public release; distribution is unlimited. 13. ABSTRACT (Maximum 200 words) Vector spherical harmonic expansions are...electric and magnetic field vectors from E rand B - r alone. Genural expressions are given relating the scattered field expansion coefficients to the source...Prescnbed by ANSI Std. Z39-18 29W-102 NCSC TR 426-90 CONTENTS Pag o INTRODUCTION 1 BACKGROUND 1 ANGULAR MOMENTUM OPERATOR AND VECTOR SPHERICAL

Studying Electromagnetic Beam Instabilities in Laser Plasmas for Alfvénic Parallel Shock Formation

NASA Astrophysics Data System (ADS)

Dorst, R. S.; Heuer, P. V.; Weidl, M. S.; Schaeffer, D. B.; Constantin, C. G.; Vincena, S.; Tripathi, S.; Gekelman, W.; Winske, D.; Niemann, C.

2017-10-01

We present measurements of the collisionless interaction between an exploding laser-produced plasma (LPP) and a large, magnetized ambient plasma. The LPP is created by focusing a high energy laser on a target embedded in the ambient Large Plasma Device (LAPD) plasma at the University of California, Los Angeles. The resulting super-Alfvénic (MA = 5) ablated material moves parallel to the background magnetic field (300 G) through 12m (80 δ i) of the LAPD, interacting with the ambient Helium plasma (ni = 9 ×1012 cm-3) through electromagnetic beam instabilities. The debris is characterized by Langmuir probes and a time-resolved fluorescence monochromator. Waves in the magnetic field produced by the instabilities are diagnosed by an array of 3-axis `bdot' magnetic field probes. Measurements are compared to hybrid simulations of both the experiment and of parallel shocks.

Compact and lightweight support platform with electromagnetic disturbance elimination for interferometer on reversed field pinch Keda Torus eXperiment

NASA Astrophysics Data System (ADS)

Mao, Wenzhe; Yuan, Peng; Zheng, Jian; Ding, Weixing; Li, Hong; Lan, Tao; Liu, Adi; Liu, Wandong; Xie, Jinlin

2016-11-01

A compact and lightweight support platform has been used as a holder for the interferometer system on the Keda Torus eXperiment (KTX), which is a reversed field pinch device. The vibration caused by the interaction between the time-varying magnetic field and the induced current driven in the metal optical components has been measured and, following comparison with the mechanical vibration of the KTX device and the refraction effect of the ambient turbulent air flow, has been identified as the primary vibration source in this case. To eliminate this electromagnetic disturbance, nonmetallic epoxy resin has been selected as the material for the support platform and the commercially available metal optical mounts are replaced. Following these optimization steps and mechanical reinforcements, the stability of the interferometer platform has improved significantly. The phase shift caused by the vibration has been reduced to the level of background noise.

What Are Electromagnetic Fields?

MedlinePlus

... Alt+0 Navigation Alt+1 Content Alt+2 Electromagnetic fields (EMF) Menu EMF Home About electromagnetic fields ... Standards EMF publications & information resources Meetings What are electromagnetic fields? Definitions and sources Electric fields are created ...

New wrinkles on black hole perturbations: Numerical treatment of acoustic and gravitational waves

NASA Astrophysics Data System (ADS)

Tenyotkin, Valery

2009-06-01

This thesis develops two main topics. A full relativistic calculation of quasinormal modes of an acoustic black hole is carried out. The acoustic black hole is formed by a perfect, inviscid, relativistic, ideal gas that is spherically accreting onto a Schwarzschild black hole. The second major part is the calculation of sourceless vector (electromagnetic) and tensor (gravitational) covariant field evolution equations for perturbations on a Schwarzschild background using the relatively recent [Special characters omitted.] decomposition method. Scattering calculations are carried out in Schwarzschild coordinates for electromagnetic and gravitational cases as validation of the method and the derived equations.

Electromagnetic Design of Feedhorn-Coupled Transition-Edge Sensors for Cosmic Microwave Background Polarimetery

NASA Technical Reports Server (NTRS)

Chuss, David T.

2011-01-01

Observations of the cosmic microwave background (CMB) provide a powerful tool for probing the evolution of the early universe. Specifically, precision measurement of the polarization of the CMB enables a direct test for cosmic inflation. A key technological element on the path to the measurement of this faint signal is the capability to produce large format arrays of background-limited detectors. We describe the electromagnetic design of feedhorn-coupled, TES-based sensors. Each linear orthogonal polarization from the feed horn is coupled to a superconducting microstrip line via a symmetric planar orthomode transducer (OMT). The symmetric OMT design allows for highly-symmetric beams with low cross-polarization over a wide bandwidth. In addition, this architecture enables a single microstrip filter to define the passband for each polarization. Care has been taken in the design to eliminate stray coupling paths to the absorbers. These detectors will be fielded in the Cosmology Large Angular Scale Surveyor (CLASS).

Electromagnetic radiation due to naked singularity formation in self-similar gravitational collapse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitsuda, Eiji; Yoshino, Hirotaka; Tomimatsu, Akira

Dynamical evolution of test fields in background geometry with a naked singularity is an important problem relevant to the Cauchy horizon instability and the observational signatures different from black hole formation. In this paper we study electromagnetic perturbations generated by a given current distribution in collapsing matter under a spherically symmetric self-similar background. Using the Green's function method, we construct the formula to evaluate the outgoing energy flux observed at the future null infinity. The contributions from 'quasinormal' modes of the self-similar system as well as 'high-frequency' waves are clarified. We find a characteristic power-law time evolution of the outgoingmore » energy flux which appears just before naked singularity formation and give the criteria as to whether or not the outgoing energy flux diverges at the future Cauchy horizon.« less

Modeling particle injections during magnetospheric substorm by a propagating earthward electromagnetic pulse.

NASA Astrophysics Data System (ADS)

Kalugin, G. A.; Kabin, K.; Donovan, E.; Spanswick, E.

2016-12-01

During substorm expansion phase the electrons and ions with energies of up to 100 keV appear in the near-Earth magnetotail. Often, this increase occurs simultaneously for a broad range of particle energies; such events are called dispersionless injections (DIs). Explanations of DIs usually relay on some form of an earthward propagating electromagnetic pulse, which is capable of effectively energizing an initial distribution of electrons and ions. Most of the previous models of such pulses were developed for the equatorial plane only. We propose a new model of an electromagnetic pulse which is two-dimensional in the meridional plane. Electric and magnetic fields in the pulse are calculated self-consistently and satisfy Maxwell's equations. We use realistic time-independent stretched magnetic field as the background. Our model has several adjustable parameters, such as the speed of the pulse propagation, its amplitude and spatial extent, which makes it versatile enough to investigate effects of the pulse characteristics on the particle energization. We present and discuss several examples of particle energization in our model and find that in some cases the energies of the seed electrons can increase by a factor of 10 or more. Two-dimensional nature of our model allows us to visualize the motion of the field lines in the meridional plane associated with the travelling electromagnetic pulse and to calculate the ionospheric footprints of the particle dynamics in the equatorial plane.

On the electrodynamics of moving particles in a quasi flat spacetime with Lorentz violation and its cosmological implications

NASA Astrophysics Data System (ADS)

Cruz, Cláudio Nassif

2016-06-01

This research aims to develop a new approach towards a consistent coupling of electromagnetic and gravitational fields, by using an electron that couples with a weak gravitational potential by means of its electromagnetic field. To accomplish this, we must first build a new model which provides the electromagnetic nature of both the mass and the energy of the electron, and which is implemented with the idea of γ-photon decay into an electron-positron pair. After this, we place the electron (or positron) in the presence of a weak gravitational potential given in the intergalactic medium, so that its electromagnetic field undergoes a very small perturbation, thus leading to a slight increase in the field’s electromagnetic energy density. This perturbation takes place by means of a tiny coupling constant ξ because gravity is a very weak interaction compared with the electromagnetic one. Thus, we realize that ξ is a new dimensionless universal constant, which reminds us of the fine structure constant α; however, ξ is much smaller than α because ξ takes into account gravity, i.e. ξ ∝G. We find ξ = V/c≅1.5302 × 10-22, where c is the speed of light and V ∝G(≅4.5876 × 10-14m/s) is a universal minimum speed that represents the lowest limit of speed for any particle. Such a minimum speed, unattainable by particles, represents a preferred reference frame associated with a background field that breaks the Lorentz symmetry. The metric of the flat spacetime shall include the presence of a uniform vacuum energy density, which leads to a negative pressure at cosmological scales (cosmological anti-gravity). The tiny values of the cosmological constant and the vacuum energy density will be successfully obtained in agreement with the observational data.

Effect of a magnetic field on Schwinger mechanism in de Sitter spacetime

NASA Astrophysics Data System (ADS)

Bavarsad, Ehsan; Kim, Sang Pyo; Stahl, Clément; Xue, She-Sheng

2018-01-01

We investigate the effect of a uniform magnetic field background on scalar QED pair production in a four-dimensional de Sitter spacetime (dS4 ). We obtain a pair production rate which agrees with the known Schwinger result in the limit of Minkowski spacetime and with Hawking radiation in dS spacetime in the zero electric field limit. Our results describe how the cosmic magnetic field affects the pair production rate in cosmological setups. In addition, using the zeta function regularization scheme we calculate the induced current and examine the effect of a magnetic field on the vacuum expectation value of the current operator. We find that, in the case of a strong electromagnetic background the current responds as E .B , while in the infrared regime, it responds as B /E , which leads to a phenomenon of infrared hyperconductivity. These results for the induced current have important applications for the cosmic magnetic field evolution.

Electromagnetic field radiation model for lightning strokes to tall structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Motoyama, H.; Janischewskyj, W.; Hussein, A.M.

1996-07-01

This paper describes observation and analysis of electromagnetic field radiation from lightning strokes to tall structures. Electromagnetic field waveforms and current waveforms of lightning strokes to the CN Tower have been simultaneously measured since 1991. A new calculation model of electromagnetic field radiation is proposed. The proposed model consists of the lightning current propagation and distribution model and the electromagnetic field radiation model. Electromagnetic fields calculated by the proposed model, based on the observed lightning current at the CN Tower, agree well with the observed fields at 2km north of the tower.

Amplification due to two-stream instability of self-electric and magnetic fields of an ion beam propagating in background plasma

NASA Astrophysics Data System (ADS)

Tokluoglu, Erinc K.; Kaganovich, Igor D.; Carlsson, Johan A.; Hara, Kentaro; Startsev, Edward A.

2018-05-01

Propagation of charged particle beams in background plasma as a method of space charge neutralization has been shown to achieve a high degree of charge and current neutralization and therefore enables nearly ballistic propagation and focusing of charged particle beams. Correspondingly, the use of plasmas for propagation of charged particle beams has important applications for transport and focusing of intense particle beams in inertial fusion and high energy density laboratory plasma physics. However, the streaming of beam ions through a background plasma can lead to the development of two-stream instability between the beam ions and the plasma electrons. The beam electric and magnetic fields enhanced by the two-stream instability can lead to defocusing of the ion beam. Using particle-in-cell simulations, we study the scaling of the instability-driven self-electromagnetic fields and consequent defocusing forces with the background plasma density and beam ion mass. We identify plasma parameters where the defocusing forces can be reduced.

Quantized Electromagnetic-Field Propagation in General Non-Local and Non-Stationary Dispersive and Absorbing Media

NASA Astrophysics Data System (ADS)

Jacobs, Verne

Dynamical descriptions for the propagation of quantized electromagnetic fields, in the presence of environmental interactions, are systematically and self-consistently developed in the complimentary Schrödinger and Heisenberg pictures. An open-systems (non-equilibrium) quantum-electrodynamics description is thereby provided for electromagnetic-field propagation in general non-local and non-stationary dispersive and absorbing optical media, including a fundamental microscopic treatment of decoherence and relaxation processes due to environmental collisional and electromagnetic interactions. Particular interest is centered on entangled states and other non-classical states of electromagnetic fields, which may be created by non-linear electromagnetic interactions and detected by the measurement of various electromagnetic-field correlation functions. Accordingly, we present dynamical descriptions based on general forms of electromagnetic-field correlation functions involving both the electric-field and the magnetic-field components of the electromagnetic field, which are treated on an equal footing. Work supported by the Office of Naval Research through the Basic Research Program at The Naval Research Laboratory.

Study on the electromagnetic radiation characteristics of discharging excimer laser system

NASA Astrophysics Data System (ADS)

Zhao, Duliang; Liang, Xu; Fang, Xiaodong; Wang, Qingsheng

2016-10-01

Excimer laser in condition of high voltage, large current and fast discharge will produce strong electromagnetic pulse radiation and electromagnetic interference on the around electrical equipment. The research on characteristics and distribution of excimer laser electromagnetic radiation could provide important basis for electromagnetic shielding and suppressing electromagnetic interference, and further improving the electromagnetic compatibility of system. Firstly, electromagnetic radiation source is analyzed according to the working principle of excimer laser. The key test points of the electromagnetic radiation, hydrogen thyratron, main discharge circuit and laser outlet, are determined by the mechanical structure and the theory of electromagnetic radiation. Secondly, characteristics of electromagnetic field were tested using a near field probe on the key positions of the vertical direction at 20, 50, and 80 cm, respectively. The main radiation frequencies and the radiation field characteristics in the near field are obtained. The experimental results show that the main radiation frequencies distribute in 47, 65, and 130 MHz for electric field and the main radiation frequencies distribute in 34, 100, and 165 MHz for magnetic field. The intensity of electromagnetic field decreases rapidly with the increase of test distance. The higher the frequency increases, the faster the amplitude attenuate. Finally, several electromagnetic interference suppression measurement methods are proposed from the perspective of electromagnetic compatibility according to the test results.

47 CFR 215.1 - Background.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

The Feynman-Vernon Influence Functional Approach in QED

NASA Astrophysics Data System (ADS)

Biryukov, Alexander; Shleenkov, Mark

2016-10-01

In the path integral approach we describe evolution of interacting electromagnetic and fermionic fields by the use of density matrix formalism. The equation for density matrix and transitions probability for fermionic field is obtained as average of electromagnetic field influence functional. We obtain a formula for electromagnetic field influence functional calculating for its various initial and final state. We derive electromagnetic field influence functional when its initial and final states are vacuum. We present Lagrangian for relativistic fermionic field under influence of electromagnetic field vacuum.

Scattering of classical and quantum particles by impulsive fields

NASA Astrophysics Data System (ADS)

Balasin, Herbert; Aichelburg, Peter C.

2018-05-01

We investigate the scattering of classical and quantum particles in impulsive backgrounds fields. These fields model short outbursts of radiation propagating with the speed of light. The singular nature of the problem will be accounted for by the use of Colombeau’s generalized function which however give rise to ambiguities. It is the aim of the paper to show that these ambiguities can be overcome by implementing additional physical conditions, which in the non-singular case would be satisfied automatically. As example we discuss the scattering of classical, Klein–Gordon and Dirac particles in impulsive electromagnetic fields.

The electromagnetic environment of hospitals: how it is affected by the strength of electromagnetic fields generated both inside and outside the hospital.

PubMed

Hanada, Eisuke

2007-01-01

Most problems with the electromagnetic environment of medical institutions have been related to radiated electromagnetic fields and have been constructed from reports about electromagnetic interference (EMI) with electronic medical equipment by the radio waves emitted from mobile telephone handsets. However, radiated electromagnetic fields are just one of the elements. For example, little attention has been placed on problems with the electric power source. Apparatus for clinical treatment and diagnosis that use electric power sources have come into wide use in hospitals. Hospitals must pay careful attention to all elements of the electromagnetic environment. Herein, I will show examples of measurements and measuring methods for radiated electromagnetic fields, static magnetic fields, and power-source noise, common components of the medical electromagnetic environment.

Loophole to the universal photon spectrum in electromagnetic cascades and application to the cosmological lithium problem.

PubMed

Poulin, Vivian; Serpico, Pasquale Dario

2015-03-06

The standard theory of electromagnetic cascades onto a photon background predicts a quasiuniversal shape for the resulting nonthermal photon spectrum. This has been applied to very disparate fields, including nonthermal big bang nucleosynthesis (BBN). However, once the energy of the injected photons falls below the pair-production threshold the spectral shape is much harder, a fact that has been overlooked in past literature. This loophole may have important phenomenological consequences, since it generically alters the BBN bounds on nonthermal relics; for instance, it allows us to reopen the possibility of purely electromagnetic solutions to the so-called "cosmological lithium problem," which were thought to be excluded by other cosmological constraints. We show this with a proof-of-principle example and a simple particle physics model, compared with previous literature.

Cluster observations of reflected EMIC-triggered emission

NASA Astrophysics Data System (ADS)

Grison, B.; Darrouzet, F.; Santolík, O.; Cornilleau-Wehrlin, N.; Masson, A.

2016-05-01

On 19 March 2001, the Cluster fleet recorded an electromagnetic rising tone on the nightside of the plasmasphere. The emission was found to propagate toward the Earth and toward the magnetic equator at a group velocity of about 200 km/s. The Poynting vector is mainly oblique to the background magnetic field and directed toward the Earth. The propagation angle θk,B0 becomes more oblique with increasing magnetic latitude. Inside each rising tone θk,B0 is more field aligned for higher frequencies. Comparing our results to previous ray tracing analysis we conclude that this emission is a triggered electromagnetic ion cyclotron (EMIC) wave generated at the nightside plasmapause. We detect the wave just after its reflection in the plasmasphere. The reflection makes the tone slope shallower. This process can contribute to the formation of pearl pulsations.

78 FR 33633 - Human Exposure to Radiofrequency Electromagnetic Fields

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-04

..., and 15, et al. Human Exposure to Radiofrequency Electromagnetic Fields; Reassessment of Exposure to Radiofrequency Electromagnetic Fields Limits and Policies; Final Rule and Proposed Rule #0;#0;Federal Register... Radiofrequency Electromagnetic Fields AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY...

Conservation laws and stress-energy-momentum tensors for systems with background fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gratus, Jonathan, E-mail: j.gratus@lancaster.ac.uk; The Cockcroft Institute, Daresbury Laboratory, Warrington WA4 4AD; Obukhov, Yuri N., E-mail: yo@thp.uni-koeln.de

2012-10-15

This article attempts to delineate the roles played by non-dynamical background structures and Killing symmetries in the construction of stress-energy-momentum tensors generated from a diffeomorphism invariant action density. An intrinsic coordinate independent approach puts into perspective a number of spurious arguments that have historically lead to the main contenders, viz the Belinfante-Rosenfeld stress-energy-momentum tensor derived from a Noether current and the Einstein-Hilbert stress-energy-momentum tensor derived in the context of Einstein's theory of general relativity. Emphasis is placed on the role played by non-dynamical background (phenomenological) structures that discriminate between properties of these tensors particularly in the context of electrodynamics inmore » media. These tensors are used to construct conservation laws in the presence of Killing Lie-symmetric background fields. - Highlights: Black-Right-Pointing-Pointer The role of background fields in diffeomorphism invariant actions is demonstrated. Black-Right-Pointing-Pointer Interrelations between different stress-energy-momentum tensors are emphasised. Black-Right-Pointing-Pointer The Abraham and Minkowski electromagnetic tensors are discussed in this context. Black-Right-Pointing-Pointer Conservation laws in the presence of nondynamic background fields are formulated. Black-Right-Pointing-Pointer The discussion is facilitated by the development of a new variational calculus.« less

Occupational Electromagnetic Field Exposures Associated with Sleep Quality: A Cross-Sectional Study

PubMed Central

Liu, Hui; Chen, Guangdi; Pan, Yifeng; Chen, Zexin; Jin, Wen; Sun, Chuan; Chen, Chunjing; Dong, Xuanjun; Chen, Kun; Xu, Zhengping; Zhang, Shanchun; Yu, Yunxian

2014-01-01

Background Exposure to electromagnetic field (EMF) emitted by mobile phone and other machineries concerns half the world’s population and raises the problem of their impact on human health. The present study aims to explore the effects of electromagnetic field exposures on sleep quality and sleep duration among workers from electric power plant. Methods A cross-sectional study was conducted in an electric power plant of Zhejiang Province, China. A total of 854 participants were included in the final analysis. The detailed information of participants was obtained by trained investigators using a structured questionnaire, which including socio-demographic characteristics, lifestyle variables, sleep variables and electromagnetic exposures. Physical examination and venous blood collection were also carried out for every study subject. Results After grouping daily occupational electromagnetic exposure into three categories, subjects with long daily exposure time had a significantly higher risk of poor sleep quality in comparison to those with short daily exposure time. The adjusted odds ratios were 1.68 (95%CI: 1.18, 2.39) and 1.57 (95%CI: 1.10, 2.24) across tertiles. Additionally, among the subjects with long-term occupational exposure, the longer daily occupational exposure time apparently increased the risk of poor sleep quality (OR (95%CI): 2.12 (1.23∼3.66) in the second tertile; 1.83 (1.07∼3.15) in the third tertile). There was no significant association of long-term occupational exposure duration, monthly electric fee or years of mobile-phone use with sleep quality or sleep duration. Conclusions The findings showed that daily occupational EMF exposure was positively associated with poor sleep quality. It implies EMF exposure may damage human sleep quality rather than sleep duration. PMID:25340654

75 FR 5009 - Proximity Detection Systems for Underground Mines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-01

... electromagnetic field based systems. After reviewing the different types of systems, MSHA determined that the electromagnetic field based system offers the greatest potential for reducing pinning, crushing, and striking... near RCCMs. An electromagnetic field based system consists of a combination of electromagnetic field...

Electronic Warfare

DTIC Science & Technology

2012-02-08

EMOE is the background electromagnetic environment and the friendly, neutral, and adversarial electronic order of battle within the...X-RayELF VLF MF VHF SHFLF HF Radio Spectrum Visible Spectrum UHF EHF Gamma Ray Cosmic Ray The top bar shows how the electromagnetic spectrum is...effects of sunspots, lightning, and precipitation static. Essentially, the EME is the global EM background . Figure I-2. Electromagnetic Environment

Topological vortices in gauge models of graphene

NASA Astrophysics Data System (ADS)

Zhang, Xin-Hui; Li, Xueqin; Hao, Jin-Bo

2018-06-01

Graphene-like structure possessing the topological vortices and knots, and the magnetic flux of the vortices configuration quantized, are proposed in this paper. The topological charges of the vortices are characterized by Hopf indices and Brower degrees. The Abelian background field action (BF action) is a topological invariant for the knot family, which is just the total sum of all the self-linking numbers and all the linking numbers. Flux quantization opens the possibility of having Aharonov-Bohm-type effects in graphene without external electromagnetic field.

Generation of the relic neutrino asymmetry in a hot plasma of the early universe

NASA Astrophysics Data System (ADS)

Semikoz, Victor B.; Dvornikov, Maxim

The neutrino asymmetry in the early universe plasma, nν ‑ nν¯, is calculated both before and after the electroweak phase transition (EWPT). In the Standard Model, before EWPT, the leptogenesis is well known to be driven by the abelian anomaly in a massless hypercharge field. The generation of the neutrino asymmetry in the Higgs phase after EWPT, in its turn, has not been considered previously because of the absence of any quantum anomaly in an external electromagnetic field for such electroneutral particles as neutrino, unlike the Adler-Bell-Jackiw anomaly for charged left and right polarized massless electrons in the same electromagnetic field. Using the neutrino Boltzmann equation, modified by the Berry curvature term in the momentum space, we establish the violation of the macroscopic neutrino current in plasma after EWPT and exactly reproduce the nonconservation of the lepton current in the symmetric phase before EWPT arising in quantum field theory due to the nonzero lepton hypercharge and corresponding triangle anomaly in an external hypercharge field. In the last case, the nonconservation of the lepton current is derived through the kinetic approach without a computation of corresponding Feynman diagrams. Then, the new kinetic equation is applied for the calculation of the neutrino asymmetry accounting for the Berry curvature and the electroweak interaction with background fermions in the Higgs phase. Such an interaction generates a neutrino asymmetry through the electroweak coupling of neutrino currents with electromagnetic fields in plasma, which is ˜ GF2. It turns out that this effect is especially efficient for maximally helical magnetic fields.

Students' Development of Representational Competence Through the Sense of Touch

NASA Astrophysics Data System (ADS)

Magana, Alejandra J.; Balachandran, Sadhana

2017-06-01

Electromagnetism is an umbrella encapsulating several different concepts like electric current, electric fields and forces, and magnetic fields and forces, among other topics. However, a number of studies in the past have highlighted the poor conceptual understanding of electromagnetism concepts by students even after instruction. This study aims to identify novel forms of "hands-on" instruction that can result in representational competence and conceptual gain. Specifically, this study aimed to identify if the use of visuohaptic simulations can have an effect on student representations of electromagnetic-related concepts. The guiding questions is How do visuohaptic simulations influence undergraduate students' representations of electric forces? Participants included nine undergraduate students from science, technology, or engineering backgrounds who participated in a think-aloud procedure while interacting with a visuohaptic simulation. The think-aloud procedure was divided in three stages, a prediction stage, a minimally visual haptic stage, and a visually enhanced haptic stage. The results of this study suggest that students' accurately characterized and represented the forces felt around a particle, line, and ring charges either in the prediction stage, a minimally visual haptic stage or the visually enhanced haptic stage. Also, some students accurately depicted the three-dimensional nature of the field for each configuration in the two stages that included a tactile mode, where the point charge was the most challenging one.

Electron Gyro-Harmonic Effects on Ionospheric Stimulated Brillouin Scatter

DTIC Science & Technology

2014-08-21

27709-2211 Brillouin, SBS, emission lines, pump frequency stepping, cyclotron , EIC, airglow, upper hybrid REPORT DOCUMENTATION PAGE 11. SPONSOR...direction and the background magnetic field vector, the excited electrostatic wave could be either ion acoustic (IA) or electrostatic ion cyclotron (EIC...A. Hedberg, B. Lundborg, P. Stubbe, H. Kopka, and M. T. Rietveld (1989), Stimulated electromagnetic emission near electron cyclotron harmonics in

Behavior of a high-temperature superconducting conductor on a round core cable at current ramp rates as high as 67.8 kA s-1 in background fields of up to 19 T

NASA Astrophysics Data System (ADS)

Michael, P. C.; Bromberg, L.; van der Laan, D. C.; Noyes, P.; Weijers, H. W.

2016-04-01

High temperature superconducting (HTS) conductor-on-round-core (CORC®) cables have been developed for use in power transmission systems and large high-field magnets. The use of high-current conductors for large-scale magnets reduces system inductance and limits the peak voltage needed for ramped field operation. A CORC® cable contains a large number of RE-Ba2Cu3O7-δ (RE = rare earth) (REBCO) coated conductors, helically wound in multiple layers on a thin, round former. Large-scale applications, such as fusion and accelerator magnets, require current ramp rates of several kilo-Amperes per second during pulsed operation. This paper presents results that demonstrate the electromagnetic stability of a CORC® cable during transient conditions. Measurements were performed at 4.2 K using a 1.55 m long CORC® cable in background fields of up to 19 T. Repeated current pulses in a background field of 19 T at current ramp rates of up to 67.8 kA s-1 to approximately 90% of the cable’s quench current at that field, did not show any sign of degradation in cable performance due to excessive ac loss or electromagnetic instability. The very high current ramp rates applied during these tests were used to compensate, to the extent possible, the limited cable length accommodated by the test facility, assuming that the measured results could be extrapolated to longer length cables operated at proportionally lower current ramp rates. No shift of the superconducting transition to lower current was measured when the current ramp rate was increased from 25 A s-1 to 67.8 kA s-1. These results demonstrate the viability of CORC® cables for use in low-inductance magnets that operate at moderate to high current ramp rates.

Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?

PubMed Central

2014-01-01

Background The past five years has seen considerable expansion of wind power generation in Ontario, Canada. Most recently worries about exposure to electromagnetic fields (EMF) from wind turbines, and associated electrical transmission, has been raised at public meetings and legal proceedings. These fears have not been based on any actual measurements of EMF exposure surrounding existing projects but appear to follow from worries from internet sources and misunderstanding of the science. Methods The study was carried out at the Kingsbridge 1 Wind Farm located near Goderich, Ontario, Canada. Magnetic field measurements were collected in the proximity of 15 Vestas 1.8 MW wind turbines, two substations, various buried and overhead collector and transmission lines, and nearby homes. Data were collected during three operational scenarios to characterize potential EMF exposure: ‘high wind’ (generating power), ‘low wind’ (drawing power from the grid, but not generating power) and ‘shut off’ (neither drawing, nor generating power). Results Background levels of EMF (0.2 to 0.3 mG) were established by measuring magnetic fields around the wind turbines under the ‘shut off’ scenario. Magnetic field levels detected at the base of the turbines under both the ‘high wind’ and ‘low wind’ conditions were low (mean = 0.9 mG; n = 11) and rapidly diminished with distance, becoming indistinguishable from background within 2 m of the base. Magnetic fields measured 1 m above buried collector lines were also within background (≤ 0.3 mG). Beneath overhead 27.5 kV and 500 kV transmission lines, magnetic field levels of up to 16.5 and 46 mG, respectively, were recorded. These levels also diminished rapidly with distance. None of these sources appeared to influence magnetic field levels at nearby homes located as close as just over 500 m from turbines, where measurements immediately outside of the homes were ≤ 0.4 mG. Conclusions The results suggest that there is nothing unique to wind farms with respect to EMF exposure; in fact, magnetic field levels in the vicinity of wind turbines were lower than those produced by many common household electrical devices and were well below any existing regulatory guidelines with respect to human health. PMID:24529028

Collective excitations in Weyl semimetals in the hydrodynamic regime

NASA Astrophysics Data System (ADS)

Sukhachov, P. O.; Gorbar, E. V.; Shovkovy, I. A.; Miransky, V. A.

2018-07-01

The spectrum of collective excitations in Weyl materials is studied by using consistent hydrodynamics. The corresponding framework includes the vortical and chiral anomaly effects, as well as the dependence on the separations between the Weyl nodes in energy b 0 and momentum . The latter are introduced via the Chern–Simons contributions to the electric current and charge densities in Maxwell’s equations. It is found that, even in the absence of a background magnetic field, certain collective excitations (e.g. the helicon-like modes and the anomalous Hall waves) are strongly affected by the chiral shift . In a background magnetic field, the existence of the distinctive longitudinal and transverse anomalous Hall waves with a linear dispersion relation is predicted. They originate from the oscillations of the electric charge density and electromagnetic fields, in which different components of the fields are connected via the anomalous Hall effect in Weyl semimetals.

Effect of high electromagnetic fields on cellular growth

NASA Astrophysics Data System (ADS)

Albalawi, Abdullah; Mustafa, Mohammed; Masood, Samina

It is already known that high-intensity electromagnetic field affect the human lung growth and forces the T-cells to decrease by 20-30 percent. The electromagnetic field had a severe impact on human T-cells in contrast to lung cells. Due to the high-intensity electromagnetic field, the growth of T-cells becomes low and release of Ca+2 increases up to 3.5 times more than the lung cells. The high-intensity electromagnetic radiations do not directly produce cancer cells but had a severe impact on the growth of T-cells. It can also be said that electromagnetic field acts a role in the cancer initiation. It creates disordered in the structure of membranes and gesture transduction. The higher exposure to electromagnetic field increases PKC-alpha and this larger release from membranes cannot be controlled. It was concluded that greater exposure to the electromagnetic field is dangerous and had a severe impact on T-cells growth and lung cells growth and due to this greater possibility of leukemia occurrence. We show a similar effect of electromagnetic fields single celled bacteria to compare the bacterial cellular growth with the human cells using the bacteria strains which are commonly found in human body.

Difficulties in applying numerical simulations to an evaluation of occupational hazards caused by electromagnetic fields

PubMed Central

Zradziński, Patryk

2015-01-01

Due to the various physical mechanisms of interaction between a worker's body and the electromagnetic field at various frequencies, the principles of numerical simulations have been discussed for three areas of worker exposure: to low frequency magnetic field, to low and intermediate frequency electric field and to radiofrequency electromagnetic field. This paper presents the identified difficulties in applying numerical simulations to evaluate physical estimators of direct and indirect effects of exposure to electromagnetic fields at various frequencies. Exposure of workers operating a plastic sealer have been taken as an example scenario of electromagnetic field exposure at the workplace for discussion of those difficulties in applying numerical simulations. The following difficulties in reliable numerical simulations of workers’ exposure to the electromagnetic field have been considered: workers’ body models (posture, dimensions, shape and grounding conditions), working environment models (objects most influencing electromagnetic field distribution) and an analysis of parameters for which exposure limitations are specified in international guidelines and standards. PMID:26323781

Assessment of Electromagnetic Fields at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Ficklen, Carter B.

1995-01-01

This report presents the results of an assessment of ElectroMagnetic Fields (EMF) completed at NASA Langley Research Center as part of the Langley Aerospace Research Summer Scholars Program. This project was performed to determine levels of electromagnetic fields, determine the significance of the levels present, and determine a plan to reduce electromagnetic field exposure, if necessary. This report also describes the properties of electromagnetic fields and their interaction with humans. The results of three major occupational epidemiological studies is presented to determine risks posed to humans by EMF exposure. The data for this report came from peer-reviewed journal articles and government publications pertaining to the health effects of electromagnetic fields.

Effects of magnetic field on the interaction between terahertz wave and non-uniform plasma slab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Yuan; Han, YiPing; Guo, LiXin

2015-10-15

In this paper, the interaction between terahertz electromagnetic wave and a non-uniform magnetized plasma slab is investigated. Different from most of the published literatures, the plasma employed in this work is inhomogeneous in both collision frequency and electron density. Profiles are introduced to describe the non-uniformity of the plasma slab. At the same time, magnetic field is applied to the background of the plasma slab. It came out with an interesting phenomenon that there would be a valley in the absorption band as the plasma's electromagnetic characteristic is affected by the magnetic field. In addition, the valley located just nearmore » the middle of the absorption peak. The cause of the valley's appearance is inferred in this paper. And the influences of the variables, such as magnetic field strength, electron density, and collision frequency, are discussed in detail. The objective of this work is also pointed out, such as the applications in flight communication, stealth, emissivity, plasma diagnose, and other areas of plasma.« less

Covariant electromagnetic field lines

NASA Astrophysics Data System (ADS)

Hadad, Y.; Cohen, E.; Kaminer, I.; Elitzur, A. C.

2017-08-01

Faraday introduced electric field lines as a powerful tool for understanding the electric force, and these field lines are still used today in classrooms and textbooks teaching the basics of electromagnetism within the electrostatic limit. However, despite attempts at generalizing this concept beyond the electrostatic limit, such a fully relativistic field line theory still appears to be missing. In this work, we propose such a theory and define covariant electromagnetic field lines that naturally extend electric field lines to relativistic systems and general electromagnetic fields. We derive a closed-form formula for the field lines curvature in the vicinity of a charge, and show that it is related to the world line of the charge. This demonstrates how the kinematics of a charge can be derived from the geometry of the electromagnetic field lines. Such a theory may also provide new tools in modeling and analyzing electromagnetic phenomena, and may entail new insights regarding long-standing problems such as radiation-reaction and self-force. In particular, the electromagnetic field lines curvature has the attractive property of being non-singular everywhere, thus eliminating all self-field singularities without using renormalization techniques.

Binary black holes' effects on electromagnetic fields.

PubMed

Palenzuela, Carlos; Anderson, Matthew; Lehner, Luis; Liebling, Steven L; Neilsen, David

2009-08-21

In addition to producing gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We here study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as a possible enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.

Three-dimensional modeling of lightning-induced electromagnetic pulses on Venus, Jupiter, and Saturn

NASA Astrophysics Data System (ADS)

Pérez-Invernón, F. J.; Luque, A.; Gordillo-Vázquez, F. J.

2017-07-01

While lightning activity in Venus is still controversial, its existence in Jupiter and Saturn was first detected by the Voyager missions and later on confirmed by Cassini and New Horizons optical recordings in the case of Jupiter, and recently by Cassini on Saturn in 2009. Based on a recently developed 3-D model, we investigate the influence of lightning-emitted electromagnetic pulses on the upper atmosphere of Venus, Saturn, and Jupiter. We explore how different lightning properties such as total energy released and orientation (vertical, horizontal, and oblique) can produce mesospheric transient optical emissions of different shapes, sizes, and intensities. Moreover, we show that the relatively strong background magnetic field of Saturn can enhance the lightning-induced quasi-electrostatic and inductive electric field components above 1000 km of altitude producing stronger transient optical emissions that could be detected from orbital probes.

Geometric Model of Topological Insulators from the Maxwell Algebra

NASA Astrophysics Data System (ADS)

Palumbo, Giandomenico

I propose a novel geometric model of time-reversal-invariant topological insulators in three dimensions in presence of an external electromagnetic field. Their gapped boundary supports relativistic quantum Hall states and is described by a Chern-Simons theory, where the gauge connection takes values in the Maxwell algebra. This represents a non-central extension of the Poincare' algebra and takes into account both the Lorentz and magnetic-translation symmetries of the surface states. In this way, I derive a relativistic version of the Wen-Zee term and I show that the non-minimal coupling between the background geometry and the electromagnetic field in the model is in agreement with the main properties of the relativistic quantum Hall states in the flat space. This work is part of the DITP consortium, a program of the Netherlands Organisation for Scientific Research (NWO) that is funded by the Dutch Ministry of Education, Culture and Science (OCW).

Single electron dynamics in a Hall thruster electromagnetic field profile

NASA Astrophysics Data System (ADS)

Marini, Samuel; Pakter, Renato

2017-05-01

In this work, the single electron dynamics in a simplified three dimensional Hall thruster model is studied. Using Hamiltonian formalism and the concept of limiting curves, one is able to determine confinement conditions for the electron in the acceleration channel. It is shown that as a given parameter of the electromagnetic field is changed, the particle trajectory may transit from regular to chaotic without affecting the confinement, which allows one to make a detailed analysis of the role played by the chaos. The ionization volume is also computed, which measures the probability of an electron to ionize background gas atoms. It is found that there is a great correlation between chaos and increased effective ionization volume. This indicates that a complex dynamical behavior may improve the device efficiency by augmenting the ionization capability of each electron, requiring an overall lower electron current.

Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?

PubMed

McCallum, Lindsay C; Whitfield Aslund, Melissa L; Knopper, Loren D; Ferguson, Glenn M; Ollson, Christopher A

2014-02-15

The past five years has seen considerable expansion of wind power generation in Ontario, Canada. Most recently worries about exposure to electromagnetic fields (EMF) from wind turbines, and associated electrical transmission, has been raised at public meetings and legal proceedings. These fears have not been based on any actual measurements of EMF exposure surrounding existing projects but appear to follow from worries from internet sources and misunderstanding of the science. The study was carried out at the Kingsbridge 1 Wind Farm located near Goderich, Ontario, Canada. Magnetic field measurements were collected in the proximity of 15 Vestas 1.8 MW wind turbines, two substations, various buried and overhead collector and transmission lines, and nearby homes. Data were collected during three operational scenarios to characterize potential EMF exposure: 'high wind' (generating power), 'low wind' (drawing power from the grid, but not generating power) and 'shut off' (neither drawing, nor generating power). Background levels of EMF (0.2 to 0.3 mG) were established by measuring magnetic fields around the wind turbines under the 'shut off' scenario. Magnetic field levels detected at the base of the turbines under both the 'high wind' and 'low wind' conditions were low (mean = 0.9 mG; n = 11) and rapidly diminished with distance, becoming indistinguishable from background within 2 m of the base. Magnetic fields measured 1 m above buried collector lines were also within background (≤ 0.3 mG). Beneath overhead 27.5 kV and 500 kV transmission lines, magnetic field levels of up to 16.5 and 46 mG, respectively, were recorded. These levels also diminished rapidly with distance. None of these sources appeared to influence magnetic field levels at nearby homes located as close as just over 500 m from turbines, where measurements immediately outside of the homes were ≤ 0.4 mG. The results suggest that there is nothing unique to wind farms with respect to EMF exposure; in fact, magnetic field levels in the vicinity of wind turbines were lower than those produced by many common household electrical devices and were well below any existing regulatory guidelines with respect to human health.

Understanding and manipulating the RF fields at high field MRI

PubMed Central

Ibrahim, Tamer S.; Hue, YiK-Kiong; Tang, Lin

2015-01-01

This paper presents a complete overview of the electromagnetics (radiofrequency aspect) of MRI at low and high fields. Using analytical formulations, numerical modeling (computational electromagnetics), and ultrahigh field imaging experiments, the physics that impacts the electromagnetic quantities associated with MRI, namely (1) the transmit field, (2) receive field, and (3) total electromagnetic power absorption, is analyzed. The physical interpretation of the above-mentioned quantities is investigated by electromagnetic theory, to understand ‘What happens, in terms of electromagnetics, when operating at different static field strengths?’ Using experimental studies and numerical simulations, this paper also examines the physical and technological feasibilities by which all or any of these specified electromagnetic quantities can be manipulated through techniques such as B1 shimming (phased array excitation) and signal combination using a receive array in order to advance MRI at high field strengths. Pertinent to this subject and with highly coupled coils operating at 7 T, this paper also presents the first phantom work on B1 shimming without B1 measurements. PMID:19621335

The therapeutic effect of a pulsed electromagnetic field on the reproductive patterns of male Wistar rats exposed to a 2.45-GHz microwave field

PubMed Central

Kumar, Sanjay; Kesari, Kavindra Kumar; Behari, Jitendra

2011-01-01

INTRODUCTION: Environmental exposure to man-made electromagnetic fields has been steadily increasing with the growing demand for electronic items that are operational at various frequencies. Testicular function is particularly susceptible to radiation emitted by electromagnetic fields. OBJECTIVES: This study aimed to examine the therapeutic effects of a pulsed electromagnetic field (100 Hz) on the reproductive systems of male Wistar rats (70 days old). METHODS: The experiments were divided into five groups: microwave sham, microwave exposure (2.45 GHz), pulsed electromagnetic field sham, pulsed electromagnetic field (100 Hz) exposure, and microwave/pulsed electromagnetic field exposure. The animals were exposed for 2 hours/day for 60 days. After exposure, the animals were sacrificed, their sperm was used for creatine and caspase assays, and their serum was used for melatonin and testosterone assays. RESULTS: The results showed significant increases in caspase and creatine kinase and significant decreases in testosterone and melatonin in the exposed groups. This finding emphasizes that reactive oxygen species (a potential inducer of cancer) are the primary cause of DNA damage. However, pulsed electromagnetic field exposure relieves the effect of microwave exposure by inducing Faraday currents. CONCLUSIONS: Electromagnetic fields are recognized as hazards that affect testicular function by generating reactive oxygen species and reduce the bioavailability of androgen to maturing spermatozoa. Thus, microwave exposure adversely affects male fertility, whereas pulsed electromagnetic field therapy is a non-invasive, simple technique that can be used as a scavenger agent to combat oxidative stress. PMID:21876981

Exposure to electromagnetic fields aboard high-speed electric multiple unit trains.

PubMed

Niu, D; Zhu, F; Qiu, R; Niu, Q

2016-01-01

High-speed electric multiple unit (EMU) trains generate high-frequency electric fields, low-frequency magnetic fields, and high-frequency wideband electromagnetic emissions when running. Potential human health concerns arise because the electromagnetic disturbances are transmitted mainly into the car body from windows, and from there to passengers and train staff. The transmission amount and amplitude distribution characteristics that dominate electromagnetic field emission need to be studied, and the exposure level of electromagnetic field emission to humans should be measured. We conducted a series of tests of the on board electromagnetic field distribution on several high-speed railway lines. While results showed that exposure was within permitted levels, the possibility of long-term health effects should be investigated.

Simulation of PEP-II Accelerator Backgrounds Using TURTLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barlow, R.J.; Fieguth, T.; /SLAC

2006-02-15

We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using LPTURTLE, a modified version of the DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full program of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modeling of limiting apertures in bothmore » collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.« less

Effect of hot injections on electromagnetic ion-cyclotron waves in inner magnetosphere of Saturn

NASA Astrophysics Data System (ADS)

Kumari, Jyoti; Kaur, Rajbir; Pandey, R. S.

2018-02-01

Encounter of Voyager with Saturn's environment revealed the presence of electromagnetic ion-cyclotron waves (EMIC) in Saturnian magnetosphere. Cassini provided the evidence of dynamic particle injections in inner magnetosphere of Saturn. Also inner magnetosphere of Saturn has highest rotational flow shear as compared to any other planet in our solar system. Hence during these injections, electrons and ions are transported to regions of stronger magnetic field, thus gaining energy. The dynamics of the inner magnetosphere of Saturn are governed by wave-particle interaction. In present paper we have investigated those EMIC waves pertaining in background plasma which propagates obliquely with respect to the magnetic field of Saturn. Applying kinetic approach, the expression for dispersion relation and growth rate has been derived. Magnetic field model has been used to incorporate magnetic field strength at different latitudes for radial distance of 6.18 R_{{s}} (1 R_{{s}}= 60{,}268 km). Various parameters affecting the growth of EMIC waves in cold bi-Maxwellian background and after the hot injections has been studied. Parametric analysis inferred that after hot injections, growth rate of EMIC waves increases till 10° and decreases eventually with increase in latitude due to ion density distribution in near-equatorial region. Also, growth rate of EMIC waves increases with increasing value of temperature anisotropy and AC frequency, but the growth rate decreases as the angle of propagation with respect to B0 (Magnetic field at equator) increases. The injection events which assume the Loss-cone distribution of particles, affect the lower wave numbers of the spectra.

Approach for describing spatial dynamics of quantum light-matter interaction in dispersive dissipative media

NASA Astrophysics Data System (ADS)

Zyablovsky, A. A.; Andrianov, E. S.; Nechepurenko, I. A.; Dorofeenko, A. V.; Pukhov, A. A.; Vinogradov, A. P.

2017-05-01

Solving the challenging problem of the amplification and generation of an electromagnetic field in nanostructures enables us to implement many properties of the electromagnetic field at the nanoscale in practical applications. A first-principles quantum-mechanical consideration of such a problem is sufficiently restricted by the exponentially large number of degrees of freedom and does not allow the electromagnetic-field dynamics to be described if it involves a high number of interacting atoms and modes of the electromagnetic field. Conversely, the classical description of electromagnetic fields is incorrect at the nanoscale due to the high level of quantum fluctuations connected to high dissipation and noise levels. In this paper, we develop a framework with a significantly reduced number of degrees of freedom, which describes the quantum spatial dynamics of electromagnetic fields interacting with atoms. As an example, we consider the interaction between atoms placed in a metallic subwavelength groove and demonstrate that a spontaneously excited electromagnetic pulse propagates with the group velocity. The developed approach may be exploited to describe nonuniform amplification and propagation of electromagnetic fields in arbitrary dispersive dissipative systems.

Covariant relativistic hydrodynamics of multispecies plasma and generalized Ohm's law

NASA Astrophysics Data System (ADS)

Gedalin, Michael

1996-04-01

Fully covariant hydrodynamical equations for a multispecies relativistic plasma in an external electromagnetic field are derived. The derived multifluid description takes into account binary Coulomb collisions, annihilation, and interaction with the photon background in terms of the invariant collision cross sections. A generalized Ohm's law is derived in a manifestly covariant form. Particular attention is devoted to the relativistic electron-positron plasma.

A study of temporal dynamics and spatial variability of power frequency electromagnetic fields in Saint-Petersburg

NASA Astrophysics Data System (ADS)

Sturman, V. I.

2018-01-01

This paper studies spatial distribution and temporal dynamics of power frequency electric and magnetic fields in Saint-Petersburg. It was determined that sanitary-protection and exclusion zones of the standard size high-voltage transmission lines (HVTL) do not always ensure maximum allowable limits of the electrical field depression. A dependence of the electric field strength on meteorological factors was defined. A series of sources create a city-wide background for magnetic fields. That said, the heavier the man-caused load is, the higher the mean values of magnetic induction are. Abnormally high values of magnetic induction are explained by the influence of underground electric cables.

A border-ownership model based on computational electromagnetism.

PubMed

Zainal, Zaem Arif; Satoh, Shunji

2018-03-01

The mathematical relation between a vector electric field and its corresponding scalar potential field is useful to formulate computational problems of lower/middle-order visual processing, specifically related to the assignment of borders to the side of the object: so-called border ownership (BO). BO coding is a key process for extracting the objects from the background, allowing one to organize a cluttered scene. We propose that the problem is solvable simultaneously by application of a theorem of electromagnetism, i.e., "conservative vector fields have zero rotation, or "curl." We hypothesize that (i) the BO signal is definable as a vector electric field with arrowheads pointing to the inner side of perceived objects, and (ii) its corresponding scalar field carries information related to perceived order in depth of occluding/occluded objects. A simple model was developed based on this computational theory. Model results qualitatively agree with object-side selectivity of BO-coding neurons, and with perceptions of object order. The model update rule can be reproduced as a plausible neural network that presents new interpretations of existing physiological results. Results of this study also suggest that T-junction detectors are unnecessary to calculate depth order. Copyright © 2017 Elsevier Ltd. All rights reserved.

78 FR 33654 - Reassessment of Exposure to Radiofrequency Electromagnetic Fields Limits and Policies

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-04

... Docket Nos. 03-137 and 13-84; FCC 13-39] Reassessment of Exposure to Radiofrequency Electromagnetic... electromagnetic fields. The Commission's further proposals reflect an effort to provide more efficient, practical... RF electromagnetic fields. The Commission underscores that in conducting this review it will work...

Coupling of pulsed electromagnetic fields (PEMF) therapy to molecular grounds of the cell

PubMed Central

Funk, Richard HW

2018-01-01

In this review we compile results cited in reliable journals that show a ratio for the use of pulsed electromagnetic fields (PEMF) in therapy, indeed. This is true especially for chronically inflamed joints. Furthermore, we try to link this therapeutic approach to the molecular background of chronic inflammation and arthritis. At first we start with the clinical outcome of PEMF therapy. Then, we look for possible triggers and an electromagnetic counterpart that is endogenously inherent in cell biology and in the tissues of interest. Finally, we want to investigate causal molecular and cellular mechanisms of possible PEMF actions. It shows that there are endogenous mechanisms, indeed, which can act as triggers for PEMF like the resting membrane potential as well as resonance mechanisms in charged moieties like membrane transporters. Especially voltage-gated calcium channels can be triggered. These may lead into specific signaling pathways and also may elicit nitric oxide as well as moderate radical reactions, which can ultimately lead to e.g. NFκB-like reactions. Concerted in the right way, these reactions can cause a kind of cell protection and ultimately lead to a dampening of inflammatory signals like interleukins. PMID:29887943

Generation of scale invariant magnetic fields in bouncing universes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sriramkumar, L.; Atmjeet, Kumar; Jain, Rajeev Kumar, E-mail: sriram@physics.iitm.ac.in, E-mail: katmjeet@physics.du.ac.in, E-mail: jain@cp3.dias.sdu.dk

2015-09-01

We consider the generation of primordial magnetic fields in a class of bouncing models when the electromagnetic action is coupled non-minimally to a scalar field that, say, drives the background evolution. For scale factors that have the power law form at very early times and non-minimal couplings which are simple powers of the scale factor, one can easily show that scale invariant spectra for the magnetic field can arise before the bounce for certain values of the indices involved. It will be interesting to examine if these power spectra retain their shape after the bounce. However, analytical solutions for themore » Fourier modes of the electromagnetic vector potential across the bounce are difficult to obtain. In this work, with the help of a new time variable that we introduce, which we refer to as the e-N-fold, we investigate these scenarios numerically. Imposing the initial conditions on the modes in the contracting phase, we numerically evolve the modes across the bounce and evaluate the spectra of the electric and magnetic fields at a suitable time after the bounce. As one could have intuitively expected, though the complete spectra depend on the details of the bounce, we find that, under the original conditions, scale invariant spectra of the magnetic fields do arise for wavenumbers much smaller than the scale associated with the bounce. We also show that magnetic fields which correspond to observed strengths today can be generated for specific values of the parameters. But, we find that, at the bounce, the backreaction due to the electromagnetic modes that have been generated can be significantly large calling into question the viability of the model. We briefly discuss the implications of our results.« less

Sensing network for electromagnetic fields generated by seismic activities

NASA Astrophysics Data System (ADS)

Gershenzon, Naum I.; Bambakidis, Gust; Ternovskiy, Igor V.

2014-06-01

The sensors network is becoming prolific and play now increasingly more important role in acquiring and processing information. Cyber-Physical Systems are focusing on investigation of integrated systems that includes sensing, networking, and computations. The physics of the seismic measurement and electromagnetic field measurement requires special consideration how to design electromagnetic field measurement networks for both research and detection earthquakes and explosions along with the seismic measurement networks. In addition, the electromagnetic sensor network itself could be designed and deployed, as a research tool with great deal of flexibility, the placement of the measuring nodes must be design based on systematic analysis of the seismic-electromagnetic interaction. In this article, we review the observations of the co-seismic electromagnetic field generated by earthquakes and man-made sources such as vibrations and explosions. The theoretical investigation allows the distribution of sensor nodes to be optimized and could be used to support existing geological networks. The placement of sensor nodes have to be determined based on physics of electromagnetic field distribution above the ground level. The results of theoretical investigations of seismo-electromagnetic phenomena are considered in Section I. First, we compare the relative contribution of various types of mechano-electromagnetic mechanisms and then analyze in detail the calculation of electromagnetic fields generated by piezomagnetic and electrokinetic effects.

Photovoltaic system test facility electromagnetic interference measurements

NASA Technical Reports Server (NTRS)

Johnson, J. A.; Herke, F. P., Jr.; Knapp, W. D.

1977-01-01

Field strength measurements on a single row of panels indicates that the operational mode of the array as configured presents no radiated EMI problems. Only one relatively significant frequency band near 200 kHz showed any degree of intensity (9 muV/m including a background level of 5 muV/m). The level was measured very near the array (at 20 ft distance) while Federal Communications Commission (FCC) regulations limit spurious emissions to 15 muV/m at 1,000 ft. No field strength readings could be obtained even at 35 ft distant.

The Seven-Segment Data Logger

NASA Astrophysics Data System (ADS)

Bates, Alan

2015-12-01

Instruments or digital meters with data values visible on a seven-segment display can easily be found in the physics lab. Examples include multimeters, sound level meters, Geiger-Müller counters and electromagnetic field meters, where the display is used to show numerical data. Such instruments, without the ability to connect to computers or data loggers, can measure and display data at a particular instant in time. The user should be present to read the display and to record the data. Unlike these digital meters, the sensor-data logger system has the advantage of automatically measuring and recording data at selectable sample rates over a desired sample time. The process of adding data logging features to a digital meter with a seven-segment display can be achieved with Seven Segment Optical Character Recognition (SSOCR) software. One might ask, why not just purchase a field meter with data logging features? They are relatively inexpensive, reliable, available online, and can be delivered within a few days. But then there is the challenge of making your own instrument, the excitement of implementing a design, the pleasure of experiencing an entire process from concept to product, and the satisfaction of avoiding costs by taking advantage of available technology. This experiment makes use of an electromagnetic field meter with a seven-segment liquid crystal display to measure background electromagnetic field intensity. Images of the meter display are automatically captured with a camera and analyzed using SSOCR to produce a text file containing meter display values.

Dirac equation in 2-dimensional curved spacetime, particle creation, and coupled waveguide arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koke, Christian, E-mail: christian.koke@stud.uni-heidelberg.de; Noh, Changsuk, E-mail: changsuk@kias.re.kr; Angelakis, Dimitris G., E-mail: dimitris.angelakis@gmail.com

When quantum fields are coupled to gravitational fields, spontaneous particle creation may occur similarly to when they are coupled to external electromagnetic fields. A gravitational field can be incorporated as a background spacetime if the back-action of matter on the field can be neglected, resulting in modifications of the Dirac or Klein–Gordon equations for elementary fermions and bosons respectively. The semi-classical description predicts particle creation in many situations, including the expanding-universe scenario, near the event horizon of a black hole (the Hawking effect), and an accelerating observer in flat spacetime (the Unruh effect). In this work, we give a pedagogicalmore » introduction to the Dirac equation in a general 2D spacetime and show examples of spinor wave packet dynamics in flat and curved background spacetimes. In particular, we cover the phenomenon of particle creation in a time-dependent metric. Photonic analogs of these effects are then proposed, where classical light propagating in an array of coupled waveguides provides a visualisation of the Dirac spinor propagating in a curved 2D spacetime background. The extent to which such a single-particle description can be said to mimic particle creation is discussed.« less

Acute neuroprotective effects of extremely low-frequency electromagnetic fields after traumatic brain injury in rats.

PubMed

Yang, Yang; Li, Ling; Wang, Yan-Gang; Fei, Zhou; Zhong, Jun; Wei, Li-Zhou; Long, Qian-Fa; Liu, Wei-Ping

2012-05-10

Traumatic brain injury commonly has a result of a short window of opportunity between the period of initial brain injury and secondary brain injury, which provides protective strategies and can reduce damages of brain due to secondary brain injury. Previous studies have reported neuroprotective effects of extremely low-frequency electromagnetic fields. However, the effects of extremely low-frequency electromagnetic fields on neural damage after traumatic brain injury have not been reported yet. The present study aims to investigate effects of extremely low-frequency electromagnetic fields on neuroprotection after traumatic brain injury. Male Sprague-Dawley rats were used for the model of lateral fluid percussion injury, which were placed in non-electromagnetic fields and 15 Hz (Hertz) electromagnetic fields with intensities of 1 G (Gauss), 3 G and 5 G. At various time points (ranging from 0.5 to 30 h) after lateral fluid percussion injury, rats were treated with kainic acid (administered by intraperitoneal injection) to induce apoptosis in hippocampal cells. The results were as follows: (1) the expression of hypoxia-inducible factor-1α was dramatically decreased during the neuroprotective time window. (2) The kainic acid-induced apoptosis in the hippocampus was significantly decreased in rats exposed to electromagnetic fields. (3) Electromagnetic fields exposure shortened the escape time in water maze test. (4) Electromagnetic fields exposure accelerated the recovery of the blood-brain barrier after brain injury. These findings revealed that extremely low-frequency electromagnetic fields significantly prolong the window of opportunity for brain protection and enhance the intensity of neuroprotection after traumatic brain injury. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Electromagnetic cellular interactions.

PubMed

Cifra, Michal; Fields, Jeremy Z; Farhadi, Ashkan

2011-05-01

Chemical and electrical interaction within and between cells is well established. Just the opposite is true about cellular interactions via other physical fields. The most probable candidate for an other form of cellular interaction is the electromagnetic field. We review theories and experiments on how cells can generate and detect electromagnetic fields generally, and if the cell-generated electromagnetic field can mediate cellular interactions. We do not limit here ourselves to specialized electro-excitable cells. Rather we describe physical processes that are of a more general nature and probably present in almost every type of living cell. The spectral range included is broad; from kHz to the visible part of the electromagnetic spectrum. We show that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and discuss experimental evidence on electromagnetic cellular interactions in the modern scientific literature. Although small, it is continuously accumulating. Copyright © 2010 Elsevier Ltd. All rights reserved.

The variation of the fine-structure constant from disformal couplings

NASA Astrophysics Data System (ADS)

van de Bruck, Carsten; Mifsud, Jurgen; Nunes, Nelson J.

2015-12-01

We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure constant, α. As a result, the theory we consider can explain the non-zero reported variation in the evolution of α by purely considering disformal couplings. We also find that if matter and photons are coupled in the same way to the scalar field, disformal couplings itself do not lead to a variation of the fine-structure constant. A number of scenarios are discussed consistent with the current astrophysical, geochemical, laboratory and the cosmic microwave background radiation constraints on the cosmological evolution of α. The models presented are also consistent with the current type Ia supernovae constraints on the effective dark energy equation of state. We find that the Oklo bound in particular puts strong constraints on the model parameters. From our numerical results, we find that the introduction of a non-minimal electromagnetic coupling enhances the cosmological variation in α. Better constrained data is expected to be reported by ALMA and with the forthcoming generation of high-resolution ultra-stable spectrographs such as PEPSI, ESPRESSO, and ELT-HIRES. Furthermore, an expected increase in the sensitivity of molecular and nuclear clocks will put a more stringent constraint on the theory.

The variation of the fine-structure constant from disformal couplings

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Bruck, Carsten van; Mifsud, Jurgen; Nunes, Nelson J., E-mail: c.vandebruck@sheffield.ac.uk, E-mail: jmifsud1@sheffield.ac.uk, E-mail: njnunes@fc.ul.pt

2015-12-01

We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure constant, α. As a result, the theory we consider can explain the non-zero reported variation in the evolution of α by purely considering disformal couplings. We also find that if matter and photons are coupled in the same way to the scalar field, disformal couplings itself do not lead to a variation of the fine-structure constant. A number of scenarios are discussed consistent with themore » current astrophysical, geochemical, laboratory and the cosmic microwave background radiation constraints on the cosmological evolution of α. The models presented are also consistent with the current type Ia supernovae constraints on the effective dark energy equation of state. We find that the Oklo bound in particular puts strong constraints on the model parameters. From our numerical results, we find that the introduction of a non-minimal electromagnetic coupling enhances the cosmological variation in α. Better constrained data is expected to be reported by ALMA and with the forthcoming generation of high-resolution ultra-stable spectrographs such as PEPSI, ESPRESSO, and ELT-HIRES. Furthermore, an expected increase in the sensitivity of molecular and nuclear clocks will put a more stringent constraint on the theory.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vieira, H.S., E-mail: horacio.santana.vieira@hotmail.com; Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba, CEP 58233-000, Araruna, PB; Bezerra, V.B., E-mail: valdir@fisica.ufpb.br

Charged massive scalar fields are considered in the gravitational and electromagnetic field produced by a dyonic black hole with a cosmic string along its axis of symmetry. Exact solutions of both angular and radial parts of the covariant Klein–Gordon equation in this background are obtained, and are given in terms of the confluent Heun functions. The role of the presence of the cosmic string in these solutions is showed up. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation spectrum and the energy flux. -- Highlights:more » •A cosmic string is introduced along the axis of symmetry of the dyonic black hole. •The covariant Klein–Gordon equation for a charged massive scalar field in this background is analyzed. •Both angular and radial parts are transformed to a confluent Heun equation. •The resulting Hawking radiation spectrum and the energy flux are obtained.« less

Electromagnetic Fields and Public Health: Mobile Phones

MedlinePlus

... Ebola virus disease » Home / News / Fact sheets / Detail Electromagnetic fields and public health: mobile phones 8 October ... fixed antennas called base stations. Radiofrequency waves are electromagnetic fields, and unlike ionizing radiation such as X- ...

The Impact of Electromagnetic Cascades of Very-high Energy Gamma Rays on the Extragalactic Gamma-ray Background

NASA Technical Reports Server (NTRS)

Venters, Tonia

2012-01-01

As very high energy (VHE) photons propagate through the extragalactic background light (EBL), they interact with the soft photons of the EBL and initiate electromagnetic cascades of photons and electrons. The collective intensity of a cosmological population emitting at VHEs (such as blazars) will be attenuated at the highest energies through interactions with the EBL and enhanced at lower energies by the resulting cascade. As such, depending on the space density and spectra of the sources and the model of the EBL, cascade radiation can provide a significant contribution to the extragalactic gamma-ray background (EGB). Through deflections of the charged particles of the cascade, an intergalactic magnetic field (IGMF) may leave an imprint on the anisotropy properties of the EGB. The impact of a strong IGMF is to isotropize lower energy cascade photons, inducing a modulation in the anisotropy energy spectrum of the EGB. We discuss the implications of cascade radiation for the origins of the EGB and the nature of the IGMF, as well as insight that will be provided by data from the Fermi Large Area Telescope in the upcoming years.

AC induction field heating of graphite foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klett, James W.; Rios, Orlando; Kisner, Roger

A magneto-energy apparatus includes an electromagnetic field source for generating a time-varying electromagnetic field. A graphite foam conductor is disposed within the electromagnetic field. The graphite foam when exposed to the time-varying electromagnetic field conducts an induced electric current, the electric current heating the graphite foam. An energy conversion device utilizes heat energy from the heated graphite foam to perform a heat energy consuming function. A device for heating a fluid and a method of converting energy are also disclosed.

Growth of etiolated barley plants in weak static and 50 Hz electromagnetic fields tuned to calcium ion cyclotron resonance

PubMed Central

Pazur, Alexander; Rassadina, Valentina; Dandler, Jörg; Zoller, Jutta

2006-01-01

Background The effects of weak magnetic and electromagnetic fields in biology have been intensively studied on animals, microorganisms and humans, but comparably less on plants. Perception mechanisms were attributed originally to ferrimagnetism, but later discoveries required additional explanations like the "radical pair mechanism" and the "Ion cyclotron resonance" (ICR), primarily considered by Liboff. The latter predicts effects by small ions involved in biological processes, that occur in definite frequency- and intensity ranges ("windows") of simultaneously impacting magnetic and electromagnetic fields related by a linear equation, which meanwhile is proven by a number of in vivo and in vitro experiments. Methods Barley seedlings (Hordeum vulgare, L. var. Steffi) were grown in the dark for 5 and 6 days under static magnetic and 50 Hz electromagnetic fields matching the ICR conditions of Ca2+. Control cultures were grown under normal geomagnetic conditions, not matching this ICR. Morphology, pigmentation and long-term development of the adult plants were subsequently investigated. Results The shoots of plants exposed to Ca2+-ICR exposed grew 15–20% shorter compared to the controls, the plant weight was 10–12% lower, and they had longer coleoptiles that were adhering stronger to the primary leaf tissue. The total pigment contents of protochlorophyllide (PChlide) and carotenoids were significantly decreased. The rate of PChlide regeneration after light irradiation was reduced for the Ca2+-ICR exposed plants, also the Shibata shift was slightly delayed. Even a longer subsequent natural growing phase without any additional fields could only partially eliminate these effects: the plants initially exposed to Ca2+-ICR were still significantly shorter and had a lower chlorophyll (a+b) content compared to the controls. A continued cultivation and observation of the adult plants under natural conditions without any artificial electromagnetic fields showed a retardation of the originally Ca2+-ICR exposed plants compared to control cultures lasting several weeks, with an increased tendency for dehydration. Conclusion A direct influence of the applied MF and EMF is discussed affecting Ca2+ levels via the ICR mechanism. It influences the available Ca2+ and thereby regulatory processes. Theoretical considerations on molecular level focus on ionic interactions with water related to models using quantum electrodynamics. PMID:16457719

The effect of a longitudinal density gradient on electron plasma wake field acceleration

NASA Astrophysics Data System (ADS)

Tsiklauri, David

2016-12-01

Three-dimensional, particle-in-cell, fully electromagnetic simulations of electron plasma wake field acceleration in the blow-out regime are presented. Earlier results are extended by (i) studying the effect of a longitudinal density gradient, (ii) avoiding the use of a co-moving simulation box, (iii) inclusion of ion motion, and (iv) studying fully electromagnetic plasma wake fields. It is established that injecting driving and trailing electron bunches into a positive density gradient of 10-fold increasing density over 10 cm long lithium vapour plasma results in spatially more compact and three times larger, compared with the uniform density case, electric fields (-6.4×1010 V m-1), leading to acceleration of the trailing bunch up to 24.4 GeV (starting from an initial 20.4 GeV), with energy transfer efficiencies from the leading to trailing bunch of 75%. In the uniform density case, a -2.5×1010 V m-1 wake is created leading to acceleration of the trailing bunch up to 22.4 GeV, with energy transfer efficiencies of 65%. It is also established that injecting the electron bunches into a negative density gradient of 10-fold decreasing density over 10 cm long plasma results in spatially more spread and two and a half smaller electric fields (-1.0×1010 V m-1), leading to a weaker acceleration of the trailing bunch up to 21.4 GeV, with energy transfer efficiencies of 45%. Taking ion motions into consideration shows that in the plasma wake ion number density can increase over a few times the background value. It is also shown that transverse electromagnetic fields in a plasma wake are of the same order as the longitudinal (electrostatic) ones.

Verification of the effects of Schumann frequency range electromagnetic fields on the human cardiovascular system

NASA Astrophysics Data System (ADS)

Tuzhilkin, D. A.; Borodin, A. S.

2017-11-01

The results of the study of variations in the electromagnetic background parameters of the Schumann resonator frequency range and the variability indices of the human heart period during its free activity are presented on the basis of 24-hour synchronous monitoring data. It is shown that the integral evaluation of the conjugacy of the heart rate variability indices from the Schumann resonance parameters is extremely weak. In this case, the differential evaluation of this dependence with separation into characteristic time intervals of the day, characterized by different motor activity of the subjects, becomes significantly higher. The number of volunteers whose conjugacy is characterized by a strong correlation in some cases reaches 35 percent of the sample.

Slowing down the speed of light using an electromagnetically-induced-transparency mechanism in a modified reservoir

NASA Astrophysics Data System (ADS)

Liu, Ronggang; Liu, Tong; Wang, Yingying; Li, Yujie; Gai, Bingzheng

2017-11-01

We propose an effective method to achieve extremely slow light by using both the mechanism of electromagnetically induced transparency (EIT) and the localization of a coupled cavity waveguide (CCW). Based on quantum mechanics theory and the dispersion relation of a CCW, we derive a group-velocity formula that reveals both the effects of the EIT and CCW. Results show that ultralow light velocity at the order of several meters per second or even static light, could be obtained feasibly. In comparison with the EIT mechanism in a background of vacuum, this proposed method is more effective and realistic to achieve extremely slow light. And it exhibits potential values in the field of light storage.

A Hamiltonian electromagnetic gyrofluid model

NASA Astrophysics Data System (ADS)

Waelbroeck, F. L.; Hazeltine, R. D.; Morrison, P. J.

2009-11-01

An isothermal truncation of the electromagnetic gyrofluid model of Snyder and Hammett [Phys. Plasmas 8, 3199 (2001)] is shown to be Hamiltonian. The corresponding noncanonical Lie-Poisson bracket and its Casimir invariants are presented. The model describes the evolution of the density, the electrostatic potential, and the component of the vector potential along a strong background field. This makes it suitable for describing such phenomena as the propagation of kinetic-Alfv'en modons, the nonlinear saturation of drift-tearing modes, and the diamagnetic stabilization of the internal kink. The invariants are used to obtain a set of coupled Grad-Shafranov equations describing equilibria and propagating coherent structures. They also lead to a Lagrangian formulation of the equations of motion that is well suited to solution with the PIC method.

Noninvasive valve monitor using alternating electromagnetic field

DOEpatents

Eissenberg, David M.; Haynes, Howard D.; Casada, Donald A.

1993-01-01

One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

Noninvasive valve monitor using alternating electromagnetic field

DOEpatents

Eissenberg, D.M.; Haynes, H.D.; Casada, D.A.

1993-03-16

One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

Nanomechanical electric and electromagnetic field sensor

DOEpatents

Datskos, Panagiotis George; Lavrik, Nickolay

2015-03-24

The present invention provides a system for detecting and analyzing at least one of an electric field and an electromagnetic field. The system includes a micro/nanomechanical oscillator which oscillates in the presence of at least one of the electric field and the electromagnetic field. The micro/nanomechanical oscillator includes a dense array of cantilevers mounted to a substrate. A charge localized on a tip of each cantilever interacts with and oscillates in the presence of the electric and/or electromagnetic field. The system further includes a subsystem for recording the movement of the cantilever to extract information from the electric and/or electromagnetic field. The system further includes a means of adjusting a stiffness of the cantilever to heterodyne tune an operating frequency of the system over a frequency range.

Introducing Electromagnetic Field Momentum

ERIC Educational Resources Information Center

Hu, Ben Yu-Kuang

2012-01-01

I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…

Hand-held UXO Discriminator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gasperikova, E.; Smith, J.T.; Kappler, K.N.

2010-04-01

With prior funding (UX-1225, MM-0437, and MM-0838), we have successfully designed and built a cart-mounted Berkeley UXO Discriminator (BUD) and demonstrated its performance at various test sites (e.g., Gasperikova et al., 2007, 2009). It is a multi-transmitter multi-receiver active electromagnetic system that is able to discriminate UXO from scrap at a single measurement position, hence eliminates equirement of a very accurate sensor location. The cart-mounted system comprises of three orthogonal transmitters and eight pairs of differenced receivers (Smith et al., 2007). Receiver coils are located on ymmetry lines through the center of the system and see identical fields during themore » on-time of the pulse in all of the transmitter coils. They can then be wired in opposition to produce zero output during the n-ime of the pulses in three orthogonal transmitters. Moreover, this configuration dramatically reduces noise in the measurements by canceling the background electromagnetic fields (these fields are uniform ver the scale of the receiver array and are consequently nulled by the differencing operation), and by canceling the noise contributed by the tilt of the receivers in the Earth's magnetic field, and therefore reatly enhances receivers sensitivity to the gradients of the target.« less

Conserved charges for black holes in Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics in AdS space

NASA Astrophysics Data System (ADS)

Mišković, Olivera; Olea, Rodrigo

2011-01-01

Motivated by possible applications within the framework of anti-de Sitter gravity/conformal field theory correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by nonlinear electrodynamics are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary nonlinear electrodynamic Lagrangian in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, it extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Falloff conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass and vacuum energy as conserved quantities associated to an asymptotic timelike Killing vector are computed using a background-independent regularization of the gravitational action based on the addition of counterterms which are a given polynomial in the intrinsic and extrinsic curvatures.

Conserved charges for black holes in Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics in AdS space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miskovic, Olivera; Olea, Rodrigo; Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso

2011-01-15

Motivated by possible applications within the framework of anti-de Sitter gravity/conformal field theory correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by nonlinear electrodynamics are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary nonlinear electrodynamic Lagrangian in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, itmore » extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Falloff conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass and vacuum energy as conserved quantities associated to an asymptotic timelike Killing vector are computed using a background-independent regularization of the gravitational action based on the addition of counterterms which are a given polynomial in the intrinsic and extrinsic curvatures.« less

Avionics electromagnetic interference immunity and environment

NASA Technical Reports Server (NTRS)

Clarke, C. A.

1986-01-01

Aircraft electromagnetic spectrum and radio frequency (RF) field strengths are charted, profiling the higher levels of electromagnetic voltages encountered by the commercial aircraft wiring. Selected military, urban, and rural electromagnetic field levels are plotted and provide a comparison of radiation amplitudes. Low frequency magnetic fields and electric fields from 400 H(Z) power systems are charted versus frequency and wire separation to indicate induced voltages on adjacent or neighboring circuits. Induced EMI levels and attenuation characteristics of electric, magnetic, RF fields, and transients are plotted and graphed for common types of wire circuits. The significance of wire circuit returns and shielding is emphasized to highlight the techniques that help block the paths of electromagnetic interference and maintain avionic interface signal quality.

Gravitational scattering of electromagnetic radiation

NASA Technical Reports Server (NTRS)

Brooker, J. T.; Janis, A. I.

1980-01-01

The scattering of electromagnetic radiation by linearized gravitational fields is studied to second order in a perturbation expansion. The incoming electromagnetic radiation can be of arbitrary multipole structure, and the gravitational fields are also taken to be advanced fields of arbitrary multipole structure. All electromagnetic multipole radiation is found to be scattered by gravitational monopole and time-varying dipole fields. No case has been found, however, in which any electromagnetic multipole radiation is scattered by gravitational fields of quadrupole or higher-order multipole structure. This lack of scattering is established for infinite classes of special cases, and is conjectured to hold in general. The results of the scattering analysis are applied to the case of electromagnetic radiation scattered by a moving mass. It is shown how the mass and velocity may be determined by a knowledge of the incident and scattered radiation.

Quark and gluon production from a boost-invariantly expanding color electric field

NASA Astrophysics Data System (ADS)

Taya, Hidetoshi

2017-07-01

Particle production from an expanding classical color electromagnetic field is extensively studied, motivated by the early stage dynamics of ultrarelativistic heavy ion collisions. We develop a formalism at one-loop order to compute the particle spectra by canonically quantizing quark, gluon, and ghost fluctuations under the presence of such an expanding classical color background field; the canonical quantization is done in the τ -η coordinates in order to take into account manifestly the expanding geometry. As a demonstration, we model the expanding classical color background field by a boost-invariantly expanding homogeneous color electric field with lifetime T , for which we obtain analytically the quark and gluon production spectra by solving the equations of motion of QCD nonperturbatively with respect to the color electric field. In this paper we study (i) the finite lifetime effect, which is found to modify significantly the particle spectra from those expected from the Schwinger formula; (ii) the difference between the quark and gluon production; and (iii) the quark mass dependence of the production spectra. Implications of these results to ultrarelativistic heavy ion collisions are also discussed.

Spacetimes dressed with stealth electromagnetic fields

NASA Astrophysics Data System (ADS)

Smolić, Ivica

2018-04-01

Stealth field configurations by definition have a vanishing energy-momentum tensor, and thus do not contribute to the gravitational field equations. While only trivial fields can be stealth in Maxwell's electrodynamics, nontrivial stealth fields appear in some nonlinear models of electromagnetism. We find the necessary and sufficient conditions for the electromagnetic fields to be stealth and analyze which models admit such configurations. Furthermore, we present some concrete exact solutions, featuring a class of black holes dressed with the stealth electromagnetic hair, closely related to force-free solutions. Stealth hair does not alter the generalized Smarr formula, but may contribute to the Komar charges.

Infrared signal generation from AC induction field heating of graphite foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klett, James W.; Rios, Orlando

A magneto-energy apparatus includes an electromagnetic field source for generating a time-varying electromagnetic field. A graphite foam conductor is disposed within the electromagnetic field. The graphite foam when exposed to the time-varying electromagnetic field conducts an induced electric current, the electric current heating the graphite foam to produce light. An energy conversion device utilizes light energy from the heated graphite foam to perform a light energy consuming function. A device for producing light and a method of converting energy are also disclosed.

Detecting Stealth Dark Matter Directly through Electromagnetic Polarizability.

PubMed

Appelquist, T; Berkowitz, E; Brower, R C; Buchoff, M I; Fleming, G T; Jin, X-Y; Kiskis, J; Kribs, G D; Neil, E T; Osborn, J C; Rebbi, C; Rinaldi, E; Schaich, D; Schroeder, C; Syritsyn, S; Vranas, P; Weinberg, E; Witzel, O

2015-10-23

We calculate the spin-independent scattering cross section for direct detection that results from the electromagnetic polarizability of a composite scalar "stealth baryon" dark matter candidate, arising from a dark SU(4) confining gauge theory-"stealth dark matter." In the nonrelativistic limit, electromagnetic polarizability proceeds through a dimension-7 interaction leading to a very small scattering cross section for dark matter with weak-scale masses. This represents a lower bound on the scattering cross section for composite dark matter theories with electromagnetically charged constituents. We carry out lattice calculations of the polarizability for the lightest "baryon" states in SU(3) and SU(4) gauge theories using the background field method on quenched configurations. We find the polarizabilities of SU(3) and SU(4) to be comparable (within about 50%) normalized to the stealth baryon mass, which is suggestive for extensions to larger SU(N) groups. The resulting scattering cross sections with a xenon target are shown to be potentially detectable in the dark matter mass range of about 200-700 GeV, where the lower bound is from the existing LUX constraint while the upper bound is the coherent neutrino background. Significant uncertainties in the cross section remain due to the more complicated interaction of the polarizablity operator with nuclear structure; however, the steep dependence on the dark matter mass, 1/m(B)(6), suggests the observable dark matter mass range is not appreciably modified. We briefly highlight collider searches for the mesons in the theory as well as the indirect astrophysical effects that may also provide excellent probes of stealth dark matter.

Department of Defense Interface Standard Electromagnetic Environmental Effects Requirements for Systems

DTIC Science & Technology

2002-12-19

effective tool in evaluating IMI. A5.2.2 Shipboard internal electromagnetic environment (EME). For ship applications, electric fields (peak V/m-rms...effects waveform parameters ........................................ 9 MIL-STD-464A v CONTENTS Page TABLES 2B Electromagnetic fields from near...blasting of hardware. 3.8 Lightning indirect effects. Electrical transients induced by lightning due to coupling of electromagnetic fields . 3.9

Quantization of Electromagnetic Fields in Cavities

NASA Technical Reports Server (NTRS)

Kakazu, Kiyotaka; Oshiro, Kazunori

1996-01-01

A quantization procedure for the electromagnetic field in a rectangular cavity with perfect conductor walls is presented, where a decomposition formula of the field plays an essential role. All vector mode functions are obtained by using the decomposition. After expanding the field in terms of the vector mode functions, we get the quantized electromagnetic Hamiltonian.

An electromagnetic method for removing the communication blackout with a space vehicle upon re-entry into the atmosphere

NASA Astrophysics Data System (ADS)

Cheng, Jianjun; Jin, Ke; Kou, Yong; Hu, Ruifeng; Zheng, Xiaojing

2017-03-01

When a hypersonic vehicle travels in the Earth and Mars atmosphere, the surface of the vehicle is surrounded by a plasma layer, which is an envelope of ionized air, created from the compression and heat of the atmosphere by the shock wave. The vehicles will lose contact with ground stations known as the reentry communication blackout. Based on the magnetohydrodynamic framework and electromagnetic wave propagation theory, an analytical model is proposed to describe the effect of the effectiveness of electromagnetic mitigation scheme on removing the reentry communication blackout. C and Global Positioning System (GPS) bands, two commonly used radio bands for communication, are taken as the cases to discuss the effectiveness of the electromagnetic field mitigation scheme. The results show that the electron density near the antenna of vehicles can be reduced by the electromagnetic field, and the required external magnetic field strength is far below the one in the magnetic window method. The directions of the external electric field and magnetic field have a significant impact on the effectiveness of the mitigation scheme. Furthermore, the effect of electron collisions on the required applied electromagnetic field is discussed, and the result indicates that electron collisions are a key factor to analyze the electromagnetic mitigation scheme. Finally, the feasible regions of the applied electromagnetic field for eliminating blackout are given. These investigations could have a significant benefit on the design and optimization of electromagnetic mitigation scheme for the blackout problem.

Aircraft Electromagnetic Compatibility.

DTIC Science & Technology

1987-06-01

Human Exposure to Radio Frequency Electromagnetic Fields , 300 KiloHertz to 100 GigaHertz." 6. ARINC 429-8, "Digital Information Transfer System (DITS...142 V EXECUTIVE SUMMARY The Aircraft Electromagnetic Compatibility guidelines document deals with electromagnetic compatibility in a... electromagnetic interference paths (figure EI. TYPE PATH 400 Hz Electrostatic MagneticCharge Electric Field Transients 5 R d t Coupling 150/i 300o Wire

Atomic-Scale Lightning Rod Effect in Plasmonic Picocavities: A Classical View to a Quantum Effect.

PubMed

Urbieta, Mattin; Barbry, Marc; Zhang, Yao; Koval, Peter; Sánchez-Portal, Daniel; Zabala, Nerea; Aizpurua, Javier

2018-01-23

Plasmonic gaps are known to produce nanoscale localization and enhancement of optical fields, providing small effective mode volumes of about a few hundred nm 3 . Atomistic quantum calculations based on time-dependent density functional theory reveal the effect of subnanometric localization of electromagnetic fields due to the presence of atomic-scale features at the interfaces of plasmonic gaps. Using a classical model, we explain this as a nonresonant lightning rod effect at the atomic scale that produces an extra enhancement over that of the plasmonic background. The near-field distribution of atomic-scale hot spots around atomic features is robust against dynamical screening and spill-out effects and follows the potential landscape determined by the electron density around the atomic sites. A detailed comparison of the field distribution around atomic hot spots from full quantum atomistic calculations and from the local classical approach considering the geometrical profile of the atoms' electronic density validates the use of a classical framework to determine the effective mode volume in these extreme subnanometric optical cavities. This finding is of practical importance for the community of surface-enhanced molecular spectroscopy and quantum nanophotonics, as it provides an adequate description of the local electromagnetic fields around atomic-scale features with use of simplified classical methods.

A Practical HTS SQUID Magnetometer System for NDI of Aircraft

DTIC Science & Technology

1994-01-10

based on present-day high Tc SQUIDs is feasible, and present a portable design cooled by a miniature cryocooler . In addition, a reevaluation of the basic...integration of this cryocooler with SQUIDs, is that there is no available electromagnetic field emission information. We did not find any for other types ...background signals. Third, there are several other types of cryocoolers , integrated or split, made of plastics available on the market. They will

The Effects of Electromagnetic Fields on The Nervous System,

DTIC Science & Technology

Superior Cervical Ganglia: Design of Waveguide Apparatus, and Calculation of Specific Absorption Rate; Effects of Electromagnetic Fields on Muscle ... Contraction ; Effects of Electromagnetic Fields on Auditory System: Effect of Noise Masking on Threshold of Evoked Auditory Responses, Microwave-induced Cochlear Microphonics in Guinea Pigs.

[Proposal for magnetic/electromagnetic fields protection norms on national level].

PubMed

Dordević, Drago; Raković, Dejan

2008-01-01

The modern life is not possible without application of magnetic/electromagnetic fields, which can be both helpful and harmful for human body. The non-ionizing radiation, especially magnetic/electromagnetic fields of all frequencies (0-300 GHz), can have many harmful effects on the human health that is confirmed by numerous epidemiological studies, studies with volunteers, animal studies, and in vitro studies. Proposal for magnetic/electromagnetic fields protection norms on national level based on the WHO Program for Environment, International Commission on Non-Ionizing Radiation Protection (ICNIRP)], and WHO International EMF Project. Protection from harmful effects of the magnetic/electromagnetic fields is still a great problem in many countries of modern society--huge costs, impaired quality of life, and more important, damage to the human health. Numerous data and publications of harmful effects of the magnetic/electromagnetic fields represents one's country basic necessary documentation for making decisions and law documents for protection norms on national level concerning the health maintenance according to the ICNIRP normatives.

Biological Effects of Nonionizing Electromagnetic Radiation. Volume IV. Number 3.

DTIC Science & Technology

1980-03-01

lines that produce EMR. perimental evidence on human health effects due to electromagnetic field exposures from high-voltage transmission lines is...1311, Mrch YOW that a permissible occupational exposure level to The biologic effects of electromagnetic fields on MW and RF radiation of 500 PW/cm 2...along with the principal physical param- eters of exposure . 6402 REGULATING POSSIBLE HEALTH EFFECTS FROM AC TRANSMISSION LINE ELECTROMAGNETIC FIELDS

Electromagnetically Induced Absorption (EIA) and a ``Twist'' on Nonlinear Magneto-optical Rotation (NMOR) with Cold Atoms

NASA Astrophysics Data System (ADS)

Kunz, Paul; Meyer, David; Quraishi, Qudsia

2015-05-01

Within the class of nonlinear optical effects that exhibit sub-natural linewidth features, electromagnetically induced transparency (EIT) and nonlinear magneto-optical rotation (NMOR) stand out as having made dramatic impacts on various applications including atomic clocks, magnetometry, and single photon storage. A related effect, known as electromagnetically induced absorption (EIA), has received less attention in the literature. Here, we report on the first observation of EIA in cold atoms using the Hanle configuration, where a single laser beam is used to both pump and probe the atoms while sweeping a magnetic field through zero along the beam direction. We find that, associated with the EIA peak, a ``twist'' appears in the corresponding NMOR signal. A similar twist has been previously noted by Budker et al., in the context of warm vapor optical magnetometry, and was ascribed to optical pumping through nearby hyperfine levels. By studying this feature through numerical simulations and cold atom experiments, thus rendering the hyperfine levels well resolved, we enhance the understanding of the optical pumping mechanism behind it, and elucidate its relation to EIA. Finally, we demonstrate a useful application of these studies through a simple and rapid method for nulling background magnetic fields within our atom chip apparatus.

Geometric phase for a static two-level atom in cosmic string spacetime

NASA Astrophysics Data System (ADS)

Cai, Huabing; Ren, Zhongzhou

2018-05-01

We investigate the geometric phase of a static two-level atom immersed in a bath of fluctuating vacuum electromagnetic field in the background of a cosmic string. Our results indicate that due to the existence of the string, the geometric phase depends crucially on the position and the polarizability of the atom relative to the string. This can be ascribed to the fact that the presence of the string profoundly modify the distribution of electric field in Minkowski spacetime. So in principle, we can detect the cosmic string by experiments involving geometric phase.

Angular momentum and torque described with the complex octonion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weng, Zi-Hua, E-mail: xmuwzh@xmu.edu.cn

2014-08-15

The paper aims to adopt the complex octonion to formulate the angular momentum, torque, and force etc in the electromagnetic and gravitational fields. Applying the octonionic representation enables one single definition of angular momentum (or torque, force) to combine some physics contents, which were considered to be independent of each other in the past. J. C. Maxwell used simultaneously two methods, the vector terminology and quaternion analysis, to depict the electromagnetic theory. It motivates the paper to introduce the quaternion space into the field theory, describing the physical feature of electromagnetic and gravitational fields. The spaces of electromagnetic field andmore » of gravitational field can be chosen as the quaternion spaces, while the coordinate component of quaternion space is able to be the complex number. The quaternion space of electromagnetic field is independent of that of gravitational field. These two quaternion spaces may compose one octonion space. Contrarily, one octonion space can be separated into two subspaces, the quaternion space and S-quaternion space. In the quaternion space, it is able to infer the field potential, field strength, field source, angular momentum, torque, and force etc in the gravitational field. In the S-quaternion space, it is capable of deducing the field potential, field strength, field source, current continuity equation, and electric (or magnetic) dipolar moment etc in the electromagnetic field. The results reveal that the quaternion space is appropriate to describe the gravitational features, including the torque, force, and mass continuity equation etc. The S-quaternion space is proper to depict the electromagnetic features, including the dipolar moment and current continuity equation etc. In case the field strength is weak enough, the force and the continuity equation etc can be respectively reduced to that in the classical field theory.« less

Note on Inverse Bremsstrahlung in a Strong Electromagnetic Field

DOE R&D Accomplishments Database

Bethe, H. A.

1972-09-01

The collisional energy loss of an electron undergoing forced oscillation in an electromagnetic field behaves quite differently in the low and high intensity limits. ... It is shown that in the case of an electromagnetic field v {sub o} >> v {sub t} the rate of transfer is much slower, and actually decreases with the strength of the field.

47 CFR 97.13 - Restrictions on station location.

Code of Federal Regulations, 2012 CFR

2012-10-01

... cause human exposure to RF electromagnetic field levels in excess of those allowed under § 1.1310 of... power). (2) If the routine environmental evaluation indicates that the RF electromagnetic fields could... action to prevent human exposure to such RF electromagnetic fields. Further information on evaluating...

SYSTEMS FOR EXPOSING MICE TO 2,450-MHZ ELECTROMAGNETIC FIELDS

EPA Science Inventory

Two systems for exposing mice to 2,450-MHz electromagnetic fields are described. In a waveguide system, four mice were placed in a Styrofoam cage and exposed dorsally to circularly polarized electromagnetic fields. The temperature and humidity in the mouse holder were kept consta...

47 CFR 97.13 - Restrictions on station location.

Code of Federal Regulations, 2011 CFR

2011-10-01

... cause human exposure to RF electromagnetic field levels in excess of those allowed under § 1.1310 of... power). (2) If the routine environmental evaluation indicates that the RF electromagnetic fields could... action to prevent human exposure to such RF electromagnetic fields. Further information on evaluating...

47 CFR 97.13 - Restrictions on station location.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cause human exposure to RF electromagnetic field levels in excess of those allowed under § 1.1310 of... power). (2) If the routine environmental evaluation indicates that the RF electromagnetic fields could... action to prevent human exposure to such RF electromagnetic fields. Further information on evaluating...

47 CFR 97.13 - Restrictions on station location.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cause human exposure to RF electromagnetic field levels in excess of those allowed under § 1.1310 of... power). (2) If the routine environmental evaluation indicates that the RF electromagnetic fields could... action to prevent human exposure to such RF electromagnetic fields. Further information on evaluating...

47 CFR 97.13 - Restrictions on station location.

Code of Federal Regulations, 2010 CFR

2010-10-01

... cause human exposure to RF electromagnetic field levels in excess of those allowed under § 1.1310 of... power). (2) If the routine environmental evaluation indicates that the RF electromagnetic fields could... action to prevent human exposure to such RF electromagnetic fields. Further information on evaluating...

Stimulated Brillouin scatter in a magnetized ionospheric plasma.

PubMed

Bernhardt, P A; Selcher, C A; Lehmberg, R H; Rodriguez, S P; Thomason, J F; Groves, K M; McCarrick, M J; Frazer, G J

2010-04-23

High power electromagnetic waves transmitted from the HAARP facility in Alaska can excite low-frequency electrostatic waves by magnetized stimulated Brillouin scatter. Either an ion-acoustic wave with a frequency less than the ion cyclotron frequency (f(CI)) or an electrostatic ion cyclotron (EIC) wave just above f(CI) can be produced. The coupled equations describing the magnetized stimulated Brillouin scatter instability show that the production of both ion-acoustic and EIC waves is strongly influenced by the wave propagation relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions using the HAARP transmitter have confirmed that only ion-acoustic waves are excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The ion composition can be obtained from the measured EIC frequency.

A novel model of interaction between high frequency electromagnetic non-ionizing fields and microtubules viewed as coupled two-degrees of freedom harmonic oscillators.

PubMed

Caligiuri, Luigi Maxmilian

2015-01-01

The question regarding the potential biological and adverse health effects of non-ionizing electromagnetic fields on living organisms is of primary importance in biophysics and medicine. Despite the several experimental evidences showing such occurrence in a wide frequency range from extremely low frequency to microwaves, a definitive theoretical model able to explain a possible mechanism of interaction between electromagnetic fields and living matter, especially in the case of weak and very weak intensities, is still missing. In this paper it has been suggested a possible mechanism of interaction involving the resonant absorption of electromagnetic radiation by microtubules. To this aim these have been modeled as non-dissipative forced harmonic oscillators characterized by two coupled "macroscopic" degrees of freedom, respectively describing longitudinal and transversal vibrations induced by the electromagnetic field. We have shown that the proposed model, although at a preliminary stage, is able to explain the ability of even weak electromagnetic radiating electromagnetic fields to transfer high quantities of energy to living systems by means of a resonant mechanism, so capable to easily damage microtubules structure.

A modified Bitter-type electromagnet and control system for cold atom experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luan, Tian; Zhou, Tianwei; Chen, Xuzong, E-mail: xuzongchen@pku.edu.cn

2014-02-15

We present a modified Bitter-type electromagnet which features high magnetic field, fine electronic properties and efficient heat removal. The electromagnet is constructed from a stack of copper layers separated by mica layers that have the same shape. A distinctive design of cooling channels on the insulating layers and the parallel ducts between the layers ensures low resistance for cooling water to flow. A continuous current control system is also made to regulate the current through the electromagnet. In our experiment, versatile electromagnets are applied to generate magnetic field and gradient field. From our measurements, a peak magnetic field of 1000more » G and a peak gradient field of 80 G/cm are generated in the center of the apparatuses which are 7 cm and 5 cm away from the edge of each electromagnet with a current of 230 A and 120 A, respectively. With the effective feedback design in the current control system and cooling water flow of 3.8 l/min, the stability of the current through the electromagnets can reach 10{sup −5}.« less

Electromagnetic perception and individual features of human beings.

PubMed

Lebedeva, N N; Kotrovskaya, T I

2001-01-01

An investigation was made of the individual reactions of human subjects exposed to electromagnetic fields. We performed the study on 86 volunteers separated into two groups. The first group was exposed to the electromagnetic field of infralow frequencies, whereas the second group was exposed to the electromagnetic field of extremely high frequencies. We found that the electromagnetic perception of human beings correlated with their individual features, such as EEG parameters, the critical frequency of flash merging, and the electric current sensitivity. Human subjects who had a high-quality perception of electromagnetic waves showed an optimal balance of cerebral processes, an excellent functional state of the central nervous system, and a good decision criterion.

Magnetic Earth Ionosphere Resonant Frequencies (NASA-MEIRF Project)

NASA Technical Reports Server (NTRS)

1994-01-01

During this current reporting period, the project has focused on completing Phase 1 of the field monitoring work and documenting research results. Highlights of these efforts include presentations of papers at the annual joint meeting of the American Physical Society/American Association of Physics Teachers, April 18-22, 1994, in Crystal City, Virginia, and at the International Space, Time, and Gravitation Conference and Etoiles de L'Ecole Polytechnique Symposium, May 23-28, 1994, in St. Petersburg, Russia. Field measurements of the background ultra low frequency (ULF) electromagnetic spectrum in the New Mexico and Texas regions show interesting differences. Included are papers entitled 'Triplet Solution of the Twin Paradox' and 'Classical Electron Mass and Fields, Part 3.'

Terahertz electromagnetic fields (0.106 THz) do not induce manifest genomic damage in vitro.

PubMed

Hintzsche, Henning; Jastrow, Christian; Kleine-Ostmann, Thomas; Kärst, Uwe; Schrader, Thorsten; Stopper, Helga

2012-01-01

Terahertz electromagnetic fields are non-ionizing electromagnetic fields in the frequency range from 0.1 to 10 THz. Potential applications of these electromagnetic fields include the whole body scanners, which currently apply millimeter waves just below the terahertz range, but future scanners will use higher frequencies in the terahertz range. These and other applications will bring along human exposure to these fields. Up to now, only a limited number of investigations on biological effects of terahertz electromagnetic fields have been performed. Therefore, research is strongly needed to enable reliable risk assessment.Cells were exposed for 2 h, 8 h, and 24 h with different power intensities ranging from 0.04 mW/cm(2) to 2 mW/cm(2), representing levels below, at, and above current safety limits. Genomic damage on the chromosomal level was measured as micronucleus formation. DNA strand breaks and alkali-labile sites were quantified with the comet assay. No DNA strand breaks or alkali-labile sites were observed as a consequence of exposure to terahertz electromagnetic fields in the comet assay. The fields did not cause chromosomal damage in the form of micronucleus induction.

Terahertz Electromagnetic Fields (0.106 THz) Do Not Induce Manifest Genomic Damage In Vitro

PubMed Central

Hintzsche, Henning; Jastrow, Christian; Kleine-Ostmann, Thomas; Kärst, Uwe; Schrader, Thorsten; Stopper, Helga

2012-01-01

Terahertz electromagnetic fields are non-ionizing electromagnetic fields in the frequency range from 0.1 to 10 THz. Potential applications of these electromagnetic fields include the whole body scanners, which currently apply millimeter waves just below the terahertz range, but future scanners will use higher frequencies in the terahertz range. These and other applications will bring along human exposure to these fields. Up to now, only a limited number of investigations on biological effects of terahertz electromagnetic fields have been performed. Therefore, research is strongly needed to enable reliable risk assessment. Cells were exposed for 2 h, 8 h, and 24 h with different power intensities ranging from 0.04 mW/cm2 to 2 mW/cm2, representing levels below, at, and above current safety limits. Genomic damage on the chromosomal level was measured as micronucleus formation. DNA strand breaks and alkali-labile sites were quantified with the comet assay. No DNA strand breaks or alkali-labile sites were observed as a consequence of exposure to terahertz electromagnetic fields in the comet assay. The fields did not cause chromosomal damage in the form of micronucleus induction. PMID:23029508

Idiopathic environmental intolerance attributed to electromagnetic fields: a content analysis of British newspaper reports.

PubMed

Eldridge-Thomas, Buffy; Rubin, G James

2013-01-01

Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) is a controversial condition in which people describe symptoms following exposure to electromagnetic fields from everyday electrical devices. However, double-blind experiments have found no convincing evidence that electromagnetic fields cause these symptoms. In this study, we assessed whether recent newspaper reporting in the UK reflected this scientific evidence. We searched a database of newspaper articles to identify all those that contained IEI-EMF related keywords and selected a random sample of 60 for content analysis. For our primary outcomes, we assessed how many articles mainly or wholly presented an electromagnetic cause for IEI-EMF and how many discussed unproven treatments for the condition such as strategies intended to reduce exposure to electromagnetic fields or the use of complementary and alternative therapies. We also assessed whether the type of information source used by a newspaper article (e.g. scientist, person with IEI-EMF, politician) or the type of newspaper (broadsheet, tabloid, local or regional) was associated with either outcome. Of the 60 articles, 43 (71.7%) presented a mainly electromagnetic cause, compared to 13 (21.7%) which presented mainly non-electromagnetic causes and 4 (6.7%) which did not discuss a cause. 29 (48.3%) did not mention any potential treatment, while 24 (40.0%) mentioned eletromagnetic field related strategies and 12 (20.0%) mentioned complementary or alternative therapies. Articles which quoted someone with IEI-EMF were significantly more likely to report an electromagnetic cause and to present unproven treatments. Those which used a scientist as a source were more likely to present a non-electromagnetic cause for the condition. The widespread poor reporting we identified is disappointing and has the potential for to encourage more people to misattribute their symptoms to electromagnetic fields. Scientists should remain engaged with the media to counteract this effect.

Note: An approach to 1000 T using the electro-magnetic flux compression.

PubMed

Nakamura, D; Sawabe, H; Takeyama, S

2018-01-01

The maximum magnetic field obtained by the electro-magnetic flux compression technique was investigated with respect to the initial seed magnetic field. It was found that the reduction in the seed magnetic field from 3.8 T to 3.0 T led to a substantial increase in the final peak magnetic field. The optical Faraday rotation method with a minimal size probe evades disturbances from electromagnetic noise and shockwave effects to detect such final peak fields in a reduced space of an inner wall of the imploding liner. The Faraday rotation signal recorded the maximum magnetic field increased significantly to the highest magnetic field of 985 T approaching 1000 T, ever achieved by the electro-magnetic flux compression technique as an indoor experiment.

Extremely low frequency 7 Hz 100 microT electromagnetic radiation promotes differentiation in the human epithelial cell line HaCaT.

PubMed

Lisi, Antonella; Foletti, Alberto; Ledda, Mario; Rosola, Emanuela; Giuliani, Livio; D'Emilia, Enrico; Grimaldi, Settimio

2006-01-01

Electromagnetic therapy is a treatment method in which an electromagnetic or magnetic stimulus is used to achieve physiological changes in the body. The specific aim of the present work concerns the effectiveness of low frequency electromagnetic fields to modify the biochemical properties of human keratinocytes (HaCaT). Cells exposed to a 7 Hz 100 microT electromagnetic field for one hour (twice daily), indicated modification in shape and morphology. These modifications were also associated with different actin distribution as revealed by phalloidin fluorescence analysis. Indirect immunofluorescence with fluorescent antibodies against involucrin and beta-Catenin, both differentiation and adhesion markers, revealed an increase in involucrin and beta-Catenin expression, supporting the conclusion that exposure to electromagnetic field carries keratinocytes to an upper differentiation level. This study confirms our previous observation and supports the hypothesis that 7 Hz electromagnetic field, may modify cell biochemistry interfering in the differentiation and cellular adhesion of normal keratinocytes.

Pulsed electromagnetic field with or without exercise therapy in the treatment of benign prostatic hyperplasia

PubMed Central

Elgohary, Hany M; Tantawy, Sayed A

2017-01-01

[Purpose] To investigate the effect of pulsed electromagnetic field with or without exercise therapy in the treatment of benign prostatic hyperplasia. [Subjects and Methods] Sixty male patients aged 55–65 years with benign prostatic hyperplasia were invited to participate in this study. Patients were randomly assigned to Group A (n=20; patients who received pulsed electromagnetic field in addition to pelvic floor and aerobic exercises), Group B (n=20; patients who received pulsed electromagnetic field), and Group C (n=20; patients who received placebo electromagnetic field). The assessments included post-void residual urine, urine flow rate, prostate specific antigen, white blood cells count, and International Prostate Symptom Score were weighed, before and after a 4-week intervention. [Results] There were significant differences in Group A and B in all parameters. Group C showed non-significant differences in all measured variables except for International Prostate Symptom Score. Among groups, all parameters showed highly significant differences in favor of Group A. There were non-significant differences between Group A and B and significant difference between Groups A and C and between Groups B and C. [Conclusion] The present study demonstrated that electromagnetic field had a significant impact on the treatment of benign prostatic hyperplasia. Accordingly, electromagnetic field can be utilized alone or in combination with other physiotherapy modalities. Moreover, clinicians should have the capacity to perceive the advantages accomplished using extra treatment alternatives. Electromagnetic field is a safe, noninvasive method and can be used for the treatment of benign prostatic hyperplasia. PMID:28878453

Ponderomotive Force in the Presence of Electric Fields

NASA Technical Reports Server (NTRS)

Khazanov, G. V.; Krivorutsky, E. N.

2013-01-01

This paper presents averaged equations of particle motion in an electromagnetic wave of arbitrary frequency with its wave vector directed along the ambient magnetic field. The particle is also subjected to an E cross B drift and a background electric field slowly changing in space and acting along the magnetic field line. The fields, wave amplitude, and the wave vector depend on the coordinate along the magnetic field line. The derivations of the ponderomotive forces are done by assuming that the drift velocity in the ambient magnetic field is comparable to the particle velocity. Such a scenario leads to new ponderomotive forces, dependent on the wave magnetic field intensity, and, as a result, to the additional energy exchange between the wave and the plasma particles. It is found that the parallel electric field can lead to the change of the particle-wave energy exchange rate comparable to that produced by the previously discussed ponderomotive forces.

The magnetic field investigation on the ARASE (ERG) mission: Data characteristics and initial scientific results

NASA Astrophysics Data System (ADS)

Matsuoka, A.; Teramoto, M.; Nomura, R.; Nose, M.; Fujimoto, A.; Tanaka, Y.; Shinohara, M.; Nagatsuma, T.; Shiokawa, K.; Obana, Y.; Miyoshi, Y.; Takashima, T.; Shinohara, I.

2017-12-01

The ARASE (ERG) satellite was successfully launched on December 20 2016. A fluxgate magnetometer (MGF) was built for the ARASE satellite to measure DC and low-frequency magnetic field. The requirements to the magnetic field measurements by ARASE was defined as (1) accuracy of the absolute field intensity is within 5 nT (2) angular accuracy of the field direction is within 1 degree (3) measurement frequency range is from DC to 60Hz or wider. MGF measures the vector magnetic field with the original sampling frequency of 256 Hz. The dynamic range is switched between +/-8000nT and +/- 60000nT according to the background field intensity. The MGF initial checkout was carried on January 10th 2017, when the MGF normal performance and downlinked data were confirmed. The 5-m length MAST for the sensor was deployed on 17th January. The nominal operation of MGF started in March 2017. The MGF data are calibrated based on the results from the ground experiments and in-orbit data analysis. The MGF CDF files are distributed by the ARASE Science Center and available by Space Physics Environment Data Analysis Software (SPEDAS). The acceleration process of the charged particles in the inner magnetosphere is considered to be closely related to the deformation and perturbation of the magnetic field. Accurate measurement of the magnetic field is required to understand the acceleration mechanism of the charged particles, which is one of the major scientific objectives of the ARASE mission. We designed a fluxgate magnetometer which is optimized to investigate following topics; (1) accurate measurement of the background magnetic field - the deformation of the magnetic field and its relationship with the particle acceleration. (2) MHD waves - measurement of the ULF electromagnetic waves of frequencies about 1mHz (Pc4-5), and investigation of the radiation-belt electrons radially diffused by the resonance with the ULF waves. (3) EMIC waves - measurement of the electromagnetic ion-cyclotron waves of frequencies about 1Hz, and investigation of the ring-current ions and radiation-belt electrons dissipated by the interaction with the EMIC waves.These scientific subjects are now investigated by the ARASE working team colleagues.

Generating highly uniform electromagnetic field characteristics

DOEpatents

Crow, James Terry

1998-01-01

An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

Generating highly uniform electromagnetic field characteristics

DOEpatents

Crow, James T.

1998-01-01

An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

Generating highly uniform electromagnetic field characteristics

DOEpatents

Crow, James T.

1997-01-01

An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially cancelling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

Influence of Electric, Magnetic, and Electromagnetic Fields on the Circadian System: Current Stage of Knowledge

PubMed Central

Żak, Arkadiusz

2014-01-01

One of the side effects of each electrical device work is the electromagnetic field generated near its workplace. All organisms, including humans, are exposed daily to the influence of different types of this field, characterized by various physical parameters. Therefore, it is important to accurately determine the effects of an electromagnetic field on the physiological and pathological processes occurring in cells, tissues, and organs. Numerous epidemiological and experimental data suggest that the extremely low frequency magnetic field generated by electrical transmission lines and electrically powered devices and the high frequencies electromagnetic radiation emitted by electronic devices have a potentially negative impact on the circadian system. On the other hand, several studies have found no influence of these fields on chronobiological parameters. According to the current state of knowledge, some previously proposed hypotheses, including one concerning the key role of melatonin secretion disruption in pathogenesis of electromagnetic field induced diseases, need to be revised. This paper reviews the data on the effect of electric, magnetic, and electromagnetic fields on melatonin and cortisol rhythms—two major markers of the circadian system as well as on sleep. It also provides the basic information about the nature, classification, parameters, and sources of these fields. PMID:25136557

Weak Broadband Electromagnetic Fields are More Disruptive to Magnetic Compass Orientation in a Night-Migratory Songbird (Erithacus rubecula) than Strong Narrow-Band Fields

PubMed Central

Schwarze, Susanne; Schneider, Nils-Lasse; Reichl, Thomas; Dreyer, David; Lefeldt, Nele; Engels, Svenja; Baker, Neville; Hore, P. J.; Mouritsen, Henrik

2016-01-01

Magnetic compass orientation in night-migratory songbirds is embedded in the visual system and seems to be based on a light-dependent radical pair mechanism. Recent findings suggest that both broadband electromagnetic fields ranging from ~2 kHz to ~9 MHz and narrow-band fields at the so-called Larmor frequency for a free electron in the Earth’s magnetic field can disrupt this mechanism. However, due to local magnetic fields generated by nuclear spins, effects specific to the Larmor frequency are difficult to understand considering that the primary sensory molecule should be organic and probably a protein. We therefore constructed a purpose-built laboratory and tested the orientation capabilities of European robins in an electromagnetically silent environment, under the specific influence of four different oscillating narrow-band electromagnetic fields, at the Larmor frequency, double the Larmor frequency, 1.315 MHz or 50 Hz, and in the presence of broadband electromagnetic noise covering the range from ~2 kHz to ~9 MHz. Our results indicated that the magnetic compass orientation of European robins could not be disrupted by any of the relatively strong narrow-band electromagnetic fields employed here, but that the weak broadband field very efficiently disrupted their orientation. PMID:27047356

[Medical and biologic research of electromagnetic fields in radiofrequencies range. Results and prospects].

PubMed

Kaliada, T V; Vishnevskiĭ, A M; Gorodetskiĭ, B N; Plekhanov, V P; Kuznetsov, A V

2014-01-01

The authors present research findings on the problem of technology-related electromagnetic fields as an occupational risk factor of workers health disturbances, and on the issue of prevention measures development against this adverse physical factor effects. Prospects for further research development in the field of electromagnetic safety are discussed.

Spectrum 101: An Introduction to Spectrum Management

DTIC Science & Technology

2004-03-01

are used to manage spectrum. 1.1 Signals A signal is broadly defined as a detectable quantity (e.g., current, voltage, electromagnetic field ...A pulse consists of a short burst of radiation. These pulses may be a simple increase in the electromagnetic field (referred to as baseband...changing current, in turn, induces an electromagnetic field about itself, with a field strength that corresponds to the current amplitude. This

Study on the adjustment capability of the excitation system located inside superconducting machine electromagnetic shield

NASA Astrophysics Data System (ADS)

Xia, D.; Xia, Z.

2017-12-01

The ability for the excitation system to adjust quickly plays a very important role in maintaining the normal operation of superconducting machines and power systems. However, the eddy currents in the electromagnetic shield of superconducting machines hinder the exciting magnetic field change and weaken the adjustment capability of the excitation system. To analyze this problem, a finite element calculation model for the transient electromagnetic field with moving parts is established. The effects of three different electromagnetic shields on the exciting magnetic field are analyzed using finite element method. The results show that the electromagnetic shield hinders the field changes significantly, the better its conductivity, the greater the effect on the superconducting machine excitation.

Energy density and stress: A new approach to teaching electromagnetism

NASA Astrophysics Data System (ADS)

Herrmann, F.

1989-08-01

By introducing the electromagnetic field in the customary way, ideas are promoted that do not correspond to those of contemporary physics: on the one hand, ideas that stem from pre-Maxwellian times when interactions were still conceived as actions at a distance and, on the other hand, ideas that can be understood only from the point of view that the electromagnetic field is carried by a medium. A part of a course in electromagnetism is sketched in which, from the beginning, the electromagnetic field is presented as a system in its own right and the local quantities energy density and stress are put into the foreground. In this way, justice is done to the views of modern physics and, moreover, the field becomes conceptually simpler.

Hydraulic continuity and biological effects of low strength very low frequency electromagnetic waves: Case of microbial biofilm growth in water treatment.

PubMed

Gérard, Merlin; Noamen, Omri; Evelyne, Gonze; Eric, Valette; Gilles, Cauffet; Marc, Henry

2015-10-15

This study aims to elucidate the interactions between water, subjected to electromagnetic waves of very low frequency (VLF) (kHz) with low strength electromagnetic fields (3.5 mT inside the coils), and the development of microbial biofilms in this exposed water. Experimental results demonstrate that in water exposed to VLF electromagnetic waves, the biomass of biofilm is limited if hydraulic continuity is achieved between the electromagnetic generator and the biofilm media. The measured amount of the biofilm's biomass is approximately a factor two lower for exposed biofilm than the non-exposed biofilm. Measurements of electromagnetic fields in the air and simulations exhibit very low intensities of fields (<10 nT and 2 V/m) in the biofilm-exposed region at a distance of 1 m from the electromagnetic generator. Exposure to electric and magnetic fields of the quoted intensities cannot explain thermal and ionizing effects on the biofilm. A variable electrical potential with a magnitude close to 20 mV was detected in the tank in hydraulic continuity with the electromagnetic generator. The application of quantum field theory may help to explain the observed effects in this case. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of radio frequency waves of electromagnetic field on the tubulin.

PubMed

Taghi, Mousavi; Gholamhosein, Riazi; Saeed, Rezayi-Zarchi

2013-09-01

Microtubules (MTs) are macromolecular structures consisting of tubulin heterodimers and present in almost every eukaryotic cell. MTs fulfill all conditions for generation of electromagnetic field and are electrically polar due to the electrical polarity of a tubulin heterodimer. The calculated static electric dipole moment of about 1000 Debye makes them capable of being aligned parallel to the applied electromagnetic field direction. In the present study, the tubulin heterodimers were extracted and purified from the rat brains. MTs were obtained by polymerization in vitro. Samples of microtubules were adsorbed in the absence and in the presence of electromagnetic fields with radio frequency of 900 Hz. Our results demonstrate the effect of electromagnetic field with 900 Hz frequency to change the structure of MTs. In this paper, a related patent was used that will help to better understand the studied subject.

Descriptive study of electromagnetic wave distribution for various seating positions: using digital textbooks.

PubMed

Seomun, GyeongAe; Kim, YoungHwan; Lee, Jung-Ah; Jeong, KwangHoon; Park, Seon-A; Kim, Miran; Noh, Wonjung

2014-04-01

To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in an elementary school that uses digital textbooks. Electric and magnetic fields from TPCs were measured using the HI-3603 Visual Display Terminal/ Very Low Frequency (VDT/VLF) radiation measurement system. Electromagnetic field values from TPCs measured at a student's seat and at a teacher's computer were deemed not harmful to health. However, electromagnetic field values varied based on the distance between students, other electronic devices such as a desktop computers, and student posture while using a TPC. Based on these results, it is necessary to guide students to observe proper posture and to arrange seats at an appropriate distance in the classroom.

Biological and Health Effects of Electromagnetic Fields Related to the Operation of MRI/TMS

NASA Astrophysics Data System (ADS)

Shigemitsu, Tsukasa; Ueno, Shoogo

This paper reviews issues of biological effects and safety aspects of the electromagnetic fields related to both Magnetic Resonance Imaging (MRI) and Transcranial Magnetic Stimulation (TMS) as a diagnostic technique. The noninvasive character of these diagnostic techniques is based on the utilization of the electromagnetic fields such as the static magnetic field, time-varying magnetic field, and radiofrequency electromagnetic field. Following the short view of the history and the principle of these noninvasive techniques, we review the biological effects of the electromagnetic fields, the health effects and safety issues related to MRI/TMS environments. Through a discussion of biological and health effects, it shows briefly guidelines which provide a consideration in human risk for both patients and medical staff. Finally, safety issues related to MRI/TMS are discussed with the highlighting of the guideline such as the International Commission on NonIonizing Radiation Protection (ICNIRP) and EMF Directive (Directve2013/35/EU) of European Union.

Entanglement control in a superconducting qubit system by an electromagnetic field

NASA Astrophysics Data System (ADS)

Zhang, Y. Q.; Xu, J. B.

2011-08-01

By making use of the dynamical algebraic method we investigate a quantum system consisting of superconducting qubits interacting with data buses, where the qubits are driven by time-dependent electromagnetic field and obtain an explicit expression of time evolution operator. Furthermore, we explore the entanglement dynamics and the influence of the time-dependent electromagnetic field and the initial state on the entanglement sudden death and birth for the system. It is shown that the entanglement between the qubit and bus as well as the entanglement sudden death and birth can be controlled by the time-dependent electromagnetic field.

[Features of control of electromagnetic radiation emitted by personal computers].

PubMed

Pal'tsev, Iu P; Buzov, A L; Kol'chugin, Iu I

1996-01-01

Measurements of PC electromagnetic irradiation show that the main sources are PC blocks emitting the waves of certain frequencies. Use of wide-range detectors measuring field intensity in assessment of PC electromagnetic irradiation gives unreliable results. More precise measurements by selective devices are required. Thus, it is expedient to introduce a term "spectral density of field intensity" and its maximal allowable level. In this case a frequency spectrum of PC electromagnetic irradiation is divided into 4 ranges, one of which is subjected to calculation of field intensity for each harmonic frequency, and others undergo assessment of spectral density of field intensity.

More on the covariant retarded Green's function for the electromagnetic field in de Sitter spacetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higuchi, Atsushi; Lee, Yen Cheong; Nicholas, Jack R.

2009-11-15

In a recent paper 2 it was shown in examples that the covariant retarded Green's functions in certain gauges for electromagnetism and linearized gravity can be used to reproduce field configurations correctly in spite of the spacelike nature of past infinity in de Sitter spacetime. In this paper we extend the work of Ref. 2 concerning the electromagnetic field and show that the covariant retarded Green's function with an arbitrary value of the gauge parameter reproduces the electromagnetic field from two opposite charges at antipodal points of de Sitter spacetime.

Numerical analysis of multicomponent responses of surface-hole transient electromagnetic method

NASA Astrophysics Data System (ADS)

Meng, Qing-Xin; Hu, Xiang-Yun; Pan, He-Ping; Zhou, Feng

2017-03-01

We calculate the multicomponent responses of surface-hole transient electromagnetic method. The methods and models are unsuitable as geoelectric models of conductive surrounding rocks because they are based on regular local targets. We also propose a calculation and analysis scheme based on numerical simulations of the subsurface transient electromagnetic fields. In the modeling of the electromagnetic fields, the forward modeling simulations are performed by using the finite-difference time-domain method and the discrete image method, which combines the Gaver-Stehfest inverse Laplace transform with the Prony method to solve the initial electromagnetic fields. The precision in the iterative computations is ensured by using the transmission boundary conditions. For the response analysis, we customize geoelectric models consisting of near-borehole targets and conductive wall rocks and implement forward modeling simulations. The observed electric fields are converted into induced electromotive force responses using multicomponent observation devices. By comparing the transient electric fields and multicomponent responses under different conditions, we suggest that the multicomponent-induced electromotive force responses are related to the horizontal and vertical gradient variations of the transient electric field at different times. The characteristics of the response are determined by the varying the subsurface transient electromagnetic fields, i.e., diffusion, attenuation and distortion, under different conditions as well as the electromagnetic fields at the observation positions. The calculation and analysis scheme of the response consider the surrounding rocks and the anomalous field of the local targets. It therefore can account for the geological data better than conventional transient field response analysis of local targets.

Detecting Stealth Dark Matter Directly through Electromagnetic Polarizability

DOE PAGES

Appelquist, T.; Berkowitz, E.; Brower, R. C.; ...

2015-10-23

We calculate the spin-independent scattering cross section for direct detection that results from the electromagnetic polarizability of a composite scalar “stealth baryon” dark matter candidate, arising from a dark SU(4) confining gauge theory—“stealth dark matter.” In the nonrelativistic limit, electromagnetic polarizability proceeds through a dimension-7 interaction leading to a very small scattering cross section for dark matter with weak-scale masses. This represents a lower bound on the scattering cross section for composite dark matter theories with electromagnetically charged constituents. We carry out lattice calculations of the polarizability for the lightest “baryon” states in SU(3) and SU(4) gauge theories using themore » background field method on quenched configurations. We find the polarizabilities of SU(3) and SU(4) to be comparable (within about 50%) normalized to the stealth baryon mass, which is suggestive for extensions to larger SU(N) groups. The resulting scattering cross sections with a xenon target are shown to be possibly detectable in the dark matter mass range of about 200–700 GeV, where the lower bound is from the existing LUX constraint while the upper bound is the coherent neutrino background. Significant uncertainties in the cross section remain due to the more complicated interaction of the polarizablity operator with nuclear structure; however, the steep dependence on the dark matter mass, 1/m 6 B, suggests the observable dark matter mass range is not appreciably modified. We highlight collider searches for the mesons in the theory as well as the indirect astrophysical effects that may also provide excellent probes of stealth dark matter.« less

Sensitivity of the Cherenkov Telescope Array to the Detection of Intergalactic Magnetic Fields

NASA Astrophysics Data System (ADS)

Meyer, Manuel; Conrad, Jan; Dickinson, Hugh

2016-08-01

Very high energy (VHE; energy E ≳ 100 GeV) γ-rays originating from extragalactic sources undergo pair production with low-energy photons of background radiation fields. These pairs can inverse-Compton-scatter background photons, initiating an electromagnetic cascade. The spatial and temporal structure of this secondary γ-ray signal is altered as the {e}+{e}- pairs are deflected in an intergalactic magnetic field (IGMF). We investigate how VHE observations with the future Cherenkov Telescope Array, with its high angular resolution and broad energy range, can potentially probe the IGMF. We identify promising sources and simulate γ-ray spectra over a wide range of values of the IGMF strength and coherence length using the publicly available ELMAG Monte Carlo code. Combining simulated observations in a joint likelihood approach, we find that current limits on the IGMF can be significantly improved. The projected sensitivity depends strongly on the time a source has been γ-ray active and on the emitted maximum γ-ray energy.

Simulation of electromagnetic ion cyclotron triggered emissions in the Earth's inner magnetosphere

NASA Astrophysics Data System (ADS)

Shoji, Masafumi; Omura, Yoshiharu

2011-05-01

In a recent observation by the Cluster spacecraft, emissions triggered by electromagnetic ion cyclotron (EMIC) waves were discovered in the inner magnetosphere. We perform hybrid simulations to reproduce the EMIC triggered emissions. We develop a self-consistent one-dimensional hybrid code with a cylindrical geometry of the background magnetic field. We assume a parabolic magnetic field to model the dipole magnetic field in the equatorial region of the inner magnetosphere. Triggering EMIC waves are driven by a left-handed polarized external current assumed at the magnetic equator in the simulation model. Cold proton, helium, and oxygen ions, which form branches of the dispersion relation of the EMIC waves, are uniformly distributed in the simulation space. Energetic protons with a loss cone distribution function are also assumed as resonant particles. We reproduce rising tone emissions in the simulation space, finding a good agreement with the nonlinear wave growth theory. In the energetic proton velocity distribution we find formation of a proton hole, which is assumed in the nonlinear wave growth theory. A substantial amount of the energetic protons are scattered into the loss cone, while some of the resonant protons are accelerated to higher pitch angles, forming a pancake velocity distribution.

Generating highly uniform electromagnetic field characteristics

DOEpatents

Crow, J.T.

1997-06-24

An apparatus and method are disclosed for generating homogeneous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set. 26 figs.

Generating highly uniform electromagnetic field characteristics

DOEpatents

Crow, J.T.

1998-05-05

An apparatus and method are disclosed for generating homogeneous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set. 55 figs.

Generating highly uniform electromagnetic field characteristics

DOEpatents

Crow, J.T.

1998-02-10

An apparatus and method for generating homogeneous electromagnetic fields within a volume is disclosed. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set. 39 figs.

Electromagnetic fields and potentials generated by massless charged particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azzurli, Francesco, E-mail: francesco.azzurli@gmail.com; Lechner, Kurt, E-mail: lechner@pd.infn.it; INFN, Sezione di Padova, Via F. Marzolo, 8, 35131 Padova

2014-10-15

We provide for the first time the exact solution of Maxwell’s equations for a massless charged particle moving on a generic trajectory at the speed of light. In particular we furnish explicit expressions for the vector potential and the electromagnetic field, which were both previously unknown, finding that they entail different physical features for bounded and unbounded trajectories. With respect to the standard Liénard–Wiechert field the electromagnetic field acquires singular δ-like contributions whose support and dimensionality depend crucially on whether the motion is (a) linear, (b) accelerated unbounded, (c) accelerated bounded. In the first two cases the particle generates amore » planar shock-wave-like electromagnetic field traveling along a straight line. In the second and third cases the field acquires, in addition, a δ-like contribution supported on a physical singularity-string attached to the particle. For generic accelerated motions a genuine radiation field is also present, represented by a regular principal-part type distribution diverging on the same singularity-string. - Highlights: • First exact solution of Maxwell’s equations for massless charges in arbitrary motion. • Explicit expressions of electromagnetic fields and potentials. • Derivations are rigorous and based on distribution theory. • The form of the field depends heavily on whether the motion is bounded or unbounded. • The electromagnetic field contains unexpected Dirac-delta-function contributions.« less

Electromagnetic Fields

PubMed Central

Ishida, Masashi; Takahashi, Kenji A.; Arai, Yuji; Kubo, Toshikazu

2008-01-01

Establishing a means to prevent osteonecrosis after corticosteroid administration is an important theme. We asked whether pulsed electromagnetic field stimulation, a noninvasive treatment, could prevent osteonecrosis. Ninety rabbits were divided into four treatment groups: (1) exposure of 10 hours per day to electromagnetic stimulation for 1 week, followed by injection of methylprednisolone (20 mg/kg), and exposure of 10 hours per day to electromagnetism for a further 4 weeks (n = 40); (2) methylprednisolone injection only (n = 40); (3) no treatment (n = 5); and (4) exposure of 10 hours per day to electromagnetism for 5 weeks (n = 5). After 5 weeks, we harvested and histologically examined femurs bilaterally. The frequency of osteonecrosis was lower in the steroid-electromagnetism group (15/40) than in the steroid-only group (26/40). No necrotic lesions were found in the two control groups. We observed no clear effects of electromagnetism on the number, location, extent, and repair of necrotic lesions and intramedullary fat cell size in affected rabbits. Pulsed electromagnetic field stimulation reportedly augments angiogenesis factors and dilates blood vessels; these effects may lower the frequency of osteonecrosis. Exposure to pulsed electromagnetic field stimulation before corticosteroid administration could be an effective means to reduce the risk of osteonecrosis. PMID:18350347

Environmental impact of the use of radiofrequency electromagnetic fields in physiotherapeutic treatment.

PubMed

Gryz, Krzysztof; Karpowicz, Jolanta

2014-01-01

Electromagnetic fields used in physiotherapeutic treatment affect not only patients, but also physiotherapists, patients not undergoing treatment and electronic medical equipment. The aim of the work was to study the parameters of the electromagnetic fields of physiotherapeutic devices with respect to requirements regarding the protection of electronic devices, including medical implants, against electromagnetic intererence, and the protection of the general public (patients not undergoing treatment and bystanders), as well as medical personnel, against the health hazards caused by electromagnetic exposure. The spatial distribution of electric and magnetic field strength was investigated near 3 capacitive short-wave and 3 long-wave diathermies and 3 ultrasound therapy units, as along with the capacitive electric currents caused by electromagnetic field interaction in the upper limbs of the physiotherapists operating these devices. The physiotherapists' exposure to electromagnetic fields depends on the spatial organisation of the workspace and their location during treatment. Electric fields able to interfere with the function of electronic medical implants and in whic anyone not undergoing treatment should not be present were measured up to 150-200 cm away from active applicators of short-wave diathermy, and up to 40-45 cm away from long-wave diathermy ones. Electric fields in which workers should not be present were measured up to 30-40 cm away from the applicators and cables of active short-wave diathermy devices. A capacitive electric current with a strength exceeding many times the international recommendations regarding workers protection was measured in the wrist while touching applicators and cables of active short-wave diathermy devices. The strongest environmental electromagnetic hazards occur near short-wave diathermy devices, and to a lesser degree near long-wave diathermy devices, but were not found near ultrasound therapy units.

The influence of electromagnetic pollution on living organisms: historical trends and forecasting changes.

PubMed

Redlarski, Grzegorz; Lewczuk, Bogdan; Żak, Arkadiusz; Koncicki, Andrzej; Krawczuk, Marek; Piechocki, Janusz; Jakubiuk, Kazimierz; Tojza, Piotr; Jaworski, Jacek; Ambroziak, Dominik; Skarbek, Łukasz; Gradolewski, Dawid

2015-01-01

Current technologies have become a source of omnipresent electromagnetic pollution from generated electromagnetic fields and resulting electromagnetic radiation. In many cases this pollution is much stronger than any natural sources of electromagnetic fields or radiation. The harm caused by this pollution is still open to question since there is no clear and definitive evidence of its negative influence on humans. This is despite the fact that extremely low frequency electromagnetic fields were classified as potentially carcinogenic. For these reasons, in recent decades a significant growth can be observed in scientific research in order to understand the influence of electromagnetic radiation on living organisms. However, for this type of research the appropriate selection of relevant model organisms is of great importance. It should be noted here that the great majority of scientific research papers published in this field concerned various tests performed on mammals, practically neglecting lower organisms. In that context the objective of this paper is to systematise our knowledge in this area, in which the influence of electromagnetic radiation on lower organisms was investigated, including bacteria, E. coli and B. subtilis, nematode, Caenorhabditis elegans, land snail, Helix pomatia, common fruit fly, Drosophila melanogaster, and clawed frog, Xenopus laevis.

The Influence of Electromagnetic Pollution on Living Organisms: Historical Trends and Forecasting Changes

PubMed Central

Żak, Arkadiusz; Koncicki, Andrzej; Piechocki, Janusz; Jakubiuk, Kazimierz; Tojza, Piotr; Jaworski, Jacek; Ambroziak, Dominik; Skarbek, Łukasz

2015-01-01

Current technologies have become a source of omnipresent electromagnetic pollution from generated electromagnetic fields and resulting electromagnetic radiation. In many cases this pollution is much stronger than any natural sources of electromagnetic fields or radiation. The harm caused by this pollution is still open to question since there is no clear and definitive evidence of its negative influence on humans. This is despite the fact that extremely low frequency electromagnetic fields were classified as potentially carcinogenic. For these reasons, in recent decades a significant growth can be observed in scientific research in order to understand the influence of electromagnetic radiation on living organisms. However, for this type of research the appropriate selection of relevant model organisms is of great importance. It should be noted here that the great majority of scientific research papers published in this field concerned various tests performed on mammals, practically neglecting lower organisms. In that context the objective of this paper is to systematise our knowledge in this area, in which the influence of electromagnetic radiation on lower organisms was investigated, including bacteria, E. coli and B. subtilis, nematode, Caenorhabditis elegans, land snail, Helix pomatia, common fruit fly, Drosophila melanogaster, and clawed frog, Xenopus laevis. PMID:25811025

Pair creation of higher dimensional black holes on a de Sitter background

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dias, Oscar J.C.; Lemos, Jose P.S.; CENTRA, Departamento de Fisica, F.C.T., Universidade do Algarve, Campus de Gambelas, 8005-139 Faro

We study in detail the quantum process in which a pair of black holes is created in a higher D-dimensional de Sitter (dS) background. The energy to materialize and accelerate the pair comes from the positive cosmological constant. The instantons that describe the process are obtained from the Tangherlini black hole solutions. Our pair creation rates reduce to the pair creation rate for Reissner-Nordstroem-dS solutions when D=4. Pair creation of black holes in the dS background becomes less suppressed when the dimension of the spacetime increases. The dS space is the only background in which we can discuss analytically themore » pair creation process of higher dimensional black holes, since the C-metric and the Ernst solutions, which describe, respectively, a pair accelerated by a string and by an electromagnetic field, are not known yet in a higher dimensional spacetime.« less

Magnetic field adjustment structure and method for a tapered wiggler

DOEpatents

Halbach, Klaus

1988-03-01

An improved method and structure is disclosed for adjusting the magnetic field generated by a group of electromagnet poles spaced along the path of a charged particle beam to compensate for energy losses in the charged particles which comprises providing more than one winding on at least some of the electromagnet poles; connecting one respective winding on each of several consecutive adjacent electromagnet poles to a first power supply, and the other respective winding on the electromagnet pole to a different power supply in staggered order; and independently adjusting one power supply to independently vary the current in one winding on each electromagnet pole in a group whereby the magnetic field strength of each of a group of electromagnet poles may be changed in smaller increments.

Magnetic field adjustment structure and method for a tapered wiggler

DOEpatents

Halbach, Klaus

1988-01-01

An improved method and structure is disclosed for adjusting the magnetic field generated by a group of electromagnet poles spaced along the path of a charged particle beam to compensate for energy losses in the charged particles which comprises providing more than one winding on at least some of the electromagnet poles; connecting one respective winding on each of several consecutive adjacent electromagnet poles to a first power supply, and the other respective winding on the electromagnet pole to a different power supply in staggered order; and independently adjusting one power supply to independently vary the current in one winding on each electromagnet pole in a group whereby the magnetic field strength of each of a group of electromagnet poles may be changed in smaller increments.

Quantum estimation of parameters of classical spacetimes

NASA Astrophysics Data System (ADS)

Downes, T. G.; van Meter, J. R.; Knill, E.; Milburn, G. J.; Caves, C. M.

2017-11-01

We describe a quantum limit to the measurement of classical spacetimes. Specifically, we formulate a quantum Cramér-Rao lower bound for estimating the single parameter in any one-parameter family of spacetime metrics. We employ the locally covariant formulation of quantum field theory in curved spacetime, which allows for a manifestly background-independent derivation. The result is an uncertainty relation that applies to all globally hyperbolic spacetimes. Among other examples, we apply our method to the detection of gravitational waves with the electromagnetic field as a probe, as in laser-interferometric gravitational-wave detectors. Other applications are discussed, from terrestrial gravimetry to cosmology.

Upper limits to the interstellar radiation field between 775 and 1050 A

NASA Technical Reports Server (NTRS)

Paresce, F.; Bowyer, S.

1976-01-01

A 40-A resolution extreme-ultraviolet spectrometer, sensitive to radiation in the 775-1050 A band, was flown on a Black Brant VC rocket to measure the night sky brightness in this region of the electromagnetic spectrum. A weak signal above background was recorded in most channels as the spectrometer's field of view scanned the sky in the vicinity of the galactic plane from Monoceros to Andromeda. Because the earth's upper atmosphere may produce some radiation in this wavelength region, the possibility cannot be excluded that some or all of the observed signal is terrestrial in origin. However, observational upper limits can be established at the 95-per cent confidence level for the intensity of an extraterrestrial extreme ultraviolet background which ranges from 6 millionths erg/sq cm/s/sr/A at 1050 A to 4 ten-millionths erg/sq cm/s/sr/A at 775 A. These results are consistent with existing theoretical predictions.

Preferential Heating and Acceleration of Heavy Ions in Impulsive Solar Flares

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Rahul; Gaspari, Massimo; Spitkovsky, Anatoly

2017-02-01

We simulate decaying turbulence in a homogeneous pair plasma using a three-dimensional electromagnetic particle-in-cell method. A uniform background magnetic field permeates the plasma such that the magnetic pressure is three times larger than the thermal pressure and the turbulence is generated by counter-propagating shear Alfvén waves. The energy predominately cascades transverse to the background magnetic field, rendering the turbulence anisotropic at smaller scales. We simultaneously move several ion species of varying charge to mass ratios in our simulation and show that the particles of smaller charge to mass ratios are heated and accelerated to non-thermal energies at a faster rate.more » This is in accordance with the enhancement of heavy ions and a non-thermal tail in their energy spectrum observed in the impulsive solar flares. We further show that the heavy ions are energized mostly in the direction perpendicular to the background magnetic field, with a rate consistent with our analytical estimate of the rate of heating due to cyclotron resonance with the Alfvén waves, of which a large fraction is due to obliquely propagating waves.« less

Stimulated Brillouin Scatter in a Magnetized Ionospheric Plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernhardt, P. A.; Selcher, C. A.; Lehmberg, R. H.

2010-04-23

High power electromagnetic waves transmitted from the HAARP facility in Alaska can excite low-frequency electrostatic waves by magnetized stimulated Brillouin scatter. Either an ion-acoustic wave with a frequency less than the ion cyclotron frequency (f{sub CI}) or an electrostatic ion cyclotron (EIC) wave just above f{sub CI} can be produced. The coupled equations describing the magnetized stimulated Brillouin scatter instability show that the production of both ion-acoustic and EIC waves is strongly influenced by the wave propagation relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions using the HAARP transmitter have confirmed that only ion-acoustic waves aremore » excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The ion composition can be obtained from the measured EIC frequency.« less

Linear and nonlinear interactions of an electron beam with oblique whistler and electrostatic waves in the magnetosphere

NASA Astrophysics Data System (ADS)

Zhang, Y. L.; Matsumoto, H.; Omura, Y.

1993-12-01

Both linear and nonlinear interactions between oblique whistler, electrostatic, quasi-upper hybrid mode waves and an electron beam are studied by linear analyses and electromagnetic particle simulations. In addition to a background cold plasma, we assumed a hot electron beam drifting along a static magnetic field. Growth rates of the oblique whistler, oblique electrostatic, and quasi-upper hybrid instabilities were first calculated. We found that there are four kinds of unstable mode waves for parallel and oblique propagations. They are the electromagnetic whistler mode wave (WW1), the electrostatic whistler mode wave (WW2), the electrostatic mode wave (ESW), and the quasi-upper hybrid mode wave (UHW). A possible mechanism is proposed to explain the satellite observations of whistler mode chorus and accompanied electrostatic waves, whose amplitudes are sometimes modulated at the chorus frequency.

The calculation of transport phenomena in electromagnetically levitated metal droplets

NASA Technical Reports Server (NTRS)

El-Kaddah, N.; Szekely, J.

1982-01-01

A mathematical representation has been developed for the electromagnetic force field, fluid flow field, and solute concentration field of levitation-melted metal specimens. The governing equations consist of the conventional transport equations combined with the appropriate expressions for the electromagnetic force field. The predictions obtained by solving the governing equations numerically on a digital computer are in good agreement with lifting force and average temperature measurements reported in the literature.

ELF Communications System Ecological Monitoring Program: Electromagnetic Field Measurements and Engineering Support-1991

DTIC Science & Technology

1992-12-01

engineering support for completed studies--namely, the wetlands, slime mold , and bird species and communities studies performed in Wisconsin-appears in previous...3 4. ENGINEERING SUPPORT ACTIVITIES 4.1 Soil Amoeba Growth Chambers 4.1.1 Background 3 The soil amoeba and now-completed slime mold studies both...cultures of soil amoeba and slime mold to the earth’s ambient temperature. It is also desirable to expose the cultures to the same EM environment that they

Electromagnetic fields and public health.

PubMed Central

Aldrich, T E; Easterly, C E

1987-01-01

A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research. General observation would accord with the implication that there is no single and manifest health effect as the result of exposure to these fields. There are persistent indications, however, that these fields have biologic activity, and consequently, there may be a deleterious component to their action, possibly in the presence of other factors. Power frequency electromagnetic field exposures are essentially ubiquitous in modern society, and their implications in the larger perspective of public health are unclear at this time. Electromagnetic fields represent a methodological obstacle for epidemiologic studies and a quandary for risk assessment; there is need for more data. PMID:3319560

The effects of 30 mT electromagnetic fields on hippocampus cells of rats

PubMed Central

Teimori, Farzaneh; Khaki, Amir A.; Rajabzadeh, Asghar; Roshangar, Leila

2016-01-01

Background: Despite the use of electromagnetic waves in the treatment of some acute and chronic diseases, application of these waves in everyday life has created several problems for humans, especially the nerve system. In this study, the effects of 30mT electromagnetic fields (EMFs) on the hippocampus is investigated. Methods: Twenty-four 5-month Wistar rats weighing 150–200 g were divided into two groups. The experimental group rats were under the influence of an EMF at an intensity of 3 mT for approximately 4 hours a day (from 8 AM to 12 PM) during 10 weeks. After the hippocampus was removed, thin slides were prepared for transmission electron microscope (TEM) to study the ultrastructural tissue. Cell death detection POD kits were used to determine the apoptosis rate. Results: The results of the TEM showed that, in the hippocampus of the experimental group, in comparison to the control group, there was a substantial shift; even intracellular organelles such as the mitochondria were morphologically abnormal and uncertain. The number of apoptotic cells in the exposed group compared to the control group showed significant changes. Conclusions: Similar to numerous studies that have reported the effects of EMFs on nerves system, it was also confirmed in this lecture. Hence, the hippocampus which is important in regulating emotions, behavior, motivation, and memory functions, may be impaired by the negative impacts of EMFs. PMID:27453795

Chiral magnetic effect in the presence of electroweak interactions as a quasiclassical phenomenon

NASA Astrophysics Data System (ADS)

Dvornikov, Maxim; Semikoz, Victor B.

2018-03-01

We elaborate the quasiclassical approach to obtain the modified chiral magnetic effect (CME) in the case when the massless charged fermions interact with electromagnetic fields and the background matter by the electroweak forces. The derivation of the anomalous current along the external magnetic field involves the study of the energy density evolution of chiral particles in parallel electric and magnetic fields. We consider both the particle acceleration by the external electric field and the contribution of the Adler anomaly. The condition of the validity of this method for the derivation of the CME is formulated. We obtain the expression for the electric current along the external magnetic field, which appears to coincide with our previous results based on the purely quantum approach. Our results are compared with the findings of other authors.

GEANT4 Simulation of Neutron Detector for DAMPE

NASA Astrophysics Data System (ADS)

He, M.; Ma, T.; Chang, J.; Zhang, Y.; Huang, Y. Y.; Zang, J. J.; Wu, J.; Dong, T. K.

2016-01-01

During recent tens of years dark matter has gradually become a hot topic in astronomical research field, and related theory researches and experiment projects change with each passing day. The Dark Matter Particle Explorer (DAMPE) of our country is proposed under this background. As the probing object involves high energy electrons, appropriate methods must be taken to distinguish them from protons in order to reduce the event probability of other charged particles (e.g. a proton) being mistaken as electrons. The experiments show that, the hadronic shower of high energy proton in BGO electromagnetic calorimeter, which is usually accompanied by the emitting of large number of secondary neutrons, is significantly different from the electromagnetic shower of high energy electron. Through the detection of secondary neutron signal emitting from the bottom of BGO electromagnetic calorimeter and the shower shape of incident particles in BGO electromagnetic calorimeter, we can effectively distinguish whether the incident particles are high energy protons or electrons. This paper introduces the structure and detecting principle of DAMPE neutron detector. We use Monte-Carlo method with GEANT4 software to simulate the signal emitting from protons and electrons at characteristic energy in the neutron detector, and finally summarize the neutron detector's ability to distinguish protons and electrons under different electron acception efficiencies.

Electromagnetic scattering and emission by a fixed multi-particle object in local thermal equilibrium: General formalism.

PubMed

Mishchenko, Michael I

2017-10-01

The majority of previous studies of the interaction of individual particles and multi-particle groups with electromagnetic field have focused on either elastic scattering in the presence of an external field or self-emission of electromagnetic radiation. In this paper we apply semi-classical fluctuational electrodynamics to address the ubiquitous scenario wherein a fixed particle or a fixed multi-particle group is exposed to an external quasi-polychromatic electromagnetic field as well as thermally emits its own electromagnetic radiation. We summarize the main relevant axioms of fluctuational electrodynamics, formulate in maximally rigorous mathematical terms the general scattering-emission problem for a fixed object, and derive such fundamental corollaries as the scattering-emission volume integral equation, the Lippmann-Schwinger equation for the dyadic transition operator, the multi-particle scattering-emission equations, and the far-field limit. We show that in the framework of fluctuational electrodynamics, the computation of the self-emitted component of the total field is completely separated from that of the elastically scattered field. The same is true of the computation of the emitted and elastically scattered components of quadratic/bilinear forms in the total electromagnetic field. These results pave the way to the practical computation of relevant optical observables.

Double gauge invariance and covariantly-constant vector fields in Weyl geometry

NASA Astrophysics Data System (ADS)

Kassandrov, Vladimir V.; Rizcallah, Joseph A.

2014-08-01

The wave equation and equations of covariantly-constant vector fields (CCVF) in spaces with Weyl nonmetricity turn out to possess, in addition to the canonical conformal-gauge, a gauge invariance of another type. On a Minkowski metric background, the CCVF system alone allows us to pin down the Weyl 4-metricity vector, identified herein with the electromagnetic potential. The fundamental solution is given by the ordinary Lienard-Wiechert field, in particular, by the Coulomb distribution for a charge at rest. Unlike the latter, however, the magnitude of charge is necessarily unity, "elementary", and charges of opposite signs correspond to retarded and advanced potentials respectively, thus establishing a direct connection between the particle/antiparticle asymmetry and the "arrow of time".

Influence of electromagnetic field on soliton-mediated charge transport in biological systems.

PubMed

Brizhik, Larissa

2015-01-01

It is shown that electromagnetic fields affect dynamics of Davydov's solitons which provide charge transport processes in macromolecules during metabolism of the system. There is a resonant frequency of the field at which it can cause the transition of electrons from bound soliton states into delocalised states. Such decay of solitons reduces the effectiveness of charge transport, and, therefore, inhibits redox processes. Solitons radiate their own electromagnetic field of characteristic frequency determined by their average velocity. This self-radiated field leads to synchronization of soliton dynamics and charge transport processes, and is the source of the coherence in the system. Exposition of the system to the oscillating electromagnetic field of the frequency, which coincides with the eigen-frequency of solitons can enhance eigen-radiation of solitons, and, therefore, will enhance synchronization of charge transpor, stimulate the redox processes and increase coherence in the system. Electromagnetic oscillating field causes also ratchet phenomenon of solitons, i.e., drift of solitons in macromolecules in the presence of unbiased periodic field. Such additional drift enhances the charge transport processes. It is shown that temperature facilitates the ratchet drift. In particular, temperature fluctuations lead to the lowering of the critical value of the intensity and period of the field, above which the drift of solitons takes place. Moreover, there is a stochastic resonance in the soliton dynamics in external electromagnetic fields. This means, that there is some optimal temperature at which the drift of solitons is maximal.

Apparatus and Methods for Mitigating Electromagnetic Emissions

NASA Technical Reports Server (NTRS)

Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

2013-01-01

Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

Apparatus and Methods for Mitigating Electromagnetic Emissions

NASA Technical Reports Server (NTRS)

Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

2016-01-01

Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

Schwinger mechanism in electromagnetic field in de Sitter spacetime

NASA Astrophysics Data System (ADS)

Bavarsad, Ehsan; Pyo Kim, Sang; Stahl, Clément; Xue, She-Sheng

2018-01-01

We investigate Schwinger scalar pair production in a constant electromagnetic field in de Sitter (dS) spacetime. We obtain the pair production rate, which agrees with the Hawking radiation in the limit of zero electric field in dS. The result describes how a cosmic magnetic field affects the pair production rate. In addition, using a numerical method we study the effect of the magnetic field on the induced current. We find that in the strong electromagnetic field the current has a linear response to the electric and magnetic fields, while in the infrared regime, is inversely proportional to the electric field and leads to infrared hyperconductivity.

Incidental/Absorbed Exposure Electromagnetic Field Energy Ratio Analysis Under Laboratory Experiment Conditions (for Russian-French Immunology Project)

DTIC Science & Technology

2007-11-07

with the International Science and Technology Center ( ISTC ), Moscow. ISTC Project No. 3629 Incidental/absorbed exposure electromagnetic field...5a. CONTRACT NUMBER ISTC Registration No: 3629 5b. GRANT NUMBER 4. TITLE AND SUBTITLE Incidental/absorbed exposure electromagnetic field...REPORT NUMBER(S) ISTC 06-7005 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution is unlimited. 13

Wireless data transmission from inside electromagnetic fields.

PubMed

Huertas, José Ignacio; Barraza, Roberto; Echeverry, Julian Mauricio

2010-01-01

This paper describes analytical and experimental work developed to evaluate the effects of the electromagnetic fields produced by high-voltage lines (400 kV) on wireless data transmission at the 900MHz band. In this work the source of the data transmission is located inside the electromagnetic field and the reception station is located at different distances from the power lines. Different atmospheric conditions are considered.

A new unified theory of electromagnetic and gravitational interactions

NASA Astrophysics Data System (ADS)

Li, Li-Xin

2016-12-01

In this paper we present a new unified theory of electromagnetic and gravitational interactions. By considering a four-dimensional spacetime as a hypersurface embedded in a five-dimensional bulk spacetime, we derive the complete set of field equations in the four-dimensional spacetime from the fivedimensional Einstein field equation. Besides the Einstein field equation in the four-dimensional spacetime, an electromagnetic field equation is obtained: ∇a F ab - ξ R b a A a = -4π J b with ξ = -2, where F ab is the antisymmetric electromagnetic field tensor defined by the potential vector A a , R ab is the Ricci curvature tensor of the hypersurface, and J a is the electric current density vector. The electromagnetic field equation differs from the Einstein-Maxwell equation by a curvature-coupled term ξ R b a A a , whose presence addresses the problem of incompatibility of the Einstein-Maxwell equation with a universe containing a uniformly distributed net charge, as discussed in a previous paper by the author [L.-X. Li, Gen. Relativ. Gravit. 48, 28 (2016)]. Hence, the new unified theory is physically different from Kaluza-Klein theory and its variants in which the Einstein-Maxwell equation is derived. In the four-dimensional Einstein field equation derived in the new theory, the source term includes the stress-energy tensor of electromagnetic fields as well as the stress-energy tensor of other unidentified matter. Under certain conditions the unidentified matter can be interpreted as a cosmological constant in the four-dimensional spacetime. We argue that, the electromagnetic field equation and hence the unified theory presented in this paper can be tested in an environment with a high mass density, e.g., inside a neutron star or a white dwarf, and in the early epoch of the universe.

Increased dielectric constant in the water treated by extremely low frequency electromagnetic field and its possible biological implication

NASA Astrophysics Data System (ADS)

Shen, Xun

2011-12-01

Water is the most abundant compound on the surface of the Earth, and can be considered to be the most important molecule in living systems. Water plays a variety of cellular functions, being the solvent of most biological molecules, a substrate and product of enzymatic catalysis, an important component of macromolecules, and more. Because of importance of water in life, many physical and chemical treatments were invented to improve the quality of drinking water. Among them, the treatment with electromagnetic field is a well-known, but much debatable physical method. Although electromagnetic field has been utilized for treating water for 80 years, many reports on beneficial biological effect of electromagnetic field-treated water were either anecdotal or less convincing. To explore if there is any physical base for understanding possible biological effects of electromagnetic field-treated water, dielectric relaxation spectra of deionized water treated with an extremely low frequency electromagnetic (ELFEM) field were measured and compared with that of untreated water. It was surprisingly found that the dielectric constant of the ELFEM field-treated water was 3.7% higher than the control over the frequency range of 1-10 GHz, which indicates a higher molecular polarization occurs in the ELFEM field-treated water. Electrostatic and thermodynamic analysis shows that proteins or other biomacromolecules would have more reduced free energy when they are hydrated in high dielectric constant water. Since free energy is of crucial importance for stability of proteins, protein folding and its conformational change, as well as catalytic activity of enzymes, the free energy reduction of the biomacromolecules hydrated with higher dielectric constant water may be responsible for many possible biological effects of electromagnetic field treated water.

Mitigation measures of electromagnetic field exposure in the vicinity of high frequency welders.

PubMed

Zubrzak, Bartłomiej; Bieńkowski, Paweł; Cała, Pawel

2017-10-17

Presented information about the welding process and equipment, focusing on the emission of electromagnetic field (EMF) with levels significant in terms of the labor safety regulations in force in Poland - the ordinances of the Minister of Family, Labour and Social Policy that came into force on June 27, 2016 and June 29, 2016 - emerged due to harmonization with European Union directive 2013/35/EU of 26 June 2013 of the European Parliament and the Council. They presented methods of determination of the EMF distribution in the welding machine surroundings and analyzed the background knowledge from the available literature. The subject of the analysis included popular high frequency welders widely used in the industry. Electromagnetic field measurements were performed in the welder operating place (in situ) during machine normal operations, using measurement methods accordant with labor safety regulations in force in Poland and according to the same guidelines, the EMF distributions and parameters having been described. They presented various scenarios of particular, real examples of excessive exposure to EMF in the dielectric welder surroundings and showed solutions, ranging from simple and costless and ending on dedicated electromagnetic shielding systems, which allowed to reduce EMF exposure in some cases of more than 80% (protection zone ranges) or eliminate dangerous zone presence. It has shown that in the dielectric welders surrounding, significant EMF strength levels may be the result of errors or omissions which often occur during development, installation, operation or modification of welding machines. It has allowed to present the measures that may significantly reduce the exposure to EMF of workers in the welder surroundings. The role of accredited laboratories in helping in such cases was underlined. Med Pr 2017;68(6):693-703. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Effect of the magnetic field on coexisting stimulated Raman and Brillouin backscattering of an extraordinary mode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vyas, Ashish, E-mail: ashishvyas.optics@gmail.com; Singh, Ram Kishor, E-mail: ram007kishor@gmail.com; Sharma, R. P., E-mail: rpsharma@ces.iitd.ernet.in

2016-01-15

This paper presents a model to study the interplay between the stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in the presence of background magnetic field. This formalism is applicable to laser produced plasma as well as to heating mechanism in toroidal system by an extraordinary electromagnetic wave. In the former case, the magnetic field is self-generated, while in the latter case (toroidal plasmas) magnetic field is applied externally. The behavior of one scattering process is explicitly dependent on the coexisting scattering process as well as on the magnetic field. Explicit expressions for the back-reflectivity of scattered beams (SRSmore » and SBS) are presented. It has been demonstrated that due to the magnetic field and coexistence of the scattering processes (SRS and SBS) the back-reflectivity gets modified significantly. Results are also compared with the three wave interaction case (isolated SRS or SBS case)« less

Environmental Assessment for North Warning System (Alaska)

DTIC Science & Technology

1986-11-10

With Respect to Human Exposure to Radio Frequency Electromagnetic Fields , 300 kHz to 100 GHz, ANSI C95.1-1982, IEEE, New York. CH 2M Hill, 1981...Council on Radiation Protection and Measurements), 1986.Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields . NCRP Report...6 4.1.3.1 Radiofrequency Radiation ..................... 4-7 4.1.3.1.1 Electromagnetic Hazards.......... 4-7 4.1.3.1.2 Electromagnetic Interference

Electromagnetic Interference Tests

DTIC Science & Technology

1994-05-31

for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields (300 kHz - 100 GHz), American National Standards Institute...Respect to Human Exposure to Radio Frequency Electromagnetic Fields (300 kHz - 100 GHz), American National Standards Institute, C95.1-1982, 30 July 1980...II il~l I!I 11 lll i 13. ABSTkACT (Waxlrnun 200woruh) This TOP is a general guideline for electromagnetic interference testing of electronic

Effects of chronic exposure to electromagnetic waves on the auditory system.

PubMed

Özgür, Abdulkadir; Tümkaya, Levent; Terzi, Suat; Kalkan, Yıldıray; Erdivanlı, Özlem Çelebi; Dursun, Engin

2015-08-01

The results support that chronic electromagnetic field exposure may cause damage by leading to neuronal degeneration of the auditory system. Numerous researches have been done about the risks of exposure to the electromagnetic fields that occur during the use of these devices, especially the effects on hearing. The aim of this study is to evaluate the effects of the electromagnetic waves emitted by the mobile phones through the electrophysiological and histological methods. Twelve adult Wistar albino rats were included in the study. The rats were divided into two groups of six rats. The study group was exposed to the electromagnetic waves over a period of 30 days. The control group was not given any exposure to the electromagnetic fields. After the completion of the electromagnetic wave application, the auditory brainstem responses of both groups were recorded under anesthesia. The degeneration of cochlear nuclei was graded by two different histologists, both of whom were blinded to group information. The histopathologic and immunohistochemical analysis showed neuronal degeneration signs, such as increased vacuolization in the cochlear nucleus, pyknotic cell appearance, and edema in the group exposed to the electromagnetic fields compared to the control group. The average latency of wave in the ABR was similar in both groups (p > 0.05).

[The influence of electromagnetic fields on flora and fauna].

PubMed

Rochalska, Małgorzata

2009-01-01

This paper presents the influence of natural and artificial electromagnetic fields (EMF) on fauna and flora. The mechanisms of Earth's magnetic field detection and the use of this skill by migratory animals to faultlessly reach the destination of their travel are discussed, as well as the positive effects of electric and magnetic fields on plants relative to their physiology, yielding and health. EMF influence on social insects and animal organisms, including possible DNA damages and DNA repair systems, is presented. The influence of high frequency electromagnetic fields on birds nesting is also discussed.

The electromagnetic bio-field: clinical experiments and interferences

PubMed Central

Burnei, G; Hodorogea, D; Georgescu, I; Gavriliu, Ş; Drăghici, I; Dan, D; Vlad, C; Drăghici, L

2012-01-01

Introduction: One of the most important factors is the technical and scientifically rapid development that is continually modifying the world we live in and polluting it with electromagnetic radiations. A functional and structural influence of magnetic and electromagnetic field on living organisms is presented in the literature by many performed experiments. Material and methods: The notion of bio-field represents the electromagnetic field generated by the bio-structures, not only in their normal physiological activities but also in their pathological states. There is a tight interdependency between the bio-field and the bio-structure, which respects the primary notion of an electromagnetic field given by the Maxwell-Faraday laws, in which, the electromagnetic phenomena are simplified to the field variations. These variations can be expressed in a coherent differential equation system that bounds the field vectors to different space points at different time moments. Results: The living organisms cannot contain electrostatic and magneto-static fields due to the intense activity of the bio-structures. The biochemical reactions that have high rhythms and speeds always impose the electrodynamics character of the biologic field that also corresponds to the stability of the protein molecule that can be explained only through a dynamic way. The existent energy is not considered an exciting agent, and it does not lead to any effects. Conclusions: The parameters of these elementary bio-fields cannot yet be fully known due to technical reasons. The biological structures are very complex ones and undergo continuous dynamical activity. That is why the calculus model should be related to the constant dynamics, nowadays being very difficult to express. PMID:22802878

The electromagnetic bio-field: clinical experiments and interferences.

PubMed

Burnei, G; Hodorogea, D; Georgescu, I; Gavriliu, Ş; Drăghici, I; Dan, D; Vlad, C; Drăghici, L

2012-06-12

One of the most important factors is the technical and scientifically rapid development that is continually modifying the world we live in and polluting it with electromagnetic radiations. A functional and structural influence of magnetic and electromagnetic field on living organisms is presented in the literature by many performed experiments. The notion of bio-field represents the electromagnetic field generated by the bio-structures, not only in their normal physiological activities but also in their pathological states. There is a tight interdependency between the bio-field and the bio-structure, which respects the primary notion of an electromagnetic field given by the Maxwell-Faraday laws, in which, the electromagnetic phenomena are simplified to the field variations. These variations can be expressed in a coherent differential equation system that bounds the field vectors to different space points at different time moments. The living organisms cannot contain electrostatic and magneto-static fields due to the intense activity of the bio-structures. The biochemical reactions that have high rhythms and speeds always impose the electrodynamics character of the biologic field that also corresponds to the stability of the protein molecule that can be explained only through a dynamic way. The existent energy is not considered an exciting agent, and it does not lead to any effects. The parameters of these elementary bio-fields cannot yet be fully known due to technical reasons. The biological structures are very complex ones and undergo continuous dynamical activity. That is why the calculus model should be related to the constant dynamics, nowadays being very difficult to express.

Particle Production in Strong Electromagnetic Fields in Relativistic Heavy-Ion Collisions

DOE PAGES

Tuchin, Kirill

2013-01-01

I reviewmore » the origin and properties of electromagnetic fields produced in heavy-ion collisions. The field strength immediately after a collision is proportional to the collision energy and reaches ~ m π 2 at RHIC and ~ 10 m π 2 at LHC. I demonstrate by explicit analytical calculation that after dropping by about one-two orders of magnitude during the first fm/c of plasma expansion, it freezes out and lasts for as long as quark-gluon plasma lives as a consequence of finite electrical conductivity of the plasma. Magnetic field breaks spherical symmetry in the direction perpendicular to the reaction plane, and therefore all kinetic coefficients are anisotropic. I examine viscosity of QGP and show that magnetic field induces azimuthal anisotropy on plasma flow even in spherically symmetric geometry. Very strong electromagnetic field has an important impact on particle production. I discuss the problem of energy loss and polarization of fast fermions due to synchrotron radiation, consider photon decay induced by magnetic field, elucidate J / ψ dissociation via Lorentz ionization mechanism, and examine electromagnetic radiation by plasma. I conclude that all processes in QGP are affected by strong electromagnetic field and call for experimental investigation.« less

Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

NASA Astrophysics Data System (ADS)

Cadena, M. S. Reyes; Chapul, L. Sánchez; Pérez, Javiér; García, M. N. Jiménez; López, M. A. Jiménez; Espíndola, M. E. Sánchez; Perez, R. Paniagua; Hernández, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodríguez

2008-08-01

We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-β) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.

Transverse electromagnetic horn antenna with resistively-loaded exterior surfaces

DOEpatents

Aurand, John F.

1999-01-01

An improved transverse electromagnetic (TEM) horn antenna comprises a resistive loading material on the exterior surfaces of the antenna plates. The resistive loading material attenuates or inhibits currents on the exterior surfaces of the TEM horn antenna. The exterior electromagnetic fields are of opposite polarity in comparison to the primary and desired interior electromagnetic field, thus inherently cause partial cancellation of the interior wave upon radiation or upon reception. Reducing the exterior fields increases the radiation efficiency of the antenna by reducing the cancellation of the primary interior field (supported by the interior surface currents). This increases the transmit gain and receive sensitivity of the TEM horn antenna, as well as improving the transient (time-domain) response.

Neutrino production in electromagnetic cascades: An extra component of cosmogenic neutrino at ultrahigh energies

NASA Astrophysics Data System (ADS)

Wang, Kai; Liu, Ruo-Yu; Li, Zhuo; Dai, Zi-Gao

2017-03-01

Muon pairs can be produced in the annihilation of ultrahigh energy (UHE, E ≳1 018 eV ) photons with low energy cosmic background radiation in the intergalactic space, giving birth to neutrinos. Although the branching ratio of muon pair production is low, products of other channels, which are mainly electron/positron pairs, will probably transfer most of their energies into the new generated UHE photon in the subsequent interaction with the cosmic background radiation via Compton scattering in deep Klein-Nishina regime. The regeneration of these new UHE photons then provides a second chance to produce the muon pairs, enhancing the neutrino flux. We investigate the neutrino production in the propagation of UHE photons in the intergalactic space at different redshifts, considering various competing processes such as pair production, double pair production for UHE photons, and triplet production and synchrotron radiation for UHE electrons. Following the analytic method raised by Gould and Rephaeli, we firstly study the electromagnetic cascade initiated by an UHE photon, with paying particular attention to the leading particle in the cascade process. Regarding the least energetic outgoing particles as energy loss, we obtain the effective penetration length of the leading particle, as well as energy loss rate including the neutrino emission rate in the cascade process. Finally, we find that an extra component of UHE neutrinos will arise from the propagation of UHE cosmic rays due to the generated UHE photons and electron/positrons. However, the flux of this component is quite small, with a flux of at most 10% of that of the conventional cosmogenic neutrino at a few EeV, in the absence of a strong intergalactic magnetic field and a strong cosmic radio background. The precise contribution of extra component depends on several factors, e.g., cosmic radio background, intergalactic magnetic field, and the spectrum of proton, which are discussed in this work.

47 CFR 1.1310 - Radiofrequency radiation exposure limits.

Code of Federal Regulations, 2013 CFR

2013-10-01

... FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields,” and in supplements to... electromagnetic energy. The SAR limits to be used for evaluation are based generally on criteria published by the... with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI/IEEE...

Exploration of the Electromagnetic Environment

ERIC Educational Resources Information Center

Fullekrug, M.

2009-01-01

The electromagnetic environment is composed of electric and magnetic fields which result from man-made and natural sources. An elementary experiment is described to explore the electromagnetic environment by measuring electric fields in the frequency range from approximately equal to 10 to 24 000 Hz. The equipment required to conduct the…

47 CFR 1.1310 - Radiofrequency radiation exposure limits.

Code of Federal Regulations, 2014 CFR

2014-10-01

... FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields,” and in supplements to... electromagnetic energy. The SAR limits to be used for evaluation are based generally on criteria published by the... with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI/IEEE...

Simplified Relativistic Force Transformation Equation.

ERIC Educational Resources Information Center

Stewart, Benjamin U.

1979-01-01

A simplified relativistic force transformation equation is derived and then used to obtain the equation for the electromagnetic forces on a charged particle, calculate the electromagnetic fields due to a point charge with constant velocity, transform electromagnetic fields in general, derive the Biot-Savart law, and relate it to Coulomb's law.…

The electromagnetic force field, fluid flow field and temperature profiles in levitated metal droplets

NASA Technical Reports Server (NTRS)

El-Kaddah, N.; Szekely, J.

1982-01-01

A mathematical representation was developed for the electromagnetic force field, the flow field, the temperature field (and for transport controlled kinetics), in a levitation melted metal droplet. The technique of mutual inductances was employed for the calculation of the electromagnetic force field, while the turbulent Navier - Stokes equations and the turbulent convective transport equations were used to represent the fluid flow field, the temperature field and the concentration field. The governing differential equations, written in spherical coordinates, were solved numerically. The computed results were in good agreement with measurements, regarding the lifting force, and the average temperature of the specimen and carburization rates, which were transport controlled.

Electromagnetic PIC modeling with a background gas

NASA Astrophysics Data System (ADS)

Verboncoeur, J. P.; Cooperberg, D.

1997-02-01

Modeling the interaction of relativistic electromagnetic plasmas with a background gas is described. The timescales range over many orders of magnitude, from the electromagnetic Courant condition (˜10-12 sec) to electron-neutral collision times (˜10-7 sec) to ion transit times (˜10-5 sec). For this work, the traditional Monte Carlo algorithm [1] is described for relativistic electrons. Subcycling is employed to improve efficiency, and smoothing is employed to reduce particle noise. Applications include plasma-focused electron guns, gas-filled microwave tubes, surface wave discharges driven at microwave frequencies, and electron-cyclotron resonance discharges. The method is implemented in the OOPIC code [2].

Meta-gated channel for the discrete control of electromagnetic fields

NASA Astrophysics Data System (ADS)

Yang, Rui; Wang, Hui; Shi, Ayuan; Zhang, Aofang; Wang, Jing; Gao, Dongxing; Lei, Zhenya; Hu, Bowei

2016-08-01

We demonstrate the meta-gate controlled wave propagation through multiple metallic plates with properly devised sub-wavelength defect apertures. Different from using gradient refractive-index meta-materials or phase-discontinuity meta-surfaces to produce the discrepancy between the incident angle and the refractive angle, our technique redirects electromagnetic fields by setting-up discrete transmission gateways between adjacent meta-gates and creates the perfect channels for the wave propagation. Electromagnetic fields can be assigned in the response of the driving frequency of meta-gates with extraordinary transmissions and propagate simply relying on their pre-set locations as illustrated by the meta-gate guided electromagnetic fields travelling in the paths of the Silk-Road and the contour line of Xi'an city where the Silk-Road starts. The meta-gate concept, offering the feasibility of the discrete control of electromagnetic fields with gating routes, may pave an alternative way for precisely transmitting of signals and efficiently sharing of resource in the communication.

Biological Effects of Weak Electromagnetic Field on Healthy and Infected Lime (Citrus aurantifolia) Trees with Phytoplasma

PubMed Central

Abdollahi, Fatemeh; Niknam, Vahid; Ghanati, Faezeh; Masroor, Faribors; Noorbakhsh, Seyyed Nasr

2012-01-01

Exposure to electromagnetic fields (EMF) has become an issue of concern for a great many people and is an active area of research. Phytoplasmas, also known as mycoplasma-like organisms, are wall-less prokaryotes that are pathogens of many plant species throughout the world. Effects of electromagnetic fields on the changes of lipid peroxidation, content of H2O2, proline, protein, and carbohydrates were investigated in leaves of two-year-old trees of lime (Citrus aurantifolia) infected by the Candidatus Phytoplasma aurantifoliae. The healthy and infected plants were discontinuously exposed to a 10 KHz quadratic EMF with maximum power of 9 W for 5 days, each 5 h, at 25°C. Fresh and dry weight of leaves, content of MDA, proline, and protein increased in both healthy and infected plants under electromagnetic fields, compared with those of the control plants. Electromagnetic fields decreased hydrogen peroxide and carbohydrates content in both healthy and infected plants compared to those of the controls. PMID:22649313

Expanding use of pulsed electromagnetic field therapies.

PubMed

Markov, Marko S

2007-01-01

Various types of magnetic and electromagnetic fields are now in successful use in modern medicine. Electromagnetic therapy carries the promise to heal numerous health problems, even where conventional medicine has failed. Today, magnetotherapy provides a non invasive, safe, and easy method to directly treat the site of injury, the source of pain and inflammation, and a variety of diseases and pathologies. Millions of people worldwide have received help in treatment of the musculoskeletal system, as well as for pain relief. Pulsed electromagnetic fields are one important modality in magnetotherapy. Recent technological innovations, implementing advancements in computer technologies, offer excellent state-of-the-art therapy.

Against dogma: On superluminal propagation in classical electromagnetism

NASA Astrophysics Data System (ADS)

Weatherall, James Owen

2014-11-01

It is deeply entrenched dogma that relativity theory prohibits superluminal propagation. It is also experimentally well-established that under some circumstances, classical electromagnetic fields propagate through a dielectric medium with superluminal group velocities and superluminal phase velocities. But it is usually claimed that these superluminal velocities do not violate the relativistic prohibition. Here I analyze electromagnetic fields in a dielectric medium within a framework for understanding superluminal propagation recently developed by Geroch (1996, 2011) and elaborated by Earman (2014). I will argue that for some parameter values, electromagnetic fields do propagate superluminally in the Geroch-Earman sense.

Electromagnetic holographic sensitivity field of two-phase flow in horizontal wells

NASA Astrophysics Data System (ADS)

Zhang, Kuo; Wu, Xi-Ling; Yan, Jing-Fu; Cai, Jia-Tie

2017-03-01

Electromagnetic holographic data are characterized by two modes, suggesting that image reconstruction requires a dual-mode sensitivity field as well. We analyze an electromagnetic holographic field based on tomography theory and Radon inverse transform to derive the expression of the electromagnetic holographic sensitivity field (EMHSF). Then, we apply the EMHSF calculated by using finite-element methods to flow simulations and holographic imaging. The results suggest that the EMHSF based on the partial derivative of radius of the complex electric potential φ is closely linked to the Radon inverse transform and encompasses the sensitivities of the amplitude and phase data. The flow images obtained with inversion using EMHSF better agree with the actual flow patterns. The EMHSF overcomes the limitations of traditional single-mode sensitivity fields.

A Comparison of Antenna Measurements in a Near-Field Range and a Newly Renovated Short-Tapered Chamber

DTIC Science & Technology

2016-09-01

SUPPLEMENTARY NOTES 14. ABSTRACT This study was undertaken to quantify and compare electromagnetic device (i.e., antenna) measurements using the US Army...15. SUBJECT TERMS electromagnetic , chamber, near-field range, anechoic chamber, antenna measurement 16. SECURITY CLASSIFICATION OF: 17...undertaken to quantify and compare electromagnetic (EM) device (i.e., antenna) measurements using the US Army Research Laboratory’s (ARL’s) near-field

Avionics System Design for High Energy Fields

DTIC Science & Technology

1988-07-01

this report describes design practices which will lead to reducc electromagnetic susceptibility of avionics systems in high energy fields . A second...nuclear reactions. Tn most cases the radiation which causes electromagnetic interference Is completely harmless to humans . Many techniqteq are used in...variety of electromagnetic compatibility problems. 1,e fIrst use EMCad to preeict the field strength from a discharge. Next, we usc’e r. a second

Linear and angular coherence momenta in the classical second-order coherence theory of vector electromagnetic fields.

PubMed

Wang, Wei; Takeda, Mitsuo

2006-09-01

A new concept of vector and tensor densities is introduced into the general coherence theory of vector electromagnetic fields that is based on energy and energy-flow coherence tensors. Related coherence conservation laws are presented in the form of continuity equations that provide new insights into the propagation of second-order correlation tensors associated with stationary random classical electromagnetic fields.

[Saccharomyces cerevisiae as a model organism for studying the carcinogenicity of non-ionizing electromagnetic fields and radiation].

PubMed

Voĭchuk, S I

2014-01-01

Medical and biological aspects of the effects of non-ionizing electromagnetic (EM) fields and radiation on human health are the important issues that have arisen as a result of anthropogenic impact on the biosphere. Safe use of man-made sources of non-ionizing electromagnetic fields and radiation in a broad range of frequencies--static, radio-frequency and microwave--is a subject of discussions and speculations. The main problem is the lack of understanding of the mechanism(s) of reception of EMFs by living organisms. In this review we have analyzed the existing literature data regarding the effects of the electromagnetic radiation on the model eukaryotic organism--yeast Saccharomyces cerevisiae. An attempt was made to estimate the probability of induction of carcinogenesis in humans under the influence of magnetic fields and electromagnetic radiation of extremely low frequency, radio frequency and microwave ranges.

Dynamic Test Method Based on Strong Electromagnetic Pulse for Electromagnetic Shielding Materials with Field-Induced Insulator-Conductor Phase Transition

NASA Astrophysics Data System (ADS)

Wang, Yun; Zhao, Min; Wang, Qingguo

2018-01-01

In order to measure the pulse shielding performance of materials with the characteristic of field-induced insulator-conductor phase transition when materials are used for electromagnetic shielding, a dynamic test method was proposed based on a coaxial fixture. Experiment system was built by square pulse source, coaxial cable, coaxial fixture, attenuator, and oscilloscope and insulating components. S11 parameter of the test system was obtained, which suggested that the working frequency ranges from 300 KHz to 7.36 GHz. Insulating performance is good enough to avoid discharge between conductors when material samples is exposed in the strong electromagnetic pulse field up to 831 kV/m. This method is suitable for materials with annular shape, certain thickness and the characteristic of field-induced insulator-conductor phase transition to get their shielding performances of strong electromagnetic pulse.

The Influence of Plasma Effects of Pair Beams on the Intergalactic Cascade Emission of Blazars

NASA Astrophysics Data System (ADS)

Menzler, Ulf; Schlickeiser, Reinhard

2014-03-01

The attenuation of TeV γ-rays from distant blazars by the extragalactic background light (EBL) produces relativistic electron-positron pair beams. It has been shown by Broderick et. al. (2012) and Schlickeiser et. al (2012) that a pair beam traversing the intergalactic medium is unstable to linear two-stream instabilities of both electrostatic and electromagnetic nature. While for strong blazars all free pair energy is dissipated in heating the intergalactic medium and a potential electromagnetic cascade via inverse-Compton scattering with the cosmic microwave background is suppressed, we investigate the case of weak blazars where the back reaction of generated electrostatic turbulence leads to a plateauing of the electron energy spectrum. In the ultra-relativistic Thomson limit we analytically calculate the inverse-Compton spectral energy distribution for both an unplateaued and a plateaued beam scenario, showing a peak reduction factor of Rpeak ≈ 0.345. This is consistent with the FERMI non-measurements of a GeV excess in the spectrum of EBL attenuated TeV blazars. Claims on the lower bound of the intergalactic magnetic field strengths, made by several authors neglecting plasma effects, are thus put into question.

[Effects of extremely low frequency electromagnetic radiation on cardiovascular system of workers].

PubMed

Zhao, Long-yu; Song, Chun-xiao; Yu, Duo; Liu, Xiao-liang; Guo, Jian-qiu; Wang, Chuan; Ding, Yuan-wei; Zhou, Hong-xia; Ma, Shu-mei; Liu, Xiao-dong; Liu, Xin

2012-03-01

To observe the exposure levels of extremely low frequency electromagnetic fields in workplaces and to analyze the effects of extremely low frequency electromagnetic radiation on cardiovascular system of occupationally exposed people. Intensity of electromagnetic fields in two workplaces (control and exposure groups) was detected with EFA-300 frequency electromagnetic field strength tester, and intensity of the noise was detected with AWA5610D integral sound level. The information of health physical indicators of 188 controls and 642 occupationally exposed workers was collected. Data were analyzed by SPSS17.0 statistic software. The intensity of electric fields and the magnetic fields in exposure groups was significantly higher than that in control group (P < 0.05), but there was no significant difference of noise between two workplaces (P > 0.05). The results of physical examination showed that the abnormal rates of HCY, ALT, AST, GGT, ECG in the exposure group were significantly higher than those in control group (P < 0.05). There were no differences of sex, age, height, weight between two groups (P > 0.05). Exposure to extremely low frequency electromagnetic radiation may have some effects on the cardiovascular system of workers.

Noise cancellation in magnetoencephalography and electroencephalography with isolated reference sensors

DOEpatents

Kraus, Jr., Robert H.; Espy, Michelle A.; Matlachov, Andrei; Volegov, Petr

2010-06-01

An apparatus measures electromagnetic signals from a weak signal source. A plurality of primary sensors is placed in functional proximity to the weak signal source with an electromagnetic field isolation surface arranged adjacent the primary sensors and between the weak signal source and sources of ambient noise. A plurality of reference sensors is placed adjacent the electromagnetic field isolation surface and arranged between the electromagnetic isolation surface and sources of ambient noise.

Measurement of Electromagnetic Properties of Lightning with 10 Nanosecond Resolution

NASA Technical Reports Server (NTRS)

Baum, C. E.; Breen, E. L.; Oneill, J. P.; Moore, C. B.; Hall, D. L.

1980-01-01

Electromagnetic data recorded from lightning strikes are presented. The data analysis reveals general characteristics of fast electromagnetic fields measured at the ground including rise times, amplitudes, and time patterns. A look at the electromagnetic structure of lightning shows that the shortest rise times in the vicinity of 30 ns are associated with leader leader streamers. Lightning location is based on electromagnetic field characteristics and is compared to a nearby sky camera. The fields from both leaders and return strokes were measured and are discussed. The data were obtained during 1978 and 1979 from lightning strikes occuring within 5 kilometers of an underground metal instrumentation room located on South Baldy peak near Langmuir Laboratory, New Mexico. The computer controlled instrumentation consisted of sensors previously used for measuring the nuclear electromagnetic pulse (EMP) and analog-digital recorders with 10 ns sampling, 256 levels of resolution, and 2 kilobytes of internal memory.

International Symposium on Electromagnetic Compatibility, 25th, Arlington, VA, August 23-25, 1983, Symposium Record

NASA Astrophysics Data System (ADS)

Subjects related to electromagnetic compatibility (EMC) analysis are discussed, taking into account forcing terms of line equations for externally excited transmission lines, E-fields over ground, electromagnetic near fields as a function of electrical size, a program for experimental verification of EMC analysis models, random susceptability of an IC 7400 TTL NAND gate, and a comparison of IEMCAP and SEMCAP. Other topics explored are concerned with EMC measurements, spectrum management, the electromagnetic pulse (EMP), a Navy EMC program, measurement systems, filters, EMC design, electromagnetic vulnerability (EMV) assessment of weapon systems, FCC rules and regulations, shielding, and electromagnetic interference (EMI) in communication systems. Attention is also given to nonsinusoidal functions in radar and communications, transients/electrostatic discharge, open field testing, cables and connectors, interference effects of induced and conducted earth current at dc and ELF, test cells, and cable coupling.

Large-scale 3D inversion of marine controlled source electromagnetic data using the integral equation method

NASA Astrophysics Data System (ADS)

Zhdanov, M. S.; Cuma, M.; Black, N.; Wilson, G. A.

2009-12-01

The marine controlled source electromagnetic (MCSEM) method has become widely used in offshore oil and gas exploration. Interpretation of MCSEM data is still a very challenging problem, especially if one would like to take into account the realistic 3D structure of the subsurface. The inversion of MCSEM data is complicated by the fact that the EM response of a hydrocarbon-bearing reservoir is very weak in comparison with the background EM fields generated by an electric dipole transmitter in complex geoelectrical structures formed by a conductive sea-water layer and the terranes beneath it. In this paper, we present a review of the recent developments in the area of large-scale 3D EM forward modeling and inversion. Our approach is based on using a new integral form of Maxwell’s equations allowing for an inhomogeneous background conductivity, which results in a numerically effective integral representation for 3D EM field. This representation provides an efficient tool for the solution of 3D EM inverse problems. To obtain a robust inverse model of the conductivity distribution, we apply regularization based on a focusing stabilizing functional which allows for the recovery of models with both smooth and sharp geoelectrical boundaries. The method is implemented in a fully parallel computer code, which makes it possible to run large-scale 3D inversions on grids with millions of inversion cells. This new technique can be effectively used for active EM detection and monitoring of the subsurface targets.

Theory and application of high temperature superconducting eddy current probes for nondestructive evaluation

NASA Astrophysics Data System (ADS)

Claycomb, James Ronald

1998-10-01

Several High-T c Superconducting (HTS) eddy current probes have been developed for applications in electromagnetic nondestructive evaluation (NDE) of conducting materials. The probes utilize high-T c SUperconducting Quantum Interference Device (SQUID) magnetometers to detect the fields produced by the perturbation of induced eddy currents resulting from subsurface flaws. Localized HTS shields are incorporated to selectively screen out environmental electromagnetic interference and enable movement of the instrument in the Earth's magnetic field. High permeability magnetic shields are employed to focus flux into, and thereby increase the eddy current density in the metallic test samples. NDE test results are presented, in which machined flaws in aluminum alloy are detected by probes of different design. A novel current injection technique performing NDE of wires using SQUIDs is also discussed. The HTS and high permeability shields are designed based on analytical and numerical finite element method (FEM) calculations presented here. Superconducting and high permeability magnetic shields are modeled in uniform noise fields and in the presence of dipole fields characteristic of flaw signals. Several shield designs are characterized in terms of (1) their ability to screen out uniform background noise fields; (2) the resultant improvement in signal-to-noise ratio and (3) the extent to which dipole source fields are distorted. An analysis of eddy current induction is then presented for low frequency SQUID NDE. Analytical expressions are developed for the induced eddy currents and resulting magnetic fields produced by excitation sources above conducting plates of varying thickness. The expressions derived here are used to model the SQUID's response to material thinning. An analytical defect model is also developed, taking into account the attenuation of the defect field through the conducting material, as well as the current flow around the edges of the flaw. Time harmonic FEM calculations are then used to model the electromagnetic response of eight probe designs, consisting of an eddy current drive coil coupled to a SQUID surrounded by superconducting and/or high permeability magnetic shielding. Simulations are carried out with the eddy current probes located a finite distance above a conducting surface. Results are quantified in terms of shielding and focus factors for each probe design.

Manager's Role in Electromagnetic Interference (EMI) Control

NASA Technical Reports Server (NTRS)

Sargent, Noel B.; Lewis, Catherine C.

2013-01-01

This presentation captures the essence of electromagnetic compatibility (EMC) engineering from a project manager's perspective. It explains the basics of EMC and the benefits to the project of early incorporation of EMC best practices. The EMC requirement products during a project life cycle are identified, along with the requirement verification methods that should be utilized. The goal of the presentation is to raise awareness and simplify the mystique surrounding electromagnetic compatibility for managers that have little or no electromagnetics background

A few categories of electromagnetic field problems treated through Fuzzy Logic

NASA Astrophysics Data System (ADS)

Lolea, M. S.; Dzitac, S.

2018-01-01

The paper deals with the problems of fuzzy logic applied in the field of electromagnetism. In the first part, there are presented some theoretical aspects regarding the characteristics and the application of the fuzzy logic in the general case. Are presented then, some categories of electromagnetic field problems treated by fuzzy logic. The accent is on the effects of exposure to the electromagnetic field on the human body. For this approach is dedicated a paragraph at the end of the paper. There is an application on how to treat by fuzzy logic the effects of electric field exposure. For this purpose, the fuzzy toolbox existing in the Matlab software and the results of some electric field strength measurements into a power substation are used. The results of the study and its conclusions are analyzed and exposed at the end of the paper.

Electromagnetic energy momentum in dispersive media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Philbin, T. G.

2011-01-15

The standard derivations of electromagnetic energy and momentum in media take Maxwell's equations as the starting point. It is well known that for dispersive media this approach does not directly yield exact expressions for the energy and momentum densities. Although Maxwell's equations fully describe electromagnetic fields, the general approach to conserved quantities in field theory is not based on the field equations, but rather on the action. Here an action principle for macroscopic electromagnetism in dispersive, lossless media is used to derive the exact conserved energy-momentum tensor. The time-averaged energy density reduces to Brillouin's simple formula when the fields aremore » monochromatic. The time-averaged momentum density for monochromatic fields corresponds to the familiar Minkowski expression DxB, but for general fields in dispersive media the momentum density does not have the Minkowski value. The results are unaffected by the debate over momentum balance in light-matter interactions.« less

Explaining Electromagnetic Plane Waves in a Vacuum at the Introductory Level

ERIC Educational Resources Information Center

Allred, Clark L.; Della-Rose, Devin J.; Flusche, Brian M.; Kiziah, Rex R.; Lee, David J.

2010-01-01

A typical introduction to electromagnetic waves in vacuum is illustrated by the following quote from an introductory physics text: "Maxwell's equations predict that an electromagnetic wave consists of oscillating electric and magnetic fields. The changing fields induce each other, which maintains the propagation of the wave; a changing electric…

47 CFR 2.1093 - Radiofrequency radiation exposure evaluation: portable devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to... Exposure Criteria for Radiofrequency Electromagnetic Fields,” NCRP Report No. 86, Section 17.4.5. Copyright... Electromagnetic Fields—RF and Microwave,” IEEE C95.3-1991. (4) For purposes of analyzing portable transmitting...

Nonlinear Generation of Electromagnetic Waves through Induced Scattering by Thermal Plasma.

PubMed

Tejero, E M; Crabtree, C; Blackwell, D D; Amatucci, W E; Mithaiwala, M; Ganguli, G; Rudakov, L

2015-12-09

We demonstrate the conversion of electrostatic pump waves into electromagnetic waves through nonlinear induced scattering by thermal particles in a laboratory plasma. Electrostatic waves in the whistler branch are launched that propagate near the resonance cone. When the amplitude exceeds a threshold ~5 × 10(-6) times the background magnetic field, wave power is scattered below the pump frequency with wave normal angles (~59°), where the scattered wavelength reaches the limits of the plasma column. The scattered wave has a perpendicular wavelength that is an order of magnitude larger than the pump wave and longer than the electron skin depth. The amplitude threshold, scattered frequency spectrum, and scattered wave normal angles are in good agreement with theory. The results may affect the analysis and interpretation of space observations and lead to a comprehensive understanding of the nature of the Earth's plasma environment.

Feasibility results of an electromagnetic compatibility test protocol to evaluate medical devices to radio frequency identification exposure

PubMed Central

2014-01-01

Background The use of radio frequency identification (RFID) systems in healthcare is increasing, and concerns for electromagnetic compatibility (EMC) pose one of the biggest obstacles for widespread adoption. Numerous studies have demonstrated that RFID systems can interfere with medical devices; however, the majority of past studies relied on time-consuming and burdensome test schemes based on ad hoc test methods applied to individual RFID systems. Methods This paper presents the results of using an RFID simulator that allows for faster evaluation of RFID-medical device EMC against a library of RFID test signals at various field strengths. Results The results of these tests demonstrate the feasibility and adequacy of simulator testing and can be used to support its incorporation into applicable consensus standards. Conclusions This work can aid the medical device community in better assessing the risks associated with medical device exposure to RFID. PMID:25086451

Accurate Modeling of Ionospheric Electromagnetic Fields Generated by a Low Altitude VLF Transmitter

DTIC Science & Technology

2009-03-31

AFRL-RV-HA-TR-2009-1055 Accurate Modeling of Ionospheric Electromagnetic Fields Generated by a Low Altitude VLF Transmitter ...m (or even 500 m) at mid to high latitudes . At low latitudes , the FDTD model exhibits variations that make it difficult to determine a reliable...Scientific, Final 3. DATES COVERED (From - To) 02-08-2006 – 31-12-2008 4. TITLE AND SUBTITLE Accurate Modeling of Ionospheric Electromagnetic Fields

Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cadena, M. S. Reyes; Chapul, L. Sanchez; Perez, Javier

2008-08-11

We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-{beta}) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animalsmore » subjected to ELF together with the transfer factor.« less

Electromagnetic ray tracing model for line structures.

PubMed

Tan, C B; Khoh, A; Yeo, S H

2008-03-17

In this paper, a model for electromagnetic scattering of line structures is established based on high frequency approximation approach - ray tracing. This electromagnetic ray tracing (ERT) model gives the advantage of identifying each physical field that contributes to the total solution of the scattering phenomenon. Besides the geometrical optics field, different diffracted fields associated with the line structures are also discussed and formulated. A step by step addition of each electromagnetic field is given to elucidate the causes of a disturbance in the amplitude profile. The accuracy of the ERT model is also discussed by comparing with the reference finite difference time domain (FDTD) solution, which shows a promising result for a single polysilicon line structure with width of as narrow as 0.4 wavelength.

Electrostatic lower hybrid waves excited by electromagnetic whistler mode waves scattering from planar magnetic-field-aligned plasma density irregularities

NASA Technical Reports Server (NTRS)

Bell, T. F.; Ngo, H. D.

1990-01-01

This paper presents a theoretical model for electrostatic lower hybrid waves excited by electromagnetic whistler mode waves propagating in regions of the magnetosphere and the topside ionosphere, where small-scale magnetic-field-aligned plasma density irregularities are thought to exist. In this model, the electrostatic waves are excited by linear mode coupling as the incident electromagnetic whistler mode waves scatter from the magnetic-field-aligned plasma density irregularities. Results indicate that high-amplitude short-wavelength (5 to 100 m) quasi-electrostatic whistler mode waves can be excited when electromagnetic whistler mode waves scatter from small-scale planar magnetic-field-aligned plasma density irregularities in the topside ionosphere and magnetosphere.

Multispacecraft Observations and 3D Structure of Electromagnetic Electron Phase-Space Holes

NASA Astrophysics Data System (ADS)

Holmes, J.; Ahmadi, N.; Ergun, R.; Wilder, F. D.; Newman, D. L.; Le Contel, O.; Torbert, R. B.; Burch, J. L.

2017-12-01

Electron phase-space holes are nonlinear plasma structures characterized by a unipolar trapping potential with a radial electric field. They commonly form from beam instabilities and other turbulent processes in many plasma environments. Due to their strong fields and long lifetimes, it has been hypothesized that phase-space holes can carry energy over long distances, contribute to large-scale currents, and accelerate individual particles to high energies. With electromagnetic field measurements at high cadence and precision on more than two spacecraft, we can compare the real 3D structure of electron phase-space holes to the models suggested by Andersson et al. (2009) and Treumann and Baumjohann (2012). In this case study, we consider a train of correlated electron phase-space holes observed by all four MMS spacecraft on the dusk flank within the magnetosphere. A number of the holes appear to pass directly through the 7 km tetrahedron formation. We use this data to compute the holes' phase velocity vector relative to the background magnetic field, and quantify their internal currents and associated magnetic moments. For these weak magnetic signatures, we find that the contribution from internal E×B0 currents is comparable to the v×E effect. This study will be interesting to compare with MMS observations in the magnetotail, which are expected to capture large, semi-relativistic phase-space holes with a strong magnetic component.

Peripheral nerve magnetic stimulation: influence of tissue non-homogeneity

PubMed Central

Krasteva, Vessela TZ; Papazov, Sava P; Daskalov, Ivan K

2003-01-01

Background Peripheral nerves are situated in a highly non-homogeneous environment, including muscles, bones, blood vessels, etc. Time-varying magnetic field stimulation of the median and ulnar nerves in the carpal region is studied, with special consideration of the influence of non-homogeneities. Methods A detailed three-dimensional finite element model (FEM) of the anatomy of the wrist region was built to assess the induced currents distribution by external magnetic stimulation. The electromagnetic field distribution in the non-homogeneous domain was defined as an internal Dirichlet problem using the finite element method. The boundary conditions were obtained by analysis of the vector potential field excited by external current-driven coils. Results The results include evaluation and graphical representation of the induced current field distribution at various stimulation coil positions. Comparative study for the real non-homogeneous structure with anisotropic conductivities of the tissues and a mock homogeneous media is also presented. The possibility of achieving selective stimulation of either of the two nerves is assessed. Conclusion The model developed could be useful in theoretical prediction of the current distribution in the nerves during diagnostic stimulation and therapeutic procedures involving electromagnetic excitation. The errors in applying homogeneous domain modeling rather than real non-homogeneous biological structures are demonstrated. The practical implications of the applied approach are valid for any arbitrary weakly conductive medium. PMID:14693034

Spaced-based search coil magnetometers

NASA Astrophysics Data System (ADS)

Hospodarsky, George B.

2016-12-01

Search coil magnetometers are one of the primary tools used to study the magnetic component of low-frequency electromagnetic waves in space. Their relatively small size, mass, and power consumption, coupled with a good frequency range and sensitivity, make them ideal for spaceflight applications. The basic design of a search coil magnetometer consists of many thousands of turns of wire wound on a high permeability core. When a time-varying magnetic field passes through the coil, a time-varying voltage is induced due to Faraday's law of magnetic induction. The output of the coil is usually attached to a preamplifier, which amplifies the induced voltage and conditions the signal for transmission to the main electronics (usually a low-frequency radio receiver). Search coil magnetometers are usually used in conjunction with electric field antenna to measure electromagnetic plasma waves in the frequency range of a few hertz to a few tens of kilohertzs. Search coil magnetometers are used to determine the properties of waves, such as comparing the relative electric and magnetic field amplitudes of the waves, or to investigate wave propagation parameters, such as Poynting flux and wave normal vectors. On a spinning spacecraft, they are also sometimes used to determine the background magnetic field. This paper presents some of the basic design criteria of search coil magnetometers and discusses design characteristics of sensors flown on a number of spacecraft.

Electromagnetic compatibility of PLC adapters for in-home/domestic networks

NASA Astrophysics Data System (ADS)

Potisk, Lukas; Hallon, Jozef; Orgon, Milos; Fujdiak, Radek

2018-01-01

The use of programable logic controllers (PLC) technology in electrical networks 230 V causes electromagnetic radiation that interferes with other electrical equipment connected to the network [1-4]. Therefore, this article describes the issues of electromagnetic compatibility (EMC) of new PLC adapters used in IP broadband services in a multi-user environment. The measurements of disturbing electromagnetic field originated in PLC adapters were made in a certified laboratory EMC (laboratory of electromagnetic compatibility) in the Institute of Electrical Engineering at Faculty of Electrical Engineering and Information Technology of the Slovak University of Technology in Bratislava. The measured spectra of the radiated electromagnetic field will be compared with the results obtained when testing older PLC modems [5].

Nonlinear mechanism for the generation of electromagnetic fields in a magnetized plasma by the beatings of waves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aburjania, G. D.; Machabeli, G. Z.; Kharshiladze, O. A.

2006-07-15

The modulational instability in a plasma in a strong constant external magnetic field is considered. The plasmon condensate is modulated not by conventional low-frequency ion sound but by the beatings of two high-frequency transverse electromagnetic waves propagating along the magnetic field. The instability reduces the spatial scales of Langmuir turbulence along the external magnetic field and generates electromagnetic fields. It is shown that, for a pump wave with a sufficiently large amplitude, the effect described in the present paper can be a dominant nonlinear process.

On the existence of the field line solutions of the Einstein-Maxwell equations

NASA Astrophysics Data System (ADS)

Vancea, Ion V.

The main result of this paper is the proof that there are local electric and magnetic field configurations expressed in terms of field lines on an arbitrary hyperbolic manifold. This electromagnetic field is described by (dual) solutions of the Maxwell’s equations of the Einstein-Maxwell theory. These solutions have the following important properties: (i) they are general, in the sense that the knot solutions are particular cases of them and (ii) they reduce to the electromagnetic fields in the field line representation in the flat space-time. Also, we discuss briefly the real representation of these electromagnetic configurations and write down the corresponding Einstein equations.

Superhorizon electromagnetic field background from Higgs loops in inflation

NASA Astrophysics Data System (ADS)

Kaya, Ali

2018-03-01

If Higgs is a spectator scalar, i.e. if it is not directly coupled to the inflaton, superhorizon Higgs modes must have been exited during inflation. Since Higgs is unstable its decay into photons is expected to seed superhorizon photon modes. We use in-in perturbation theory to show that this naive physical expectation is indeed fulfilled via loop effects. Specifically, we calculate the first order Higgs loop correction to the magnetic field power spectrum evaluated at some late time after inflation. It turns out that this loop correction becomes much larger than the tree-level power spectrum at the superhorizon scales. This suggests a mechanism to generate cosmologically interesting superhorizon vector modes by scalar-vector interactions.

Searching for CPT violation with cosmic microwave background data from WMAP and BOOMERANG.

PubMed

Feng, Bo; Li, Mingzhe; Xia, Jun-Qing; Chen, Xuelei; Zhang, Xinmin

2006-06-09

We search for signatures of Lorentz and violations in the cosmic microwave background (CMB) temperature and polarization anisotropies by using the Wilkinson Microwave Anisotropy Probe (WMAP) and the 2003 flight of BOOMERANG (B03) data. We note that if the Lorentz and symmetries are broken by a Chern-Simons term in the effective Lagrangian, which couples the dual electromagnetic field strength tensor to an external four-vector, the polarization vectors of propagating CMB photons will get rotated. Using the WMAP data alone, one could put an interesting constraint on the size of such a term. Combined with the B03 data, we found that a nonzero rotation angle of the photons is mildly favored: [Formula: See Text].

Wave-Particle Interactions Associated with Nongyrotropic Distribution Functions: A Hybrid Simulation Study

NASA Technical Reports Server (NTRS)

Convery, P. D.; Schriver, D.; Ashour-Abdalla, M.; Richard, R. L.

2002-01-01

Nongyrotropic plasma distribution functions can be formed in regions of space where guiding center motion breaks down as a result of strongly curved and weak ambient magnetic fields. Such are the conditions near the current sheet in the Earth's middle and distant magnetotail, where observations of nongyrotropic ion distributions have been made. Here a systematic parameter study of nongyrotropic proton distributions using electromagnetic hybrid simulations is made. We model the observed nongyrotropic distributions by removing a number of arc length segments from a cold ring distribution and find significant differences with the results of simulations that initially have a gyrotropic ring distribution. Model nongyrotropic distributions with initially small perpendicular thermalization produce growing fluctuations that diffuse the ions into a stable Maxwellian-like distribution within a few proton gyro periods. The growing waves produced by nongyrotropic distributions are similar to the electromagnetic proton cyclotron waves produced by a gyrotropic proton ring distribution in that they propagate parallel to the background magnetic field and occur at frequencies on the order of the proton gyrofrequency, The maximum energy of the fluctuating magnetic field increases as the initial proton distribution is made more nongyrotropic, that is, more highly bunched in perpendicular velocity space. This increase can be as much as twice the energy produced in the gyrotropic case.

Quantum entanglement of a harmonic oscillator with an electromagnetic field.

PubMed

Makarov, Dmitry N

2018-05-29

At present, there are many methods for obtaining quantum entanglement of particles with an electromagnetic field. Most methods have a low probability of quantum entanglement and not an exact theoretical apparatus based on an approximate solution of the Schrodinger equation. There is a need for new methods for obtaining quantum-entangled particles and mathematically accurate studies of such methods. In this paper, a quantum harmonic oscillator (for example, an electron in a magnetic field) interacting with a quantized electromagnetic field is considered. Based on the exact solution of the Schrodinger equation for this system, it is shown that for certain parameters there can be a large quantum entanglement between the electron and the electromagnetic field. Quantum entanglement is analyzed on the basis of a mathematically exact expression for the Schmidt modes and the Von Neumann entropy.

Electromagnetic potential vectors and the Lagrangian of a charged particle

NASA Technical Reports Server (NTRS)

Shebalin, John V.

1992-01-01

Maxwell's equations can be shown to imply the existence of two independent three-dimensional potential vectors. A comparison between the potential vectors and the electric and magnetic field vectors, using a spatial Fourier transformation, reveals six independent potential components but only four independent electromagnetic field components for each mode. Although the electromagnetic fields determined by Maxwell's equations give a complete description of all possible classical electromagnetic phenomena, potential vectors contains more information and allow for a description of such quantum mechanical phenomena as the Aharonov-Bohm effect. A new result is that a charged particle Lagrangian written in terms of potential vectors automatically contains a 'spontaneous symmetry breaking' potential.

Emergent spin electromagnetism induced by magnetization textures in the presence of spin-orbit interaction (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tatara, Gen, E-mail: gen.tatara@riken.jp; Nakabayashi, Noriyuki; Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397 Japan

2014-05-07

Emergent electromagnetic field which couples to electron's spin in ferromagnetic metals is theoretically studied. Rashba spin-orbit interaction induces spin electromagnetic field which is in the linear order in gradient of magnetization texture. The Rashba-induced effective electric and magnetic fields satisfy in the absence of spin relaxation the Maxwell's equations as in the charge-based electromagnetism. When spin relaxation is taken into account besides spin dynamics, a monopole current emerges generating spin motive force via the Faraday's induction law. The monopole is expected to play an important role in spin-charge conversion and in the integration of spintronics into electronics.

The Role of Higher-Order Modes on the Electromagnetic Whistler-Cyclotron Wave Fluctuations of Thermal and Non-Thermal Plasmas

NASA Technical Reports Server (NTRS)

Vinas, Adolfo F.; Moya, Pablo S.; Navarro, Roberto; Araneda, Jamie A.

2014-01-01

Two fundamental challenging problems of laboratory and astrophysical plasmas are the understanding of the relaxation of a collisionless plasmas with nearly isotropic velocity distribution functions and the resultant state of nearly equipartition energy density with electromagnetic plasma turbulence. Here, we present the results of a study which shows the role that higher-order-modes play in limiting the electromagnetic whistler-like fluctuations in a thermal and non-thermal plasma. Our main results show that for a thermal plasma the magnetic fluctuations are confined by regions that are bounded by the least-damped higher order modes. We further show that the zone where the whistler-cyclotron normal modes merges the electromagnetic fluctuations shifts to longer wavelengths as the beta(sub e) increases. This merging zone has been interpreted as the beginning of the region where the whistler-cyclotron waves losses their identity and become heavily damped while merging with the fluctuations. Our results further indicate that in the case of nonthermal plasmas, the higher-order modes do not confine the fluctuations due to the effective higher-temperature effects and the excess of suprathermal plasma particles. The analysis presented here considers the second-order theory of fluctuations and the dispersion relation of weakly transverse fluctuations, with wave vectors parallel to the uniform background magnetic field, in a finite temperature isotropic bi-Maxwellian and Tsallis-kappa-like magnetized electron-proton plasma. Our results indicate that the spontaneously emitted electromagnetic fluctuations are in fact enhanced over these quasi modes suggesting that such modes play an important role in the emission and absorption of electromagnetic fluctuations in thermal or quasi-thermal plasmas.

Quantum mechanical probability current as electromagnetic 4-current from topological EM fields

NASA Astrophysics Data System (ADS)

van der Mark, Martin B.

2015-09-01

Starting from a complex 4-potential A = αdβ we show that the 4-current density in electromagnetism and the probability current density in relativistic quantum mechanics are of identical form. With the Dirac-Clifford algebra Cl1,3 as mathematical basis, the given 4-potential allows topological solutions of the fields, quite similar to Bateman's construction, but with a double field solution that was overlooked previously. A more general nullvector condition is found and wave-functions of charged and neutral particles appear as topological configurations of the electromagnetic fields.

Electromagnetic fields in curved spacetimes

NASA Astrophysics Data System (ADS)

Tsagas, Christos G.

2005-01-01

We consider the evolution of electromagnetic fields in curved spacetimes and calculate the exact wave equations for the associated electric and magnetic components. Our analysis is fully covariant, applies to a general spacetime and isolates all the sources that affect the propagation of these waves. Among others, we explicitly show how the different components of the gravitational field act as driving sources of electromagnetic disturbances. When applied to perturbed Friedmann Robertson Walker cosmologies, our results argue for a superadiabatic-type amplification of large-scale cosmological magnetic fields in Friedmann models with open spatial curvature.

EM-ANIMATE: A Computer Program for Displaying and Animating Electromagnetic Near-Field and Surface-Current Solutions: Video Supplement to NASA Technical Memorandum 4539

NASA Technical Reports Server (NTRS)

Hom, Kam W.

1994-01-01

In this video, several examples of electromagnetic field and surface-current animation sequences are shown to demonstrate the visualization capabilities of the EM-ANIMATE computer program. These examples show the animation of total and scattered electric near fields from test bodies of a flat plate, a corner reflector, and a sphere. These test cases show the electric-field behavior caused by different scattering mechanisms through the animation of electromagnetic data from the EM-ANIMATE routine.

Rat testicular impairment induced by electromagnetic radiation from a conventional cellular telephone and the protective effects of the antioxidants vitamins C and E

PubMed Central

Al-Damegh, Mona Abdullah

2012-01-01

OBJECTIVE: The aim of this study was to investigate the possible effects of electromagnetic radiation from conventional cellular phone use on the oxidant and antioxidant status in rat blood and testicular tissue and determine the possible protective role of vitamins C and E in preventing the detrimental effects of electromagnetic radiation on the testes. MATERIALS AND METHODS: The treatment groups were exposed to an electromagnetic field, electromagnetic field plus vitamin C (40 mg/kg/day) or electromagnetic field plus vitamin E (2.7 mg/kg/day). All groups were exposed to the same electromagnetic frequency for 15, 30, and 60 min daily for two weeks. RESULTS: There was a significant increase in the diameter of the seminiferous tubules with a disorganized seminiferous tubule sperm cycle interruption in the electromagnetism-exposed group. The serum and testicular tissue conjugated diene, lipid hydroperoxide, and catalase activities increased 3-fold, whereas the total serum and testicular tissue glutathione and glutathione peroxidase levels decreased 3-5 fold in the electromagnetism-exposed animals. CONCLUSION: Our results indicate that the adverse effect of the generated electromagnetic frequency had a negative impact on testicular architecture and enzymatic activity. This finding also indicated the possible role of vitamins C and E in mitigating the oxidative stress imposed on the testes and restoring normality to the testes. PMID:22892924

Rat testicular impairment induced by electromagnetic radiation from a conventional cellular telephone and the protective effects of the antioxidants vitamins C and E.

PubMed

Al-Damegh, Mona Abdullah

2012-07-01

The aim of this study was to investigate the possible effects of electromagnetic radiation from conventional cellular phone use on the oxidant and antioxidant status in rat blood and testicular tissue and determine the possible protective role of vitamins C and E in preventing the detrimental effects of electromagnetic radiation on the testes. The treatment groups were exposed to an electromagnetic field, electromagnetic field plus vitamin C (40 mg/kg/day) or electromagnetic field plus vitamin E (2.7 mg/kg/day). All groups were exposed to the same electromagnetic frequency for 15, 30, and 60 min daily for two weeks. There was a significant increase in the diameter of the seminiferous tubules with a disorganized seminiferous tubule sperm cycle interruption in the electromagnetism-exposed group. The serum and testicular tissue conjugated diene, lipid hydroperoxide, and catalase activities increased 3-fold, whereas the total serum and testicular tissue glutathione and glutathione peroxidase levels decreased 3-5 fold in the electromagnetism-exposed animals. Our results indicate that the adverse effect of the generated electromagnetic frequency had a negative impact on testicular architecture and enzymatic activity. This finding also indicated the possible role of vitamins C and E in mitigating the oxidative stress imposed on the testes and restoring normality to the testes.

[Patient exposure to electromagnetic fields in magnetic resonance scanners: a review].

PubMed

Guibelalde del Castillo, E

2013-12-01

The use of non-ionizing electromagnetic fields in the low frequency end of the electromagnetic spectrum and static fields, radiofrequencies (RF), and microwaves is fundamental both in modern communication systems and in diagnostic medical imaging techniques like magnetic resonance imaging (MRI). The proliferation of these applications in recent decades has led to intense activity in developing regulations to guarantee their safety and to the establishment of guidelines and legal recommendations for the public, workers, and patients. In April 2012 it was foreseen that the European Parliament and Council would approve and publish a directive on the minimum health and safety requirements regarding the exposure of workers to the risks arising from electromagnetic fields, which would modify Directive 2004/40/EC. New studies related to the exposure to electromagnetic radiation and its impact on health published in recent years have led to a new postponement, and it is now foreseen that the directive will come into effect in October 2013. One of the most noteworthy aspects of the new version of the directive is the exclusion of the limits of occupational exposure to electromagnetic fields in the clinical use of MRI. In exchange for this exception, physicians and experts in protection against non-ionizing radiation are asked to make additional efforts to train workers exposed to non-ionizing radiation and to establish mechanisms to guarantee the correct application of non-ionizing electromagnetic fields in patients, along similar lines to the principles of justification and optimization established for ionizing radiation. On the basis of the most recently published studies, this article reviews some safety-related aspects to take into account when examining patients with MRI with high magnetic fields. Copyright © 2013 SERAM. Published by Elsevier Espana. All rights reserved.

Effects of exposure to 2100MHz GSM-like radiofrequency electromagnetic field on auditory system of rats.

PubMed

Çeliker, Metin; Özgür, Abdulkadir; Tümkaya, Levent; Terzi, Suat; Yılmaz, Mustafa; Kalkan, Yıldıray; Erdoğan, Ender

The use of mobile phones has become widespread in recent years. Although beneficial from the communication viewpoint, the electromagnetic fields generated by mobile phones may cause unwanted biological changes in the human body. In this study, we aimed to evaluate the effects of 2100MHz Global System for Mobile communication (GSM-like) electromagnetic field, generated by an electromagnetic fields generator, on the auditory system of rats by using electrophysiological, histopathologic and immunohistochemical methods. Fourteen adult Wistar albino rats were included in the study. The rats were divided randomly into two groups of seven rats each. The study group was exposed continuously for 30days to a 2100MHz electromagnetic fields with a signal level (power) of 5.4dBm (3.47mW) to simulate the talk mode on a mobile phone. The control group was not exposed to the aforementioned electromagnetic fields. After 30days, the Auditory Brainstem Responses of both groups were recorded and the rats were sacrificed. The cochlear nuclei were evaluated by histopathologic and immunohistochemical methods. The Auditory Brainstem Responses records of the two groups did not differ significantly. The histopathologic analysis showed increased degeneration signs in the study group (p=0.007). In addition, immunohistochemical analysis revealed increased apoptotic index in the study group compared to that in the control group (p=0.002). The results support that long-term exposure to a GSM-like 2100MHz electromagnetic fields causes an increase in neuronal degeneration and apoptosis in the auditory system. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Quasinormal modes, scattering, and Hawking radiation of Kerr-Newman black holes in a magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kokkotas, K. D.; Konoplya, R. A.; Zhidenko, A.

2011-01-15

We perform a comprehensive analysis of the spectrum of proper oscillations (quasinormal modes), transmission/reflection coefficients, and Hawking radiation for a massive charged scalar field in the background of the Kerr-Newman black hole immersed in an asymptotically homogeneous magnetic field. There are two main effects: the Zeeman shift of the particle energy in the magnetic field and the difference of values of an electromagnetic potential between the horizon and infinity, i.e. the Faraday induction. We have shown that 'turning on' the magnetic field induces a stronger energy-emission rate and leads to 'recharging' of the black hole. Thus, a black hole immersedmore » in a magnetic field evaporates much quicker, achieving thereby an extremal state in a shorter period of time. Quasinormal modes are moderately affected by the presence of a magnetic field which is assumed to be relatively small compared to the gravitational field of the black hole.« less

Electromagnetic homeostasis and the role of low-amplitude electromagnetic fields on life organization.

PubMed

De Ninno, Antonella; Pregnolato, Massimo

2017-01-01

The appearance of endogenous electromagnetic fields in biological systems is a widely debated issue in modern science. The electrophysiological fields have very tiny intensities and it can be inferred that they are rapidly decreasing with the distance from the generating structure, vanishing at very short distances. This makes very hard their detection using standard experimental methods. However, the existence of fast-moving charged particles in the macromolecules inside both intracellular and extracellular fluids may envisage the generation of localized electric currents as well as the presence of closed loops, which implies the existence of magnetic fields. Moreover, the whole set of oscillatory frequencies of various substances, enzymes, cell membranes, nucleic acids, bioelectrical phenomena generated by the electrical rhythm of coherent groups of cells, cell-to-cell communication among population of host bacteria, forms the increasingly complex hierarchies of electromagnetic signals of different frequencies which cover the living being and represent a fundamental information network controlling the cell metabolism. From this approach emerges the concept of electromagnetic homeostasis: that is, the capability of the human body to maintain the balance of highly complex electromagnetic interactions within, in spite of the external electromagnetic noisy environment. This concept may have an important impact on the actual definitions of heal and disease.

Topological responses from chiral anomaly in multi-Weyl semimetals

NASA Astrophysics Data System (ADS)

Huang, Ze-Min; Zhou, Jianhui; Shen, Shun-Qing

2017-08-01

Multi-Weyl semimetals are a kind of topological phase of matter with discrete Weyl nodes characterized by multiple monopole charges, in which the chiral anomaly, the anomalous nonconservation of an axial current, occurs in the presence of electric and magnetic fields. Electronic transport properties related to the chiral anomaly in the presence of both electromagnetic fields and axial electromagnetic fields in multi-Weyl semimetals are systematically studied. It has been found that the anomalous Hall conductivity has a modification linear in the axial vector potential from inhomogeneous strains. The axial electric field leads to an axial Hall current that is proportional to the distance of Weyl nodes in momentum space. This axial current may generate chirality accumulation of Weyl fermions through delicately engineering the axial electromagnetic fields even in the absence of external electromagnetic fields. Therefore this work provides a nonmagnetic mechanism of generation of chirality accumulation in Weyl semimetals and might shed new light on the application of Weyl semimetals in the emerging field of valleytronics.

3-D Electromagnetic field analysis of wireless power transfer system using K computer

NASA Astrophysics Data System (ADS)

Kawase, Yoshihiro; Yamaguchi, Tadashi; Murashita, Masaya; Tsukada, Shota; Ota, Tomohiro; Yamamoto, Takeshi

2018-05-01

We analyze the electromagnetic field of a wireless power transfer system using the 3-D parallel finite element method on K computer, which is a super computer in Japan. It is clarified that the electromagnetic field of the wireless power transfer system can be analyzed in a practical time using the parallel computation on K computer, moreover, the accuracy of the loss calculation becomes better as the mesh division of the shield becomes fine.

Comparison of the Effects of Manual Acupuncture, Laser Acupuncture, and Electromagnetic Field Stimulation at Acupuncture Point BL15 on Heart Rate Variability.

PubMed

Lee, Na Ra; Kim, Soo Byeong; Heo, Hyun; Lee, Yong Heum

2016-10-01

The aim of this study was to compare the influences of manual acupuncture, laser acupuncture, and electromagnetic field stimulation on the autonomic nervous system. We monitored the heart rate variability before and after stimulation to check the influence on the autonomic nervous system. The heart rate variabilities at low frequency (LF; 0.04-0.15 Hz) and high frequency (HF; 0.15-0.4 Hz) were analyzed to acquire LF/HF ratio. Xinshu (BL15) was selected as the stimulation point. Methods included manual acupuncture with a 1-cm depth and laser acupuncture at a wavelength of 660 nm and output power of 50 mW. An electromagnetic field of 2 Hz and 460 gauss (46 mT) was chosen. The LF and the LF/HF ratio were found to be lower in the manual acupuncture and the electromagnetic field groups, but to be higher in the laser acupuncture group. The HF was found to be lower in the laser acupuncture group, but higher in the manual acupuncture and the electromagnetic field groups. In conclusion, we found that manual acupuncture and electromagnetic field stimulation at BL15 activated the parasympathetic nervous system, whereas laser acupuncture at BL15 activated the sympathetic nervous system. Copyright © 2016. Published by Elsevier B.V.

47 CFR 2.1093 - Radiofrequency radiation exposure evaluation: portable devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI/IEEE C95.1-1992... Electromagnetic Fields,” NCRP Report No. 86, Section 17.4.5. Copyright NCRP, 1986, Bethesda, Maryland 20814. SAR... Potentially Hazardous Electromagnetic Fields—RF and Microwave,” IEEE C95.3-1991. (4) For purposes of analyzing...

47 CFR 2.1093 - Radiofrequency radiation exposure evaluation: portable devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI/IEEE C95.1-1992... Electromagnetic Fields,” NCRP Report No. 86, Section 17.4.5. Copyright NCRP, 1986, Bethesda, Maryland 20814. SAR... Potentially Hazardous Electromagnetic Fields—RF and Microwave,” IEEE C95.3-1991. (4) For purposes of analyzing...

Electromagnetic Imaging Methods for Nondestructive Evaluation Applications

PubMed Central

Deng, Yiming; Liu, Xin

2011-01-01

Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions. PMID:22247693

Scattering theory of stochastic electromagnetic light waves.

PubMed

Wang, Tao; Zhao, Daomu

2010-07-15

We generalize scattering theory to stochastic electromagnetic light waves. It is shown that when a stochastic electromagnetic light wave is scattered from a medium, the properties of the scattered field can be characterized by a 3 x 3 cross-spectral density matrix. An example of scattering of a spatially coherent electromagnetic light wave from a deterministic medium is discussed. Some interesting phenomena emerge, including the changes of the spectral degree of coherence and of the spectral degree of polarization of the scattered field.

Evaluation of effect of high frequency electromagnetic field on growth and antibiotic sensitivity of bacteria.

PubMed

Salmen, Saleh H; Alharbi, Sulaiman A; Faden, Asmaa A; Wainwright, M

2018-01-01

This study was aimed to evaluate the impact of high frequency electromagnetic fields (HF-EMF at 900 and 1800 MHz) on DNA, growth rate and antibiotic susceptibility of S. aureus , S. epidermidis , and P. aeruginosa . In this study, bacteria were exposed to 900 and 1800 MHz for 2 h and then inoculated to new medium when their growth rate and antibiotic susceptibility were evaluated. Results for the study of bacterial DNA unsuccessful to appearance any difference exposed and non-exposed S. aureus and S. epidermidis . Exposure of S. epidermidis and S. aureus to electromagnetic fields mostly produced no statistically significant decrease in bacterial growth, except for S. aureus when exposure to 900 MHz at 12 h. Exposure of P. aeruginosa to electromagnetic fields at 900 MHz however, lead to a significant reduction in growth rate, while 1800 MHz had insignificant effect. With the exception of S. aureus , treated with amoxicillin (30 µg) and exposed to electromagnetic fields, radiation treatment had no significant effect on bacterial sensitivity to antibiotics.

Association between Exposure to Electromagnetic Fields from High Voltage Transmission Lines and Neurobehavioral Function in Children

PubMed Central

Huang, Jiongli; Tang, Tiantong; Hu, Guocheng; Zheng, Jing; Wang, Yuyu; Wang, Qiang; Su, Jing; Zou, Yunfeng; Peng, Xiaowu

2013-01-01

Background Evidence for a possible causal relationship between exposure to electromagnetic fields (EMF) emitted by high voltage transmission (HVT) lines and neurobehavioral dysfunction in children is insufficient. The present study aims to investigate the association between EMF exposure from HVT lines and neurobehavioral function in children. Methods Two primary schools were chosen based on monitoring data of ambient electromagnetic radiation. A cross-sectional study with 437 children (9 to 13 years old) was conducted. Exposure to EMF from HVT lines was monitored at each school. Information was collected on possible confounders and relevant exposure predictors using standardized questionnaires. Neurobehavioral function in children was evaluated using established computerized neurobehavioral tests. Data was analyzed using multivariable regression models adjusted for relevant confounders. Results After controlling for potential confounding factors, multivariable regression revealed that children attending a school near 500 kV HVT lines had poorer performance on the computerized neurobehavioral tests for Visual Retention and Pursuit Aiming compared to children attending a school that was not in close proximity to HVT lines. Conclusions The results suggest long-term low-level exposure to EMF from HVT lines might have a negative impact on neurobehavioral function in children. However, because of differences in results only for two of four tests achieved statistical significance and potential limitations, more studies are needed to explore the effects of exposure to extremely low frequency EMF on neurobehavioral function and development in children. PMID:23843999

Axion induced oscillating electric dipole moments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, Christopher T.

In this study, the axion electromagnetic anomaly induces an oscillating electric dipole for any magnetic dipole. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion. The electron will acquire an oscillating electric dipole of frequency m a and strength ~ 10-32 e-cm, within four orders of magnitude of the present standard model DC limit, and two orders of magnitude above the nucleon, assuming standard axion model and dark matter parameters. This may suggest sensitive new experimental venues for the axion dark matter search.

Investigation of ionospheric stimulated Brillouin scatter generated at pump frequencies near electron gyroharmonics

NASA Astrophysics Data System (ADS)

Mahmoudian, A.; Scales, W. A.; Bernhardt, P. A.; Fu, H.; Briczinski, S. J.; McCarrick, M. J.

2013-11-01

Stimulated Electromagnetic Emissions (SEEs), secondary electromagnetic waves excited by high power electromagnetic waves transmitted into the ionosphere, produced by the Magnetized Stimulated Brillouin Scatter (MSBS) process are investigated. Data from four recent research campaigns at the High Frequency Active Auroral Research Program (HAARP) facility is presented in this work. These experiments have provided additional quantitative interpretation of the SEE spectrum produced by MSBS to yield diagnostic measurements of the electron temperature and ion composition in the heated ionosphere. SEE spectral emission lines corresponding to ion acoustic (IA) and electrostatic ion cyclotron (EIC) mode excitation were observed with a shift in frequency up to a few tens of Hz from the pump frequency for heating near the third harmonic of the electron gyrofrequency 3fce. The threshold of each emission line has been measured by changing the pump wave power. The excitation threshold of IA and EIC emission lines originating at the reflection and upper hybrid altitudes is measured for various beam angles relative to the magnetic field. Variation of strength of MSBS emission lines with pump frequency relative to 3fce and 4fce is also studied. A full wave solution has been used to estimate the amplitude of the electric field at the interaction altitude. The estimated instability threshold using the theoretical model is compared with the threshold of MSBS lines in the experiment and possible diagnostic information for the background ionospheric plasma is discussed. Simultaneous formation of artificial field-aligned irregularities (FAIs) and suppression of the MSBS process is investigated. This technique can be used to estimate the growth time of artificial FAIs which may result in determination of plasma waves and physical process involved in the formation of FAIs.

Does Short-Term Exposure to Mobile Phone Base Station Signals Increase Symptoms in Individuals Who Report Sensitivity to Electromagnetic Fields? A Double-Blind Randomized Provocation Study

PubMed Central

Eltiti, Stacy; Wallace, Denise; Ridgewell, Anna; Zougkou, Konstantina; Russo, Riccardo; Sepulveda, Francisco; Mirshekar-Syahkal, Dariush; Rasor, Paul; Deeble, Roger; Fox, Elaine

2007-01-01

Background Individuals with idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) believe they suffer negative health effects when exposed to electromagnetic fields from everyday objects such as mobile phone base stations. Objectives This study used both open provocation and double-blind tests to determine if sensitive and control individuals experience more negative health effects when exposed to base station-like signals compared with sham. Methods Fifty-six self-reported sensitive and 120 control participants were tested in an open provocation test. Of these, 12 sensitive and 6 controls withdrew after the first session. The remainder completed a series of double-blind tests. Subjective measures of well-being and symptoms as well as physiological measures of blood volume pulse, heart rate, and skin conductance were obtained. Results During the open provocation, sensitive individuals reported lower levels of well-being in both the global system for mobile communication (GSM) and universal mobile telecommunications system (UMTS) compared with sham exposure, whereas controls reported more symptoms during the UMTS exposure. During double-blind tests the GSM signal did not have any effect on either group. Sensitive participants did report elevated levels of arousal during the UMTS condition, whereas the number or severity of symptoms experienced did not increase. Physiological measures did not differ across the three exposure conditions for either group. Conclusions Short-term exposure to a typical GSM base station-like signal did not affect well-being or physiological functions in sensitive or control individuals. Sensitive individuals reported elevated levels of arousal when exposed to a UMTS signal. Further analysis, however, indicated that this difference was likely to be due to the effect of order of exposure rather than the exposure itself. PMID:18007992

Microfabricated sensors for the measurement of electromagnetic fields in biological tissues

NASA Astrophysics Data System (ADS)

Monberg, James; Henning, Albert K.

1995-09-01

Public awareness of the risks of exposure to electromagnetic radiation has grown over the past ten yeras. The effects of power lines on human and animal health have drawn particular attention. Some longitudinal studies of cancer rates near power lines show a significant correlation, while others show a null result. The studies have suffered from inadequate sensors for the measurement of electromagnetic radiation in vivo. In this work, we describe the design, construction, and testing of electrically passive, microfabricated single-pole antennas and coils. These sensors will be used in vivo to study the effects of electromagnetic radiation on animals. Our testing to date has been limited to in vitro studies of the magnetic field probes. Magnetic field pickup coils were fabricated with up to 100 turns, over a length of up to 1000 micrometers . Measurements were carried out with the sensors in air, and in water of various saline concentrations. Magnetic fields were applied using a Helmholtz coil. Both dc and ac fields were applied. The results indicate that small-area measurements of electromagnetic fields in vitro can be made successfully, provided adequate shielding and amplification are used.

[The electroporation effects of high power pulse microwave and electromagnetic pulse irradiation on the membranes of cardiomyocyte cells and the mechanism therein involved].

PubMed

Deng, Hua; Wang, Dewen; Peng, Ruiyun; Wang, Shuiming; Chen, Jiankui; Zhang, Sa; Dong, Bo; Wang, Xiaomin

2005-08-01

Though there is ongoing public concern on potential hazards and risk of electromagnetic radiation, the bioeffects mechanism of electromagnetic fields remains obscure. Heart is one of the organs susceptive to electromagnetic fields (EMF). This study was designed to assess the influence of high power pulse microwave and electromagnetic pulse irradiation on cardiomyocytes, to explore the critical mechanism of electromagnetic fields, and to explain the regular course of injury caused by exposure to pulse EMF. Cultured cardiomyocytes were irradiated by high power pulse microwave and electromagnetic pulse first, then a series of apparatus including atom force microscope, laser scanning confocal microscope and flow cytometer were used to examine the changes of cell membrane conformation, structure and function. After irradiation, the cardiomyocytes pulsated slower or stop, the cells conformation was abnormal, the cells viability declined, and the percentage of apoptosis and necrosis increased significantly (P< 0.01). The cell membrane had pores unequal in size, and lost its penetration character. The concentration of Na+, K+, Ca2+, Cl-, Mg2+, Ca2+ and P3+ in cell culture medium increased significantly (P< 0.01). and the concentration of Ca2+ in cells ([Ca2+]i) decreased significantly (P<0.01). The results indicated that cardiomyocytes are susceptible to non-ionizing radiation. Pulse electromagnetic field can induce cardiomyocytes electroporation, and can do great damage to cells conformation, structure and function. Electroporation is one of the most critical mechanisms to explain the athermal effects of electromagnetic radiation.

Electromagnetic interference with cardiac pacemakers and implantable cardioverter-defibrillators from low-frequency electromagnetic fields in vivo.

PubMed

Tiikkaja, Maria; Aro, Aapo L; Alanko, Tommi; Lindholm, Harri; Sistonen, Heli; Hartikainen, Juha E K; Toivonen, Lauri; Juutilainen, Jukka; Hietanen, Maila

2013-03-01

Electromagnetic interference (EMI) can pose a danger to workers with pacemakers and implantable cardioverter-defibrillators (ICDs). At some workplaces electromagnetic fields are high enough to potentially inflict EMI. The purpose of this in vivo study was to evaluate the susceptibility of pacemakers and ICDs to external electromagnetic fields. Eleven volunteers with a pacemaker and 13 with an ICD were exposed to sine, pulse, ramp, and square waveform magnetic fields with frequencies of 2-200 Hz using Helmholtz coil. The magnetic field flux densities varied to 300 µT. We also tested the occurrence of EMI from an electronic article surveillance (EAS) gate, an induction cooktop, and a metal inert gas (MIG) welding machine. All pacemakers were tested with bipolar settings and three of them also with unipolar sensing configurations. None of the bipolar pacemakers or ICDs tested experienced interference in any of the exposure situations. The three pacemakers with unipolar settings were affected by the highest fields of the Helmholtz coil, and one of them also by the EAS gate and the welding cable. The induction cooktop did not interfere with any of the unipolarly programmed pacemakers. Magnetic fields with intensities as high as those used in this study are rare even in industrial working environments. In most cases, employees can return to work after implantation of a bipolar pacemaker or an ICD, after an appropriate risk assessment. Pacemakers programmed to unipolar configurations can cause danger to their users in environments with high electromagnetic fields, and should be avoided, if possible.

Electromagnetic resonance in the asymmetric terahertz metamaterials with triangle microstructure

NASA Astrophysics Data System (ADS)

Xing, Yuanyuan; Zhang, Xiaoyu; Zhang, Qiang; Gu, Yanping; Qian, Yunan; Lin, Xingyue; Tang, Yunhai; Cheng, Xinli; Qin, Changfa; Shen, Jiaoyan; Zang, Taocheng; Ma, Chunlan

2018-05-01

We investigate terahertz transmission properties and electromagnetic resonance modes in the asymmetric triangle structures with the change of asymmetric distance and the direction of electric field. When the THz electric field is perpendicular to the split gap of triangle, the electric field can better excite the THz absorption in the triangle structures. Importantly, electromagnetically induced transparency (EIT) characteristics are observed in the triangle structures due to the destructive interference of the different excited modes. The distributions of electric field and surface current density simulated by finite difference time domain indicate that the bright mode is excited by the side of triangle structures and dark mode is excited by the gap-side of triangle. The present study is helpful to understand the electromagnetic resonance in the asymmetric triangular metamaterials.

Growth Stimulation of Biological Cells and Tissue by Electromagnetic Fields and Uses Thereof

NASA Technical Reports Server (NTRS)

Wolf, David A. (Inventor); Goodwin, Thomas J. (Inventor)

2002-01-01

The present invention provides systems for growing two or three dimensional mammalian cells within a culture medium facilitated by an electromagnetic field, and preferably, a time varying electromagnetic field. The cells, and culture medium are contained within a fixed or rotating culture vessel, and the electromagnetic field is emitted from at least one electrode. In one embodiment, the electrode is spaced from the vessel. The invention further provides methods to promote neural tissue regeneration by means of culturing the neural cells in the claimed system. In one embodiment, neuronal cells are grown within longitudinally extending tissue strands extending axially along and within electrodes comprising electrically conductive channels or guides through which a time varying electrical current is conducted, the conductive channels being positioned within a culture medium.

Electron microscopy of electromagnetic waveforms.

PubMed

Ryabov, A; Baum, P

2016-07-22

Rapidly changing electromagnetic fields are the basis of almost any photonic or electronic device operation. We report how electron microscopy can measure collective carrier motion and fields with subcycle and subwavelength resolution. A collimated beam of femtosecond electron pulses passes through a metamaterial resonator that is previously excited with a single-cycle electromagnetic pulse. If the probing electrons are shorter in duration than half a field cycle, then time-frozen Lorentz forces distort the images quasi-classically and with subcycle time resolution. A pump-probe sequence reveals in a movie the sample's oscillating electromagnetic field vectors with time, phase, amplitude, and polarization information. This waveform electron microscopy can be used to visualize electrodynamic phenomena in devices as small and fast as available. Copyright © 2016, American Association for the Advancement of Science.

Growth stimulation of biological cells and tissue by electromagnetic fields and uses thereof

NASA Technical Reports Server (NTRS)

Wolf, David A. (Inventor); Goodwin, Thomas J. (Inventor)

2004-01-01

The present invention provides systems for growing two or three dimensional mammalian cells within a culture medium facilitated by an electromagnetic field, and preferably, a time varying electromagnetic field. The cells and culture medium are contained within a fixed or rotating culture vessel, and the electromagnetic field is emitted from at least one electrode. In one embodiment, the electrode is spaced from the vessel. The invention further provides methods to promote neural tissue regeneration by means of culturing the neural cells in the claimed system. In one embodiment, neuronal cells are grown within longitudinally extending tissue strands extending axially along and within electrodes comprising electrically conductive channels or guides through which a time varying electrical current is conducted, the conductive channels being positioned within a culture medium.

Primary experimental study on safety of deep brain stimulation in RF electromagnetic field.

PubMed

Jun, Xu; Luming, Li; Hongwei, Hao

2009-01-01

With the rapid growth of clinical application of Deep Brain Stimulation, its safety and functional concern in the electromagnetic field, another pollution becoming much more serious, has become more and more significant. Meanwhile, the measuring standards on Electromagnetic Compatibility (EMC) for DBS are still incomplete. Particularly, the knowledge of the electromagnetic field induced signals on the implanted lead is ignorant while some informal reports some side effects. This paper briefly surmised the status of EMC standards on implantable medical devices. Based on the EMC experiments of DBS device we developed, two experiments for measuring the induced voltage of the deep brain stimulator in RF electromagnetic field were reported. The measured data showed that the induced voltage in some frequency was prominent, for example over 2V. As a primary research, we think these results would be significant to cause researcher to pay more attention to the EMC safety problem and biological effects of the induced voltage in deep brain stimulation and other implantable devices.

Classical electromagnetic fields from quantum sources in heavy-ion collisions

NASA Astrophysics Data System (ADS)

Holliday, Robert; McCarty, Ryan; Peroutka, Balthazar; Tuchin, Kirill

2017-01-01

Electromagnetic fields are generated in high energy nuclear collisions by spectator valence protons. These fields are traditionally computed by integrating the Maxwell equations with point sources. One might expect that such an approach is valid at distances much larger than the proton size and thus such a classical approach should work well for almost the entire interaction region in the case of heavy nuclei. We argue that, in fact, the contrary is true: due to the quantum diffusion of the proton wave function, the classical approximation breaks down at distances of the order of the system size. We compute the electromagnetic field created by a charged particle described initially as a Gaussian wave packet of width 1 fm and evolving in vacuum according to the Klein-Gordon equation. We completely neglect the medium effects. We show that the dynamics, magnitude and even sign of the electromagnetic field created by classical and quantum sources are different.

Electromagnetic waves propagating in the string axiverse

NASA Astrophysics Data System (ADS)

Yoshida, Daiske; Soda, Jiro

2018-04-01

It is widely believed that axions are ubiquitous in string theory and could be dark matter. The peculiar features of axion dark matter are coherent oscillations and a coupling to the electromagnetic field through the Chern-Simons term. In this letter, we study the consequences of these two features of axions with mass in the range 10^{-13} eV to 103 eV. First, we study the parametric resonance of electromagnetic waves induced by the coherent oscillation of the axion. Since the resonance frequency is determined by the mass of the axion dark matter, if we detect this signal, we can get information on the mass of the axion dark matter. Second, we study the velocity of light in the background of the axion dark matter. In the presence of the Chern-Simons term, the dispersion relation is modified and the speed of light will oscillate in time. It turns out that the change in the speed of light would be difficult to observe. We argue that future radio wave observations of the resonance can give rise to a stronger constraint on the coupling constant and/or the density of the axion dark matter.

Electromagnetic Gun With Commutated Coils

NASA Technical Reports Server (NTRS)

Elliott, David G.

1991-01-01

Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.

Measurement of electromagnetic fields generated by air traffic control radar systems with spectrum analysers.

PubMed

Barellini, A; Bogi, L; Licitra, G; Silvi, A M; Zari, A

2009-12-01

Air traffic control (ATC) primary radars are 'classical' radars that use echoes of radiofrequency (RF) pulses from aircraft to determine their position. High-power RF pulses radiated from radar antennas may produce high electromagnetic field levels in the surrounding area. Measurement of electromagnetic fields produced by RF-pulsed radar by means of a swept-tuned spectrum analyser are investigated here. Measurements have been carried out both in the laboratory and in situ on signals generated by an ATC primary radar.

[Dynamics of biomacromolecules in coherent electromagnetic radiation field].

PubMed

Leshcheniuk, N S; Apanasevich, E E; Tereshenkov, V I

2014-01-01

It is shown that induced oscillations and periodic displacements of the equilibrium positions occur in biomacromolecules in the absence of electromagnetic radiation absorption, due to modulation of interaction potential between atoms and groups of atoms forming the non-valence bonds in macromolecules by the external electromagnetic field. Such "hyperoscillation" state causes inevitably the changes in biochemical properties of macromolecules and conformational transformation times.

Electromagnetic coherence theory of laser resonator modes.

PubMed

Saastamoinen, Toni; Turunen, Jari; Tervo, Jani; Setälä, Tero; Friberg, Ari T

2005-01-01

A theory of open laser resonators is formulated within the framework of the electromagnetic coherence theory. It is shown that if only one Fox-Li mode contributes to the field at a given frequency, then the field at that frequency is necessarily completely coherent in view of the space-frequency counterpart of the recently introduced degree of coherence of electromagnetic fields [Opt. Express 11, 1137 (2003)]. It is also shown that the relation between the number of Fox-Li modes and the new degree of coherence is analogous to the relation established in the scalar theory of laser resonator modes. Difficulties that arise with the formerly introduced visibility-based definition of the electromagnetic degree of coherence are briefly discussed.

Identifying Electromagnetic Attacks against Airports

NASA Astrophysics Data System (ADS)

Kreth, A.; Genender, E.; Doering, O.; Garbe, H.

2012-05-01

This work presents a new and sophisticated approach to detect and locate the origin of electromagnetic attacks. At the example of an airport, a normal electromagnetic environment is defined, in which electromagnetic attacks shall be identified. After a brief consideration of the capabilities of high power electromagnetic sources to produce high field strength values, this contribution finally presents the approach of a sensor network, realizing the identification of electromagnetic attacks.

Assessments and Viewpoints on the Biological and Human Health Effects of Extremely Low Frequency (ELF) Electromagnetic Fields. Compilation of Commissioned Papers for the ELF Literature Review Project.

DTIC Science & Technology

1985-05-01

Environ. Biophys. 20:53-65. 1983. Electric field effects on bacteria and yeast cells . Radiat. Environ. Biophys. 22 :149-162. Husing, J. 0., F. Strauss, and...Jr., Ph.D. 141 A Review of Cell Effects Induced by Exposure of Extremely Low 155 Frequency Electromagnetic Fields - Eugene M. Goodman, Ph.D. and Ben...and E. M. Goodman. 1983. Cell surface effects of 60 Hz electromagnetic fields. Radiat. Res. 94:217-220. artucci, G. I., P. C. Gailey, and R. A. Tell

Gauge invariant fractional electromagnetic fields

NASA Astrophysics Data System (ADS)

Lazo, Matheus Jatkoske

2011-09-01

Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators.

Threats to ultra-high-field MRI

NASA Astrophysics Data System (ADS)

Le Bihan, Denis

2009-08-01

In 2004 the European Commission (EC) adopted a directive restricting occupational exposure to electromagnetic fields. This directive (2004/40/CE), which examines the possible health risks of the electromagnetic fields from mobile phones, Wi-Fi, Bluetooth and other devices, concluded that upper limits on radiation and applied electromagnetic fields are necessary to prevent workers from suffering any undue acute health effects. But although not initially intended, the biggest impact of the directive could be on magnetic resonance imaging (MRI), which is used in hospitals worldwide to produce images of unrivalled quality of the brain and other soft tissues.

Electromagnetic cyclotron-loss-cone instability associated with weakly relativistic electrons

NASA Technical Reports Server (NTRS)

Wong, H. K.; Wu, C. S.; Ke, F. J.; Schneider, R. S.; Ziebell, L. F.

1982-01-01

The amplification of fast extraordinary mode waves at frequencies very close to the electron cyclotron frequency, due to the presence of a population of energetic electrons with a loss-cone type distribution, is studied. Low-energy background electrons are included in the analysis. Two types of loss-cone distribution functions are considered, and it is found that the maximum growth rates for both distribution functions are of the same order of magnitude. When the thermal effects of the energetic electrons are included in the dispersion equation, the real frequencies of the waves are lower than those obtained by using the cold plasma approximation. This effect tends to enhance the growth rate. An idealized case including a parallel electric field such that the distribution function of the trapped energetic electrons is modified is also considered. It is assumed that the parallel electric field can remove the low-energy background electrons away from the source region of radiation. Both these effects increase the growth rate.

Narrow field electromagnetic sensor system and method

DOEpatents

McEwan, Thomas E.

1996-01-01

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.

Narrow field electromagnetic sensor system and method

DOEpatents

McEwan, T.E.

1996-11-19

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.

Cell Phones: Current Research Results

MedlinePlus

... possibly carcinogenic to humans": Coffee Extremely low frequency electromagnetic fields (power line frequency) Talc-based body powder ... Effects of Wireless Communication Devices World Health Organization: Electromagnetic Fields and Public Health: Mobile Phones International Agency ...

Unexplored biophysical problem of manned flight to Mars

NASA Astrophysics Data System (ADS)

Avakyan, Sergey; Voronin, Nikolai; Kovalenok, Vladimir; Trchounian, Armen

The presentation discusses so far unexplored biophysical problem of manned flight to the Mars, scheduled for the next decade. In long-term manned space flights on the orbital stations "Salyut-6" Soviet cosmonaut crews under the command of one of the co-authors (cosmonaut V.V. Kovalenok) had repeatedly observed the effect of certain geophysical conditions on the psychological state of each crew. These effects were coinciding with the increased intensity of global illumination in the upper ionosphere space on flight altitudes (300-360 km). It is important that, during all these periods, the geomagnetic pulsation's were completely absent. Previously a new but very important for long interplanetary expeditions problem of psychophysical state of the crew in the absence of alternating electromagnetic fields and radiation, including the ionosphere one, was first raised for evolutionarily adapted humanity. However, up to date, this subject, particularly during the long simulation experiments such as "Mars 500", which eliminates much of their value and contribution to the Mars mission, has almost no attention. Indeed, the obtained results have clearly shown that the cosmonaut crews in orbital flight, even deep one within geomagnetic sphere, might experience severe psychological discomfort, the nature of which is fully defined. This is the appearance of such rather unusual geophysical periods of different durations (from minutes to days) those are in the form of an almost complete lack of geomagnetic pulsations on the Earth. The aim is to confirm the need of considering possible pathological effects of the complete lack of rhythm forming, inherent for terrestrial environment geomagnetic pulsation's on psychological and physical state of the cosmonaut crew. This is important for the preparation and conducting the manned flights beyond the Earth's magnetosphere, particularly to the Mars. The influence of the presence of different types of geomagnetic pulsation's recorded by the Geophysical Observatory "Borok" of the Joint Institute of Physics of the Earth after O.Yu. Schmidt, Russian Academy of Sciences, on the statistics manifestations of various diseases for Murom City, located in the same region (Central Russia) at a distance of about 50 km has been investigated. It has been observed that the period of the absence of pulsation's is typical for the maximum number of events in the manifestation of the diseases, especially nervous ones. High-frequency pulsation's similar to frequency in the basic human biorhythms are absent in 60-100 % for neurasthenia and 100 % - for neurosis and psychosis. All these electromagnetic waves are usually the background for the earthling to disappear with the release of the interplanetary spacecraft beyond the magnetosphere, and after a few days of flight the cosmonauts will be out of the usual electromagnetic "noise", as well as outside the geomagnetic field. It is unknown however if under the simultaneous absence either the geomagnetic field or electromagnetic waves in a wide range of frequencies - from low (including those of the field of brain rhythms, heart, etc.) to the highest ones the extremely high frequencies affect the human organism upon the resonance effects on the body cells. Therefore, in the coming years, during the preparatory stages of the first interplanetary flight, it is required to study synergistic effects of exposure to the fields on human - under expected absence of the usual "sets" oscillations of electromagnetic fields, especially geomagnetic pulsations, when real background of hypo-magnetic field exists. It should be emphasized that the flights and landings on the Moon cannot be analogous for discussion of the situation, as the flights continued outside the magnetosphere of the Earth are less than a week. Most importantly, the Moon during each lunar month (29 days) for several days is trailing geomagnetic sphere.

The distinguishing effects of low-intensity electromagnetic radiation of different extremely high frequencies on Enterococcus hirae: growth rate inhibition and scanning electron microscopy analysis.

PubMed

Hovnanyan, K; Kalantaryan, V; Trchounian, A

2017-09-01

A low-intensity electromagnetic field of extremely high frequency has inhibitory and stimulatory effects on bacteria, including Enterococcus hirae. It was shown that the low-intensity (the incident power density of 0·06 mW cm -2 ) electromagnetic field at the frequencies of 51·8 GHz and 53 GHz inhibited E. hirae ATCC 9790 bacterial growth rate; a stronger effect was observed with 53 GHz, regardless of exposure duration (0·5 h, 1 h or 2 h). Scanning electron microscopy analysis of these effects has been done; the cells were of spherical shape. Electromagnetic field at 53 GHz, but not 51·8 GHz, changed the cell size-the diameter was enlarged 1·3 fold at 53 GHz. These results suggest the difference in mechanisms of action on bacteria for electromagnetic fields at 51·8 GHz and 53 GHz. A stronger inhibitory effect of low-intensity electromagnetic field on Enterococcus hirae ATCC 9790 bacterial growth rate was observed with 53 GHz vs 51·8 GHz, regardless of exposure duration. Scanning electron microscopy analysis showed that almost all irradiated cells in the population have spherical shapes similar to nonirradiated ones, but they have increased diameters in case of irradiated cells at 53 GHz, but not 51·8 GHz. The results are novel, showing distinguishing effects of low-intensity electromagnetic field of different frequencies. They could be applied in treatment of food and different products in medicine and veterinary, where E. hirae plays an important role. © 2017 The Society for Applied Microbiology.

Electron dynamics in Hall thruster

NASA Astrophysics Data System (ADS)

Marini, Samuel; Pakter, Renato

2015-11-01

Hall thrusters are plasma engines those use an electromagnetic fields combination to confine electrons, generate and accelerate ions. Widely used by aerospace industries those thrusters stand out for its simple geometry, high specific impulse and low demand for electric power. Propulsion generated by those systems is due to acceleration of ions produced in an acceleration channel. The ions are generated by collision of electrons with propellant gas atoms. In this context, we can realize how important is characterizing the electronic dynamics. Using Hamiltonian formalism, we derive the electron motion equation in a simplified electromagnetic fields configuration observed in hall thrusters. We found conditions those must be satisfied by electromagnetic fields to have electronic confinement in acceleration channel. We present configurations of electromagnetic fields those maximize propellant gas ionization and thus make propulsion more efficient. This work was supported by CNPq.

Differential form representation of stochastic electromagnetic fields

NASA Astrophysics Data System (ADS)

Haider, Michael; Russer, Johannes A.

2017-09-01

In this work, we revisit the theory of stochastic electromagnetic fields using exterior differential forms. We present a short overview as well as a brief introduction to the application of differential forms in electromagnetic theory. Within the framework of exterior calculus we derive equations for the second order moments, describing stochastic electromagnetic fields. Since the resulting objects are continuous quantities in space, a discretization scheme based on the Method of Moments (MoM) is introduced for numerical treatment. The MoM is applied in such a way, that the notation of exterior calculus is maintained while we still arrive at the same set of algebraic equations as obtained for the case of formulating the theory using the traditional notation of vector calculus. We conclude with an analytic calculation of the radiated electric field of two Hertzian dipole, excited by uncorrelated random currents.

Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

NASA Astrophysics Data System (ADS)

Yeung, Sai Ho; Pradhan, Raunaq; Feng, Xiaohua; Zheng, Yuanjin

2015-09-01

Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF) stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC) stimulation, magnetic stimulation (MS) and transcutaneous electrical nerve stimulation (TENS) are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeung, Sai Ho; Pradhan, Raunaq; Feng, Xiaohua

Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF) stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC) stimulation, magnetic stimulation (MS) and transcutaneous electrical nerve stimulation (TENS) are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissuemore » voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.« less

Electromagnetic radiation accompanying gravitational waves from black hole binaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolgov, A.; Postnov, K., E-mail: dolgov@fe.infn.it, E-mail: kpostnov@gmail.com

The transition of powerful gravitational waves, created by the coalescence of massive black hole binaries, into electromagnetic radiation in external magnetic fields is considered. In contrast to the previous calculations of the similar effect we study the realistic case of the gravitational radiation frequency below the plasma frequency of the surrounding medium. The gravitational waves propagating in the plasma constantly create electromagnetic radiation dragging it with them, despite the low frequency. The plasma heating by the unattenuated electromagnetic wave may be significant in hot rarefied plasma with strong magnetic field and can lead to a noticeable burst of electromagnetic radiationmore » with higher frequency. The graviton-to-photon conversion effect in plasma is discussed in the context of possible electromagnetic counterparts of GW150914 and GW170104.« less

A seafloor electromagnetic receiver for marine magnetotellurics and marine controlled-source electromagnetic sounding

NASA Astrophysics Data System (ADS)

Chen, Kai; Wei, Wen-Bo; Deng, Ming; Wu, Zhong-Liang; Yu, Gang

2015-09-01

In planning and executing marine controlled-source electromagnetic methods, seafloor electromagnetic receivers must overcome the problems of noise, clock drift, and power consumption. To design a receiver that performs well and overcomes the abovementioned problems, we performed forward modeling of the E-field abnormal response and established the receiver's characteristics. We describe the design optimization and the properties of each component, that is, low-noise induction coil sensor, low-noise Ag/AgCl electrode, low-noise chopper amplifier, digital temperature-compensated crystal oscillator module, acoustic telemetry modem, and burn wire system. Finally, we discuss the results of onshore and offshore field tests to show the effectiveness of the developed seafloor electromagnetic receiver and its performance: typical E-field noise of 0.12 nV/m/rt(Hz) at 0.5 Hz, dynamic range higher than 120 dB, clock drift lower than 1 ms/day, and continuous operation of at least 21 days.

Health Effects of Electromagnetic Fields: A Review of Literature.

ERIC Educational Resources Information Center

White, George L.; And Others

1995-01-01

Current evidence suggests that the effects of electromagnetic fields (EMF) disturb cell homeostasis at very low intensities by influencing discrete intracellular magnetic fields. The article reviews current research about the health effects of EMF, examining historical implications, childhood studies, adult studies, and popular press reports, and…

The Theory of Quantized Fields. II

DOE R&D Accomplishments Database

Schwinger, J.

1951-01-01

The arguments leading to the formulation of the Action Principle for a general field are presented. In association with the complete reduction of all numerical matrices into symmetrical and anti-symmetrical parts, the general field is decomposed into two sets, which are identified with Bose-Einstein and Fermi-Dirac fields. The spin restriction on the two kinds of fields is inferred from the time reflection invariance requirement. The consistency of the theory is verified in terms of a criterion involving the various generators of infinitesimal transformations. Following a discussion of charged fields, the electromagnetic field is introduced to satisfy the postulate of general gauge invariance. As an aspect of the latter, it is recognized that the electromagnetic field and charged fields are not kinematically independent. After a discussion of the field-strength commutation relations, the independent dynamical variable of the electromagnetic field are exhibited in terms of a special gauge.

Influence of electromagnetic signal of antibiotics excited by low-frequency pulsed electromagnetic fields on growth of Escherichia coli.

PubMed

Ke, Yin-Lung; Chang, Fu-Yu; Chen, Ming-Kun; Li, Shun-Lai; Jang, Ling-Sheng

2013-01-01

Energy medicine (EM) provides a new medical choice for patients, and its advantages are the noninvasive detection and nondrug treatment. An electromagnetic signal, a kind of EM, induced from antibiotic coupling with weak, extremely low-frequency pulsed electromagnetic fields (PEMFs) is utilized for investigating the growth speed of Escherichia coli (E. coli). PEMFs are produced by solenoidal coils for coupling the electromagnetic signal of antibiotics (penicillin). The growth retardation rate (GRR) of E. coli is used to investigate the efficacy of the electromagnetic signal of antibiotics. The E. coli is cultivated in the exposure of PEMFs coupling with the electromagnetic signal of antibiotics. The maximum GRR of PEMFs with and without the electromagnetic signal of antibiotics on the growth of E. coli cells in the logarithmic is 17.4 and 9.08%, respectively. The electromagnetic signal of antibiotics is successfully coupled by the electromagnetic signal coupling instrument to affect the growth of E. coli. In addition, the retardation effect on E. coli growth can be improved of by changing the carrier frequency of PEMFs coupling with the electromagnetic signal of antibiotics. GRR caused by the electromagnetic signal of antibiotics can be fixed by a different carrier frequency in a different phase of E. coli growth.

Overview on the standardization in the field of electromagnetic compatibility

NASA Astrophysics Data System (ADS)

Goldberg, Georges

1989-04-01

Standardization in the domain of electromagnetic compatibility (EMC) is discussed, with specific reference to the standards of the International Electrotechnical Commission, the Comite International Special des Perturbations Radioelectriques, and the Comite Europeen de Normalisation Electrotechnique. EMC fields considered include radiocommunications, telecommunications, biological effects, and data transmission. Standards are presented for such electromagnetic disturbances as low-frequency, high-frequency, conduction, and radiation phenomena.

Innovative Magnetic-Field Array Probe for TRUST Integrated Circuits

DTIC Science & Technology

2017-03-01

real-time an IC device. This non-invasive solution is cost effective, with a small form factor. Keywords: Electromagnetic radiation; Near-Field...solicitation was to design, develop and fabricate a low cost electromagnetic probe array for ICs counterfeit. The probe array should operate in the near...Our overall effort was focus on modeling, designing, fabricating, and utilizing novel electromagnetic probes for the analysis, characterization

Two Dimensional Steady State Eddy Current Analysis of a Spinning Conducting Cylinder

DTIC Science & Technology

2017-03-09

generate electromagnetic effects which can disrupt the electronic components contained inside the round. Finite element analyses were conducted to...which affect the magnetic field inside the cylinder were analyzed by varying the angular velocities and the electromagnetic properties (permeability and...the magnetic field distribution inside the cylinder was affected by angular velocity and the electromagnetic properties of the cylinder. 15

Direct Measurements of Energy Transfer between Hot Protons and He+ via EMIC Waves Observed by MMS in the Outer Magnetosphere

NASA Astrophysics Data System (ADS)

Kitamura, N.; Kitahara, M.; Shoji, M.; Miyoshi, Y.; Hasegawa, H.; Nakamura, S.; Katoh, Y.; Saito, Y.; Yokota, S.; Gershman, D. J.; Vinas, A. F.; Giles, B. L.; Moore, T. E.; Paterson, W.; Pollock, C. J.; Russell, C. T.; Strangeway, R. J.; Fuselier, S. A.; Burch, J. L.

2017-12-01

Wave-particle interactions have been suggested to play a crucial role in energy transfer in collisionless space plasmas in which the motion of charged particles is controlled by electromagnetic fields. Using an electromagnetic ion cyclotron (EMIC) wave event observed by MMS, we investigate energy transfer between ions and EMIC waves via cyclotron type interactions. To directly detect energy exchange between ions and EMIC waves, we apply the Wave-Particle Interaction Analyzer (WPIA) method that is to calculate the dot product between the wave electric field (Ewave) and ion current perpendicular to the background magnetic field (j). In the cases of resonance, this current is called the resonant current. Near the beginning of the wave event, 15-second averages of j • Ewave reached -0.3 pW/m3 for ions with energies of 14-30 keV and pitch angles of 33.25°-78.75°. The negative value in this pitch angle range indicates that the perpendicular energy of ions was being transferred to the EMIC waves propagating toward Southern higher latitudes at the MMS location by cyclotron resonance. Ion data show non-gyrotropic distributions around the resonance velocity, and that is consistent with the nonlinear trapping of protons by the wave and formation of an electromagnetic proton hole. Near the beginning of the same wave event, strongly phase bunched He+ up to 2 keV with pitch angles slightly larger than 90° were also detected. A positive j • Ewave for the phase bunched He+ indicates that the He+ was being accelerated by the electric field of the EMIC waves. The observed feature of He+ ions is consistent with non-resonant interaction with the wave but is inconsistent with cyclotron resonance. Significantly non-gyrotropic distributions observed in this event demonstrate that different particle populations can strongly couple through wave-particle interactions in the collisionless plasma.

Compact orthogonal NMR field sensor

DOEpatents

Gerald, II, Rex E.; Rathke, Jerome W [Homer Glen, IL

2009-02-03

A Compact Orthogonal Field Sensor for emitting two orthogonal electro-magnetic fields in a common space. More particularly, a replacement inductor for existing NMR (Nuclear Magnetic Resonance) sensors to allow for NMR imaging. The Compact Orthogonal Field Sensor has a conductive coil and a central conductor electrically connected in series. The central conductor is at least partially surrounded by the coil. The coil and central conductor are electrically or electro-magnetically connected to a device having a means for producing or inducing a current through the coil and central conductor. The Compact Orthogonal Field Sensor can be used in NMR imaging applications to determine the position and the associated NMR spectrum of a sample within the electro-magnetic field of the central conductor.

Survey of the Effects of Exposure to 900 MHz Radiofrequency Radiation Emitted by a GSM Mobile Phone on the Pattern of Muscle Contractions in an Animal Model.

PubMed

Mortazavi, S M J; Rahimi, S; Talebi, A; Soleimani, A; Rafati, A

2015-09-01

The rapid development of wireless telecommunication technologies over the past decades, has led to significant changes in the exposure of the general public to electromagnetic fields. Nowadays, people are continuously exposed to different sources of electromagnetic fields such as mobile phones, mobile base stations, cordless phones, Wi-Fi routers, and power lines. Therefore, the last decade witnessed a rapidly growing concern about the possible health effects of exposure to electromagnetic fields emitted by these sources. In this study that was aimed at investigating the effects of exposure to radiofrequency (RF) radiation emitted by a GSM mobile phone on the pattern of contraction in frog's isolated gastrocnemius muscle after stimulation with single square pulses of 1V (1 Hz), pulse height of contractions, the time interval between two subsequent contractions and the latency period were measured. Our findings showed that the pulse height of contractions muscle could be affected by the exposure to electromagnetic fields. Especially, the latency period was effectively altered in RF-exposed samples. However, none of the experiments could show an alteration in the time interval between two subsequent contractions after exposure to electromagnetic fields. These findings support early reports which indicated a wide variety of non-thermal effects of electromagnetic radiation on amphibians including the effects on the pattern of muscle extractions.

Influence of extremely low frequency electromagnetic fields on growth performance, innate immune response, biochemical parameters and disease resistance in rainbow trout, Oncorhynchus mykiss.

PubMed

Nofouzi, Katayoon; Sheikhzadeh, Najmeh; Mohamad-Zadeh Jassur, Davood; Ashrafi-Helan, Javad

2015-06-01

The effects of extremely low frequency electromagnetic fields on rainbow trout growth performance, innate immunity and biochemical parameters were studied. Rainbow trout (17-18 g) were exposed to electromagnetic fields (15 Hz) at 0.01, 0.1, 0.5, 5 and 50 µT, for 1 h daily over period of 60 days. Growth performance of fish improved in different treatment groups, especially at 0.1, 0.5, 5 and 50 µT. Immunological parameters, specifically hemagglutinating titer, total antiprotease and α1-antiprotease levels in treatment groups, were also enhanced. Total protein and globulin contents in the serum of fish exposed to 0.1, 0.5, 5 and 50 µT were significantly higher than those in the control group. No significant differences were found in serum enzyme activities, namely aspartate aminotransferase and alanine aminotransferase of fish in all treatment groups. Conversely, alkaline phosphatase level decreased in fish exposed to 0.01 and 50 µT electromagnetic fields. Meanwhile, electromagnetic induction at 0.1, 0.5, 5 and 50 µT enhanced fish protection against Yersinia ruckeri. These results indicated that these specific electromagnetic fields had possible effects on growth performance, nonspecific immunity and disease resistance of rainbow trout.

REVIEWS OF TOPICAL PROBLEMS: "Magnetized" black holes

NASA Astrophysics Data System (ADS)

Aliev, A. N.; Gal'tsov, D. V.

1989-01-01

Physical aspects of the theory of black holes in an external electromagnetic field are reviewed. The "magnetized" black hole model is currently widely discussed in astrophysics because it provides a basis for the explanation of the high energy activity of galactic cores and quasars. The particular feature of this model is that it predicts unusual "gravimagnetic" phenomena that arise as a result of a natural combination of effects in electrodynamics and gravitation, namely, the appearance of an inductive potential difference during the rotation of a black hole in a magnetic field, the drift of a black hole in an external electromagnetic field, the change in the chemical potential of the event horizon, the creation of an effective ergosphere of a black hole in a magnetic field, and so on. Questions relating to the description of electromagnetic fields in Kerr space-time are examined, including their influence on the space-time metric, the interaction between a rotating charged black hole and an external electromagnetic field, the motion of charged particles near "magnetized" black holes, including their spontaneous and stimulated emission, and the influence of magnetic fields on quantum-mechanical processes in black holes.

Navy Lasers, Railgun, and Hypervelocity Projectile: Background and Issues for Congress

DTIC Science & Technology

2016-05-27

surface ships to defend themselves against enemy missiles—solid state lasers (SSLs), the electromagnetic railgun (EMRG), and the hypervelocity... electromagnetic railgun (EMRG), and the hypervelocity projectile (HVP). 1 Any one of these new weapon technologies, if successfully developed and deployed...Number: N00024-15-R-4132, FedBizOpps.gov, July 29, 2015. See also Justin Doubleday, “Navy Developing Integrated Mount For Electromagnetic Railgun

Navy Lasers, Railgun, and Hypervelocity Projectile: Background and Issues for Congress

DTIC Science & Technology

2016-10-21

surface ships to defend themselves against enemy missiles—solid state lasers (SSLs), the electromagnetic railgun (EMRG), and the hypervelocity...SSLs), the electromagnetic railgun (EMRG), and the hypervelocity projectile (HVP). 1 Any one of these new weapon technologies, if successfully...Integrated Mount For Electromagnetic Railgun,” Inside the Navy, July 31, 2015.) 12 Sources for cost of HVP: David Martin, “Navy’s Newest Weapon Kills at

Split Octonion Reformulation for Electromagnetic Chiral Media of Massive Dyons

NASA Astrophysics Data System (ADS)

Chanyal, B. C.

2017-12-01

In an explicit, unified, and covariant formulation of an octonion algebra, we study and generalize the electromagnetic chiral fields equations of massive dyons with the split octonionic representation. Starting with 2×2 Zorn’s vector matrix realization of split-octonion and its dual Euclidean spaces, we represent the unified structure of split octonionic electric and magnetic induction vectors for chiral media. As such, in present paper, we describe the chiral parameter and pairing constants in terms of split octonionic matrix representation of Drude-Born-Fedorov constitutive relations. We have expressed a split octonionic electromagnetic field vector for chiral media, which exhibits the unified field structure of electric and magnetic chiral fields of dyons. The beauty of split octonionic representation of Zorn vector matrix realization is that, the every scalar and vector components have its own meaning in the generalized chiral electromagnetism of dyons. Correspondingly, we obtained the alternative form of generalized Proca-Maxwell’s equations of massive dyons in chiral media. Furthermore, the continuity equations, Poynting theorem and wave propagation for generalized electromagnetic fields of chiral media of massive dyons are established by split octonionic form of Zorn vector matrix algebra.

On gravitational chirality as the genesis of astrophysical jets

NASA Astrophysics Data System (ADS)

Tucker, R. W.; Walton, T. J.

2017-02-01

It has been suggested that single and double jets observed emanating from certain astrophysical objects may have a purely gravitational origin. We discuss new classes of plane-fronted and pulsed gravitational wave solutions to the equation for perturbations of Ricci-flat spacetimes around Minkowski metrics, as models for the genesis of such phenomena. These solutions are classified in terms of their chirality and generate a family of non-stationary spacetime metrics. Particular members of these families are used as backgrounds in analysing time-like solutions to the geodesic equation for test particles. They are found numerically to exhibit both single and double jet-like features with dimensionless aspect ratios suggesting that it may be profitable to include such backgrounds in simulations of astrophysical jet dynamics from rotating accretion discs involving electromagnetic fields.

Drift waves control using emissive cathodes in the laboratory

NASA Astrophysics Data System (ADS)

Plihon, N.; Desangles, V.; De Giorgio, E.; Bousselin, G.; Marino, R.; Pustelnik, N.; Poye, A.

2017-12-01

Low frequency plasma fluctuations are known to be the cause of strong transport perpendicular to magnetic guiding field line. These low frequency drift waves have been studied in linear devices in the laboratory over the last two decades. Their excitation or mitigation have been addressed using different drives, such as ring biasing or electromagnetic low frequency fields. Here we present an experimental characterization of the behavior of drift waves when the profile of the background plasma rotation is controlled using hot emissive cathodes. We show that electron emission from the cathodes modify the plasma potential, which in turn controls the rotation profile. Mitigation or enhancement of drift waves (on the amplitude or azimuthal mode number) is observed depending on the plasma rotation profile.

Radiation Forces and Torques without Stress (Tensors)

ERIC Educational Resources Information Center

Bohren, Craig F.

2011-01-01

To understand radiation forces and torques or to calculate them does not require invoking photon or electromagnetic field momentum transfer or stress tensors. According to continuum electromagnetic theory, forces and torques exerted by radiation are a consequence of electric and magnetic fields acting on charges and currents that the fields induce…

Velocity damper for electromagnetically levitated materials

DOEpatents

Fox, Richard J.

1994-01-01

A system for damping oscillatory and spinning motions induced in an electromagnetically levitated material. Two opposed field magnets are located orthogonally to the existing levitation coils for providing a DC quadrupole field (cusp field) around the material. The material used for generating the DC quadrupole field must be nonconducting to avoid eddy-current heating and of low magnetic permeability to avoid distorting the induction fields providing the levitation.

Field test of electromagnetic geophysical techniques for locating simulated in situ mining leach solution. Report of investigations/1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tweeton, D.R.; Hanson, J.C.; Friedel, M.J.

1994-01-01

The U.S. Bureau of Mines, the University of Arizona, Sandia National Laboratory, and Zonge Engineering and Research, Inc., conducted cooperative field tests of six electromagnetic geophysical methods to compare their effectiveness in locating a brine solution simulating in situ leach solution or a high-conductivity plume of contamination. The brine was approximately 160 meters below the surface. The test site was the University's San Xavier experimental mine near Tucson, Arizona. Geophysical surveys using surface and surface-borehole time-domain electromagnetics (TEM), surface controlled source audio-frequency magnetotellurics (CSAMT), surface-borehole frequency-domain electromagnetics (FEM), crosshole FEM and surface magnetic field ellipticity were conducted before and duringmore » brine injection.« less

Pseudoclassical Foldy-Wouthuysen transformation and canonical quantization of (D-2n)-dimensional relativistic particle with spin in an external electromagnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grigoryan, G.V.; Grigoryan, R.P.

1995-09-01

The canonical quantization of a (D=2n)-dimensional Dirac particle with spin in an arbitrary external electromagnetic field is performed in a gauge that makes it possible to describe simultaneously particles and antiparticles (both massive and massless) already at the classical level. A pseudoclassical Foldy-Wouthuysen transformation is used to find the canonical (Newton-Wigner) coordinates. The connection between this quantization scheme and Blount`s picture describing the behavior of a Dirac particle in an external electromagnetic field is discussed.

Nonlinear properties of gated graphene in a strong electromagnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avetisyan, A. A., E-mail: artakav@ysu.am; Djotyan, A. P., E-mail: adjotyan@ysu.am; Moulopoulos, K., E-mail: cos@ucy.ac.cy

We develop a microscopic theory of a strong electromagnetic field interaction with gated bilayer graphene. Quantum kinetic equations for density matrix are obtained using a tight binding approach within second quantized Hamiltonian in an intense laser field. We show that adiabatically changing the gate potentials with time may produce (at resonant photon energy) a full inversion of the electron population with high density between valence and conduction bands. In the linear regime, excitonic absorption of an electromagnetic radiation in a graphene monolayer with opened energy gap is also studied.

Compendium of the ULF/ELF Electromagnetic Fields Generated above a Sea of Finite Depth by Submerged Harmonic Dipoles

DTIC Science & Technology

1980-01-01

CATALOG NUMBER Tech. Report No. E715-1 4. TTE (ln tlitts LTYPE RPOT’ QcOIJj. Compendium of the ULF/ELF Electromagnetic Fields nccnicat Generated above...sidi if noeess’ry arid Identify hy bulock mriifi.rnb) ULF/ELF Electromagnetic Fields VMD, VED, HED, HMD Submerged Dipoles Undersea /Air Communication...a whole, it appears that the vertical electric component produced by th HED in the plane of the dipole (• =0) should be the most useful for undersea

Massive Black Hole Mergers: Can We "See" what LISA will "Hear"?

NASA Technical Reports Server (NTRS)

Centrella, Joan

2010-01-01

The final merger of massive black holes produces strong gravitational radiation that can be detected by the space-borne LISA. If the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We will review current efforts to simulate these systems, and discuss possibilities for observing the electromagnetic signals they produce.

Sliding mode control of electromagnetic tethered satellite formation

NASA Astrophysics Data System (ADS)

Hallaj, Mohammad Amin Alandi; Assadian, Nima

2016-08-01

This paper investigates the control of tethered satellite formation actuated by electromagnetic dipoles and reaction wheels using the robust sliding mode control technique. Generating electromagnetic forces and moments by electric current coils provides an attractive control actuation alternative for tethered satellite system due to the advantages of no propellant consumption and no obligatory rotational motion. Based on a dumbbell model of tethered satellite in which the flexibility and mass of the tether is neglected, the equations of motion in Cartesian coordinate are derived. In this model, the J2 perturbation is taken into account. The far-field and mid-field models of electromagnetic forces and moments of two satellites on each other and the effect of the Earth's magnetic field are presented. A robust sliding mode controller is designed for precise trajectory tracking purposes and to deal with the electromagnetic force and moment uncertainties and external disturbances due to the Earth's gravitational and magnetic fields inaccuracy. Numerical simulation results are presented to validate the effectiveness of the developed controller and its superiority over the linear controller.

Analogy between electromagnetic potentials and wave-like dynamic variables with connections to quantum theory

NASA Astrophysics Data System (ADS)

Yang, Chen

2018-05-01

The transitions from classical theories to quantum theories have attracted many interests. This paper demonstrates the analogy between the electromagnetic potentials and wave-like dynamic variables with their connections to quantum theory for audiences at advanced undergraduate level and above. In the first part, the counterpart relations in the classical electrodynamics (e.g. gauge transform and Lorenz condition) and classical mechanics (e.g. Legendre transform and free particle condition) are presented. These relations lead to similar governing equations of the field variables and dynamic variables. The Lorenz gauge, scalar potential and vector potential manifest a one-to-one similarity to the action, Hamiltonian and momentum, respectively. In the second part, the connections between the classical pictures of electromagnetic field and particle to quantum picture are presented. By characterising the states of electromagnetic field and particle via their (corresponding) variables, their evolution pictures manifest the same algebraic structure (isomorphic). Subsequently, pictures of the electromagnetic field and particle are compared to the quantum picture and their interconnections are given. A brief summary of the obtained results are presented at the end of the paper.

Novel Aspects of Evolution of the Stokes Parameters for an Electromagnetic Wave in Anisotropic Media

NASA Astrophysics Data System (ADS)

Botet, R.; Kuratsuji, H.; Seto, R.

2006-08-01

Polarization of a plane electromagnetic wave travelling through a medium is studied in the slowly-varying field envelope approximation. It is shown that the problem is identical to the 4-momentum evolution of a negatively-charged massless relativistic particle in an electromagnetic field. The approach is exemplified by the resonant oscillations of circular polarization in a medium embedded in a static magnetic field and a modulated electric field. The effect of dissipation in the medium is discussed. It is shown that the Rabi oscillations are stable below a threshold depending on the absorption coefficient. Above it, oscillations disappear.

Phase control of squeezed state in double electromagnetically induced transparency system with a loop-transition structure

NASA Astrophysics Data System (ADS)

Li, Yuan; Zhou, Yusheng; Wang, Yong; Ling, Qiang; Chen, Bing; Dou, Yan; Zhang, Wei; Gao, Weiqing; Guo, Zhiqiang; Zhang, Junxiang

2018-03-01

We theoretically study the squeezed probe light passing through a double electromagnetically induced transparency (DEIT) system, in which a microwave field and two coupling lights drive a loop transition. It is shown that the output squeezing can be maintained in both two transparency windows of DEIT, and it can also be manipulated by the relative phase of the three driving fields. The influence of the intensity of applied fields and the optical depth of atoms on the squeezing is also investigated. This study offers possibilities to manipulate the squeezing propagation in atomic media by the phase of electromagnetic fields.

Electromagnetic wave energy converter

NASA Technical Reports Server (NTRS)

Bailey, R. L. (Inventor)

1973-01-01

Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

Electromagnetic flat sheet forming by spiral type actuator coil

NASA Astrophysics Data System (ADS)

Akbar, S.; Aleem, M. A.; Sarwar, M. N.; Zillohu, A. U.; Awan, M. S.; Haider, A.; Ahmad, Z.; Akhtar, S.; Farooque, M.

2016-08-01

Focus of present work is to develop a setup for high strain rate electromagnetic forming of thin aluminum sheets (0.5, 1.0, 1.5 and 2.0 mm) and optimization of forming parameters. Flat spiral coil of 99.9% pure Cu strip (2.5x8.0 mm) with self-inductance 11 μH, 13 no. of turns and resultant outer diameter of 130mm has been fabricated and was coupled to a capacitor bank of energy, voltage and capacitance of 9 kJ, 900 V and 22.8 mF, respectively. To optimize the coil design, a commercially available software FEMM-4.2 was used to simulate the electromagnetic field profile generated by the coils of different pitch but same number of turns. Results of electromagnetic field intensity proposed by simulation agree in close proximity with those of theoretical as well as experimental data. The calculation of electromagnetic force and magnetic couplings between the coil and metal sheet are made. Forming parameters were optimized for different sheet thicknesses. Electromagnetic field intensity's profile plays a principal role in forming of typical shapes and patterns in sheets.

Effects of short-term resistance training and pulsed electromagnetic fields on bone metabolism and joint function in severe haemophilia A patients with osteoporosis: a randomized controlled trial.

PubMed

Parhampour, Behrouz; Torkaman, Giti; Hoorfar, Hamid; Hedayati, Mehdi; Ravanbod, Roya

2014-05-01

To assess the effects of short-term resistance training and pulsed electromagnetic fields on bone metabolism and joint function in patients with haemophilia with osteoporosis. A randomized, controlled, patient and blood sample assessor-blinded, six-week trial, three times weekly. Hospital outpatients with severe haemophilia A and osteoporosis. Forty-eight patients were randomly assigned to resistance training (RT, n = 13), combined resistance training with pulsed electromagnetic fields (RTPEMF, n = 12), pulsed electromagnetic fields (PEMF, n = 11) and control (n = 12) groups. The RT group received 30-40 minutes of resistance exercises and placebo pulsed electromagnetic fields. The RTPEMF group received the same exercises with lower repetition and 30 minutes of pulsed electromagnetic fields. The PEMF group was exposed to 60 minutes of pulsed electromagnetic fields (30 Hz and 40 Gauss). Bone-specific alkaline phosphatase, N-terminal telopeptide of type 1 collagen, and joint function, using the modified Colorado Questionnaire, were measured before and after the programme. The absolute change of bone-specific alkaline phosphatase was significant in the RT and RTPEMF groups compared with the control group (25.41 ± 14.40, 15.09 ± 5.51, and -4.73 ± 2.93 U/L, respectively). The absolute changes in the total score for joint function were significant for knees, ankles, and elbows in the RT group (9.2 ± 1.38, 5.1 ± 0.5, and 3.2 ± 0.8, respectively) and the RTPEMF group (7.7 ± 1.0, 3.3 ± 0.6, and 2.5 ± 0.7, respectively) compared to the PEMF and control groups. This value was significant for knee joints in the PEMF group compared to the control group (3.4 ± 0.5 and 0.66 ± 0.4, respectively). Resistance training is effective for improving bone formation and joint function in severe haemophilia A patients with osteoporosis.

Electromagnetic Education in India

ERIC Educational Resources Information Center

Bajpai, Shrish; Asif, Siddiqui Sajida; Akhtar, Syed Adnan

2016-01-01

Out of the four fundamental interactions in nature, electromagnetics is one of them along with gravitation, strong interaction and weak interaction. The field of electromagnetics has made much of the modern age possible. Electromagnets are common in day-to-day appliances and are becoming more conventional as the need for technology increases.…

Descriptive Study of Electromagnetic Wave Distribution for Various Seating Positions: Using Digital Textbooks

ERIC Educational Resources Information Center

Seomun, GyeongAe; Kim, YoungHwan; Lee, Jung-Ah; Jeong, KwangHoon; Park, Seon-A; Kim, Miran; Noh, Wonjung

2014-01-01

To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in…

Equilibrium Shape of Ferrofluid in the Uniform External Field

DTIC Science & Technology

2017-07-14

applied external electromagnetic fields. Even in the static regimes, they demonstrate a variety of qualitative and quantitative transformations often...ellipsoidal solutions in the problems of electromagnetism , can be found in the works of Stratton,3 Landau and Lifshitz,4 and Akhiezer et al.5 Fig...controversies, the “static” approaches are much older and face less objections than the “dynamics” of electromagnetic media. This report will analyze the

Recommended E3 HEMP Heave Electric Field Waveform for the Critical Infrastructures. Volume 2

DTIC Science & Technology

2017-07-31

OF THE COMMISSION TO ASSESS THE THREAT TO THE UNITED STATES FROM ELECTROMAGNETIC PULSE (EMP) ATTACK The cover photo depicts Fishbowl Starfish...Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack. The Commission was established by Congress in the FY2001 National...Department of Defense E electric field EMP electromagnetic pulse EPRI Electric Power Research Institute FERC Federal Energy Regulatory Commission GMD

78 FR 74171 - Notice of Intent To Grant Partially Exclusive License

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-10

... Of Biological Cells And Tissue By Electromagnetic Fields (EMF) And Uses Thereof, NASA Case No. MSC-22633-1 and USPN 6,673,597, Growth Stimulation Of Biological Cells And Tissue By Electromagnetic Fields...

The measurement procedure in the SEMONT monitoring system.

PubMed

Djuric, Nikola; Kljajic, Dragan; Kasas-Lazetic, Karolina; Bajovic, Vera

2014-03-01

The measurement procedure of the open area in situ electric field strength is presented, acquiring the real field data for testing of the Serbian electromagnetic field monitoring network (SEMONT) and its Internet portal. The SEMONT monitoring system introduces an advanced approach of wireless sensor network utilization for the continuous supervision of overall and cumulative level of electromagnetic field over the observed area. The aim of the SEMONT system is to become a useful tool for the national and municipal agencies for the environmental protection, regarding the electromagnetic pollution monitoring and the exposure assessment of the general population. Considering the public concern on the potentially harmful effects of the long-term exposure to electromagnetic radiation, as well as the public transparency principle that is incorporated into the Serbian law on non-ionizing radiation protection, the SEMONT monitoring system is designed for the long-term continuous monitoring, presenting real-time measurement results, and corresponding exposure assessment over the public Internet network.

The electric field changes and UHF radiations caused by the triggered lightning in Japan

NASA Technical Reports Server (NTRS)

Kawasaki, Zen-Ichiro; Kanao, Tadashi; Matsuura, Kenji; Nakano, Minoru; Horii, Kenji; Nakamura, Koichi

1991-01-01

In the rocket triggered lightning experiment of fiscal 1989, researchers observed electromagnetic field changes and UHF electromagnetic radiation accompanying rocket triggered lightning. It was found that no rapid changes corresponding to the return stroke of natural lightning were observed in the electric field changes accompanying rocket triggered lightning. However, continuous currents were present. In the case of rocket triggered lightning to the tower, electromagnetic field changes corresponding to the initiation of triggered lightning showed a bipolar pulse of a relatively large amplitude. In contrast, the rocket triggered lightning to the ground did not have such a bipolar pulse. The UHF radiation accompanying the rocket triggered lightning preceded the waveform portions corresponding to the first changes in electromagnetic fields. The number of isolated pulses in the UHF radiation showed a correlation with the time duration from rocket launching up to triggered lightning. The time interval between consecutive isolated pulses tended to get shorter with the passage of time, just like the stepped leaders of natural lightning.

The high-performance electric field detector EFD for space-based measurements

NASA Astrophysics Data System (ADS)

Badoni, Davide

2016-04-01

We present the prototype of a new electric field detector (EFD) for space applications, that has been built and fully tested in laboratory in the framework of the LIMADOU collaboration between Italy and China aimed at developing the CSES (China Seismo-Electromagnetic Satellite) space mission (launch scheduled by the end of 2016). Investigations of the electromagnetic near-Earth space environment represent an important field of research as demonstrated by the satellite missions, already accomplished and/or planned to be launched in the near future, devoted to such issue (e.g. INJUN-5; POLAR, DEMETER, THEMIS, TARANIS, CSES, etc.). The payload of these satellites includes several instruments to measure electric fields in a broad frequency band along with magnetic field, plasma parameters and high energy particles fluxes. Even though these phenomena are mainly dominated by the solar activity, they are also conditioned by atmospheric and ionospheric processes, seismic activity, and human electromagnetic sources. The CSES mission will prosecute the exploratory study performed by the DEMETER satellite, by studying the electromagnetic, plasma and particle perturbations caused by seismicity in the ionosphere, magnetosphere and inner Van Allen belts. This task will be carried out through a detailed investigation of the anomalous electromagnetic field fluctuations, ionospheric plasma perturbations and instabilities accompanying earthquakes of moderate and strong magnitude, as observed by numerous satellite. As a secondary objective, the CSES satellite will also investigate the influence of the electromagnetic emissions of anthropogenic origin on the ionosphere and magnetosphere. The EFD detector consists of four probes designed to be installed on four booms deployed from the 3-axes stabilized satellite. The instrument has been conceived for space-borne measurements of electromagnetic phenomena such as magnetospheric waves, seimo-electromagnetic perturbations, anthropogenic electromagnetic emissions and more in general to investigate lithosphere-atmosphere-ionosphere EM coupling. The EFD can measure electric field in a wide band of frequencies extending from quasi-DC up to about 5 MHz. The resolution in the ULF band is better than 1μV/m with a dynamic range of 120 dB. This is a value 40 times better than that of any other recent instrument of similar quality. The sensitivity, in measuring d.o.p., in the other bands (ELF, VLF and HF) is better than 300 nV/√Hz, i.e. - by considering the boom lengths - the sensitivity in measuring electric field is of the order of 50 nV/(√Hz m). With these bandwidth and precision, the described electric field detector represents the most performing and updated device so far developed for electric field measurements in near-space applications. We present the description of the EFD instrument electronics and the results of the preliminary tests performed on the prototype in laboratory.

Coherent hybrid electromagnetic field imaging

DOEpatents

Cooke, Bradly J [Jemez Springs, NM; Guenther, David C [Los Alamos, NM

2008-08-26

An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

Numerical Simulation of Electromagnetic Field Variation in the Lithosphere-Atmosphere-Ionosphere Associated with Seismogenic Process in a Curvature Coordinate System

NASA Astrophysics Data System (ADS)

Liu, L.; Zhao, Z.; Wang, Y.; Huang, Q.

2013-12-01

The lithosphere-atmosphere- ionosphere (LAI) system formed an electromagnetic (EM) cavity that hosts the EM field excited by electric currents generated by lightning and other natural sources. There have also been numerous reports on variations of the EM field existing in LAI system prior to some significance earthquakes. We simulated the EM field in the lithosphere-ionosphere waveguide with a whole-earth model using a curvature coordinate by the hybrid pseudo-spectral and finite difference time domain method. Considering the seismogensis as a fully coupled seismoelectric process, we simulate the seismic wave and the EM wave in this 2D model. In the model we have observed the excitation of the Schumann Resonance (SR) as the background EM field generated by randomly placed electric-current impulses within the lowest 10 kilometers of the atmosphere. The diurnal variation and the latitude-dependence in ion concentration in the ionosphere are included in the model. After the SR reaching a steady state, an electric impulse is introduced in the shallow lithosphere to mimic the seismogenic process (pre-, co- and post-seismic) to assess the possible precursory effects on SR strength and frequency. The modeling results can explain the observed fact of why SR has a much more sensitive response to continental earthquakes, and much less response to oceanic events. The fundamental reason is simply due to the shielding effect of the conductive ocean that prevents effective radiation of the seismoelectric signals from oceanic earthquake events into the LAI waveguide.

Velocity damper for electromagnetically levitated materials

DOEpatents

Fox, R.J.

1994-06-07

A system for damping oscillatory and spinning motions induced in an electromagnetically levitated material is disclosed. Two opposed field magnets are located orthogonally to the existing levitation coils for providing a DC quadrupole field (cusp field) around the material. The material used for generating the DC quadrupole field must be nonconducting to avoid eddy-current heating and of low magnetic permeability to avoid distorting the induction fields providing the levitation. 1 fig.

Calculating corner singularities by boundary integral equations.

PubMed

Shi, Hualiang; Lu, Ya Yan; Du, Qiang

2017-06-01

Accurate numerical solutions for electromagnetic fields near sharp corners and edges are important for nanophotonics applications that rely on strong near fields to enhance light-matter interactions. For cylindrical structures, the singularity exponents of electromagnetic fields near sharp edges can be solved analytically, but in general the actual fields can only be calculated numerically. In this paper, we use a boundary integral equation method to compute electromagnetic fields near sharp edges, and construct the leading terms in asymptotic expansions based on numerical solutions. Our integral equations are formulated for rescaled unknown functions to avoid unbounded field components, and are discretized with a graded mesh and properly chosen quadrature schemes. The numerically found singularity exponents agree well with the exact values in all the test cases presented here, indicating that the numerical solutions are accurate.

[Effect of 50 Hz 1.8 mT sinusoidal electromagnetic fields on bone mineral density in growing rats].

PubMed

Gao, Yu-Hai; Zhou, Yan-Feng; Li, Shao-Feng; Li, Wen-Yuan; Xi, Hui-Rong; Yang, Fang-Fang; Chen, Ke-Ming

2017-12-25

To study effects of 50 Hz 1.8 mT sinusoidal electromagnetic fields (SEMFs) on bone mineral density (BMD) in SD rats. Thirty SD rats weighted(110±10) and aged 1 month were randomly divided into control group and electromagnetic field group, 15 in each group. Normal control group of 50 Hz 0 mT density and sinusoidal electromagnetic field group of 50 Hz 1.8 mT were performed respectively with 1.5 h/d and weighted weight once a week, and observed food-intake. Rats were anesthesia by intraperitoneal injection and dual energy X-ray absorptiometry were used to detect bone density of whole body, and detected bone density of femur and vertebral body. Osteocalcin and tartrate-resistant acid phosphatase 5b were detected by ELSA; weighted liver, kidney and uterus to calculate purtenance index, then detected pathologic results by HE. Compared with control group, there was no significant change in weight every week, food-intake every day; no obvious change of bone density of whole body at 2 and 4 weeks, however bone density of whole body, bone density of excised femur and vertebra were increased at 6 weeks. Expression of OC was increased, and TRACP 5b expression was decreased. No change of HE has been observed in liver, kidney and uterus and organic index. 50 Hz 1.8 mT sinusoidal electromagnetic fields could improve bone formation to decrease relevant factors of bone absorbs, to improve peak bone density of young rats, in further provide a basis for clinical research electromagnetic fields preventing osteoporosis foundation.

Design of portable electric and magnetic field generators

NASA Astrophysics Data System (ADS)

Stewart, M. G.; Siew, W. H.; Campbell, L. C.; Stewart, M. G.; Siew, W. H.

2000-11-01

Electric and magnetic field generators capable of producing high-amplitude output are not readily available. This presents difficulties for electromagnetic compatibility testing of new measurement systems where these systems are intended to operate in a particularly hostile electromagnetic environment. A portable electric and a portable magnetic field generator having high pulsed field output are described in this paper. The output of these generators were determined using an electromagnetic-compatible measurement system. These generators allow immunity testing in the laboratory of electronic systems to very high electrical fields, as well as for functional verification of the electronic systems on site. In the longer term, the basic design of the magnetic field generator may be developed as the generator to provide the damped sinusoid magnetic field specified in IEC 61000-4-10, which is adopted in BS EN 61000-4-10.

78 FR 65601 - Revised Filing Deadlines Following Resumption of Normal Commission Operations; 2014 Modification...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-01

... of Exposure to Radiofrequency Electromagnetic Fields Limits and Policies AGENCY: Federal... Electromagnetic Fields Limits and Policies, ET Docket Nos. 03-137 and 13-84; FCC 13-39. The date for filing reply...

78 FR 4071 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-18

... hazards associated with the U.S. Army Corps of Engineers Electromagnetic Fields evaluation operations... Michigan has determined that the U.S. Army Corps of Engineers Electromagnetic Fields evaluation operations...

78 FR 57663 - Notice of Intent To Grant Exclusive License

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-19

... Tissue by Electromagnetic Fields and Uses Theorof, NASA Case No. MSC-22633-1; and USPN 6,673,597, Growth Stimulation of Biological Cells and Tissue by Electromagnetic Fields and Uses Thereof, NASA Case No. MSC-22633...

Effects of electromagnetic radiation exposure on bone mineral density, thyroid, and oxidative stress index in electrical workers

PubMed Central

Kunt, Halil; Şentürk, İhsan; Gönül, Yücel; Korkmaz, Mehmet; Ahsen, Ahmet; Hazman, Ömer; Bal, Ahmet; Genç, Abdurrahman; Songur, Ahmet

2016-01-01

Background In the literature, some articles report that the incidence of numerous diseases increases among the individuals who live around high-voltage electric transmission lines (HVETL) or are exposed vocationally. However, it was not investigated whether HVETL affect bone metabolism, oxidative stress, and the prevalence of thyroid nodule. Methods Dual-energy X-ray absorptiometry (DEXA) bone density measurements, serum free triiodothyronine (FT3), free thyroxine (FT4), RANK, RANKL, osteoprotegerin (OPG), alkaline phosphatase (ALP), phosphor, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) levels were analyzed to investigate this effect. Results Bone mineral density levels of L1–L4 vertebrae and femur were observed significantly lower in the electrical workers. ALP, phosphor, RANK, RANKL, TOS, OSI, and anteroposterior diameter of the left thyroid lobe levels were significantly higher, and OPG, TAS, and FT4 levels were detected significantly lower in the study group when compared with the control group. Conclusion Consequently, it was observed that the balance between construction and destruction in the bone metabolism of the electrical workers who were employed in HVETL replaced toward destruction and led to a decrease in OPG levels and an increase in RANK and RANKL levels. In line with the previous studies, long-term exposure to an electromagnetic field causes disorders in many organs and systems. Thus, it is considered that long-term exposure to an electromagnetic field affects bone and thyroid metabolism and also increases OSI by increasing the TOS and decreasing the antioxidant status. PMID:26929645

Exact solutions for the source-excited cylindrical electromagnetic waves in a nonlinear nondispersive medium.

PubMed

Es'kin, V A; Kudrin, A V; Petrov, E Yu

2011-06-01

The behavior of electromagnetic fields in nonlinear media has been a topical problem since the discovery of materials with a nonlinearity of electromagnetic properties. The problem of finding exact solutions for the source-excited nonlinear waves in curvilinear coordinates has been regarded as unsolvable for a long time. In this work, we present the first solution of this type for a cylindrically symmetric field excited by a pulsed current filament in a nondispersive medium that is simultaneously inhomogeneous and nonlinear. Assuming that the medium has a power-law permittivity profile in the linear regime and lacks a center of inversion, we derive an exact solution for the electromagnetic field excited by a current filament in such a medium and discuss the properties of this solution.

Electro-suppression of water nano-droplets' solidification in no man's land: Electromagnetic fields' entropic trapping of supercooled water

NASA Astrophysics Data System (ADS)

Nandi, Prithwish K.; Burnham, Christian J.; English, Niall J.

2018-01-01

Understanding water solidification, especially in "No Man's Land" (NML) (150 K < T < 235 K) is crucially important (e.g., upper-troposphere cloud processes) and challenging. A rather neglected aspect of tropospheric ice-crystallite formation is inevitably present electromagnetic fields' role. Here, we employ non-equilibrium molecular dynamics of aggressively quenched supercooled water nano-droplets in the gas phase under NML conditions, in externally applied electromagnetic (e/m) fields, elucidating significant differences between effects of static and oscillating fields: although static fields induce "electro-freezing," e/m fields exhibit the contrary - solidification inhibition. This anti-freeze action extends not only to crystal-ice formation but also restricts amorphisation, i.e., suppression of low-density amorphous ice which forms otherwise in zero-field NML environments. E/m-field applications maintain water in the deeply supercooled state in an "entropic trap," which is ripe for industrial impacts in cryo-freezing, etc.

The monitoring results of electromagnetic radiation of 110-kV high-voltage lines in one urban location in Chongqing P.R. China.

PubMed

Qin, Qi-Zhong; Chen, Yu; Fu, Ting-Ting; Ding, Li; Han, Ling-Li; Li, Jian-Chao

2012-03-01

To understand electromagnetic radiation field strength and its influencing factors of certain 110-kV high-voltage lines in one urban area of Chongqing by measuring 110-kV high-voltage line's electromagnetic radiation level. According to the methodology as determined by the National Hygienic Standards, we selected certain adjacent residential buildings, high-voltage lines along a specific street and selected different distances around its vertical projection point as monitoring points. The levels of electromagnetic radiations were measured respectively. In this investigation within the frequency of 5-1,000 Hz both the electric field strength and magnetic field strength of each monitoring sites were lower than the public exposure standards as determined by the International Commission on Non-Ionizing Radiation Protection. However, the electrical field strength on the roof adjacent to the high-voltage lines was significantly higher than that as measured on the other floors in the same buildings (p < 0.05). The electromagnetic radiation measurements of different monitoring points, under the same high-voltage lines, showed the location which is nearer the high-voltage line maintain a consistently higher level of radiation than the more distant locations (p < 0.05). Electromagnetic radiation generated by high-voltage lines decreases proportionally to the distance from the lines. The buildings can to some extent shield (or absorb) the electric fields generated by high-voltage lines nearby. The electromagnetic radiation intensity near high-voltage lines may be mitigated or intensified by the manner in which the high-voltage lines are set up, and it merits attention for the potential impact on human health.

Development of New Methods for Predicting the Bistatic Electromagnetic Scattering from Absorbing Shapes

DTIC Science & Technology

1990-01-01

least-squares sense by adding a penalty term proportional to the square of the divergence to the variational principle At the start of this project... principle required for stable solutions of the electromagnetic field: It must be possible to express the basis functions used in the finite element method as... principle to derive several different methods for computing stable solutions to electromagnetic field problems. To understand above principle , notice that

Electromagnetic structure of light nuclei

DOE PAGES

Pastore, Saori

2016-03-25

Here, the present understanding of nuclear electromagnetic properties including electromagnetic moments, form factors and transitions in nuclei with A ≤ 10 is reviewed. Emphasis is on calculations based on nuclear Hamiltonians that include two- and three-nucleon realistic potentials, along with one- and two-body electromagnetic currents derived from a chiral effective field theory with pions and nucleons.

Electromagnetic structure of light nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pastore, Saori

Here, the present understanding of nuclear electromagnetic properties including electromagnetic moments, form factors and transitions in nuclei with A ≤ 10 is reviewed. Emphasis is on calculations based on nuclear Hamiltonians that include two- and three-nucleon realistic potentials, along with one- and two-body electromagnetic currents derived from a chiral effective field theory with pions and nucleons.

Low-loss planar metamaterials electromagnetically induced transparency for sensitive refractive index sensing

NASA Astrophysics Data System (ADS)

Tian, Ying; Hu, Sen; Huang, Xiaojun; Yu, Zetai; Lin, Hai; Yang, Helin

2017-10-01

A low-loss and high transmission electromagnetically induced transparency like (EIT- like) structure is experimentally and numerically demonstrated in this paper. The proposed planar structure based on EIT-like metamaterial consists of two separate split-ring resonators, and its resulting transmission level can maximally reach 0.89 with significant suppression of radiation loss. According to the effective medium theory, the imaginary parts of the effective permittivity and permeability of the metamaterial are used as the evidence of low-loss. In the analysis, the simulated surface current, magnetic field distribution and coupled oscillator model reveal the principle of high transmittance EIT-effect. Furthermore, the peak of transparency frequency is highly sensitive to the variation of refractive index in the background medium. The sensor based on the proposed EIT structure can achieve a sensitivity of 1.69 GHz/RIU (refractive index unit) and a figure of merit of 11.66. Such metamaterials have potential perspectives in sensing and chiral slow light devices.

Spacetime algebra as a powerful tool for electromagnetism

NASA Astrophysics Data System (ADS)

Dressel, Justin; Bliokh, Konstantin Y.; Nori, Franco

2015-08-01

We present a comprehensive introduction to spacetime algebra that emphasizes its practicality and power as a tool for the study of electromagnetism. We carefully develop this natural (Clifford) algebra of the Minkowski spacetime geometry, with a particular focus on its intrinsic (and often overlooked) complex structure. Notably, the scalar imaginary that appears throughout the electromagnetic theory properly corresponds to the unit 4-volume of spacetime itself, and thus has physical meaning. The electric and magnetic fields are combined into a single complex and frame-independent bivector field, which generalizes the Riemann-Silberstein complex vector that has recently resurfaced in studies of the single photon wavefunction. The complex structure of spacetime also underpins the emergence of electromagnetic waves, circular polarizations, the normal variables for canonical quantization, the distinction between electric and magnetic charge, complex spinor representations of Lorentz transformations, and the dual (electric-magnetic field exchange) symmetry that produces helicity conservation in vacuum fields. This latter symmetry manifests as an arbitrary global phase of the complex field, motivating the use of a complex vector potential, along with an associated transverse and gauge-invariant bivector potential, as well as complex (bivector and scalar) Hertz potentials. Our detailed treatment aims to encourage the use of spacetime algebra as a readily available and mature extension to existing vector calculus and tensor methods that can greatly simplify the analysis of fundamentally relativistic objects like the electromagnetic field.

47 CFR 1.1310 - Radiofrequency radiation exposure limits.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Criteria for Radiofrequency Electromagnetic Fields,” NCRP Report No. 86, Sections 17.4.1, 17.4.1.1, 17.4.2... Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI...

47 CFR 2.1093 - Radiofrequency radiation exposure evaluation: portable devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI/IEEE C95.1-1992, Copyright 1992 by the Institute of Electrical and... Exposure Criteria for Radiofrequency Electromagnetic Fields,” NCRP Report No. 86, Section 17.4.5. Copyright...

47 CFR 1.1310 - Radiofrequency radiation exposure limits.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Criteria for Radiofrequency Electromagnetic Fields,” NCRP Report No. 86, Sections 17.4.1, 17.4.1.1, 17.4.2... Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI...

78 FR 17099 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-20

... associated with the U.S. Army Corps of Engineers Electromagnetic Fields evaluation operations. During any of... has determined that the U.S. Army Corps of Engineers Electromagnetic Fields evaluation operation poses...

Effects of Electromagnetic Fields in Spinal Muscular Atrophy: A Case Report

NASA Astrophysics Data System (ADS)

Cañedo, L.; Martínez-Mata, J.; Serrano-Luna, G.

2004-09-01

Spinal Muscular Atrophy Type I is a disease that rapidly progress to death in early infancy. A case report of a child with Werdnig-Hoffmann disease Type I that recovered at three years of age after two years exposure to electromagnetic fields (ELF) is presented. The child is now eleven years old and with the exception of slightly abnormal gait, the muscle mass of tights and gluteus, high, weight and his everyday activities correspond to those of a normal child his age. Hypothetical explanations for the effects of the electromagnetic fields are discussed.

High-frequency electromagnetic scarring in three-dimensional axisymmetric convex cavities

DOE PAGES

Warne, Larry K.; Jorgenson, Roy E.

2016-04-13

Here, this article examines the localization of high-frequency electromagnetic fields in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. When these orbits lead to unstable localized modes, they are known as scars. This article treats the case where the opposing sides, or mirrors, are convex. Particular attention is focused on the normalization through the electromagnetic energy theorem. Both projections of the field along the scarred orbit as well as field point statistics are examined. Statistical comparisons are made with a numerical calculation of the scars run with an axisymmetric simulation.

Intravital Computer Morphometry on Protozoa: A Method for Monitoring of the Morphofunctional Disorders in Cells Exposed in the Cell Phone Communication Electromagnetic Field.

PubMed

Uskalova, D V; Igolkina, Yu V; Sarapultseva, E I

2016-08-01

Morphofunctional disorders in unicellular aquatic protozoa - Spirostomum ambiguum infusorians after 30-, 60-, and 360-min exposure in electromagnetic field at a radiation frequency of 1 GHz and energy flow density of 50 μW/cm(2) were analyzed by intravital computer morphometry. Significant disorders in morphometric values correlated with low mobility of the protozoa. The results suggested the use of intravital computer morphometry on the protozoa for early diagnosis of radiation-induced effects of the mobile communication electromagnetic field, for example, low mobility of spermatozoa.

Effect of electromagnetic field emitted by cellular phones on fetal heart rate patterns.

PubMed

Celik, Onder; Hascalik, Seyma

2004-01-15

The study was planned to determine the effects of electromagnetic fields produced by cellular phones on baseline fetal heart rate, acceleration and deceleration. Forty pregnant women undergoing non-stress test were admitted to the study. Non-stress test was obtained while the subjects were holding the CP on stand by mode and on dialing mode, each for 5 min. Similar recordings were taken while there were no phones around for 10 min. Electromagnetic fields produced by cellular phones do not cause any demonstrable affect in fetal heart rate, acceleration and deceleration.

Pulsed or continuous electromagnetic field induce p53/p21-mediated apoptotic signaling pathway in mouse spermatogenic cells in vitro and thus may affect male fertility.

PubMed

Solek, Przemyslaw; Majchrowicz, Lena; Bloniarz, Dominika; Krotoszynska, Ewelina; Koziorowski, Marek

2017-05-01

The impact of electromagnetic field (EMF) on the human health and surrounding environment is a common topic investigated over the years. A significant increase in the electromagnetic field concentration arouses public concern about the long-term effects of EMF on living organisms associated with many aspects. In the present study, we investigated the effects of pulsed and continuous electromagnetic field (PEMF/CEMF) on mouse spermatogenic cell lines (GC-1 spg and GC-2 spd) in terms of cellular and biochemical features in vitro. We evaluated the effect of EMF on mitochondrial metabolism, morphology, proliferation rate, viability, cell cycle progression, oxidative stress balance and regulatory proteins. Our results strongly suggest that EMF induces oxidative and nitrosative stress-mediated DNA damage, resulting in p53/p21-dependent cell cycle arrest and apoptosis. Therefore, spermatogenic cells due to the lack of antioxidant enzymes undergo oxidative and nitrosative stress-mediated cytotoxic and genotoxic events, which contribute to infertility by reduction in healthy sperm cells pool. In conclusion, electromagnetic field present in surrounding environment impairs male fertility by inducing p53/p21-mediated cell cycle arrest and apoptosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Magnetic radiation shielding - An idea whose time has returned?

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

1991-01-01

One solution to the problem of shielding crew from particulate radiation in space is to use active electromagnetic shielding. Practical types of shield include the magnetic shield, in which a strong magnetic field diverts charged particles from the crew region, and the magnetic/electrostatic plasma shield, in which an electrostatic field shields the crew from positively charged particles, while a magnetic field confines electrons from the space plasma to provide charge neutrality. Advances in technology include high-strength composite materials, high-temperature superconductors, numerical computational solutions to particle transport in electromagnetic fields, and a technology base for construction and operation of large superconducting magnets. These advances make electromagnetic shielding a practical alternative for near-term future missions.

On the determination of the electromagnetic field upon scattering by a small inhomogeneous spherical object

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shalashov, A. G., E-mail: ags@appl.sci-nnov.ru; Gospodchikov, E. D.

An efficient and fairly simple method of solving the problem of the incidence of a plane electromagnetic wave on an inhomogeneous object with specified spherically symmetric distributions of its electric permittivity and magnetic permeability is presented. The fields inside the object and the integrated scattering and absorption cross sections are found by assuming the object to be small compared to the vacuum wavelength. Since no constraints are imposed on the scales of the fields inside the object, the method is suitable for investigating complex cases, including those associated with the local amplification and absorption of the electromagnetic field in inhomogeneousmore » resonant media.« less

Vector solution for the mean electromagnetic fields in a layer of random particles

NASA Technical Reports Server (NTRS)

Lang, R. H.; Seker, S. S.; Levine, D. M.

1986-01-01

The mean electromagnetic fields are found in a layer of randomly oriented particles lying over a half space. A matrix-dyadic formulation of Maxwell's equations is employed in conjunction with the Foldy-Lax approximation to obtain equations for the mean fields. A two variable perturbation procedure, valid in the limit of small fractional volume, is then used to derive uncoupled equations for the slowly varying amplitudes of the mean wave. These equations are solved to obtain explicit expressions for the mean electromagnetic fields in the slab region in the general case of arbitrarily oriented particles and arbitrary polarization of the incident radiation. Numerical examples are given for the application to remote sensing of vegetation.

Direct Visualization of Local Electromagnetic Field Structures by Scanning Transmission Electron Microscopy.

PubMed

Shibata, Naoya; Findlay, Scott D; Matsumoto, Takao; Kohno, Yuji; Seki, Takehito; Sánchez-Santolino, Gabriel; Ikuhara, Yuichi

2017-07-18

The functional properties of materials and devices are critically determined by the electromagnetic field structures formed inside them, especially at nanointerface and surface regions, because such structures are strongly associated with the dynamics of electrons, holes and ions. To understand the fundamental origin of many exotic properties in modern materials and devices, it is essential to directly characterize local electromagnetic field structures at such defect regions, even down to atomic dimensions. In recent years, rapid progress in the development of high-speed area detectors for aberration-corrected scanning transmission electron microscopy (STEM) with sub-angstrom spatial resolution has opened new possibilities to directly image such electromagnetic field structures at very high-resolution. In this Account, we give an overview of our recent development of differential phase contrast (DPC) microscopy for aberration-corrected STEM and its application to many materials problems. In recent years, we have developed segmented-type STEM detectors which divide the detector plane into 16 segments and enable simultaneous imaging of 16 STEM images which are sensitive to the positions and angles of transmitted/scattered electrons on the detector plane. These detectors also have atomic-resolution imaging capability. Using these segmented-type STEM detectors, we show DPC STEM imaging to be a very powerful tool for directly imaging local electromagnetic field structures in materials and devices in real space. For example, DPC STEM can clearly visualize the local electric field variation due to the abrupt potential change across a p-n junction in a GaAs semiconductor, which cannot be observed by normal in-focus bright-field or annular type dark-field STEM imaging modes. DPC STEM is also very effective for imaging magnetic field structures in magnetic materials, such as magnetic domains and skyrmions. Moreover, real-time imaging of electromagnetic field structures can now be realized through very fast data acquisition, processing, and reconstruction algorithms. If we use DPC STEM for atomic-resolution imaging using a sub-angstrom size electron probe, it has been shown that we can directly observe the atomic electric field inside atoms within crystals and even inside single atoms, the field between the atomic nucleus and the surrounding electron cloud, which possesses information about the atomic species, local chemical bonding and charge redistribution between bonded atoms. This possibility may open an alternative way for directly visualizing atoms and nanostructures, that is, seeing atoms as an entity of electromagnetic fields that reflect the intra- and interatomic electronic structures. In this Account, the current status of aberration-corrected DPC STEM is highlighted, along with some applications in real material and device studies.

The assessment of electromagnetic field radiation exposure for mobile phone users.

PubMed

Buckus, Raimondas; Strukcinskiene, Birute; Raistenskis, Juozas

2014-12-01

During recent years, the widespread use of mobile phones has resulted in increased human ex- posure to electromagnetic field radiation and to health risks. Increased usage of mobile phones at the close proximity raises questions and doubts in safety of mobile phone users. The aim of the study was to assess an electromagnetic field radiation exposure for mobile phone users by measuring electromagnetic field strength in different settings at the distance of 1 to 30 cm from the mobile user. In this paper, the measurements of electric field strength exposure were conducted on different brand of mobile phones by the call-related factors: urban/rural area, indoor/outdoor setting and moving/stationary mode during calls. The different types of mobile phone were placed facing the field probe at 1 cm, 10 cm, 20 cm and 30 cm distance. The highest electric field strength was recorded for calls made in rural area (indoors) while the lowest electric field strength was recorded for calls made in urban area (outdoors). Calls made from a phone in a moving car gave a similar result like for indoor calls; however, calls made from a phone in a moving car exposed electric field strength two times more than that of calls in a standing (motionless) position. Electromagnetic field radiation depends on mobile phone power class and factors, like urban or rural area, outdoor or indoor, moving or motionless position, and the distance of the mobile phone from the phone user. It is recommended to keep a mobile phone in the safe distance of 10, 20 or 30 cm from the body (especially head) during the calls.

The Sterilization Effect of Cooperative Treatment of High Voltage Electrostatic Field and Variable Frequency Pulsed Electromagnetic Field on Heterotrophic Bacteria in Circulating Cooling Water

NASA Astrophysics Data System (ADS)

Gao, Xuetong; Liu, Zhian; Zhao, Judong

2018-01-01

Compared to other treatment of industrial circulating cooling water in the field of industrial water treatment, high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization technology, an advanced technology, is widely used because of its special characteristics--low energy consumption, nonpoisonous and environmentally friendly. In order to get a better cooling water sterilization effect under the premise of not polluting the environment, some experiments about sterilization of heterotrophic bacteria in industrial circulating cooling water by cooperative treatment of high voltage electrostatic field and variable frequency pulsed electromagnetic field were carried out. The comparison experiment on the sterilization effect of high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization on heterotrophic bacteria in industrial circulating cooling water was carried out by change electric field strength and pulse frequency. The results show that the bactericidal rate is selective to the frequency and output voltage, and the heterotrophic bacterium can only kill under the condition of sweep frequency range and output voltage. When the voltage of the high voltage power supply is 4000V, the pulse frequency is 1000Hz and the water temperature is 30°C, the sterilization rate is 48.7%, the sterilization rate is over 90%. Results of this study have important guiding significance for future application of magnetic field sterilization.

Exact Electromagnetic Fields Produced by a Finite Wire with Constant Current

ERIC Educational Resources Information Center

Jimenez, J. L.; Campos, I.; Aquino, N.

2008-01-01

We solve exactly the problem of calculating the electromagnetic fields produced by a finite wire with a constant current, by using two methods: retarded potentials and Jefimenko's formalism. One result in this particular case is that the usual Biot-Savart law of magnetostatics gives the correct magnetic field of the problem. We also show…

Influence of dielectric protective layer on laser damage resistance of gold coated gratings

NASA Astrophysics Data System (ADS)

Wu, Kepeng; Ma, Ping; Pu, Yunti; Xia, Zhilin

2016-03-01

Aiming at the problem that the damage threshold of gold coated grating is relatively low, a dielectric film is considered on the gold coated gratings as a protective layer. The thickness range of the protective layer is determined under the prerequisite that the diffraction efficiency of the gold coated grating is reduced to an acceptable degree. In this paper, the electromagnetic field, the temperature field and the stress field distribution in the grating are calculated when the silica and hafnium oxide are used as protective layers, under the preconditions of the electromagnetic field distribution of the gratings known. The results show that the addition of the protective layer changes the distribution of the electromagnetic field, temperature field and stress field in the grating, and the protective layer with an appropriate thickness can improve the laser damage resistance of the grating.

Selected Issues in DoD’s Radio Frequency Identification (RFID) Implementation

DTIC Science & Technology

2006-04-01

Evaluation of human exposure to electromagnetic fields from devices operating in the frequency range 0 Hz to 10 GHz, used in Electronic...standard for human exposure to RF Signal, 3 kHz-300 GHz BS EN 50364 Limitation of human exposure to electromagnetic fields from devices operating in the...Management and DoD Explosives Safety Board, and DoDD 6055.9-STD, DoD Ammunition and Explosives Safety Standards. Exposure of people to electromagnetic

Reducing electromagnetic irradiation and fields alleviates experienced health hazards of VDU work.

PubMed

Hagström, M; Auranen, J; Johansson, O; Ekman, R

2012-04-01

Word Heath Organisation (WHO) outlined in 2005 recommendations, how to treat people suffering from the functional impairment electrohypersensitivity in its document "Electromagnetic fields and public health". Unfortunately the reduction of electromagnetic fields was not considered as a treatment option. The aim of the current study was to shield the computer user from the emitted electromagnetic irradiation and fields and to correlate that to the subjective symptoms reported by electrohypersensitive volunteers. The irradiation of the shielding cabinets was recorded. They housed either separate computer screens or whole laptops. When the volunteers had used the shielding cabinet for 1-7 years, they were able work with their computers whole working day, Those who had used the shielding cabined for 2-3 months were partially symptom free. The person who had used the cabinet only for 1 week reported some alleviation of her nausea. it seems that reducing the electromagnetic irradiation of the computer can lessen the symptoms of electrohypersensitivity and permit working without problems. Further studies are needed to clarify how the symptoms of different organ systems recover and make computer users to work also professionally. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Self-reported symptoms associated with exposure to electromagnetic fields: a questionnaire study.

PubMed

Küçer, Nermin; Pamukçu, Tuğba

2014-01-01

Abstract In the last years, it has been discussed frequently whether there are any harmful effects of electromagnetic fields on human health. Electromagnetic fields are generated by several natural and man-made sources. Part of the electromagnetic spectrum called Radiofrequency is used in communication systems such as mobile (cellular) phone and computer. The aim of our study was to explore different self-reported symptoms that may be associated with exposure to electromagnetic fields. This survey study was conducted, using a questionnaire, on 350 people aged +9 years in Turkey. The chi-square test was used for data analysis. Self-reported symptoms were headache, vertigo/dizziness, fatigue, forgetfulness, sleep disturbance-insomnia, tension-anxiety, joint and bone pain, lacrimation of the eyes, hearing loss and tinnitus. As a result of the survey, the study has shown that users of mobile phone and computer more often complained of headache, joint and bone pain, hearing loss, vertigo/dizziness, tension-anxiety symptoms according to time of daily usage (p < 0.05). In users of mobile phone and computer, women significantly (p < 0.05) complained more often of headache, vertigo/dizziness, fatigue, forgetfulness and tension-anxiety than men.

Vegetation Use for Resolving Electromagnetic Compatibility and Ecology Issues

NASA Astrophysics Data System (ADS)

Zvezdina, M. Yu; Shokova, Yu A.; Cherckesova, L. V.; Golovko, T. M.; Cherskaya, A. A.

2017-05-01

The wide spread of Information and Communication Technologies and the development of Internet-enabled mobile applications have aggravated electromagnetic compatibility and ecology problems. Inability to excite electromagnetic field of a desired structure and strength with traditional approaches actualizes additional actions, including providing diffraction on propagation path, to resolve these issues. Diffraction on a stand-alone obstacle along the propagation path and the one on set of obstacles near receive antenna location can be considered as the additional actions in ultrashort band. The accomplished studies have shown that one the most effective means to lower electromagnetic field strength is to shield the receive antenna with vegetation from jamming radio equipment. Moreover, vegetation resolves electromagnetic ecology issues, for the energy flux density can be lowered by about two orders of magnitude.

Semiannual Status Report. [excitation of electromagnetic waves in the whistler frequency range

NASA Technical Reports Server (NTRS)

1994-01-01

During the last six months, we have continued our study of the excitation of electromagnetic waves in the whistler frequency range and the role that these waves will play in the acceleration of electrons and ions in the auroral region. A paper entitled 'Electron Beam Excitation of Upstream Waves in the Whistler Mode Frequency Range' was listed in the Journal of Geophysical Research. In this paper, we have shown that an anisotropic electron beam (or gyrating electron beam) is capable of generating both left-hand and right-hand polarized electromagnetic waves in the whistler frequency range. Since right-hand polarized electromagnetic waves can interact with background electrons and left-hand polarized waves can interact with background ions through cyclotron resonance, it is possible that these beam generated left-hand and right-hand polarized electromagnetic waves can accelerate either ions or electrons (or both), depending on the physical parameters under consideration. We are currently carrying out a comprehensive study of the electromagnetic whistler and lower hybrid like waves observed in the auroral zone using both wave and particle data. Our first task is to identify these wave modes and compare it with particle observations. Using both the DE-1 particle and wave measurements, we can positively identify those electromagnetics lower hybrid like waves as fast magnetosonic waves and the upper cutoff of these waves is the local lower hybrid frequency. From the upper cutoff of the frequency spectrum, one can infer the particle density and the result is in very good agreement with the particle data. Since these electromagnetic lower hybrid like waves can have frequencies extended down to the local ion cyclotron frequency, it practically confirms that they are not whistler waves.

Magnetic correlates in electromagnetic consciousness.

PubMed

Liboff, A R

2016-01-01

We examine the hypothesis that consciousness is a manifestation of the electromagnetic field, finding supportive factors not previously considered. It is not likely that traditional electrophysiological signaling modes can be readily transmitted throughout the brain to properly enable this field because of electric field screening arising from the ubiquitous distribution of high dielectric lipid membranes, a problem that vanishes for low-frequency magnetic fields. Many reports over the last few decades have provided evidence that living tissue is robustly sensitive to ultrasmall (1-100 nT) ELF magnetic fields overlapping the γ-frequency range often associated with awareness. An example taken from animal behavior (coherent bird flocking) lends support to the possibility of a disembodied electromagnetic consciousness. In contrast to quantum consciousness hypotheses, the present approach is open to experimental trial.

Electric toothbrushes induce electric current in fixed dental appliances by creating magnetic fields.

PubMed

Kameda, Takashi; Ohkuma, Kazuo; Ishii, Nozomu; Sano, Natsuki; Ogura, Hideo; Terada, Kazuto

2012-01-01

Magnetic fields can represent a health problem, especially low frequency electromagnetic fields sometimes induced by electric current in metallic objects worn or used in or on the body (as opposed to high frequency electromagnetic fields that produce heat). Electric toothbrushes are widely used because of their convenience, but the electric motors that power them may produce electromagnetic waves. In this study, we showed that electric toothbrushes generate low frequency (1-2000 Hz) magnetic fields and induce electric current in dental appliances (e. g. orthodontic and prosthetic appliances and dental implants). Current induced by electric toothbrushes might be dependent on the quantity and types of metals used, and the shape of the appliances. Furthermore, these induced currents in dental appliances could impact upon human oral health, producing pain and discomfort.

Propagation of electromagnetic waves parallel to the magnetic field in the nightside Venus ionosphere

NASA Technical Reports Server (NTRS)

Huba, J. D.; Rowland, H. L.

1993-01-01

The propagation of electromagnetic waves parallel to the magnetic field in the nightside Venus ionosphere is presented in a theoretical and numerical analysis. The model assumes a source of electromagnetic radiation in the Venus atmosphere, such as that produced by lightning. Specifically addressed is wave propagation in the altitude range z = 130-160 km at the four frequencies detectable by the Pioneer Venus Orbiter Electric Field Detector: 100 Hz, 730 Hz, 5.4 kHz, and 30 kHz. Parameterizations of the wave intensities, peak electron density, and Poynting flux as a function of magnetic field are presented. The waves are found to propagate most easily in conditions of low electron density and high magnetic field. The results of the model are consistent with observational data.

Occupational exposure to electromagnetic fields in the Polish Armed Forces.

PubMed

Sobiech, Jaromir; Kieliszek, Jarosław; Puta, Robert; Bartczak, Dagmara; Stankiewicz, Wanda

2017-06-19

Standard devices used by military personnel that may pose electromagnetic hazard include: radars, missile systems, radio navigation systems and radio transceivers. The aim of this study has been to evaluate the exposure of military personnel to electromagnetic fields. Occupational exposure to electromagnetic fields was analyzed in the work environment of personnel of 204 devices divided into 5 groups (surface-to-air missile system radars, aircraft and helicopters, communication devices, surveillance and height finder radars, airport radars and radio navigation systems). Measurements were carried out at indicators, device terminals, radio panels, above vehicle seats, in vehicle hatches, by cabinets containing high power vacuum tubes and other transmitter components, by transmission lines, connectors, etc. Portable radios emit the electric field strength between 20-80 V/m close to a human head. The manpack radio operator's exposure is 60-120 V/m. Inside vehicles with high frequency/very high frequency (HF/VHF) band radios, the electric field strength is between 7-30 V/m and inside the radar cabin it ranges between 9-20 V/m. Most of the personnel on ships are not exposed to the electromagnetic field from their own radar systems but rather by accidental exposure from the radar systems of other ships. Operators of surface-to-air missile systems are exposed to the electric field strength between 7-15 V/m and the personnel of non-directional radio beacons - 100-150 V/m. In 57% of military devices Polish soldiers work in the occupational protection zones. In 35% of cases, soldiers work in intermediate and hazardous zones and in 22% - only in the intermediate zone. In 43% of devices, military personnel are not exposed to electromagnetic field. Int J Occup Med Environ Health 2017;30(4):565-577. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Evolution of the axial electron cyclotron maser instability, with applications to solar microwave spikes

NASA Technical Reports Server (NTRS)

Vlahos, Loukas; Sprangle, Phillip

1987-01-01

The nonlinear evolution of cyclotron radiation from streaming and gyrating electrons in an external magnetic field is analyzed. The nonlinear dynamics of both the fields and the particles are treated fully relativistically and self-consistently. The model includes a background plasma and electrostatic effects. The analytical and numerical results show that a substantial portion of the beam particle energy can be converted to electromagnetic wave energy at frequencies far above the electron cyclotron frequency. In general, the excited radiation can propagate parallel to the magnetic field and, hence, escape gyrothermal absorption at higher cyclotron harmonics. The high-frequency Doppler-shifted cyclotron instability can have saturation efficiencies far higher than those associated with well-known instabilities of the electron cyclotron maser type. Although the analysis is general, the possibility of using this model to explain the intense radio emission observed from the sun is explored in detail.

Electron Injections Caused by a Dipolarization Flux Bundle

NASA Astrophysics Data System (ADS)

Kabin, K.; Kalugin, G. A.; Donovan, E.; Spanswick, E.

2017-12-01

We study electron injections caused by an earthward propagating electromagnetic pulse. The background magnetic field model is fully three-dimensional and includes the day-night asymmetry, however, the field lines are contained in the meridional planes. The transient pulse fields, which are prescribed analytically, are also three-dimensional. We study electron energization as a function of the initial radial position and the initial energy. We present results for equatorially-mirroring particles as well as for particles with several other values of the initial pitch angles. The pitch-angle dependence of the energization rates is relatively weak for the equatorial pitch angles greater than about 60o, but particles with smaller pitch angles gain significantly less energy than the equatorial ones. Energy gain factors of 3 to 10 are easily achievable in our model which is sufficient to produce observable features in ground based observations, such as those done by riometers.

Domain wall network as QCD vacuum: confinement, chiral symmetry, hadronization

NASA Astrophysics Data System (ADS)

Nedelko, Sergei N.; Voronin, Vladimir V.

2017-03-01

An approach to QCD vacuum as a medium describable in terms of statistical ensemble of almost everywhere homogeneous Abelian (anti-)self-dual gluon fields is reviewed. These fields play the role of the confining medium for color charged fields as well as underline the mechanism of realization of chiral SUL(Nf) × SUR(Nf) and UA(1) symmetries. Hadronization formalism based on this ensemble leads to manifestly defined quantum effective meson action. Strong, electromagnetic and weak interactions of mesons are represented in the action in terms of nonlocal n-point interaction vertices given by the quark-gluon loops averaged over the background ensemble. Systematic results for the mass spectrum and decay constants of radially excited light, heavy-light mesons and heavy quarkonia are presented. Relationship of this approach to the results of functional renormalization group and Dyson-Schwinger equations, and the picture of harmonic confinement is briefly outlined.

Modified coulomb law in a strongly magnetized vacuum.

PubMed

Shabad, Anatoly E; Usov, Vladimir V

2007-05-04

We study the electric potential of a charge placed in a strong magnetic field B>B(0) approximately 4.4x10(13) G, as modified by the vacuum polarization. In such a field the electron Larmour radius is much less than its Compton length. At the Larmour distances a scaling law occurs, with the potential determined by a magnetic-field-independent function. The scaling regime implies short-range interaction, expressed by the Yukawa law. The electromagnetic interaction regains its long-range character at distances larger than the Compton length, the potential decreasing across B faster than along. Correction to the nonrelativistic ground-state energy of a hydrogenlike atom is found. In the limit B = infinity, the modified potential becomes the Dirac delta function plus a regular background. With this potential the ground-state energy is finite--the best pronounced effect of the vacuum polarization.

A Challenging Issue in the Etiology of Speech Problems: The Effect of Maternal Exposure to Electromagnetic Fields on Speech Problems in the Offspring.

PubMed

Zarei, S; Mortazavi, S M J; Mehdizadeh, A R; Jalalipour, M; Borzou, S; Taeb, S; Haghani, M; Mortazavi, S A R; Shojaei-Fard, M B; Nematollahi, S; Alighanbari, N; Jarideh, S

2015-09-01

Nowadays, mothers are continuously exposed to different sources of electromagnetic fields before and even during pregnancy.  It has recently been shown that exposure to mobile phone radiation during pregnancy may lead to adverse effects on the brain development in offspring and cause hyperactivity. Researchers have shown that behavioral problems in laboratory animals which have a similar appearance to ADHD are caused by intrauterine exposure to mobile phones. The purpose of this study was to investigate whether the maternal exposure to different sources of electromagnetic fields affect on the rate and severity of speech problems in their offspring. In this study, mothers of 35 healthy 3-5 year old children (control group) and 77 children and diagnosed with speech problems who had been referred to a speech treatment center in Shiraz, Iran were interviewed. These mothers were asked whether they had exposure to different sources of electromagnetic fields such as mobile phones, mobile base stations, Wi-Fi, cordless phones, laptops and power lines. We found a significant association between either the call time (P=0.002) or history of mobile phone use (months used) and speech problems in the offspring (P=0.003). However, other exposures had no effect on the occurrence of speech problems. To the best of our knowledge, this is the first study to investigate a possible association between maternal exposure to electromagnetic field and speech problems in the offspring. Although a major limitation in our study is the relatively small sample size, this study indicates that the maternal exposure to common sources of electromagnetic fields such as mobile phones can affect the occurrence of speech problems in the offspring.

Guidance of Magnetic Nanocontainers for Treating Alzheimer's Disease Using an Electromagnetic, Targeted Drug-Delivery Actuator.

PubMed

Do, Ton Duc; Ul Amin, Faiz; Noh, Yeongil; Kim, Myeong Ok; Yoon, Jungwon

2016-03-01

The "impermeability" of the blood-brain barrier (BBB) has hindered effective treatment of central nervous system (CNS) disorders such as Alzheimer's disease (AD), which is one of the most common neurodegenerative disorders. A drug can be delivered to a targeted disease site effectively by applying a strong electromagnetic force to the conjugate of a drug and magnetic nanocontainers. This study developed a novel nanotechnology-based strategy to deliver therapeutic agents to the brain via the BBB as a possible therapeutic approach for AD. First, a novel approach for an electromagnetic actuator for guiding nanocontainers is introduced. Then, we analyzed the in vivo uptake in mice experimentally to evaluate the capacity of the nanocontainers. In the mouse model, we demonstrated that magnetic particles can cross the normal BBB when subjected to external electromagnetic fields of 28 mT (0.43 T/m) and 79.8 mT (1.39 T/m). Our study also assessed the differential effects of pulsed (0.25, 0.5, and 1 Hz) and constant magnetic fields on the transport of particles across the BBB in mice injected with magnetic nanoparticles (MNPs) via a tail vein. The applied magnetic field was either kept constant or pulsed on and off. Relative to a constant magnetic field, the rate of MNP uptake and transport across the BBB was enhanced significantly by a pulsed magnetic field. Localization inside the brain was established using fluorescent MNPs. These results using 770-nm fluorescent carboxyl magnetic nanocontainers demonstrated the feasibility of the proposed electromagnetic targeted drug delivery actuator. These results establish an effective strategy for regulating the biodistribution of MNPs in the brain through the application of an external electromagnetic field. This might be a valuable targeting system for AD diagnosis and therapy.

Electromagnetic field induced biological effects in humans.

PubMed

Kaszuba-Zwoińska, Jolanta; Gremba, Jerzy; Gałdzińska-Calik, Barbara; Wójcik-Piotrowicz, Karolina; Thor, Piotr J

2015-01-01

Exposure to artificial radio frequency electromagnetic fields (EMFs) has increased significantly in recent decades. Therefore, there is a growing scientific and social interest in its influence on health, even upon exposure significantly below the applicable standards. The intensity of electromagnetic radiation in human environment is increasing and currently reaches astronomical levels that had never before experienced on our planet. The most influential process of EMF impact on living organisms, is its direct tissue penetration. The current established standards of exposure to EMFs in Poland and in the rest of the world are based on the thermal effect. It is well known that weak EMF could cause all sorts of dramatic non-thermal effects in body cells, tissues and organs. The observed symptoms are hardly to assign to other environmental factors occurring simultaneously in the human environment. Although, there are still ongoing discussions on non-thermal effects of EMF influence, on May 31, 2011--International Agency for Research on Cancer (IARC)--Agenda of World Health Organization (WHO) has classified radio electromagnetic fields, to a category 2B as potentially carcinogenic. Electromagnetic fields can be dangerous not only because of the risk of cancer, but also other health problems, including electromagnetic hypersensitivity (EHS). Electromagnetic hypersensitivity (EHS) is a phenomenon characterized by the appearance of symptoms after exposure of people to electromagnetic fields, generated by EHS is characterized as a syndrome with a broad spectrum of non-specific multiple organ symptoms including both acute and chronic inflammatory processes located mainly in the skin and nervous systems, as well as in respiratory, cardiovascular systems, and musculoskeletal system. WHO does not consider the EHS as a disease-- defined on the basis of medical diagnosis and symptoms associated with any known syndrome. The symptoms may be associated with a single source of EMF or be derived from a combination of many sources. Reported symptoms associated with electromagnetic fields are characterized by the overlapping effect with other individuals with these symptoms exhibited a broad spectrum of clinical manifestations, related to exposure to a single or multiple sources of EMF. The phenomenon of electromagnetic hypersensitivity in the form of dermatological disease is associated with mastocytosis. The biopsies taken from skin lesions of patients with EHS indicated on infiltration of the skin layers of the epidermis with mastocytes and their degranulation, as well as on release anaphylactic reaction mediators such as histamine, chymase and tryptase. The number of people suffering from EHS in the world is growing describing themselves as severely dysfunctional, showing multi organ non-specific symptoms upon exposure to low doses of electromagnetic radiation, often associated with hypersensitivity to many chemical agents (Multiple Chemical Sensitivity-MCS) and/or other environmental intolerances (Sensitivity Related Illness-SRI).

The impact of background radiation, illumination and temperature on EMF-induced changes of aqua medium properties.

PubMed

Naira, Baghdasaryan; Yerazik, Mikayelyan; Anna, Nikoghosyan; Sinerik, Ayrapetyan

2013-09-01

The effects of extremely low frequency electromagnetic field (ELF EMF) on physicochemical properties of physiological solution at different environmental media were studied. The existence of frequency "windows" at 4 and 8 Hz frequencies of ELF EMF having effects on heat fusion period, hydrogen peroxide (H2O2) formation and oxygen (O2) content of water solution and different dependency on temperature, background radiation and illumination was shown. Obtained data allow us to suggest that EMF-induced effect on water physicochemical properties depends on abovementioned environmental factors. As cell bathing medium is a target for biological effects of ELF EMF, the variability of experimental data on biological effects of EMF, obtained in different laboratories, can be explained by different environmental conditions of experiments, which very often are not considered adequately.

Generalized Case ``Van Kampen theory for electromagnetic oscillations in a magnetized plasma

NASA Astrophysics Data System (ADS)

Bairaktaris, F.; Hizanidis, K.; Ram, A. K.

2017-10-01

The Case-Van Kampen theory is set up to describe electrostatic oscillations in an unmagnetized plasma. Our generalization to electromagnetic oscillations in magnetized plasma is formulated in the relativistic position-momentum phase space of the particles. The relativistic Vlasov equation includes the ambient, homogeneous, magnetic field, and space-time dependent electromagnetic fields that satisfy Maxwell's equations. The standard linearization technique leads to an equation for the perturbed distribution function in terms of the electromagnetic fields. The eigenvalues and eigenfunctions are obtained from three integrals `` each integral being over two different components of the momentum vector. Results connecting phase velocity, frequency, and wave vector will be presented. Supported in part by the Hellenic National Programme on Controlled Thermonuclear Fusion associated with the EUROfusion Consortium, and by DoE Grant DE-FG02-91ER-54109.

Molecular based magnets comprising vanadium tetracyanoethylene complexes for shielding electromagnetic fields

DOEpatents

Epstein, A.J.; Morin, B.G.

1998-10-13

The invention presents a vanadium tetracyanoethylene solvent complex for electromagnetic field shielding, and a method for blocking low frequency and magnetic fields using these vanadium tetracyanoethylene compositions. The compositions of the invention can be produced at ambient temperature and are light weight, low density and flexible. The materials of the present invention are useful as magnetic shields to block low frequency fields and static fields, and for use in cores in transformers and motors. 21 figs.

Molecular based magnets comprising vanadium tetracyanoethylene complexes for shielding electromagnetic fields

DOEpatents

Epstein, Arthur J.; Morin, Brian G.

1998-01-01

The invention presents a vanadium tetracyanoethylene solvent complex for electromagnetic field shielding, and a method for blocking low frequency and magnetic fields using these vanadium tetracyanoethylene compositions. The compositions of the invention can be produced at ambient temperature and are light weight, low density and flexible. The materials of the present invention are useful as magnetic shields to block low frequency fields and static fields, and for use in cores in transformers and motors.

‘…a paper …I hold to be great guns’: a commentary on Maxwell (1865) ‘A dynamical theory of the electromagnetic field’

PubMed Central

Longair, Malcolm

2015-01-01

Maxwell's great paper of 1865 established his dynamical theory of the electromagnetic field. The origins of the paper lay in his earlier papers of 1856, in which he began the mathematical elaboration of Faraday's researches into electromagnetism, and of 1861–1862, in which the displacement current was introduced. These earlier works were based upon mechanical analogies. In the paper of 1865, the focus shifts to the role of the fields themselves as a description of electromagnetic phenomena. The somewhat artificial mechanical models by which he had arrived at his field equations a few years earlier were stripped away. Maxwell's introduction of the concept of fields to explain physical phenomena provided the essential link between the mechanical world of Newtonian physics and the theory of fields, as elaborated by Einstein and others, which lies at the heart of twentieth and twenty-first century physics. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750155

Electromagnetic field redistribution induced selective plasmon driven surface catalysis in metal nanowire-film systems

PubMed Central

Pan, Liang; Huang, Yingzhou; Yang, Yanna; Xiong, Wen; Chen, Guo; Su, Xun; Wei, Hua; Wang, Shuxia; Wen, Weijia

2015-01-01

For the novel interpretation of Raman spectrum from molecule at metal surface, the plasmon driven surface catalysis (PDSC) reactions have become an interesting topic in the research field of surface enhanced Raman scattering (SERS). In this work, the selective PDSC reactions of p,p’-dimercaptoazobenzene (DMAB) produced from para-aminothiophenol (PATP) or 4-nitrobenzenethiol (4NBT) were demonstrated in the Ag nanowires dimer-Au film systems. The different SERS spectra collected at individual part and adjacent part of the same nanowire-film system pointed out the importance of the electromagnetic field redistribution induced by image charge on film in this selective surface catalysis, which was confirmed by the simulated electromagnetic simulated electro- magnetic field distributions. Our result indicated this electromagnetic field redistribution induced selective surface catalysis was largely affected by the polarization and wavelength of incident light but slightly by the difference in diameters between two nanowires. Our work provides a further understanding of PDSC reaction in metal nanostructure and could be a deep support for the researches on surface catalysis and surface analysis. PMID:26601698

[Changes in the chromatin structure of lymphoid cells under the influence of low-intensity extremely high-frequency electromagnetic radiation against the background of inflammatory process].

PubMed

Gapeev, A B; Romanova, N A; Chemeris, N K

2011-01-01

Using the alkaline single cell gel electrophoresis technique (comet assay), changes in chromatin structure of peripheral blood leukocytes and peritoneal neutrophils have been studied in mice exposed to low-intensity extremely high-frequency electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20 min at 1 h after induction of inflammation) against the background of the systemic inflammatory process. It was revealed that the exposure of mice with the developing inflammation leads to a pronounced decrease in the level of DNA damage to peripheral blood leukocytes and peritoneal neutrophils. It is supposed that the changes in the chromatin structure of lymphoid cells have a genoprotective character in the inflammatory process and can underlie the mechanisms of realization of antiinflammatory effects of the electromagnetic radiation.

Obtaining source current density related to irregularly structured electromagnetic target field inside human body using hybrid inverse/FDTD method.

PubMed

Han, Jijun; Yang, Deqiang; Sun, Houjun; Xin, Sherman Xuegang

2017-01-01

Inverse method is inherently suitable for calculating the distribution of source current density related with an irregularly structured electromagnetic target field. However, the present form of inverse method cannot calculate complex field-tissue interactions. A novel hybrid inverse/finite-difference time domain (FDTD) method that can calculate the complex field-tissue interactions for the inverse design of source current density related with an irregularly structured electromagnetic target field is proposed. A Huygens' equivalent surface is established as a bridge to combine the inverse and FDTD method. Distribution of the radiofrequency (RF) magnetic field on the Huygens' equivalent surface is obtained using the FDTD method by considering the complex field-tissue interactions within the human body model. The obtained magnetic field distributed on the Huygens' equivalent surface is regarded as the next target. The current density on the designated source surface is derived using the inverse method. The homogeneity of target magnetic field and specific energy absorption rate are calculated to verify the proposed method.

Interference Processes During Reradiation of Attosecond Pulses of Electromagnetic Field by Graphene

NASA Astrophysics Data System (ADS)

Makarov, D. N.; Matveev, V. I.; Makarova, K. A.

2018-05-01

Interference spectra during reradiation of attosecond pulses of electromagnetic field by graphene sheets are considered. Analytical expressions for calculations of spectral distributions are derived. As an example, the interference spectra of a graphene sheet and a flat rectangular lattice are compared.

Modeling Density Variation in the Thermosphere

DTIC Science & Technology

2011-04-29

static electromagnetic fields as follows: when a volume of the ionosphere is bounded on the sides by an equipotential surface and on the bottom by the...generation of electromagnetic energy along that geomagnetic-field line. An Equipotential -Boundary Poynting-Flux (EBPF) theorem was presented for quasi

Electromagnetic Field Redistribution in Metal Nanoparticle on Graphene.

PubMed

Li, Keke; Liu, Anping; Wei, Dapeng; Yu, Keke; Sun, Xiaonan; Yan, Sheng; Huang, Yingzhou

2018-04-25

Benefiting from the induced image charge on metal film, the light energy is confined on a film surface under metal nanoparticle dimer, which is called electromagnetic field redistribution. In this work, electromagnetic field distribution of metal nanoparticle monomer or dimer on graphene is investigated through finite-difference time-domain method. The results point out that the electromagnetic field (EM) redistribution occurs in this nanoparticle/graphene hybrid system at infrared region where light energy could also be confined on a monolayer graphene surface. Surface charge distribution was analyzed using finite element analysis, and surface-enhanced Raman spectrum (SERS) was utilized to verify this phenomenon. Furthermore, the data about dielectric nanoparticle on monolayer graphene demonstrate this EM redistribution is attributed to strong coupling between light-excited surface charge on monolayer graphene and graphene plasmon-induced image charge on dielectric nanoparticle surface. Our work extends the knowledge of monolayer graphene plasmon, which has a wide range of applications in monolayer graphene-related film.

Transient regime in second harmonic generation

NASA Astrophysics Data System (ADS)

Szeftel, Jacob; Sandeau, Laure; Sandeau, Nicolas; Delezoide, Camille; Khater, Antoine

2013-09-01

The time growth of the electromagnetic field at the fundamental and double frequencies is studied from the very onset of the second harmonic generation (SHG) process for a set of dipoles lacking a symmetry centre and exhibiting a nonresonant coupling with a classical electromagnetic field. This approach consists first of solving the Schrödinger equation by applying a generalised Rabi rotation to the Hamiltonian describing the light-dipole interaction. This rotation has been devised for the resulting Hamiltonian to show up time-independent for both components of the electromagnetic field at the fundamental frequency and the second harmonic one. Then an energy conservation argument, derived from the Poynting theorem, is introduced to work out an additional relationship between the electromagnetic field and its associated electric polarisation. Finally this analysis yields the full time behaviour of all physical quantities of interest. The calculated results reproduce accurately both the observed spatial oscillations of the SHG intensity (Maker's fringes) and its power law dependence on the intensity of the incoming light at the fundamental frequency.

Electric Field Feature of Moving Magnetic Field

NASA Astrophysics Data System (ADS)

Chen, You Jun

2001-05-01

A new fundamental relationship of electric field with magnetic field has been inferred from the fundamental experimental laws and theories of classical electromagnetics. It can be described as moving magnetic field has or gives electric feature. When a field with magnetic induction of B moves in the velocity of V, it will show electric field character, the electric field intensity E is E = B x V and the direction of E is in the direction of the vector B x V. It is improper to use the time-varying electromagnetics theories as the fundamental theory of the electromagnetics and group the electromagnetic field into static kind and time-varying kind for the static is relative to motional not only time-varying. The relationship of time variation of magnetic field induction or magnetic flux with electric field caused by magnetic field is fellowship not causality. Thus time-varying magnetic field can cause electric field is not a nature principle. Sometime the time variation of magnetic flux is equal to the negative electromotive force or the time variation of magnetic field induction is equal to the negative curl of electric field caused by magnetic field motion, but not always. And not all motion of magnetic field can cause time variation of magnetic field. Therefore Faraday-Lenz`s law can only be used as mathematics tool to calculate the quantity relation of the electricity with the magnetism in some case like the magnetic field moving in uniform medium. Faraday-Lenz`s law is unsuitable to be used in moving uniform magnetic field or there is magnetic shield. Key word: Motional magnetic field, Magnetic induction, Electric field intensity, Velocity, Faraday-Lenz’s law

Measurement of electromagnetic pulses generated during interactions of high power lasers with solid targets

NASA Astrophysics Data System (ADS)

De Marco, M.; Krása, J.; Cikhardt, J.; Pfeifer, M.; Krouský, E.; Margarone, D.; Ahmed, H.; Borghesi, M.; Kar, S.; Giuffrida, L.; Vrana, R.; Velyhan, A.; Limpouch, J.; Korn, G.; Weber, S.; Velardi, L.; Delle Side, D.; Nassisi, V.; Ullschmied, J.

2016-06-01

A target irradiated with a high power laser pulse, blows off a large amount of charge and as a consequence the target itself becomes a generator of electromagnetic pulses (EMP) owing to high return current flowing to the ground through the target holder. The first measurement of the magnetic field induced by the neutralizing current reaching a value of a few kA was performed with the use of an inductive target probe at the PALS Laser Facility (Cikhardt et al. Rev. Sci. Instrum. 85 (2014) 103507). A full description of EMP generation should contain information on the spatial distribution and temporal variation of the electromagnetic field inside and outside of the interaction chamber. For this reason, we consider the interaction chamber as a resonant cavity in which different modes of EMP oscillate for hundreds of nanoseconds, until the EMP is transmitted outside through the glass windows and EM waves are attenuated. Since the experimental determination of the electromagnetic field distribution is limited by the number of employed antennas, a mapping of the electromagnetic field has to be integrated with numerical simulations. Thus, this work reports on a detailed numerical mapping of the electromagnetic field inside the interaction chamber at the PALS Laser Facility (covering a frequency spectrum from 100 MHz to 3 GHz) using the commercial code COMSOL Multiphysics 5.2. Moreover we carried out a comparison of the EMP generated in the parallelepiped-like interaction chamber used in the Vulcan Petawatt Laser Facility at the Rutherford Appleton Laboratory, against that produced in the spherical interaction chamber of PALS.

Nonlinear gyrokinetics: a powerful tool for the description of microturbulence in magnetized plasmas

NASA Astrophysics Data System (ADS)

Krommes, John A.

2010-12-01

Gyrokinetics is the description of low-frequency dynamics in magnetized plasmas. In magnetic-confinement fusion, it provides the most fundamental basis for numerical simulations of microturbulence; there are astrophysical applications as well. In this tutorial, a sketch of the derivation of the novel dynamical system comprising the nonlinear gyrokinetic (GK) equation (GKE) and the coupled electrostatic GK Poisson equation will be given by using modern Lagrangian and Lie perturbation methods. No background in plasma physics is required in order to appreciate the logical development. The GKE describes the evolution of an ensemble of gyrocenters moving in a weakly inhomogeneous background magnetic field and in the presence of electromagnetic perturbations with wavelength of the order of the ion gyroradius. Gyrocenters move with effective drifts, which may be obtained by an averaging procedure that systematically, order by order, removes gyrophase dependence. To that end, the use of the Lagrangian differential one-form as well as the content and advantages of Lie perturbation theory will be explained. The electromagnetic fields follow via Maxwell's equations from the charge and current density of the particles. Particle and gyrocenter densities differ by an important polarization effect. That is calculated formally by a 'pull-back' (a concept from differential geometry) of the gyrocenter distribution to the laboratory coordinate system. A natural truncation then leads to the closed GK dynamical system. Important properties such as GK energy conservation and fluctuation noise will be mentioned briefly, as will the possibility (and difficulties) of deriving nonlinear gyrofluid equations suitable for rapid numerical solution—although it is probably best to directly simulate the GKE. By the end of the tutorial, students should appreciate the GKE as an extremely powerful tool and will be prepared for later lectures describing its applications to physical problems.

Electromagnetic fields produced by incubators influence heart rate variability in newborns.

PubMed

Bellieni, C V; Acampa, M; Maffei, M; Maffei, S; Perrone, S; Pinto, I; Stacchini, N; Buonocore, G

2008-07-01

Incubators are largely used to preserve preterm and sick babies from postnatal stressors, but their motors produce high electromagnetic fields (EMFs). Newborns are chronically exposed to these EMFs, but no studies about their effects on the fragile developing neonatal structure exist. To verify whether the exposure to incubator motor electric power may alter autonomous nervous system activity in newborns. Heart rate variability (HRV) of 43 newborns in incubators was studied. The study group comprised 27 newborns whose HRV was studied throughout three 5-minute periods: with incubator motor on, off, and on again, respectively. Mean HRV values obtained during each period were compared. The control group comprised 16 newborns with constantly unrecordable EMF and exposed to changes in background noise, similar to those provoked by the incubator motor. Mean (SD) total power and the high-frequency (HF) component of HRV increased significantly (from 87.1 (76.2) ms2 to 183.6 (168.5) ms2) and the mean low-frequency (LF)/HF ratio decreased significantly (from 2.0 (0.5) to 1.5 (0.6)) when the incubator motor was turned off. Basal values (HF = 107.1 (118.1) ms2 and LF/HF = 1.9 (0.6)) were restored when incubators were turned on again. The LF spectral component of HRV showed a statistically significant change only in the second phase of the experiment. Changes in background noise did not provoke any significant change in HRV. EMFs produced by incubators influence newborns' HRV, showing an influence on their autonomous nervous system. More research is needed to assess possible long-term consequences, since premature newborns may be exposed to these high EMFs for months.

Experimental demonstration of invisible electromagnetic impedance matching cylindrical transformation optics cloak shell

NASA Astrophysics Data System (ADS)

Chen, Mingji; Wang, Changxian; Cheng, Xiaodong; Gong, Congcheng; Song, Weili; Yuan, Xujin; Fang, Daining

2018-04-01

The realization of an ideal invisible cloak implementing transformation optics is still missing. An impedance matching concept is implanted into transformation optics cloak to generate an impedance matching cloak (IMC) shell. In this work, it is proved that impedance matching structure reduces the cloaking structure’s disturbance to a propagating electromagnetic field and improves its invisibility measured by scattering field intensity. Such a cylindrical IMC shell is designed, fabricated with proposed rounded rectangular split-ring-resonators (RR-SRRs), and experimental measurements show the total scattering field of a perfect electric conductor (PEC) cylinder surrounded by an IMC shell is improved greatly compared to the PEC cylinder showing electromagnetic wave front ripple suppression and a considerable scattering shrinking effect. IMC shell backward scattering field is suppressed down to 7.29%, compared to the previous value of 86.7% due to its impedance matching character, and overall scattering field intensity shrinking is down to 19.3% compared to the previously realized value of 56.4%. Sideward scattering field recorded in the experiment also has a remarkable improvement compared to the PEC cylinder. The impedance matching concept might enlighten the realization of an ideal cloak and other novel electromagnetic cloaking and shielding structures.

Electromagnetic signals are produced by aqueous nanostructures derived from bacterial DNA sequences.

PubMed

Montagnier, Luc; Aïssa, Jamal; Ferris, Stéphane; Montagnier, Jean-Luc; Lavallée, Claude

2009-06-01

A novel property of DNA is described: the capacity of some bacterial DNA sequences to induce electromagnetic waves at high aqueous dilutions. It appears to be a resonance phenomenon triggered by the ambient electromagnetic background of very low frequency waves. The genomic DNA of most pathogenic bacteria contains sequences which are able to generate such signals. This opens the way to the development of highly sensitive detection system for chronic bacterial infections in human and animal diseases.

Extremely low-frequency electromagnetic field influences the survival and proliferation effect of human adipose derived stem cells

PubMed Central

Razavi, Shahnaz; Salimi, Marzieh; Shahbazi-Gahrouei, Daryoush; Karbasi, Saeed; Kermani, Saeed

2014-01-01

Background: Extremely low-frequency electromagnetic fields (ELF-EMF) can effect on biological systems and alters some cell functions like proliferation rate. Therefore, we aimed to attempt the evaluation effect of ELF-EMF on the growth of human adipose derived stem cells (hADSCs). Materials and Methods: ELF-EMF was generated by a system including autotransformer, multi-meter, solenoid coils, teslameter and its probe. We assessed the effect of ELF-EMF with intensity of 0.5 and 1 mT and power line frequency 50 Hz on the survival of hADSCs for 20 and 40 min/day for 7 days by MTT assay. One-way analysis of variance was used to assessment the significant differences in groups. Results: ELF-EMF has maximum effect with intensity of 1 mT for 20 min/day on proliferation of hADSCs. The survival and proliferation effect (PE) in all exposure groups were significantly higher than that in sham groups (P < 0.05) except in group of 1 mT and 40 min/day. Conclusion: Our results show that between 0.5 m and 1 mT ELF-EMF could be enhances survival and PE of hADSCs conserving the duration of exposure. PMID:24592372

Test of 60 kA coated conductor cable prototypes for fusion magnets

NASA Astrophysics Data System (ADS)

Uglietti, D.; Bykovsky, N.; Sedlak, K.; Stepanov, B.; Wesche, R.; Bruzzone, P.

2015-12-01

Coated conductors could be promising materials for the fabrication of the large magnet systems of future fusion devices. Two prototype conductors (flat cables in steel conduits), each about 2 m long, were manufactured using coated conductor tapes (4 mm wide) from Super Power and SuperOx, with a total tape length of 1.6 km. Each flat cable is assembled from 20 strands, each strand consisting of a stack of 16 tapes surrounded by two half circular copper profiles, twisted and soldered. The tapes were measured at 12 T and 4.2 K and the results of the measurements were used for the assessment of the conductor electromagnetic properties at low temperature and high field. The two conductors were assembled together in a sample that was tested in the European Dipole (EDIPO) facility. The current sharing temperatures of the two conductors were measured at background fields from 8 T up to 12 T and for currents from 30 kA up to 70 kA: the measured values are within a few percent of the values expected from the measurements on tapes (short samples). After electromagnetic cycling, T cs at 12 T and 50 kA decreased from about 12 K to 11 K (about 10%), corresponding to less than 3% of I c.

Monitoring of people and workers exposure to the electric, magnetic and electromagnetic fields in an Italian national cancer Institute

PubMed Central

Di Nallo, Anna Maria; Strigari, Lidia; Giliberti, Claudia; Bedini, Angelico; Palomba, Raffaele; Benassi, Marcello

2008-01-01

Background The paper reports the electric, magnetic and electromagnetic fields (emf) measurements carried out in the Regina Elena National Cancer Institute (NCI). Several devices, used in diagnostics and in medical cures, can represent sources of emf for the workers and for the public subjected to the treatments. The aim is to evaluate their exposition, in order to assess the compliance with the law. Methods The investigations have been carried out in the departments of: intensive care, physiotherapy, MR presstherapy and in the surgical rooms. The measurements have been performed using broad band probes in the frequency ranges 5 Hz÷30 kHz and 100 kHz-3 GHz. Results The variability of the magnetic induction (B(μT)) levels is between 0,05 μT and 80 μT. The statistical distribution shows that most of the measurements are in the range 0,05