Science.gov

Sample records for strong electromagnetic fields

  1. Super strong electromagnetic fields and their applications

    SciTech Connect

    Bulanov, Sergei V.

    2007-07-11

    The progress in the ultra-intense laser technologies continues to open up new fields of physics. The laser accelerator development enters a new matured stage at which it becomes possible to manipulate in a controllable way the parameters of accelerated charged particle beams. In the electron acceleration the particle injection by breaking wake waves left by the laser pulse in underdense plasmas or by interacting two laser pulses results in the quasi-mono-energetic beam production. When the ions are accelerated during the laser-matter interaction the tailored multi-layer foil targets provide conditions for the high quality proton beam generation. When the laser pulse radiation pressure is dominant, the laser energy is transformed efficiently into the energy of fast ions. Ultrahigh intense electromagnetic fields can be generated due to the laser pulse compression, carrier frequency upshifting, and focusing by a counterpropagating breaking plasma wave, relativistic flying mirrors.

  2. An experiment to study strong electromagnetic fields at RHIC

    SciTech Connect

    Fatyga, M. ); Norbury, J.W. . Dept. of Physics)

    1990-01-01

    We present a description of an experiment which can be used to search for effects of strong electromagnetic fields on the production of e{sup +}e{sup {minus}} pairs in the elastic scattering of two heavy ions at RHIC. A very brief discussion of other possible studies of electromagnetic phenomena at RHIC is also presented.

  3. Transducer measures temperature differentials in presence of strong electromagnetic fields

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Measurement of temperature rise of cooling water under pressure and in strong electromagnetic fields is accomplished by a transducer using a magnetically shielded thermocouple arrangement. The thermocouple junctions are immersed in oil to isolate them from electric currents in the water.

  4. 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.

  5. Using strong electromagnetic fields to control x-ray processes.

    SciTech Connect

    Young, L.; Buth, C.; Dunford, R. W.; Ho, P.; Kanter, E. P.; Kraessig, B.; Peterson, E. R.; Rohringer, N.; Santra, R.; Southworth, S. H.

    2010-06-01

    Exploration of a new ultrafast-ultrasmall frontier in atomic and molecular physics has begun. Not only is is possible to control outer-shell electron dynamics with intense ultrafast optical lasers, but now control of inner-shell processes has become possible by combining intense infrared/optical lasers with tunable sources of X-ray radiation. This marriage of strong-field laser and X-ray physics has led to the discovery of methods to control reversibly resonant X-ray absorption in atoms and molecules on ultrafast timescales. Using a strong optical dressing field, resonant X-ray absorption in atoms can be markedly suppressed, yielding an example of electromagnetically induced transparency for x rays. Resonant X-ray absorption can also be controlled in molecules using strong non-resonant, polarized laser fields to align the framework of a molecule, and therefore its unoccupied molecular orbitals to which resonant absorption occurs. At higher laser intensities, ultrafast field ionization produces an irreversible change in X-ray absorption. Finally, the advent of X-ray free electron lasers enables first exploration of non-linear X-ray processes.

  6. Biological effects of electromagnetic fields and recently updated safety guidelines for strong static magnetic fields.

    PubMed

    Yamaguchi-Sekino, Sachiko; Sekino, Masaki; Ueno, Shoogo

    2011-01-01

    Humans are exposed daily to artificial and naturally occurring magnetic fields that originate from many different sources. We review recent studies that examine the biological effects of and medical applications involving electromagnetic fields, review the properties of static and pulsed electromagnetic fields that affect biological systems, describe the use of a pulsed electromagnetic field in combination with an anticancer agent as an example of a medical application that incorporates an electromagnetic field, and discuss the recently updated safety guidelines for static electromagnetic fields. The most notable modifications to the 2009 International Commission on Non-Ionizing Radiation Protection guidelines are the increased exposure limits, especially for those who work with or near electromagnetic fields (occupational exposure limits). The recommended increases in exposure were determined using recent scientific evidence obtained from animal and human studies. Several studies since the 1994 publication of the guidelines have examined the effects on humans after exposure to high static electromagnetic fields (up to 9.4 tesla), but additional research is needed to ascertain further the safety of strong electromagnetic fields.

  7. Ionization of atoms in strong low-frequency electromagnetic field

    SciTech Connect

    Krainov, V. P.

    2010-08-15

    The ionization of atoms in a low-frequency linearly polarized electromagnetic field (the photon energy is much lower than the ionization potential of an atom) is considered under new conditions, in which the Coulomb interaction of an electron with the atomic core in the final state of the continuum cannot be considered in perturbation theory in the interaction of the electron with the electromagnetic field. The field is assumed to be much weaker that the atomic field. In these conditions, the classical motion of the electron in the final state of the continuum becomes chaotic (so-called dynamic chaos). Using the well-known Chirikov method of averaging over chaotic variations of the phase of motion, the problem can be reduced to non-linear diffusion on the energy scale. We calculate the classical electron energy in the final state, which is averaged over fast chaotic oscillations and takes into account both the Coulomb field and the electromagnetic field. This energy is used to calculate the probability of ionization from the ground state of the atom to a lower-lying state in the continuum using the Landau-Dykhne approximation (to exponential accuracy). This ionization probability noticeably depends on the field frequency. Upon a decrease in frequency, a transition to the well-known tunnel ionization limit with a probability independent of the field frequency is considered.

  8. Impact of the strong electromagnetic field on the QCD effective potential for homogeneous Abelian gluon field configurations

    SciTech Connect

    Galilo, Bogdan V.; Nedelko, Sergei N.

    2011-11-01

    The one-loop quark contribution to the QCD effective potential for the homogeneous Abelian gluon field in the presence of an external strong electromagnetic field is evaluated. The structure of extrema of the potential as a function of the angles between chromoelectric, chromomagnetic, and electromagnetic fields is analyzed. In this setup, the electromagnetic field is considered as an external one while the gluon field represents domain structured nonperturbative gluon configurations related to the QCD vacuum in the confinement phase. Two particularly interesting gluon configurations, (anti-)self-dual and crossed orthogonal chromomagnetic and chromoelectric fields, are discussed specifically. Within this simplified framework it is shown that the strong electromagnetic fields can play a catalyzing role for a deconfinement transition. At the qualitative level, the present consideration can be seen as a highly simplified study of an impact of the electromagnetic fields generated in relativistic heavy ion collisions on the strongly interacting hadronic matter.

  9. 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

  10. Motion of particles of magnetically hard powder in a constant magnetic and strongly nonuniform electromagnetic fields

    SciTech Connect

    Bitkina, N.S.; Vernigorov, Yu.M.; Ignatov, B.P.; Lemeshko, G.F.

    1988-04-01

    The breakup process of floccules in the fluid state under the action of a constant magnetic and of strongly nonuniform electromagnetic fields was described and recorded by comparing the magnetic properties of samples pressed from powders, texturized, and prefluidized. Commercial barium ferrite powder was fluidized in a dielectric mold. A vibration magnetometer measured the magnetic properties. To evaluate the role of the resonance response to magnetic properties, a system of magnetic strings was formed and held in an oscillation regime induced by an alternating field with different frequency. It was found from the results of these formations that the magnetic structure of the sample consists of magnetic strings formed predominantly by separate particles and whose magnetic moments are oriented along the direction of the texturizing field. Results are also given for the fluidization of samarium-cobalt and samarium-cobalt-copper alloy powders.

  11. Influence of strong field vacuum polarization on gravitational-electromagnetic wave interaction

    SciTech Connect

    Forsberg, M.; Brodin, G.; Papadopoulos, D.

    2010-07-15

    The interaction between gravitational and electromagnetic waves in the presence of a static magnetic field is studied. The field strength of the static field is allowed to surpass the Schwinger critical field, such that the QED effects of vacuum polarization and magnetization are significant. Equations governing the interaction are derived and analyzed. It turns out that the energy conversion from gravitational to electromagnetic waves can be significantly altered due to the QED effects. The consequences of our results are discussed.

  12. In vitro stimulation with a strongly pulsed electromagnetic field on rat basophilic leukemia cells

    NASA Astrophysics Data System (ADS)

    Choi, J. W.; Shin, S. C.; Kim, S.; Chung, E. R.; Bang, J. H.; Cho, G. I.; Choi, S. D.; Park, Y. S.; Jang, T. S.; Yoo, Y. M.; Lee, S. S.; Hwang, D. G.

    2010-05-01

    In this study, the effects of pulsed electromagnetic field stimulation with a strong magnetic field on rat basophilic leukemia (RBL-2H3) cells were investigated to confirm the efficacy of the magnetic stimulator for biomedical applications. The maximum intensity of the magnetic field generated from the stimulation coil was 0.203 T, and the transition time was 126 μs. The oscillation time and frequency of the pulsed field were almost 0.1 ms and 8 kHz, respectively. The cell count as well as the mRNA expression and DNA sequence of the cytokine genes, such as the tumor necrosis factor-α (TNF-α) and interleukin-4 (IL-4), of the stimulated RBL-2H3 cells were analyzed with a hemocytometer and via reverse transcriptase polymerase chain reaction to determine the physiological response under a strong pulse field. After 12 h stimulation, cell death was observed at an increasing scale with the increase in the stimulation time. On the other hand, the cells that were stimulated for 10 min almost doubled as the interval time between the stimulations was extended.

  13. Electrons in strong electromagnetic fields: spin effects and radiation reaction (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Bauke, Heiko; Wen, Meng; Keitel, Christoph H.

    2017-05-01

    Various different classical models of electrons including their spin degree of freedom are commonly applied to describe the coupled dynamics of relativistic electron motion and spin precession in strong electromagnetic fields. The spin dynamics is usually governed by the Thomas-Bargmann-Michel-Telegdi equation [1, 2] in these models, while the electron's orbital motion follows the (modified) Lorentz force and a spin-dependent Stern-Gerlach force. Various classical models can lead to different or even contradicting predictions how the spin degree of freedom modifies the electron's orbital motion when the electron moves in strong electromagnetic fields. This discrepancy is rooted in the model-specific energy dependency of the spin induced relativistic Stern-Gerlach force acting on the electron. The Frenkel model [3, 4] and the classical Foldy-Wouthuysen model 5 are compared exemplarily against each other and against the quantum mechanical Dirac equation in order to identify parameter regimes where these classical models make different predictions [6, 7]. Our theoretical results allow for experimental tests of these models. In the setup of the longitudinal Stern-Gerlach effect, the Frenkel model and classical Foldy-Wouthuysen model lead in the relativistic limit to qualitatively different spin effects on the electron trajectory. Furthermore, it is demonstrated that in tightly focused beams in the near infrared the effect of the Stern-Gerlach force of the Frenkel model becomes sufficiently large to be potentially detectable in an experiment. Among the classical spin models, the Frenkel model is certainly prominent for its long history and its wide application. Our results, however, suggest that the classical Foldy-Wouthuysen model is superior as it is qualitatively in better agreement with the quantum mechanical Dirac equation. In ultra strong laser setups at parameter regimes where effects of the Stern-Gerlach force become relevant also radiation reaction effects are

  14. Electromagnetic strong plasma turbulence

    SciTech Connect

    Melatos, A.; Jenet, F. A.; Robinson, P. A.

    2007-02-15

    The first large-scale simulations of continuously driven, two-dimensional electromagnetic strong plasma turbulence are performed, for electron thermal speeds 0.01c{<=}v{<=}0.57c, by integrating the Zakharov equations for coupled Langmuir and transverse (T) waves near the plasma frequency. Turbulence scalings and wave number spectra are calculated, a transition is found from a mix of trapped and free T eigenstates for v{>=}0.1c to just free eigenstates for v{<=}0.1c, and wave energy densities are observed to undergo slow quasiperiodic oscillations.

  15. Strong nonlinear focusing of light in nonlinearly controlled electromagnetic active metamaterial field concentrators

    NASA Astrophysics Data System (ADS)

    Rapoport, Yu G.; Boardman, A. D.; Grimalsky, V. V.; Ivchenko, V. M.; Kalinich, N.

    2014-05-01

    The idea of nonlinear ‘transformation optics-inspired’ [1-6] electromagnetic cylindrical field concentrators has been taken up in a preliminary manner in a number of conference reports [7-9]. Such a concentrator includes both external linear region with a dielectric constant increased towards the centre and internal region with nonlinearity characterized by constant coefficients. Then, in the process of farther investigations we realized the following factors considered neither in [7-9] nor in the recent paper [10]: saturation of nonlinearity, nonlinear losses, linear gain, numerical convergence, when nonlinear effect becomes very strong and formation of ‘hotspots’ starts. It is clearly demonstrated here that such a strongly nonlinear process starts when the nonlinear amplitude of any incident beam(s) exceeds some ‘threshold’ value. Moreover, it is shown that the formation of hotspots may start as the result of any of the following processes: an increase of the input amplitude, increasing the linear amplification in the central nonlinear region, decreasing the nonlinear losses, a decrease in the saturation of the nonlinearity. Therefore, a tendency to a formation of ‘hotspots’ is a rather universal feature of the strongly nonlinear behaviour of the ‘nonlinear resonator’ system, while at the same time the system is not sensitive to the ‘prehistory’ of approaching nonlinear threshold intensity (amplitude). The new proposed method includes a full-wave nonlinear solution analysis (in the nonlinear region), a new form of complex geometric optics (in the linear inhomogeneous external cylinder), and new boundary conditions, matching both solutions. The observed nonlinear phenomena will have a positive impact upon socially and environmentally important devices of the future. Although a graded-index concentrator is used here, it is a direct outcome of transformation optics. Numerical evaluations show that for known materials these nonlinear effects

  16. A letter of intent for an experiment to study strong electromagnetic fields at RHIC via multiple electromagnetic processes

    NASA Technical Reports Server (NTRS)

    Fatyga, M.; Norbury, John W.

    1992-01-01

    An experimental program at the Relativistic Heavy Ion Collider (RHIC) which is designed to study nonperturbative aspects of electrodynamics is outlined. Additional possibilities for new studies of electrodynamics via multiple electromagnetic processes are also described.

  17. Bending of electromagnetic wave in an ultra-strong magnetic field

    NASA Astrophysics Data System (ADS)

    Kim, Jin Young

    2012-10-01

    We consider the bending of light by nonlinear electrodynamics when the magnetic field B exceeds the critical value Bc = m2c2/ehbar = 4.4 × 109T. Using the index of refraction derived from the analytic series representation in one-loop effective action of QED, we found the trajectory and the bending angle of light in geometric optics. The angle bent by ultra-strong magnetic field of magnetar was estimated and compared with the gravitational bending. The result may be useful in studying the lensing, birefringence, and other nonlinear quantum electrodynamic effects above Bc.

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

    PubMed

    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.

  19. 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

  20. What Are Electromagnetic Fields?

    MedlinePlus

    ... sources of electromagnetic fields Besides natural sources the electromagnetic spectrum also includes fields generated by human-made sources: ... ability to break bonds between molecules. In the electromagnetic spectrum, gamma rays given off by radioactive materials, cosmic ...

  1. Evidence for creation of strong electromagnetic fields in relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Toneev, V.; Rogachevsky, O.; Voronyuk, V.

    2016-08-01

    It is proposed to identify the strong electric field created during relativistic collisions of asymmetric nuclei via observation of pseudorapidity and transverse-momentum distributions of hadrons with the same mass but opposite charges. The detailed calculation results for the directed flow within the Parton-Hadron String Dynamics model are given for Cu-Au interactions at the NICA collision energies of √{s_{NN}} = 9 and 5 GeV. The separation effect is observable at 9GeV as clearly as at 200 GeV.

  2. Bending of electromagnetic wave in an ultra-strong magnetic field

    SciTech Connect

    Kim, Jin Young

    2012-10-01

    We consider the bending of light by nonlinear electrodynamics when the magnetic field B exceeds the critical value B{sub c} = m{sup 2}c{sup 2}/e h-bar = 4.4 × 10{sup 9}T. Using the index of refraction derived from the analytic series representation in one-loop effective action of QED, we found the trajectory and the bending angle of light in geometric optics. The angle bent by ultra-strong magnetic field of magnetar was estimated and compared with the gravitational bending. The result may be useful in studying the lensing, birefringence, and other nonlinear quantum electrodynamic effects above B{sub c}.

  3. Spontaneous Electromagnetic Superconductivity of Vacuum in a Strong Magnetic Field: Evidence from the Nambu-Jona-Lasinio Model

    NASA Astrophysics Data System (ADS)

    Chernodub, M. N.

    2011-04-01

    Using an extended Nambu-Jona-Lasinio model as a low-energy effective model of QCD, we show that the vacuum in a strong external magnetic field (stronger than 1016T) experiences a spontaneous phase transition to an electromagnetically superconducting state. The unexpected superconductivity of, basically, empty space is induced by emergence of quark-antiquark vector condensates with quantum numbers of electrically charged rho mesons. The superconducting phase possesses an anisotropic inhomogeneous structure similar to a periodic Abrikosov lattice in a type-II superconductor. The superconducting vacuum is made of a new type of vortices which are topological defects in the charged vector condensates. The superconductivity is realized along the axis of the magnetic field only. We argue that this effect is absent in pure QED.

  4. Spontaneous electromagnetic superconductivity of vacuum in a strong magnetic field: evidence from the Nambu-Jona-Lasinio model.

    PubMed

    Chernodub, M N

    2011-04-08

    Using an extended Nambu-Jona-Lasinio model as a low-energy effective model of QCD, we show that the vacuum in a strong external magnetic field (stronger than 10(16)   T) experiences a spontaneous phase transition to an electromagnetically superconducting state. The unexpected superconductivity of, basically, empty space is induced by emergence of quark-antiquark vector condensates with quantum numbers of electrically charged rho mesons. The superconducting phase possesses an anisotropic inhomogeneous structure similar to a periodic Abrikosov lattice in a type-II superconductor. The superconducting vacuum is made of a new type of vortices which are topological defects in the charged vector condensates. The superconductivity is realized along the axis of the magnetic field only. We argue that this effect is absent in pure QED.

  5. Hot electromagnetic outflows. III. Displaced fireball in a strong magnetic field

    SciTech Connect

    Thompson, Christopher; Gill, Ramandeep

    2014-08-10

    The evolution of a dilute electron-positron fireball is calculated in the regime of strong magnetization and high compactness (ℓ ∼ 10{sup 3}-10{sup 8}). Heating is applied at a low effective temperature (<25 keV), appropriate to breakout from a confining medium, so that relaxation to a blackbody is inhibited by pair annihilation. The diffusion equation for Compton scattering by thermal pairs is coupled to a trans-relativistic cyclo-synchrotron source. We find that the photon spectrum develops a quasi-thermal peak at energy ∼0.1 m{sub e}c {sup 2} in the comoving frame, with a power-law slope below it that is characteristic of gamma-ray bursts (GRBs; F{sub ω} ∼ const). The formation of a thermal high-energy spectrum is checked using the full kinetic equations. Calculations for a baryon-dominated photosphere reveal a lower spectral peak energy, and a harder low-energy spectrum, unless ion rest mass carries ≲ 10{sup –5} of the energy flux. We infer that (1) the GRB spectrum is inconsistent with the neutron-rich wind emitted by a young magnetar or neutron torus, and points to an event horizon in the engine; (2) neutrons play a negligible role in prompt gamma-ray emission; (3) the relation between observed peak frequency and burst energy is bounded below by the observed Amati relation if the Lorentz factor ∼(opening angle){sup –1} at breakout, and the jet is surrounded by a broader sheath that interacts with a collapsing stellar core; (4) X-ray flashes are consistent with magnetized jets with ion-dominated photospheres; (5) high-frequency Alfvén waves may become charge starved in the dilute pair gas; (6) limitations on magnetic reconnection from plasma collisionality have been overestimated.

  6. L. V. Keldysh's "Ionization in the Field of a Strong Electromagnetic Wave" and modern physics of atomic interaction with a strong laser field

    NASA Astrophysics Data System (ADS)

    Fedorov, M. V.

    2016-03-01

    Basic premises, approximations, and results of L.V. Keldysh's 1964 work on multiphoton ionization of atoms are discussed, as well as its influence on the modern science of the interaction of atomic-molecular systems with a strong laser field.

  7. L. V. Keldysh’s “Ionization in the Field of a Strong Electromagnetic Wave” and modern physics of atomic interaction with a strong laser field

    SciTech Connect

    Fedorov, M. V.

    2016-03-15

    Basic premises, approximations, and results of L.V. Keldysh’s 1964 work on multiphoton ionization of atoms are discussed, as well as its influence on the modern science of the interaction of atomic–molecular systems with a strong laser field.

  8. 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…

  9. 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…

  10. 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.

  11. Strong permanent magnet-assisted electromagnetic undulator

    DOEpatents

    Halbach, Klaus

    1988-01-01

    This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles.

  12. Spontaneous Electromagnetic Emission from a Strongly Localized Plasma Flow

    NASA Astrophysics Data System (ADS)

    Tejero, Erik; Amatucci, William; Ganguli, Gurudas; Cothran, Christopher; Thomas, Edward, Jr.

    2010-11-01

    Laboratory observations of electromagnetic ion cyclotron waves generated by a localized transverse dc electric field are reported. Experiments indicate that these waves result from a strong ExB flow inhomogeneity in a mildly collisional plasma with sub-critical magnetic field-aligned current. The wave amplitude scales with the magnitude of the applied radial dc electric field. The electromagnetic signatures become stronger with increasing plasma β, and the radial extent of the power is larger than that of the electrostatic counterpart.

  13. [Electromagnetic fields hypersensitivity].

    PubMed

    Sobiczewska, Elzbieta; Szmigielski, Stanisław

    2009-01-01

    The development of industry, particularly of new technologies in communication systems, gives rise to the number and diversty of electromagnetic field (EMF) sources in the environment. These sources, including power-frequent, radiofrequent and microwaves, make human life richer, safer and easier. But at the same time, there is growing concern about possible health risks connected with EMF exposure. An increasing number of persons have recently reported on a variety of health problems induced, in their opinion, by exposure to EMF. It is important to note that EMF levels to which these individuals are exposed are generally well below the recommended exposure limits and are certainly far below those known to produce any adverse effects. These persons call themselves "electromagnetic hypersensitivity individuals" And complain about experiencing various types of non-specific symptoms, including dermatological, neurological and vegetative. In the present paper, the problem of electromagnetic hypersensitivity phenomenon is discussed based on the recently published literature.

  14. Relativistically strong electromagnetic radiation in a plasma

    SciTech Connect

    Bulanov, S. V. E-mail: bulanov.sergei@jaea.go.jp; Esirkepov, T. Zh.; Kando, M.; Kiriyama, H.; Kondo, K.

    2016-03-15

    Physical processes in a plasma under the action of relativistically strong electromagnetic waves generated by high-power lasers have been briefly reviewed. These processes are of interest in view of the development of new methods for acceleration of charged particles, creation of sources of bright hard electromagnetic radiation, and investigation of macroscopic quantum-electrodynamical processes. Attention is focused on nonlinear waves in a laser plasma for the creation of compact electron accelerators. The acceleration of plasma bunches by the radiation pressure of light is the most efficient regime of ion acceleration. Coherent hard electromagnetic radiation in the relativistic plasma is generated in the form of higher harmonics and/or electromagnetic pulses, which are compressed and intensified after reflection from relativistic mirrors created by nonlinear waves. In the limit of extremely strong electromagnetic waves, radiation friction, which accompanies the conversion of radiation from the optical range to the gamma range, fundamentally changes the behavior of the plasma. This process is accompanied by the production of electron–positron pairs, which is described within quantum electrodynamics theory.

  15. Electromagnetic Field Penetration Studies

    NASA Technical Reports Server (NTRS)

    Deshpande, M.D.

    2000-01-01

    A numerical method is presented to determine electromagnetic shielding effectiveness of rectangular enclosure with apertures on its wall used for input and output connections, control panels, visual-access windows, ventilation panels, etc. Expressing EM fields in terms of cavity Green's function inside the enclosure and the free space Green's function outside the enclosure, integral equations with aperture tangential electric fields as unknown variables are obtained by enforcing the continuity of tangential electric and magnetic fields across the apertures. Using the Method of Moments, the integral equations are solved for unknown aperture fields. From these aperture fields, the EM field inside a rectangular enclosure due to external electromagnetic sources are determined. Numerical results on electric field shielding of a rectangular cavity with a thin rectangular slot obtained using the present method are compared with the results obtained using simple transmission line technique for code validation. The present technique is applied to determine field penetration inside a Boeing-757 by approximating its passenger cabin as a rectangular cavity filled with a homogeneous medium and its passenger windows by rectangular apertures. Preliminary results for, two windows, one on each side of fuselage were considered. Numerical results for Boeing-757 at frequencies 26 MHz, 171-175 MHz, and 428-432 MHz are presented.

  16. Proca and electromagnetic fields

    SciTech Connect

    Hillion, P.; Quinnerz, S.

    1986-07-01

    In the framework of the proper orthochronous Lorentz group, the old connection is revived between the electromagnetic field characterized by a self-dual tensor and a traceless second-rank spinor obeying the Proca equation. The relationship between this spinor and the Hertz potential also considered as a self-dual tensor is emphasized. The extension of this formalism to meet the covariance under the full Lorentz group is also discussed.

  17. Carter separable electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Lynden-Bell, D.

    2000-02-01

    The purely electromagnetic analogue in flat space of Kerr's metric in general relativity is only rarely considered. Here we carry out in flat space a programme similar to Carter's investigation of metrics in general relativity in which the motion of a charged particle is separable. We concentrate on the separability of the motion (be it classical, relativistic or quantum) of a charged particle in electromagnetic fields that lie in planes through an axis of symmetry. In cylindrical polar coordinates (t,R,φ,z) the four-vector potential takes the form [formmu2] is the unit toroidal vector. The forms of the functions Φ(R,z) and A(R,z) are sought that allow separable motion. This occurs for relativistic motion only when AR,Φ and A2-Φ2 are all of the separable form ζ(λ)-η(μ)]/(λ-μ), where ζ and η are arbitrary functions, and λ and μ are spheroidal coordinates or degenerations thereof. The special forms of A and Φ that allow this are deduced. They include the Kerr metric analogue, with E+iB=-∇{q[(r-ia).(r-ia)]-1/2}. Rather more general electromagnetic fields allow separation when the motion is non-relativistic. The investigation is extended to fields that lie in parallel planes. Connections to Larmor's theorem are remarked upon.

  18. Spontaneous Electromagnetic Emission from a Strongly Localized Plasma Flow

    NASA Astrophysics Data System (ADS)

    Tejero, E. M.; Amatucci, W. E.; Ganguli, G.; Cothran, C. D.; Crabtree, C.; Thomas, E., Jr.

    2011-05-01

    Laboratory observations of electromagnetic ion-cyclotron waves generated by a localized transverse dc electric field are reported. Experiments indicate that these waves result from a strong E×B flow inhomogeneity in a mildly collisional plasma with subcritical magnetic field-aligned current. The wave amplitude scales with the magnitude of the applied radial dc electric field. The electromagnetic signatures become stronger with increasing plasma β, and the radial extent of the power is larger than that of the electrostatic counterpart. Near-Earth space weather implications of the results are discussed.

  19. Electromagnetic Fields and Cancer

    MedlinePlus

    ... are in the ionizing radiation part of the electromagnetic spectrum and can damage DNA or cells directly. Low- ... in the non-ionizing radiation part of the electromagnetic spectrum and are not known to damage DNA or ...

  20. Interactions between electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Schwan, H. P.

    1985-02-01

    We applied for this grant to support a workshop at Erice, Italy. This workshop has been commonly called Erice School and the main subject of this workshop is the interaction of electromagnetic fields with biological cells and molecules. The grant from ONR enabled us to invite American scientists to participants in this workshop and deliver scientific papers. The duration of the Erice School was ten days. Therefore, we had sufficient time to discuss the problems of electromagnetic radiations. Vigorous discussions took place during official sessions and during private conversations. The participants of this workshop are mostly those who have been active in the research on bioelectromagnetics, but there are some numbers of speakers who discussed the basic electrical and magnetic properties of polyelectrolytes, biological membranes and tissue. The workshop was unique in that there were participants with a variety of training backgrounds. This enabled us to exchange the information between applied scientists and basic scientists. Also, active exchanges of opinions took place between biological scientists and physical scientists.

  1. Coherent hybrid electromagnetic field imaging

    DOEpatents

    Cooke, Bradly J.; Guenther, David C.

    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.

  2. Electromagnetic waves in a strong Schwarzschild plasma

    SciTech Connect

    Daniel, J.; Tajima, T.

    1996-11-01

    The physics of high frequency electromagnetic waves in a general relativistic plasma with the Schwarzschild metric is studied. Based on the 3 + 1 formalism, we conformalize Maxwell`s equations. The derived dispersion relations for waves in the plasma contain the lapse function in the plasma parameters such as in the plasma frequency and cyclotron frequency, but otherwise look {open_quotes}flat.{close_quotes} Because of this property this formulation is ideal for nonlinear self-consistent particle (PIC) simulation. Some of the physical consequences arising from the general relativistic lapse function as well as from the effects specific to the plasma background distribution (such as density and magnetic field) give rise to nonuniform wave equations and their associated phenomena, such as wave resonance, cutoff, and mode-conversion. These phenomena are expected to characterize the spectroscopy of radiation emitted by the plasma around the black hole. PIC simulation results of electron-positron plasma are also presented.

  3. Nonlinear electromagnetic fields and symmetries

    NASA Astrophysics Data System (ADS)

    Barjašić, Irena; Gulin, Luka; Smolić, Ivica

    2017-06-01

    We extend the classical results on the symmetry inheritance of the canonical electromagnetic fields, described by the Maxwell's Lagrangian, to a much wider class of models, which include those of the Born-Infeld, power Maxwell and the Euler-Heisenberg type. Symmetry inheriting fields allow the introduction of electromagnetic scalar potentials and these are proven to be constant on the Killing horizons. Finally, using the relations obtained along the analysis, we generalize and simplify the recent proof for the symmetry inheritance of the 3-dimensional case, as well as give the first constraint for the higher dimensional electromagnetic fields.

  4. Electromagnetic Field Effects in Explosives

    NASA Astrophysics Data System (ADS)

    Tasker, D. G.; Whitley, V. H.; Lee, R. J.

    2009-12-01

    Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: enhancement of performance; and control of initiation and growth of reaction. Two series of experiments were performed to determine the effects of 1-T magnetic fields on explosive initiation and growth in the modified gap test and on the propagation of explosively generated plasma into air. The results have implications for the control of reactions in explosives and for the use of electromagnetic particle velocity gauges.

  5. 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

  6. Dual field theory of strong interactions

    SciTech Connect

    Akers, D.

    1987-07-01

    A dual field theory of strong interactions is derived from a Lagrangian of the Yang-Mills and Higgs fields. The existence of a magnetic monopole of mass 2397 MeV and Dirac charge g = (137/2)e is incorporated into the theory. Unification of the strong, weak, and electromagnetic forces is shown to converge at the mass of the intermediate vector boson W/sup +/-/. The coupling constants of the strong and weak interactions are derived in terms of the fine-structure constant ..cap alpha.. = 1/137.

  7. A strong permanent magnet-assisted electromagnetic undulator

    DOEpatents

    Halbach, K.

    1987-01-30

    This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles. 4 figs.

  8. Strong Magnetic Field Characterisation

    DTIC Science & Technology

    2012-04-01

    coils were driven by a pulsed-power system to generate the fields. All the sources were characterised through a series of measurements and modelling... generated for the coils. Options for further investigation were provided. UNCLASSIFIED UNCLASSIFIED This...investigation. The desired field strength was based on assessments [1] from preliminary magnetohydrodynamic ( MHD ) modelling and while not achievable by

  9. String theory in electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Ambjørn, Jan; Makeenko, Yuri M.; Semenoff, Gordon W.; Szabo, Richard J.

    2003-02-01

    A review of various aspects of superstrings in background electromagnetic fields is presented. Topics covered include the Born-Infeld action, spectrum of open strings in background gauge fields, the Schwinger mechanism, finite-temperature formalism and Hagedorn behaviour in external fields, Debye screening, D-brane scattering, thermodynamics of D-branes, and noncommutative field and string theories on D-branes. The electric field instabilities are emphasized throughout and contrasted with the case of magnetic fields. A new derivation of the velocity-dependent potential between moving D-branes is presented, as is a new result for the velocity corrections to the one-loop thermal effective potential.

  10. Explanations, Education, and Electromagnetic Fields.

    ERIC Educational Resources Information Center

    Friedman, Sharon M.

    Explaining complex scientific and environmental subjects in the mass media is difficult to do, particularly under such constraints as short deadlines and lack of space or time. When a scientific controversy and human health risk are involved, this becomes an even harder task to accomplish. The subject of electromagnetic fields (EMF) involves…

  11. Health hazards and electromagnetic fields.

    PubMed

    Saunders, T

    2003-11-01

    Biological rhythms, physical wellbeing and mental states are dependent on our electrical brainwave system interacting with the extremely weak electromagnetic fields generated by the Earth's telluric and Cosmic radiations. In a single generation, since the evolution of humankind over millions of years, we are exposed to a wide range of powerful, artificially generated electromagnetic radiation which adversely affects the subtle balance in nature's energy fields and has become the source of so-called 'diseases of civilization'. This also includes electromagnetic sensitivity. Generally, there is a lack of awareness and understanding of the impact electromagnetic fields can have upon health and wellbeing.Our ancestors were acutely aware that certain locations, were perceived to have a positive energy field which was beneficial to health and vitality. Over time, these areas are now referred to as sacred sites for spiritual ceremony and as healing centres. In contrast, there are other geographical locations that can have a negative effect upon health and these are known as geopathic stress zones. It is believed that such zones can interfere with the brain's normal function that inhibits the release of melatonin and other endocrine secretions needed to replenish the immune system. Geopathic stress can affect animals and plant life as well as human beings and significantly contributes to sick building syndrome (SBS). Whilst there is an increasing body of opinion amongst eminent researchers and scientists who are addressing these issues, the establishment professions are slow to change. However, very gradually, modern allopathic medicine and attitudes are beginning to recognise the extraordinary wisdom and efficacy of ancient traditions such as acupuncture, light, colour and other therapies based on the understanding and treatment of the interaction of a person's electromagnetic subtle body and the immediate environment. These and many other 'complementary' therapies may

  12. Extremely low frequency electromagnetic fields

    SciTech Connect

    Wilson, B.W. . Chemical Sciences Dept.); Stevens, R.G. ); Anderson, L.E. . Life Sciences Center)

    1990-01-01

    The authors focus on that which seems to be the central scientific issue emerging from current ELF research in epidemiology and in the laboratory; namely, can ELF electromagnetic fields interact with biological systems in such a way as to increase cancer risk The authors examine how cancer risk might be related to two reproducible biological effects of ELF exposure: effects on the pineal gland and circadian biology, and effects on calcium homeostasis in cells. Because they are concerned with the possible biological mechanisms of carcinogenesis, epidemiological studies are only briefly reviewed.

  13. 78 FR 33633 - Human Exposure to Radiofrequency Electromagnetic Fields

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-04

    ... to Radiofrequency Electromagnetic Fields; Reassessment of Exposure to Radiofrequency Electromagnetic..., and 95 Human Exposure to Radiofrequency Electromagnetic Fields AGENCY: Federal Communications... electromagnetic fields. More specifically, the Commission clarifies evaluation procedures and references...

  14. Collision of strong gravitational and electromagnetic waves in the expanding universe

    NASA Astrophysics Data System (ADS)

    Alekseev, G. A.

    2016-03-01

    An exact analytical model of the process of collision and nonlinear interaction of gravitational and/or electromagnetic soliton waves and strong nonsoliton electromagnetic traveling waves of arbitrary profile propagating in the expanding universe (the symmetric Kasner spacetime) is presented. In contrast to intuitive expectations that rather strong traveling waves can destroy the soliton, it occurs that the soliton survives during its interaction with electromagnetic waves of arbitrary amplitude and profile, but its parameters begin to evolve under the influence of this interaction. If a traveling electromagnetic wave possesses a finite duration, the soliton parameters after interaction take constant values again, but these values in general are different from those before the interaction. Based on exact solutions of the Einstein-Maxwell equations, our model demonstrates a series of nonlinear phenomena, such as (a) creation of gravitational waves in the collision of two electromagnetic waves, (b) creation of electromagnetic soliton waves in the collision of a gravitational soliton with traveling electromagnetic waves, (c) scattering of a part of a soliton wave in the direction of propagation of a traveling electromagnetic wave, and (d) quasiperiodic oscillating character of fields in the wave interaction region and multiple mutual transformations of gravitational and electromagnetic waves in this region. The figures illustrate these features of nonlinear wave interactions in general relativity.

  15. Semimetallization of dielectrics in strong optical fields

    NASA Astrophysics Data System (ADS)

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; Kim, Bum-Kyu; Kim, Ju-Jin; Stockman, Mark I.; Kim, D.

    2016-02-01

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics.

  16. Semimetallization of dielectrics in strong optical fields

    DOE PAGES

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; ...

    2016-02-18

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drivemore » this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Lastly, our results may blaze a trail to PHz-rate optoelectronics.« less

  17. Semimetallization of dielectrics in strong optical fields

    SciTech Connect

    Kwon, Ojoon; Apalkov, Vadym; Kim, Bum -Kyu; Kim, Ju -Jin; Stockman, Mark I.; Kim, D.

    2016-02-18

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Lastly, our results may blaze a trail to PHz-rate optoelectronics.

  18. Semimetallization of dielectrics in strong optical fields

    PubMed Central

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; Kim, Bum-Kyu; Kim, Ju-Jin; Stockman, Mark I.; Kim, D.

    2016-01-01

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics. PMID:26888147

  19. Longitudinal ELF to LF electromagnetic oscillations and waves generated in the ionosphere under the influence of strong high-frequency electric field

    SciTech Connect

    Alpert, Y.L.

    1995-01-01

    Results of detailed numerical calculations of some parametric decay effects, arising in a magnetoplasma under the influence of a HF, sufficiently strong electric field {rvec E} = {rvec E}{sub p} {center_dot} cos{omega}{sub E}t, are given in this paper. The resonance branches and the VLF parametric resonances are calculated in the ionosphere at altitudes Z = 200, 300, and 400 km. Calculations in the resonance regions {omega}{sub E} = s{omega}{sub o} ({omega}{sub o} is the electron Langmuir frequency, s=1,2...) were done in the cold palsma and also in the kinetic approximations. It is shown that the angle dependence {omega}{sub 1}({Theta}, E{sub p}=0) of the ELF (0 < w {le} {Omega}{sub B}) resonance branch is close to the cosine law. This is in contrast with the earlier published results and with the angle dependence {omega}{sub 1}({Theta}, E=0). This important effect and the other dependencies given in the paper may be used for the search of the parametric instabilities and of the electric field in the ionosphere and magnetosphere, especially by experiments in situ on satellites. 9 refs., 5 figs., 11 tabs.

  20. Quantum processes in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Canuto, V.

    1975-01-01

    Quantum-mechanical processes that occur in a piece of matter embedded in a magnetic field with a strength of the order of 10 to the 13th power G are described which either are entirely due to the presence of the field or become modified because of it. The conversion of rotational energy into electromagnetic energy in pulsars is analyzed as a mechanism for producing such a field, and it is shown that a strong magnetic field is not sufficient for quantum effects to play a significant role; in addition, the density must be adjusted to be as low as possible. The pressure and energy density of a free electron gas in a uniform magnetic field are evaluated, neutron beta-decay in the presence of a strong field is examined, and the effect of such a field on neutrino reactions is discussed. The thermal history of a neutron star is studied, and it is concluded that a strong magnetic field helps to increase the cooling rate of the star by producing new channels through which neutrinos can carry away energy.

  1. Quantum processes in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Canuto, V.

    1975-01-01

    Quantum-mechanical processes that occur in a piece of matter embedded in a magnetic field with a strength of the order of 10 to the 13th power G are described which either are entirely due to the presence of the field or become modified because of it. The conversion of rotational energy into electromagnetic energy in pulsars is analyzed as a mechanism for producing such a field, and it is shown that a strong magnetic field is not sufficient for quantum effects to play a significant role; in addition, the density must be adjusted to be as low as possible. The pressure and energy density of a free electron gas in a uniform magnetic field are evaluated, neutron beta-decay in the presence of a strong field is examined, and the effect of such a field on neutrino reactions is discussed. The thermal history of a neutron star is studied, and it is concluded that a strong magnetic field helps to increase the cooling rate of the star by producing new channels through which neutrinos can carry away energy.

  2. 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.

  3. Cyclotron resonance cooling by strong laser field

    SciTech Connect

    Tagcuhi, Toshihiro; Mima, Kunioka

    1995-12-31

    Reduction of energy spread of electron beam is very important to increase a total output radiation power in free electron lasers. Although several cooling systems of particle beams such as a stochastic cooling are successfully operated in the accelerator physics, these cooling mechanisms are very slow and they are only applicable to high energy charged particle beams of ring accelerators. We propose here a new concept of laser cooling system by means of cyclotron resonance. Electrons being in cyclotron motion under a strong magnetic field can resonate with circular polarized electromagnetic field, and the resonance take place selectively depending on the velocity of the electrons. If cyclotron frequency of electrons is equal to the frequency of the electromagnetic field, they absorb the electromagnetic field energy strongly, but the other electrons remain unchanged. The absorbed energy will be converted to transverse kinetic energy, and the energy will be dumped into the radiation energy through bremastrahlung. To build a cooling system, we must use two laser beams, where one of them is counter-propagating and the other is co-propagating with electron beam. When the frequency of the counter-propagating laser is tuned with the cyclotron frequency of fast electrons and the co-propagating laser is tuned with the cyclotron frequency of slow electrons, the energy of two groups will approach and the cooling will be achieved. We solve relativistic motions of electrons with relativistic radiation dumping force, and estimate the cooling rate of this mechanism. We will report optimum parameters for the electron beam cooling system for free electron lasers.

  4. Electromagnetic fields in cased borehole

    SciTech Connect

    Lee, Ki Ha; Kim, Hee Joon; Uchida, Toshihiro

    2001-07-20

    Borehole electromagnetic (EM) measurements, using fiberglass-cased boreholes, have proven useful in oil field reservoir characterization and process monitoring (Wilt et al., 1995). It has been presumed that these measurements would be impossible in steel-cased wells due to the very large EM attenuation and phase shifts. Recent laboratory and field studies have indicated that detection of EM signals through steel casing should be possible at low frequencies, and that these data provide a reasonable conductivity image at a useful scale. Thus, we see an increased application of this technique to mature oilfields, and an immediate extension to geothermal industry as well. Along with the field experiments numerical model studies have been carried out for analyzing the effect of steel casing to the EM fields. The model used to be an infinitely long uniform casing embedded in a homogeneous whole space. Nevertheless, the results indicated that the formation signal could be accurately recovered if the casing characteristics were independently known (Becker et al., 1998; Lee el al., 1998). Real steel-cased wells are much more complex than the simple laboratory models used in work to date. The purpose of this study is to develop efficient numerical methods for analyzing EM fields in realistic settings, and to evaluate the potential application of EM technologies to cross-borehole and single-hole environment for reservoir characterization and monitoring.

  5. Resonant Strong Field Nonlinear Optical Interactions

    NASA Astrophysics Data System (ADS)

    Coppeta, David Anthony

    This work considers the steady state nonlinear response of a medium subjected to electromagnetic fields which are resonant and/or strong. In this regime, pertubation expansions in the field amplitude(s) diverge and non-pertubative techniques are required. Two general cases are considered. In the first case, radiative renormalization is applied to Four Wave Mixing (FWM) in a four level system with three resonant driving fields. The absorption and generation of a weak FWM signal are considered. Several variants including coherent anti-Stokes Raman scattering are considered. The second case is a two level atom subject to excitation by an arbitrarily amplitude modulated field. The domain of solution is extended to non-equal damping rates with zero detuning from resonance. As an example, the steady state response to step function amplitude modulation is treated.

  6. Electron-Ion collisions in relativistically strong laser fields

    SciTech Connect

    Balakin, A. A.

    2008-04-15

    Electron-ion collisions in relativistically strong electromagnetic fields are considered. Analytical and numerical analyses both show that all qualitative effects characteristic of collisions in nonrelativistic strong fields [1-3] occur at relativistic intensities of an electromagnetic wave as well. Expressions for Joule plasma heating and for the energy distributions of fast particles are derived from simple analytic considerations and are confirmed by numerical simulations. It is found, in particular, that, due to the relativistic increase in the mass of a scattered electron, Joule heating in ultrarelativistic fields becomes more intense as the field amplitude grows.

  7. 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.

  8. 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.

  9. Interaction of relativistically strong electromagnetic waves with a layer of overdense plasma

    SciTech Connect

    Korzhimanov, A. V.; Eremin, V. I. Kim, A. V.; Tushentsov, M. R.

    2007-10-15

    Plasma-field structures that arise under the interaction between a relativistically strong electromagnetic wave and a layer of overdense plasma are considered within a quasistationary approximation. It is shown that, together with known solutions, which are nonlinear generalizations of skin-layer solutions, multilayer structures containing cavitation regions with completely removed electrons (ion layers) can be excited when the amplitude of the incident field exceeds a certain threshold value. Under symmetric irradiation, these cavitation regions, which play the role of self-consistent resonators, may amplify the field and accumulate electromagnetic energy.

  10. Medical applications of electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Lai, Henry C.; Singh, Narendra P.

    2010-04-01

    In this article, we describe two possible applications of low-intensity non-ionizing electromagnetic fields (EMF) for the treatment of malaria and cancer, respectively. In malaria treatment, a low-intensity extremely-low frequency magnetic field can be used to induce vibration of hemozoin, a super-paramagnetic polymer particle, inside malaria parasites. This disturbance could cause free radical and mechanical damages leading to the death of the parasite. This concept has been tested in vitro on malaria parasites and found to be effective. This may provide a low cost effective treatment for malaria infection in humans. The rationale for cancer treatment using low-intensity EMF is based on two concepts that have been well established in the literature: (1) low-intensity non-thermal EMF enhances cytotoxic free radicals via the iron-mediated Fenton reaction; and (2) cancer cells have higher amounts of free iron, thus are more susceptible to the cytotoxic effects of EMF. Since normal cells contain minimal amount of free iron, the effect would be selectively targeting cancer cells. Thus, no adverse side effect would be expected as in traditional chemotherapy and radiation therapy. This concept has also been tested on human cancer cell and normal cells in vitro and proved to be feasible.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Electrophoresis in strong electric fields.

    PubMed

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  18. 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.

  19. Interaction of electromagnetic fields and biological tissues

    NASA Astrophysics Data System (ADS)

    Darshan Shrivastava, Bhakt; Barde, Ravindra; Mishra, Ashutosh; Phadke, S.

    2014-09-01

    This paper deals with the electromagnetic field interact in biological tissues. It is actually one of the important challenges for the electromagnetic field for the recent years. The experimental techniques are use in Broad-band Dielectric Measurement (BDM) with LCR meters. The authors used Bones and scales of Fish taken from Narmada River (Rajghat Dist. Barwani) as biological tissues. Experimental work carried out done in inter-university consortium (IUC) Indore. The major difficulties that appear are related to the material properties, to the effect of the electromagnetic problem and to the thermal model of the biological tissues.

  20. 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.

  1. 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.

  2. Quantum processes in short and intensive electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Titov, A. I.; Kämpfer, Burkhard; Hosaka, Atsushi; Takabe, Hideaki

    2016-05-01

    This work provides an overview of our recent results in studying two most important and widely discussed quantum processes: electron-positron pairs production off a probe photon propagating through a polarized short-pulsed electromagnetic (e.g. laser) wave field or generalized Breit-Wheeler process, and a single a photon emission off an electron interacting with the laser pules, so-called non-linear Compton scattering. We show that the probabilities of particle production in both processes are determined by interplay of two dynamical effects, where the first one is related to the shape and duration of the pulse and the second one is non-linear dynamics of the interaction of charged fermions with a strong electromagnetic field. We elaborate suitable expressions for the production probabilities and cross sections, convenient for studying evolution of the plasma in presence of strong electromagnetic fields.

  3. Program For Displaying Computed Electromagnetic Fields

    NASA Technical Reports Server (NTRS)

    Hom, Kam W.

    1995-01-01

    EM-ANIMATE computer program specialized visualization displays and animates output data on near fields and surface currents computed by electromagnetic-field program - in particular MOM3D (LAR-15074). Program based on windows and contains user-friendly, graphical interface for setting viewing options, selecting cases, manipulating files, and like. Written in FORTRAN 77. EM-ANIMATE also available as part of package, COS-10048, includes MOM3D, IRIS program computing near-field and surface-current solutions of electromagnetic-field equations.

  4. Controlling the Electromagnetic Field Confinement with Metamaterials

    PubMed Central

    Bonache, Jordi; Zamora, Gerard; Paredes, Ferran; Zuffanelli, Simone; Aguilà, Pau; Martín, Ferran

    2016-01-01

    The definition of a precise illumination region is essential in many applications where the electromagnetic field should be confined in some specific volume. By using conventional structures, it is difficult to achieve an adequate confinement distance (or volume) with negligible levels of radiation leakage beyond it. Although metamaterial structures and metasurfaces are well-known to provide high controllability of their electromagnetic properties, this feature has not yet been applied to solve this problem. We present a method of electromagnetic field confinement based on the generation of evanescent waves by means of metamaterial structures. With this method, the confinement volume can be controlled, namely, it is possible to define a large area with an intense field without radiation leakage. A prototype working in the microwave region has been implemented, and very good agreement between the measurements and the theoretical prediction of field distribution has been obtained. PMID:27886230

  5. Controlling the Electromagnetic Field Confinement with Metamaterials

    NASA Astrophysics Data System (ADS)

    Bonache, Jordi; Zamora, Gerard; Paredes, Ferran; Zuffanelli, Simone; Aguilà, Pau; Martín, Ferran

    2016-11-01

    The definition of a precise illumination region is essential in many applications where the electromagnetic field should be confined in some specific volume. By using conventional structures, it is difficult to achieve an adequate confinement distance (or volume) with negligible levels of radiation leakage beyond it. Although metamaterial structures and metasurfaces are well-known to provide high controllability of their electromagnetic properties, this feature has not yet been applied to solve this problem. We present a method of electromagnetic field confinement based on the generation of evanescent waves by means of metamaterial structures. With this method, the confinement volume can be controlled, namely, it is possible to define a large area with an intense field without radiation leakage. A prototype working in the microwave region has been implemented, and very good agreement between the measurements and the theoretical prediction of field distribution has been obtained.

  6. Characterizing and Designing Localized Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Borzdov, Georgy N.

    2004-11-01

    An approach to characterizing and designing localized electromagnetic fields in complex media and free space, based on the use of differentiable manifolds, differentiable mappings, and the rotation group, is discussed. Families of exact time-harmonic solutions to Maxwell's equations -- standing waves defined by spherical harmonics, and localized fields defined by the rotation group -- are presented.

  7. 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.

  8. Electromagnetic fields in bone repair and adaptation

    NASA Astrophysics Data System (ADS)

    McLeod, Kenneth J.; Rubin, Clinton T.; Donahue, Henry J.

    1995-01-01

    The treatment of delayed union of bone fractures has served for the past 20 years as the principal testing ground for determining whether nonionizing electromagnetic fields can have any substantial, long-term effects in clinical medicine. Recent double-blinded clinical trials have confirmed the significance of the reported effects on bone healing and have led to the suggestion that electromagnetic fields may also be useful in the treatment of other orthopedic problems such as fresh fractures, stabilization of prosthetic implants, or even the prevention or treatment of osteoporosis. However, the design of appropriate treatment regimens for these new applications would be greatly facilitated if it were understood how the biological cells within bone tissue sense these low-frequency, and remarkably low level, electromagnetic fields. Here we address the engineering and physical science aspects of this problem. We review the characteristics of clinically used electromagnetic fields and discuss which components of these fields may actually be responsible for altering the activity of the bone cells. We then consider several physical mechanisms which have been proposed to explain how the cells within the bone or fracture tissue detect this field component.

  9. Guided plasmonic modes in nanorod assemblies: strong electromagnetic coupling regime.

    PubMed

    Wurtz, G A; Dickson, W; O'Connor, D; Atkinson, R; Hendren, W; Evans, P; Pollard, R; Zayats, A V

    2008-05-12

    We demonstrate that the coupling between plasmonic modes of oriented metallic nanorods results in the formation of an extended (guided) plasmonic mode of the nanorod array. The electromagnetic field distribution associated to this mode is found to be concentrated between the nanorods within the assembly and propagates normally to the nanorod long axes, similar to a photonic mode waveguided by an anisotropic slab. This collective plasmonic mode determines the optical properties of nanorod assemblies and can be tuned in a wide spectral range by changing the nanorod array geometry. This geometry represents a unique opportunity for light guiding applications and manipulation at the nanoscale as well as sensing applications and development of molecular plasmonic devices.

  10. Electromagnetic field interactions with biological systems

    SciTech Connect

    Frey, A.H. )

    1993-02-01

    This is a report on Symposia organized by the International Society for Bioelectricity and presented at the 1992 FASEB Meeting. The presentations summarized here were intended to provide a sampling of new and fruitful lines of research. The theme topics for the Symposia were cancer, neural function, cell signaling, pineal gland function, and immune system interactions. Living organisms are complex electrochemical systems that evolved over billions of years in a world with a relatively simple weak magnetic field and with few electromagnetic energy emitters. As is characteristic of living organisms, they interacted with and adapted to this environment of electric and magnetic fields. In recent years there has been a massive introduction of equipment that emits electromagnetic fields in an enormous range of new frequencies, modulations, and intensities. As living organisms have only recently found themselves immersed in this new and virtually ubiquitous environment, they have not had the opportunity to adapt to it. This gives biologists the opportunity to use these electromagnetic fields as probes to study the functioning of living systems. This is a significant opportunity, as new approaches to studying living systems so often provide the means to make great leaps in science. In recent years, a diversity of biologists have carried out experiments using electromagnetic fields to study the function of living cells and systems. This approach is now becoming quite fruitful and is yielding data that are advancing our knowledge in diverse areas of biology. 25 refs., 6 figs., 3 tabs.

  11. Caution: Strong Gravitational Field Present

    ERIC Educational Resources Information Center

    Reif, Marc

    2014-01-01

    I came up with a new way to introduce the concept of a constant gravitational field near the surface of the Earth. I made "g-field detectors" (see Fig. 1 ) and suspended them by strings from the ceiling in a regular spacing. The detectors are cardstock arrows with a hole punched out of them and the letter "g" in the center.

  12. Caution: Strong Gravitational Field Present

    ERIC Educational Resources Information Center

    Reif, Marc

    2014-01-01

    I came up with a new way to introduce the concept of a constant gravitational field near the surface of the Earth. I made "g-field detectors" (see Fig. 1 ) and suspended them by strings from the ceiling in a regular spacing. The detectors are cardstock arrows with a hole punched out of them and the letter "g" in the center.

  13. Photon Propagation in Slowly Varying Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Karbstein, F.

    2017-03-01

    Effective theory of soft photons in slowly varying electromagnetic background fields is studied at one-loop order in QED. This is of relevance for the study of all-optical signatures of quantum vacuum nonlinearity in realistic electromagnetic background fields as provided by high-intensity lasers. The central result derived in this article is a new analytical expression for the photon polarization tensor in two linearly polarized counterpropagating pulsed Gaussian laser beams. Treating the peak field strengths of both laser beams as free parameters, this field configuration can be considered as interpolating between the limiting cases of a purely right- or left-moving laser beam (if one of the peak field strengths is set equal to zero) and the standing-wave type scenario with two counter-propagating beams of equal strength.

  14. Radiated fields from an electromagnetic pulse simulator

    NASA Astrophysics Data System (ADS)

    Pelletier, M.; Delisle, G. Y.; Kashyap, S.

    Simulators of electromagnetic pulses allow generation within a limited time of very high-intensity fields such as those produced in a nuclear explosion. These fields can be radiated out of the test zone at a lower but nevertheless significant level; if the intensity of these fields is sufficiently high, damage to humans and electronic equipment can result. An evaluation of the potential danger of these simulator emissions requires knowledge of the amplitude, duration, and the energy of the radiated impulses. A technique is presented for calculating the fields radiated by a parallel-plane electromagnetic pulse simulator. The same method can also be applied to a rhombic type simulator. Sample numerical results are presented along with the calculations of the energy and power density and a discussion of the formation of the field in the frequency domain.

  15. Electromagnetic fields and infant incubators.

    PubMed

    Bearer, C F

    1994-01-01

    Two models of infant incubators were studied to determine the strength of the magnetic field generated by the heater and fan motors. Measurements were taken at intervals along the center line of the incubator. The results show that fields greater than 100 milligauss and 25 milligauss were measured in the C-86 and C-100 model Isolettes, respectively.

  16. Electromagnetic field parameters and instrumentation

    NASA Astrophysics Data System (ADS)

    Sheppard, A. R.; Jones, R. A.; Stell, M. E.; Adey, W. R.; Bawin, S.

    1986-07-01

    We studied the effects of the electric and magnetic components of a Loran-C type waveform on three biological systems. Neurochemical assays of brain neurotransmitter substances indicate field-related changes in the levels of norepinephrine in the hippocampus and in the number and affinities of the opiate receptors in the cortex. Behavioral data showed that rats trained in an operant conditioning task did not reliably detect any electric field strength used. Biochemical data demonstrated that the Loran-C field did not modify basal ornithine decarboxylase activity in primary bone cells.

  17. LEM—electromagnetic fields measurement laboratory

    NASA Astrophysics Data System (ADS)

    Annino, A.; Falciglia, F.; Musumeci, F.; Oliveri, M.; Privitera, G.; Triglia, A.

    2000-04-01

    The widespread presence of electromagnetic waves and the relative problems regarding them have favored the constitution of the LEM at the DMFCI in Catania University, where competence has been developing in this sector for about 10 years. Full operativeness has been reached as far as the electromagnetic field measurements in anthropized environments are concerned. Other research will be undertaken as soon as further funds are available. Some problems connected with the perfecting of measurements instruments and the results of emission measurements of cellular telephones are presented.

  18. Physics in strong magnetic fields near neutron stars

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    1991-01-01

    Electromagnetic phenomena occurring in the strong magnetic fields of neutron stars are currently of great interest in high-energy astrophysics. Observations of rotation rate changes and cyclotron lines in pulsars and gamma-ray bursts indicate that surface magnetic fields of neutron stars often exceed a trillion gauss. In fields this strong, where electrons behave much as if they were in bound atomic states, familiar processes undergo profound changes, and exotic processes become important. Strong magnetic fields affect the physics in several fundamental ways: energies perpendicular to the field are quantized, transverse momentum is not conserved, and electron-positron spin is important. Neutron stars therefore provide a unique laboratory for the study of physics in extremely high fields that cannot be generated on earth.

  19. Gene transcription and electromagnetic fields

    SciTech Connect

    Henderson, A.S.

    1992-01-01

    Our overall aim is to obtain sufficient information to allow us to ultimately determine whether ELF EM field exposure is an initiating factor in neoplastic transformation and/or if exposure can mimic characteristics of the second-step counterpart in neoplastic disease. This aim is based on our previous findings that levels of some transcripts are increased in cells exposed to EM fields. While the research is basic in nature, the ramifications have bearing on the general safety of exposure to EM fields in industrial and everyday life. A large array of diverse biological effects are reported to occur as the result of exposure to elf EM fields, suggesting that the cell response to EM fields is at a basic level, presumably initiated by molecular and/or biophysical events at the cell membrane. The hypothesized route is a signal transduction pathway involving membrane calcium fluxes. Information flow resulting from signal transduction can mediate the induction of regulatory factors in the cell, and directly affect how transcription is regulated.

  20. Vacuum in a strong magnetic field as a hyperbolic metamaterial.

    PubMed

    Smolyaninov, Igor I

    2011-12-16

    As demonstrated by Chernodub, vacuum in a strong magnetic field behaves as Abrikosov vortex lattice in a type-II superconductor. We investigate electromagnetic behavior of vacuum in this state and demonstrate that vacuum behaves as a hyperbolic metamaterial. If the magnetic field is constant, low frequency extraordinary photons experience this medium as a (3+1) Minkowski spacetime in which the role of time is played by the spatial z coordinate. Variations of the magnetic field curve this spacetime, and may lead to formation of "electromagnetic black holes." Since hyperbolic metamaterials behave as diffractionless "perfect lenses," and large enough magnetic fields probably existed in the early Universe, the demonstrated hyperbolic behavior of early vacuum may have imprints in the large scale structure of the present-day Universe. © 2011 American Physical Society

  1. Vacuum in a Strong Magnetic Field as a Hyperbolic Metamaterial

    SciTech Connect

    Smolyaninov, Igor I.

    2011-12-16

    As demonstrated by Chernodub, vacuum in a strong magnetic field behaves as Abrikosov vortex lattice in a type-II superconductor. We investigate electromagnetic behavior of vacuum in this state and demonstrate that vacuum behaves as a hyperbolic metamaterial. If the magnetic field is constant, low frequency extraordinary photons experience this medium as a (3+1) Minkowski spacetime in which the role of time is played by the spatial z coordinate. Variations of the magnetic field curve this spacetime, and may lead to formation of ''electromagnetic black holes''. Since hyperbolic metamaterials behave as diffractionless ''perfect lenses'', and large enough magnetic fields probably existed in the early Universe, the demonstrated hyperbolic behavior of early vacuum may have imprints in the large scale structure of the present-day Universe.

  2. Understanding possible electromagnetic counterparts to loud gravitational wave events: Binary black hole effects on electromagnetic fields

    SciTech Connect

    Palenzuela, Carlos; Lehner, Luis; Yoshida, Shin

    2010-04-15

    In addition to producing loud 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 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 an 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.

  3. Coherent polarization driven by external electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Apostol, M.; Ganciu, M.

    2010-11-01

    The coherent interaction of the electromagnetic radiation with an ensemble of polarizable, identical particles with two energy levels is investigated in the presence of external electromagnetic fields. The coupled non-linear equations of motion are solved in the stationary regime and in the limit of small coupling constants. It is shown that an external electromagnetic field may induce a macroscopic occupation of both the energy levels of the particles and the corresponding photon states, governed by a long-range order of the quantum phases of the internal motion (polarization) of the particles. A lasing effect is thereby obtained, controlled by the external field. Its main characteristics are estimated for typical atomic matter and atomic nuclei. For atomic matter the effect may be considerable (for usual external fields), while for atomic nuclei the effect is extremely small (practically insignificant), due to the great disparity in the coupling constants. In the absence of the external field, the solution, which is non-analytic in the coupling constant, corresponds to a second-order phase transition (super-radiance), which was previously investigated.

  4. Electromagnetic field of a linear antenna

    NASA Astrophysics Data System (ADS)

    Derby, Norman; Olbert, Stanislaw

    2008-11-01

    Animated computer simulations of the electric field of a radiating antenna can capture the attention of students in introductory electromagnetism courses and stimulate active discussions. The simulations raise questions not usually addressed in textbooks. In certain cases, some of the field lines appear to move toward the antenna, the speed of the field lines can change as they move, and the field lines exhibit strange behavior (circling or splitting) at certain points. Because their fields can be expressed in terms of elementary functions, animations of point dipole antennas are common, but animations showing the fields of antennas with more realistic lengths are not as common because analytical expressions for these fields are not as well known. We show that it is possible to derive analytical expressions in terms of elementary functions for the electromagnetic field of linear antennas of finite length. We draw attention to an open-source method for displaying the fine details within the field patterns and then give a general discussion of singular points and their motions, derive expressions for their location and phase velocity, and apply these results to some of the phenomena that are visible in visualizations of the fields of various antennas.

  5. 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

  6. Electromagnetic time reversal focusing of near field waves in metamaterials

    NASA Astrophysics Data System (ADS)

    Chabalko, Matthew J.; Sample, Alanson P.

    2016-12-01

    Precise control of electromagnetic energy on a deeply subwavelength scale in the near field regime is a fundamentally challenging problem. In this letter we demonstrate the selective focusing of electromagnetic energy via the electromagnetic time reversal in the near field of a metamaterial. Our analysis begins with fundamental mathematics, and then is extended to the experimental realm where focusing in space and time of the magnetic fields in the near field of a 1-Dimensional metamaterial is shown. Under time reversal focusing, peak instantaneous fields at receiver locations are at minimum ˜200% greater than other receivers. We then leverage the strong selective focusing capabilities of the system to show individual and selective powering of light emitting diodes connected to coil receivers placed in the near field of the metamaterial. Our results show the possibility of improving display technologies, near field imaging systems, increasing channel capacity of near field communication systems, and obtaining a greater control of energy delivery in wireless power transfer systems.

  7. Basic Discoveries in Electromagnetic Field Visualization

    NASA Astrophysics Data System (ADS)

    Shindo, Daisuke

    2014-01-01

    Basic discoveries in the electromagnetic field visualization are presented, mentioning the late Dr. A. Tonomura's significant achievements in this field. First, the discovery of the electron biprism interferences by G. Möllenstedt and his colleagues was noted. Having studied Möllenstedt's interference experiments, A. Tonomura and his colleagues have extended the electron holography system to clearly prove the physical reality of vector potentials, the so-called Aharonov-Bohm effect. They also succeeded in observing the dynamic motions of magnetic flux quanta (fluxons) in a superconducting Nb film. In a joint research with A. Tonomura, we succeeded in visualizing a fluxon pinned by an insulating particle in a high-Tc Y-Ba-Cu-O superconductor by combining electron holography and scanning ion microscopy. As the study of a scalar potential, the visualization of the orbits of electron-induced secondary electrons around positively charged biological specimens was noted. Finally, although the electromagnetic field analysis using electron holography on the basis of Maxwell's equations seems to be promising, it is pointed out that there have been some controversies on the interpretation and treatment of electromagnetic field.

  8. Electromagnetic field radiation model for lightning strokes to tall structures

    SciTech Connect

    Motoyama, H.; Janischewskyj, W.; Hussein, A.M.; Chisholm, W.A.; Chang, J.S.; Rusan, R.

    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.

  9. [Safety and electromagnetic compatibility in sanitary field].

    PubMed

    Bini, M; Feroldi, P; Ferri, C; Ignesti, A; Olmi, R; Priori, S; Riminesi, C; Tobia, L

    2012-01-01

    In sanitary field and especially in a hospital, multiple sources of non ionizing radiation are used for diagnostic and therapeutic aims. In sanitary sector both workers and users are present at the same time, and in some cases general population could need higher protection than workers in relationship to the exposition to electromagnetic fields. In order to protect health and safety of patients, general population and workers of hospitals and with the aim to identify, analyze, evaluate and study its level of significance, electrical, magnetic and electromagnetic sources Research Italian project Si.C.E.O. (Safety And Electromagnetic Compatibility In Sanitary Field) was instituted. Target of our research project was to deepen risk of exposition elements with analysis of outdoor (e.g. power lines, transmission cabinets) and indoor (e.g. equipment for physical therapy) sources, located in sanitary structures and to verify the level exposition of workers and common population end the respect of specific regulation, and finally to define technical and organizational measures really useful for protection and reduction of risk.

  10. On electromagnetic field problems in inhomogeneous media

    NASA Technical Reports Server (NTRS)

    Mohsen, A.

    1973-01-01

    Analysis of electromagnetic fields in inhomogeneous media is of practical interest in general scattering and propagation problems and in the study of lenses. For certain types of inhomogeneities, the fields may be represented in terms of two scalars. In a general orthogonal coordinate system, these potentials satisfy second order differential equations. Exact solutions of these equations are known only for a few particular cases and in general, an approximate or numerical technique must be employed. The present work reviews and generalizes some of the main methods of attack of the problem. The results are presented in a form appropriate for numerical computation.

  11. A New Theory of the Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Kriske, Richard

    2017-01-01

    This author has previously introduced a new theory of the Electromagnetic Field and its interaction with matter. There was from the start a problem with Einstein's formulation of Invariants and its use in describing The EM field. The photon produced by first varying a stationary Electric field in one observer's reference frame is not the same as a photon produced from varying the a stationary Magnetic Field. The Magnetic field photon is thought of as being ``off the mass shell''. The Quantum information seems to carry with it an ordering of these events. You see this ordering in Wick's theory and in Feynman diagrams. This author is proposing that other fields can vary first in another Observers reference frame, not just the ``Scalar Field'' or the ``Fermion Field'', but many other forms of Energy. If the ``Nuclear Field'' varies first, it results in Quantum information that produces a photon that has the Nuclear Field in it and also the Magnetic Field, this is the strange effect seen in Nuclear Magnetic Resonance. This author proposed that there is a large number of photons with different properties, because of this ordering of events that occurs in Quantum Information. One of these photons is the Neutrino which appears to be a three field photon. This is Kriske's Field Theory.

  12. Optimization methods in control of electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Angell, Thomas S.; Kleinman, Ralph E.

    1991-05-01

    This program is developing constructive methods for certain constrained optimization problems arising in the design and control of electromagnetic fields and in the identification of scattering objects. The problems addressed fall into three categories: (1) the design of antennas with optimal radiation characteristics measured in terms of directivity; (2) the control of the electromagnetic scattering characteristics of an object, in particular the minimization of its radar cross section, by the choice of material properties; and (3) the determination of the shape of scattering objects with various electromagnetic properties from scattered field data. The main thrust of the program is toward the development of constructive methods based on the use of complete families of solutions of the time-harmonic Maxwell equations in the infinite domain exterior to the radiating or scattering body. During the course of the work an increasing amount of attention has been devoted to the use of iterative methods for the solution of various direct and inverse problems. The continued investigation and development of these methods and their application in parameter identification has become a significant part of the program.

  13. Dynamics of emitting electrons in strong laser fields

    SciTech Connect

    Sokolov, Igor V.; Naumova, Natalia M.; Nees, John A.; Yanovsky, Victor P.; Mourou, Gerard A.

    2009-09-15

    A new derivation of the motion of a radiating electron is given, leading to a formulation that differs from the Lorentz-Abraham-Dirac equation and its published modifications. It satisfies the proper conservation laws. Particularly, it conserves the generalized momentum, eliminating the symmetry-breaking runaway solution. The equation allows a consistent calculation of the electron current, the radiation effect on the electron momentum, and the radiation itself, for a single electron or plasma electrons in strong electromagnetic fields. The equation is then applied to a simulation of a strong laser pulse interaction with a plasma target. Some analytical solutions are also provided.

  14. Self field electromagnetism and quantum phenomena

    NASA Astrophysics Data System (ADS)

    Schatten, Kenneth H.

    1994-07-01

    Quantum Electrodynamics (QED) has been extremely successful inits predictive capability for atomic phenomena. Thus the greatest hope for any alternative view is solely to mimic the predictive capability of quantum mechanics (QM), and perhaps its usefulness will lie in gaining a better understanding of microscopic phenomena. Many ?paradoxes? and problematic situations emerge in QED. To combat the QED problems, the field of Stochastics Electrodynamics (SE) emerged, wherein a random ?zero point radiation? is assumed to fill all of space in an attmept to explain quantum phenomena, without some of the paradoxical concerns. SE, however, has greater failings. One is that the electromagnetic field energy must be infinit eto work. We have examined a deterministic side branch of SE, ?self field? electrodynamics, which may overcome the probelms of SE. Self field electrodynamics (SFE) utilizes the chaotic nature of electromagnetic emissions, as charges lose energy near atomic dimensions, to try to understand and mimic quantum phenomena. These fields and charges can ?interact with themselves? in a non-linear fashion, and may thereby explain many quantum phenomena from a semi-classical viewpoint. Referred to as self fields, they have gone by other names in the literature: ?evanesccent radiation?, ?virtual photons?, and ?vacuum fluctuations?. Using self fields, we discuss the uncertainty principles, the Casimir effects, and the black-body radiation spectrum, diffraction and interference effects, Schrodinger's equation, Planck's constant, and the nature of the electron and how they might be understood in the present framework. No new theory could ever replace QED. The self field view (if correct) would, at best, only serve to provide some understanding of the processes by which strange quantum phenomena occur at the atomic level. We discuss possible areas where experiments might be employed to test SFE, and areas where future work may lie.

  15. [Combined biological effect of electromagnetic fields and chemical substances (toxic)].

    PubMed

    Kamedula, M; Kamedula, T

    1996-01-01

    The authors present results of own measurements and examinations as well as the literature data on the occurrence and effect of direct, low and high frequency electromagnetic fields and chemicals. In real working conditions and in experimental conditions, the following relations can be observed: 1) concomitant occurrence of electromagnetic fields and chemicals, e.g. processes of electrolysis, inductive and dielectric heating; 2) experimental studies of combined effect of electromagnetic fields and chemicals on e.g. cancer development: 3) drug effect modified by electromagnetic fields; 4) effect of chemicals produced in materials under the influence of electromagnetic fields. There are only a few publications on medical examinations of workers exposed simultaneously to electromagnetic fields and chemicals. However, even in those reported studies, an attempt to distinguish changes in the health state due to electromagnetic fields, and due to chemicals has field. The studies of the effect of electromagnetic fields which modify the effect of carcinogenic substances have not yielded unequivocal results. Electromagnetic fields may modify significantly the effect of some psychotropic and hormonal drugs. Under the influence of pyrolisis, induced by thermal effect of electromagnetic fields, toxic substances or substances with harmful biological effect may occur in some materials.

  16. CLASSSTRONG: Classical simulations of strong field processes

    NASA Astrophysics Data System (ADS)

    Ciappina, M. F.; Pérez-Hernández, J. A.; Lewenstein, M.

    2014-01-01

    A set of Mathematica functions is presented to model classically two of the most important processes in strong field physics, namely high-order harmonic generation (HHG) and above-threshold ionization (ATI). Our approach is based on the numerical solution of the Newton-Lorentz equation of an electron moving on an electric field and takes advantage of the symbolic languages features and graphical power of Mathematica. Like in the Strong Field Approximation (SFA), the effects of atomic potential on the motion of electron in the laser field are neglected. The SFA was proven to be an essential tool in strong field physics in the sense that it is able to predict with great precision the harmonic (in the HHG) and energy (in the ATI) limits. We have extended substantially the conventional classical simulations, where the electric field is only dependent on time, including spatial nonhomogeneous fields and spatial and temporal synthesized fields. Spatial nonhomogeneous fields appear when metal nanosystems interact with strong and short laser pulses and temporal synthesized fields are routinely generated in attosecond laboratories around the world. Temporal and spatial synthesized fields have received special attention nowadays because they would allow to exceed considerably the conventional harmonic and electron energy frontiers. Classical simulations are an invaluable tool to explore exhaustively the parameters domain at a cheap computational cost, before massive quantum mechanical calculations, absolutely indispensable for the detailed analysis, are performed.

  17. Giant field enhancement in electromagnetic Helmholtz nanoantenna

    NASA Astrophysics Data System (ADS)

    Chevalier, Paul; Bouchon, Patrick; Greffet, Jean-Jacques; Pelouard, Jean-Luc; Haïdar, Riad; Pardo, Fabrice

    2014-11-01

    Inspired by the acoustic Helmholtz resonator, we propose a slit-box electromagnetic nanoantenna able to concentrate the energy of an incident beam into surfaces a thousand times smaller than with a classical lens. This design produces a giant electric field enhancement throughout the slit. The intensity enhancement reaches 104 in the visible range up to 108 in the THz range even with focused beams, thanks to an omnidirectional reception. These properties could target applications requiring extreme light concentration, such as surface-enhanced infrared absorption, nonlinear optics, and biophotonics.

  18. Biomarkers of induced electromagnetic field and cancer.

    PubMed

    Behari, J; Paulraj, R

    2007-01-01

    The present article delineates the epidemiological and experimental studies of electromagnetic field which affects various tissues of human body. These affects lead to cell proliferation, which may lead to cancer formation. Certain biomarkers have been identified which are one way or the other responsible for tumor promotion or co-promotion. These are (i) melatonin, a hormone secreted by pineal gland, (ii) Ca2+, which is essential in the regulation of the resting membrane potential and in the sequence of events in synaptic excitation and neurotransmitter, release are affected by electromagnetic field, (iii) ornithine decarboxylase (ODC), a rate-limiting enzyme in the biosynthesis of polyamines, considered as a useful biological marker; over expression of ODC can cause cell transformation and enhancement of tumor promotion. (iv) protein kinase is an enzyme, which transfers phosphate groups from ATP to hydroxyl groups in the amino acid chains of acceptor proteins, and (v) Na+-K+ ATPase, which transports sodium and potassium ions across the membrane has a critical role in living cells. The various possible mechanisms depending upon non equilibrium thermodynamics, co-operativism, stochastic and resonance are discussed as possible models of signal transduction in cytosol, thereby controlling the transcription phenomena. Finally a mechanism comprising the extremely low frequency and radio frequency (RF)/microwave (MW) modulated field is compared.

  19. Geometrization conditions for perfect fluids, scalar fields, and electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Torre, Charles; Krongos, Dionisios

    2016-03-01

    The classical Rainich conditions are a system of geometric conditions, expressed purely in terms of the spacetime metric, which are necessary and sufficient for the metric to define a solution to the Einstein-Maxwell equations with a non-null electromagnetic field. We obtain analogous ``geometrization'' conditions for other matter sources. Specifically, we find geometric conditions which are necessary and sufficient for a metric to define a solution to the Einstein equations with a perfect fluid source, and to define a solution to the Einstein-scalar field equations. These conditions work in any dimension, allow for a cosmological constant, and allow for an arbitrary self-interaction potential in the scalar field case. We also generalize the classical Rainich conditions to include a cosmological constant and we obtain geometrization conditions which are applicable to the case of null electromagnetic fields. This work was supported in part by Grant No. OCI-1148331 from the National Science Foundation.

  20. Transient electromagnetic fields near large earthing systems

    SciTech Connect

    Grcev, L.D.; Menter, F.E.

    1996-05-01

    Electromagnetic compatibility studies require knowledge of transient voltages that may be developed near earthing systems during lightning discharge, since such voltages may be coupled to sensitive electronic circuits. For such purpose accurate evaluation of transient electric field near to and/or at the surface of the grounding conductors is necessary. In this paper, a procedure for computation of transient fields near large earthing systems, as a response to a typical lightning current impulse, based on computational methodology developed in the field of antennas, is presented. Computed results are favorably compared with published measurement results. The model is applied to check the common assumption that the soil ionization can be neglected in case of large earthing systems. Presented results show that the soil ionization threshold is met and exceeded during typical lightning discharge in a large earthing system.

  1. Strong transverse fields in delta-spots

    NASA Technical Reports Server (NTRS)

    Zirin, Harold; Wang, Haimin

    1993-01-01

    Spectroscopic measurements of the strength and direction of transverse magnetic fields in six delta-spots are presented. The field direction is determined by the relative strength of the pi- and sigma-components at different polarizer orientations, and is, with one exception, parallel to the neutral line and as strong as the umbral field. Field strengths determined by line splitting are as high as 3980 G.

  2. Strong transverse fields in delta-spots

    NASA Technical Reports Server (NTRS)

    Zirin, Harold; Wang, Haimin

    1993-01-01

    Spectroscopic measurements of the strength and direction of transverse magnetic fields in six delta-spots are presented. The field direction is determined by the relative strength of the pi- and sigma-components at different polarizer orientations, and is, with one exception, parallel to the neutral line and as strong as the umbral field. Field strengths determined by line splitting are as high as 3980 G.

  3. Thermodynamical instabilities under strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Chen, Y. J.

    2017-03-01

    The thermodynamical instabilities of low densities in the n p matter and n p e matter are studied within several relativistic nuclear models under some values of magnetic fields. The results are compared between each other and the effects of the symmetry energy slope at saturation density on the instability are investigated. The instability regions can exhibit bands due to the presence of Landau levels for very strong magnetic fields of the order of 1017 G, while for weaker magnetic fields, the bands are replaced by many diffused or scattered pieces. It also shows that the proton fraction in the inner crust of neutron stars may be complex under strong magnetic fields.

  4. Near-field radiofrequency electromagnetic exposure assessment.

    PubMed

    Rubtsova, Nina; Perov, Sergey; Belaya, Olga; Kuster, Niels; Balzano, Quirino

    2015-09-01

    Personal wireless telecommunication devices, such as radiofrequency (RF) electromagnetic field (EMF) sources operated in vicinity of human body, have possible adverse health effects. Therefore, the correct EMF assessment is necessary in their near field. According to international near-field measurement criteria, the specific absorption rate (SAR) is used for absorbed energy distribution assessment in tissue simulating liquid phantoms. The aim of this investigation is to validate the relationship between the H-field of incident EMF and absorbed energy in phantoms. Three typical wireless telecommunication system frequencies are considered (900, 1800 and 2450 MHz). The EMF source at each frequency is an appropriate half-wave dipole antenna and the absorbing medium is a flat phantom filled with the suitable tissue simulating liquid. Two methods for SAR estimation have been used: standard procedure based on E-field measured in tissue simulating medium and a proposed evaluation by measuring the incident H-field. Compared SAR estimations were performed for various distances between sources and phantom. Also, these research data were compared with simulation results, obtained by using finite-difference time-domain method. The acquired data help to determine the source near-field space characterized by the smallest deviation between SAR estimation methods. So, this region near the RF source is suitable for correct RF energy absorption assessment using the magnetic component of the RF fields.

  5. Electromagnetic fields with vanishing scalar invariants

    NASA Astrophysics Data System (ADS)

    Ortaggio, Marcello; Pravda, Vojtěch

    2016-06-01

    We determine the class of p-forms {\\boldsymbol{F}} that possess vanishing scalar invariants (VSIs) at arbitrary order in an n-dimensional spacetime. Namely, we prove that {\\boldsymbol{F}} is a VSI if and only if if it is of type N, its multiple null direction {\\boldsymbol{\\ell }} is ‘degenerate Kundt’, and {\\pounds }{\\boldsymbol{\\ell }}{\\boldsymbol{F}}=0. The result is theory-independent. Next, we discuss the special case of Maxwell fields, both at the level of test fields and of the full Einstein-Maxwell equations. These describe electromagnetic non-expanding waves propagating in various Kundt spacetimes. We further point out that a subset of these solutions possesses a universal property, i.e. they also solve (virtually) any generalized (non-linear and with higher derivatives) electrodynamics, possibly also coupled to Einstein’s gravity.

  6. Electromagnetic field patterning or crystal light

    NASA Astrophysics Data System (ADS)

    Słupski, Piotr; Wymysłowski, Artur; Czarczyński, Wojciech

    2016-12-01

    Using the orbital angular momentum of light for the development of a vortex interferometer, the underlying physics requires microwave/RF models,1 as well as quantum mechanics for light1, 2 and fluid flow for semiconductor devices.3, 4 The combination of the aforementioned physical models yields simulations and results such as optical lattices,1 or an Inverse Farday effect.5 The latter is explained as the absorption of optical angular momentum, generating extremely high instantenous magnetic fields due to radiation friction. An algorithmic reduction across the computational methods used in microwaves, lasers, quantum optics and holography is performed in order to explain electromagnetic field interactions in a single computational framework. This work presents a computational model for photon-electron interactions, being a simplified gauge theory described using differentials or disturbances (photons) instead of integrals or fields. The model is based on treating the Z-axis variables as a Laplace fluid with spatial harmonics, and the XY plane as Maxwell's equations on boundaries. The result is a unified, coherent, graphical computational method of describing the photon qualitatively, quantitatively and with proportion. The model relies on five variables and is described using two equations, which use emitted power, cavity wavelength, input frequency, phase and time. Phase is treated as a rotated physical dimension under gauge theory of Feynmann's QED. In essence, this model allows the electromagnetic field to be treated with it's specific crystallography. The model itself is described in Python programming language. PACS 42.50.Pq, 31.30.J-, 03.70.+k, 11.10.-z, 67.10.Hk

  7. On Acceptable Exposures to Short Pulses of Electromagnetic Fields

    DTIC Science & Technology

    2015-09-01

    NAWCWD TP 8791 On Acceptable Exposures to Short Pulses of Electromagnetic Fields by Francis X. Canning, PhD Physics...prepared in response to a request to study the effects of exposure to short pulses of electromagnetic fields. The author is a physicist at the Naval... Exposures to Short Pulses of Electromagnetic Fields (U) 5a. CONTRACT NUMBER N/A 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER N/A 6. AUTHOR(S

  8. Evaluation of uncertainty in the measurement of environmental electromagnetic fields.

    PubMed

    Vulević, B; Osmokrović, P

    2010-09-01

    With regard to Non-ionising radiation protection, the relationship between human exposure to electromagnetic fields and health is controversial. Electromagnetic fields have become omnipresent in the daily environment. This paper assesses the problem of how to compare a measurement result with a limit fixed by the standard for human exposure to electric, magnetic and electromagnetic fields (0 Hz-300 GHz). The purpose of the paper is an appropriate representation of the basic information about evaluation of measurement uncertainty.

  9. Decay of Resonaces in Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Filip, Peter

    2015-08-01

    We suggest that decay properties (branching ratios) of hadronic resonances may become modified in strong external magnetic field. The behavior of K±*, K0* vector mesons as well as Λ* (1520) and Ξ0* baryonic states is considered in static fields 1013-1015 T. In particular, n = 0 Landau level energy increase of charged particles in the external magnetic field, and the interaction of hadron magnetic moments with the field is taken into account. We suggest that enhanced yield of dileptons and photons from ρ0(770) mesons may occur if strong decay channel ρ0 → π+π- is significantly suppressed. CP - violating π+π- decays of pseudoscalar ηc and η(547) mesons in the magnetic field are discussed, and superpositions of quarkonium states ηc,b and χc,b(nP) with Ψ(nS), ϒ(nS) mesons in the external field are considered.

  10. On refractive processes in strong laser field quantum electrodynamics

    SciTech Connect

    Di Piazza, A.

    2013-11-15

    Refractive processes in strong-field QED are pure quantum processes, which involve only external photons and the background electromagnetic field. We show analytically that such processes occurring in a plane-wave field and involving external real photons are all characterized by a surprisingly modest net exchange of energy and momentum with the laser field, corresponding to a few laser photons, even in the limit of ultra-relativistic laser intensities. We obtain this result by a direct calculation of the transition matrix element of an arbitrary refractive QED process and accounting exactly for the background plane-wave field. A simple physical explanation of this modest net exchange of laser photons is provided, based on the fact that the laser field couples with the external photons only indirectly through virtual electron–positron pairs. For stronger and stronger laser fields, the pairs cover a shorter and shorter distance before they annihilate again, such that the laser can transfer to them an energy corresponding to only a few photons. These results can be relevant for the future experiments aiming to test strong-field QED at present and next-generation facilities. -- Highlights: •Investigation of the one-loop amplitude of refractive QED processes in a laser field. •The amplitude is suppressed for a large number of net-exchanged laser photons. •Suggestion for first observation of high-nonlinear vacuum effects in a laser field.

  11. Strong intrinsic mixing in vortex magnetic fields.

    PubMed

    Martin, James E; Shea-Rohwer, Lauren; Solis, Kyle J

    2009-07-01

    We report a method of magnetic mixing wherein a "vortex" magnetic field applied to a suspension of magnetic particles creates strong homogeneous mixing throughout the fluid volume. Experiments designed to elucidate the microscopic mechanism of mixing show that the torque is quadratic in the field, decreases with field frequency, and is optimized at a vortex field angle of approximately 55 degrees . Theory and simulations indicate that the field-induced formation of volatile particle chains is responsible for these phenomena. This technique has applications in microfluidic devices and is ideally suited to applications such as accelerating the binding of target biomolecules to biofunctionalized magnetic microbeads.

  12. Strongly interacting phases of metallic wires in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Bulmash, Daniel; Jian, Chao-Ming; Qi, Xiao-Liang

    2017-07-01

    We investigate theoretically an interacting metallic wire with a strong magnetic field directed along its length and show that it is a highly tunable one-dimensional system. By considering a suitable change in spatial geometry, we build an analogy between the problem in the zeroth Landau level with Landau level degeneracy N to one-dimensional fermions with an N -component pseudospin degree of freedom and S U (2 ) -symmetric interactions. This analogy allows us to establish the phase diagram as a function of the interactions for small N (and make conjectures for large N ) using renormalization group and bosonization techniques. We find pseudospin-charge separation with a gapless U (1 ) charge sector and several possible strong-coupling phases in the pseudospin sector. For odd N , we find a fluctuating pseudospin-singlet charge density wave phase and a fluctuating pseudospin-singlet superconducting phase which are topologically distinct. For even N >2 , similar phases exist, although they are not topologically distinct, and an additional novel pseudospin-gapless phase appears. We discuss experimental conditions for observing our proposals.

  13. Optical field enhancement by strong plasmon interaction in graphene nanostructures.

    PubMed

    Thongrattanasiri, Sukosin; García de Abajo, F Javier

    2013-05-03

    The ability of plasmons to enhance the electromagnetic field intensity in the gap between metallic nanoparticles derives from their strong optical confinement relative to the light wavelength. The spatial extension of plasmons in doped graphene has recently been shown to be boldly reduced with respect to conventional plasmonic metals. Here, we show that graphene nanostructures are capable of capitalizing such strong confinement to yield unprecedented levels of field enhancement, well beyond what is found in noble metals of similar dimensions (~ tens of nanometers). We perform realistic, quantum-mechanical calculations of the optical response of graphene dimers formed by nanodisks and nanotriangles, showing a strong sensitivity of the level of enhancement to the type of carbon edges near the gap region, with armchair edges favoring stronger interactions than zigzag edges. Our quantum-mechanical description automatically incorporates nonlocal effects that are absent in classical electromagnetic theory, leading to over an order of magnitude higher enhancement in armchair structures. The classical limit is recovered for large structures. We predict giant levels of light concentration for dimers ~200 nm, leading to infrared-absorption enhancement factors ~10(8). This extreme light enhancement and confinement in nanostructured graphene has great potential for optical sensing and nonlinear devices.

  14. Plant Responses to High Frequency Electromagnetic Fields

    PubMed Central

    Vian, Alain; Davies, Eric; Gendraud, Michel; Bonnet, Pierre

    2016-01-01

    High frequency nonionizing electromagnetic fields (HF-EMF) that are increasingly present in the environment constitute a genuine environmental stimulus able to evoke specific responses in plants that share many similarities with those observed after a stressful treatment. Plants constitute an outstanding model to study such interactions since their architecture (high surface area to volume ratio) optimizes their interaction with the environment. In the present review, after identifying the main exposure devices (transverse and gigahertz electromagnetic cells, wave guide, and mode stirred reverberating chamber) and general physics laws that govern EMF interactions with plants, we illustrate some of the observed responses after exposure to HF-EMF at the cellular, molecular, and whole plant scale. Indeed, numerous metabolic activities (reactive oxygen species metabolism, α- and β-amylase, Krebs cycle, pentose phosphate pathway, chlorophyll content, terpene emission, etc.) are modified, gene expression altered (calmodulin, calcium-dependent protein kinase, and proteinase inhibitor), and growth reduced (stem elongation and dry weight) after low power (i.e., nonthermal) HF-EMF exposure. These changes occur not only in the tissues directly exposed but also systemically in distant tissues. While the long-term impact of these metabolic changes remains largely unknown, we propose to consider nonionizing HF-EMF radiation as a noninjurious, genuine environmental factor that readily evokes changes in plant metabolism. PMID:26981524

  15. Properties of electromagnetic field focusing probe.

    PubMed

    Yamanashi, W S; Yassa, N A; Hill, D L; Patil, A A; Lester, P D

    1988-11-01

    The electromagnetic field focusing (EFF) apparatus consists of a radio frequency generator, solenoidal coil, and a hand-held or catheter probe. Applications such as aneurysm treatment, angioplasty, and neurosurgery in various models have been reported. The probe is operated in the near field (within one wavelength of an electromagnetic field source) of a coil inducing eddy currents in biological tissues, producing maximal convergence of the induced current at the probe tip. The probe produces very high temperatures depending on the wattage selected for the given radio frequency of output power. The high temperature can be used in cutting, cauterizing, or vaporizing. The EFF probe is comparable to different types of lasers and to bipolar and monopolar cautery. The EFF probe can be used with catheters or endoscopes. Objectives of this study were to determine what the thermal properties of the EFF probe are and how instrument parameters can be varied to obtain different temperatures in the tissue near the probe tip. In this study an F2 catheter was used as an insulated sheath and the tip of the guide wire was used as the probe tip. Different powers, wave forms, coil-to-probe distances, and probe-tip lengths were tested on a phantom that simulates tissue electrical properties. Some of the experiments were conducted under normal saline to simulate treatment of tissue with body fluids such as blood vessels or brain tissue under normal physiologic conditions. It is concluded that the EFF probe has the advantages of easy manipulation, relative safety, cost effectiveness, and a high degree of spatial control.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Radiation from electrons in graphene in strong electric field

    SciTech Connect

    Yokomizo, N.

    2014-12-15

    We study the interaction of electrons in graphene with the quantized electromagnetic field in the presence of an applied uniform electric field using the Dirac model of graphene. Electronic states are represented by exact solutions of the Dirac equation in the electric background, and amplitudes of first-order Feynman diagrams describing the interaction with the photon field are calculated for massive Dirac particles in both valleys. Photon emission probabilities from a single electron and from a many-electron system at the charge neutrality point are derived, including the angular and frequency dependence, and several limiting cases are analyzed. The pattern of photon emission at the Dirac point in a strong field is determined by an interplay between the nonperturbative creation of electron–hole pairs and spontaneous emission, allowing for the possibility of observing the Schwinger effect in measurements of the radiation emitted by pristine graphene under DC voltage.

  17. Introduction to gauge theories of the strong, weak, and electromagnetic interactions

    SciTech Connect

    Quigg, C.

    1980-07-01

    The plan of these notes is as follows. Chapter 1 is devoted to a brief evocative review of current beliefs and prejudices that form the context for the discussion to follow. The idea of Gauge Invariance is introduced in Chapter 2, and the connection between conservation laws and symmetries of the Lagrangian is recalled. Non-Abelian gauge field theories are constructed in Chapter 3, by analogy with the familiar case of electromagnetism. The Yang-Mills theory based upon isospin symmetry is constructed explicitly, and the generalization is made to other gauge groups. Chapter 4 is concerned with spontaneous symmetry breaking and the phenomena that occur in the presence or absence of local gauge symmetries. The existence of massless scalar fields (Goldstone particles) and their metamorphosis by means of the Higgs mechanism are illustrated by simple examples. The Weinberg-Salam model is presented in Chapter 5, and a brief resume of applications to experiment is given. Quantum Chromodynamics, the gauge theory of colored quarks and gluons, is developed in Chapter 6. Asymptotic freedom is derived schematically, and a few simple applications of perturbative QCD ae exhibited. Details of the conjectured confinement mechanism are omitted. The strategy of grand unified theories of the strong, weak, and electromagnetic interactions is laid out in Chapter 7. Some properties and consequences of the minimal unifying group SU(5) are presented, and the gauge hierarchy problem is introduced in passing. The final chapter contains an essay on the current outlook: aspirations, unanswered questions, and bold scenarios.

  18. The electromagnetic field equations for moving media

    NASA Astrophysics Data System (ADS)

    Ivezić, T.

    2017-05-01

    In this paper a formulation of the field equation for moving media is developed by the generalization of an axiomatic geometric formulation of the electromagnetism in vacuum (Ivezić T 2005 Found. Phys. Lett. 18 401). First, the field equations with bivectors F (x) and ℳ(x) are presented and then these equations are written with the 4D vectors E(x), B(x), P (x) and M(x). The latter contain both the 4D velocity vector u of a moving medium and the 4D velocity vector v of the observers who measure E and B fields. They do not appear in previous literature. All these equations are also written in the standard basis and compared with Maxwell’s equations with 3D vectors. In this approach the Ampère-Maxwell law and Gauss’s law are inseparably connected in one law and the same happens with Faraday’s law and the law that expresses the absence of magnetic charge. It is shown that Maxwell’s equations with 3D vectors and the field equations with 4D geometric quantities are not equivalent in 4D spacetime

  19. Visualizing electromagnetic fields in metals by MRI

    NASA Astrophysics Data System (ADS)

    Chandrashekar, Chandrika Sefcikova; Shellikeri, Annadanesh; Chandrashekar, S.; Taylor, Erika A.; Taylor, Deanne M.

    2017-02-01

    Based upon Maxwell's equations, it has long been established that oscillating electromagnetic (EM) fields incident upon a metal surface, decay exponentially inside the conductor, leading to a virtual absence of EM fields at sufficient depths. Magnetic resonance imaging (MRI) utilizes radiofrequency (r.f.) EM fields to produce images. Here we present a visualization of a virtual EM vacuum inside a bulk metal strip by MRI, amongst several findings. At its simplest, an MRI image is an intensity map of density variations across voxels (pixels) of identical size (=Δ x Δ y Δ z ). By contrast in bulk metal MRI, we uncover that despite uniform density, intensity variations arise from differing effective elemental volumes (voxels) from different parts of the bulk metal. Further, we furnish chemical shift imaging (CSI) results that discriminate different faces (surfaces) of a metal block according to their distinct nuclear magnetic resonance (NMR) chemical shifts, which holds much promise for monitoring surface chemical reactions noninvasively. Bulk metals are ubiquitous, and MRI is a premier noninvasive diagnostic tool. Combining the two, the emerging field of bulk metal MRI can be expected to grow in importance. The findings here may impact further development of bulk metal MRI and CSI.

  20. Above-threshold ionization in two electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Bardfield, Rina Shoshana

    1997-11-01

    Above-threshold ionization (ATI) is a process in which a target atom absorbs more than the minimum number of photons from an applied electromagnetic field than are required for ionization, and is characterized by several peaks in the photoelectron spectrum which are separated from each other by the energy of a single photon (Agostini et al. 1979). The experiments of interest in this work involve ATI at microwave frequencies (Gallagher 1988, Gallagher and Scholz 1989), where the frequency of the field is too low to be able to see individual peaks in the spectrum. What is seen is that, in the presence of a weak assisting field, a very large number of microwave photons are absorbed. This problem cannot be treated using standard methods, due both to the intensity of the microwave field and to the large numbers of photons absorbed. The focus of this work is on the development of new analytical techniques to examine the interaction of an atomic system with two simultaneous electromagnetic fields. Specifically, the work focuses on above-threshold ionization in combined microwave and laser fields, where the microwave field is a very strong, very low frequency field, so that standard techniques, such as perturbation theory, do not apply. The work is based on two theoretical methods especially designed for use in intense field problems. These are the Strong Field Approximation (SFA) (Reiss 1980, 1992, 1996), which describes the ionization of an atom by an intense field in which the detached electron remains free in the field after ionization occurs, and the Momentum Translation Approximation (MTA) (Reiss 1970a, 1970b, 1989), which describes the dressing of a bound atomic state by a strong field in which the field can alter the state of the electron without necessarily causing transitions. The laser field, which is much weaker, is treated by traditional techniques. The theory is developed in general terms using S-matrix methods, with particular cases being modeled using

  1. Inelastic deformation of conductive bodies in electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Altenbach, Holm; Morachkovsky, Oleg; Naumenko, Konstantin; Lavinsky, Denis

    2016-09-01

    Inelastic deformation of conductive bodies under the action of electromagnetic fields is analyzed. Governing equations for non-stationary electromagnetic field propagation and elastic-plastic deformation are presented. The variational principle of minimum of the total energy is applied to formulate the numerical solution procedure by the finite element method. With the proposed method, distributions of vector characteristics of the electromagnetic field and tensor characteristics of the deformation process are illustrated for the inductor-workpiece system within a realistic electromagnetic forming process.

  2. Mortality in workers exposed to electromagnetic fields.

    PubMed Central

    Milham, S

    1985-01-01

    In an occupational mortality analysis of 486,000 adult male death records filed in Washington State in the years 1950-1982, leukemia and the non-Hodgkin's lymphomas show increased proportionate mortality ratios (PMRs) in workers employed in occupations with intuitive exposures to electromagnetic fields. Nine occupations of 219 were considered to have electric or magnetic field exposures. These were: electrical and electronic technicians, radio and telegraph operators, radio and television repairmen, telephone and power linemen, power station operators, welders, aluminum reduction workers, motion picture projectionists and electricians. There were 12,714 total deaths in these occupations. Eight of the nine occupations had PMR increases for leukemia [International Classification of Diseases (ICD), seventh revision 204] and seven of the nine occupations had PMR increases for the other lymphoma category (7th ICD 200.2, 202). The highest PMRs were seen for acute leukemia: (67 deaths observed, 41 deaths expected; PMR 162), and in the other lymphomas (51 deaths observed, 31 deaths expected; PMR 164). No increase in mortality was seen for Hodgkin's disease or multiple myeloma. These findings offer some support for the hypothesis that electric and magnetic fields may be carcinogenic. PMID:4085433

  3. Mortality in workers exposed to electromagnetic fields

    SciTech Connect

    Milham, S. Jr.

    1985-10-01

    In an occupational mortality analysis of 486,000 adult male death records filed in Washington State in the years 1950-1982, leukemia and the non-Hodgkin's lymphomas show increased proportionate mortality ratios (PMRs) in workers employed in occupations with intuitive exposures to electromagnetic fields. Nine occupations of 219 were considered to have electric or magnetic field exposures. These were: electrical and electronic technicians, radio and telegraph operators, radio and television repairmen, telephone and power linemen, power station operators, welders, aluminum reduction workers, motion picture projectionists and electricians. There were 12,714 total deaths in these occupations. Eight of the nine occupations had PMR increases for leukemia (International Classification of Diseases (ICD), seventh revision 204) and seven of the nine occupations had PMR increases for the other lymphoma category (7th ICD 200.2, 202). The highest PMRs were seen for acute leukemia: (67 deaths observed, 41 deaths expected; PMR 162), and in the other lymphomas (51 deaths observed, 31 deaths expected; PMR 164). No increase in mortality was seen for Hodgkin's disease or multiple myeloma. These findings offer some support for the hypothesis that electric and magnetic fields may be carcinogenic.

  4. Electromagnetic polarizabilities: Lattice QCD in background fields

    SciTech Connect

    W. Detmold, B.C. Tiburzi, A. Walker-Loud

    2012-04-01

    Chiral perturbation theory makes definitive predictions for the extrinsic behavior of hadrons in external electric and magnetic fields. Near the chiral limit, the electric and magnetic polarizabilities of pions, kaons, and nucleons are determined in terms of a few well-known parameters. In this limit, hadrons become quantum mechanically diffuse as polarizabilities scale with the inverse square-root of the quark mass. In some cases, however, such predictions from chiral perturbation theory have not compared well with experimental data. Ultimately we must turn to first principles numerical simulations of QCD to determine properties of hadrons, and confront the predictions of chiral perturbation theory. To address the electromagnetic polarizabilities, we utilize the background field technique. Restricting our attention to calculations in background electric fields, we demonstrate new techniques to determine electric polarizabilities and baryon magnetic moments for both charged and neutral states. As we can study the quark mass dependence of observables with lattice QCD, the lattice will provide a crucial test of our understanding of low-energy QCD, which will be timely in light of ongoing experiments, such as at COMPASS and HI gamma S.

  5. Electromagnetic fields and male breast cancer.

    PubMed

    Tynes, T

    1993-01-01

    The aetiology of male breast cancer is still considered to be rather unclear. Epidemiological studies have recently shown an excess risk of male breast cancer in "electrical workers" with potential exposure to electromagnetic (EM) fields. Interest on the possible association between pineal function and breast cancer has come into focus. The pineal hormone melatonin has been shown to reduce the incidence of experimentally-induced breast cancer in rats, the hormone is oncostatic and cytotoxic to breast, ovarian, and bladder cancer cell lines in vitro. Treatment of cancer patients with orally administered melatonin has been tried. Pineal function in humans is suppressed by light-at-night (LAN). Animal studies have shown that exposure to 60-Hz electric fields may also suppress the nocturnal rise in pineal melatonin production in adult rats. Breast cancer is the leading cause of cancer death among women in industrialised world. No good explanation has so far been provided for the increased incidence of this site during the last decades, although changes in fertility factors have had some effect. If new epidemiological and experimental data give support to the hypothesis that exposure to LAN and EM fields may increase breast cancer risk, this may have regulatory and political consequences for future use of electric power.

  6. MRS photodiode in strong magnetic field

    SciTech Connect

    Beznosko, D.; Blazey, G.; Dyshkant, A.; Francis, K.; Kubik, D.; Rykalin, V.; Tartaglia, M.A.; Zutshi, v.; /Northern Illinois U.

    2004-12-01

    The experimental results on the performance of the MRS (Metal/Resistor/Semiconductor) photodiode in the strong magnetic field of 4.4T, and the possible impact of the quench of the magnet at 4.5T on sensor's operation are reported.

  7. Charm production in a strong magnetic field

    SciTech Connect

    Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G. de; Strickland, M.

    2014-11-11

    We discuss the effects of a strong magnetic field on B and D mesons, focusing on the changes of the energy levels and the masses of the bound states. Using the Color Evaporation Model we discuss the possible changes in the production of J/ψ and Υ. We briefly comment the recent experimental data.

  8. Electromagnetic field at finite temperature: A first order approach

    NASA Astrophysics Data System (ADS)

    Casana, R.; Pimentel, B. M.; Valverde, J. S.

    2006-10-01

    In this work we study the electromagnetic field at finite temperature via the massless DKP formalism. The constraint analysis is performed and the partition function for the theory is constructed and computed. When it is specialized to the spin 1 sector we obtain the well-known result for the thermodynamic equilibrium of the electromagnetic field.

  9. Electromagnetically induced transparency in modulated laser fields

    NASA Astrophysics Data System (ADS)

    Jiao, Yuechun; Yang, Zhiwei; Zhang, Hao; Zhang, Linjie; Raithel, Georg; Zhao, Jianming; Jia, Suotang

    2017-02-01

    We study electromagnetically induced transparency (EIT) in a room-temperature cesium vapor cell using wavelength-modulated probe laser light. In the utilized cascade level scheme, the probe laser drives the lower transition 6S {}1/2(F = 4) → 6P {}3/2 (F’ = 5), while the coupling laser drives the Rydberg transition 6P {}3/2 → 57S {}1/2. The probe laser has a fixed average frequency and is modulated at a frequency of a few kHz, with a variable modulation amplitude in the range of tens of MHz. The probe transmission is measured as a function of the detuning of the coupling laser from the Rydberg resonance. The first-harmonic demodulated EIT signal has two peaks that are, in the case of large modulation amplitude, separated by the peak-to-peak modulation amplitude of the probe laser times a scaling factor {λ }{{p}}/{λ }{{c}}, where {λ }{{p}} and {λ }{{c}} are the probe- and coupling-laser wavelengths. The scaling factor is due to Doppler shifts in the EIT geometry. Second-harmonic demodulated EIT signals, obtained with small modulation amplitudes, yield spectral lines that are much narrower than corresponding lines in the modulation-free EIT spectra. The resultant spectroscopic resolution enhancement is conducive to improved measurements of radio-frequency (RF) fields based on Rydberg-atom EIT, an approach in which the response of Rydberg atoms to RF fields is exploited to characterize RF fields. Here, we employ wavelength modulation spectroscopy to reduce the uncertainty of atom-based frequency and field measurement of an RF field in the VHF radio band.

  10. 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.

  11. Photoneutrino energy losses in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Previously computed rates of energy losses (Petrosian et al., 1967) ignored the presence of strong magnetic fields, hence the change brought in when such a field (about 10 to the 12th to 10 to the 13th power G) is included is studied. The results indicate that for T about 10 to the 8th power K and densities rho of about 10,000 g/cu cm, the presence of a strong H field decreases the energy losses by at the most a factor between 10 and 100 in the region up to rho = 1,000,000 g/cu cm. At higher densities the neutrino emissivities are almost identical.

  12. Firefly flashing under strong static magnetic field.

    PubMed

    Barua, Anurup Gohain; Iwasaka, Masakazu; Miyashita, Yuito; Kurita, Satoru; Owada, Norio

    2012-02-01

    Firefly flashing has been the subject of numerous scientific investigations. Here we present in vivo flashes from male specimens of three species of fireflies-two Japanese species Luciola cruciata, Luciola lateralis and one Indian species Luciola praeusta-positioned under a superconducting magnet. When the OFF state of the firefly becomes long after flashing in an immobile state under the strong static magnetic field of strength 10 Tesla for a long time, which varies widely from species to species as well as from specimen to specimen, the effect of the field becomes noticeable. The flashes in general are more rapid, and occasionally overlap to produce broad compound flashes. We present the broadest flashes recorded to date, and propose that the strong static magnetic field affects the neural activities of fireflies, especially those in the spent up or 'exhausted' condition.

  13. Photoneutrino energy losses in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Previously computed rates of energy losses (Petrosian et al., 1967) ignored the presence of strong magnetic fields, hence the change brought in when such a field (about 10 to the 12th to 10 to the 13th power G) is included is studied. The results indicate that for T about 10 to the 8th power K and densities rho of about 10,000 g/cu cm, the presence of a strong H field decreases the energy losses by at the most a factor between 10 and 100 in the region up to rho = 1,000,000 g/cu cm. At higher densities the neutrino emissivities are almost identical.

  14. Molecular systems in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Turbiner, Alexander V.

    2007-04-01

    Brief overview of one-two electron molecular systems made out of protons and/or α-particles in a strong magnetic field B≤4.414×1013 G is presented. A particular emphasis is given to the one-electron exotic ions H 3 ++ (pppe), He 2 3+ (α α e) and to two-electron ionsH 3 + (pppee), He 2 ++ (α α ee). Quantitative studies in a strong magnetic field are very complicated technically. Novel approach to the few-electron Coulomb systems in magnetic field, which provides accurate results, based on variational calculus with physically relevant trial functions is briefly described.

  15. 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.

  16. Fluxes of electromagnetic field energy in HTSC transformers

    NASA Astrophysics Data System (ADS)

    Volkov, E. P.; Dzhafarov, E. A.

    2016-12-01

    The transfer of electric power in an HTSC electromagnetic system is considered using the Poynting vector. An analysis of the process of transfer of electromagnetic field energy in HTSC transformers with and without an iron core is given. It is shown that the power of an HTSC transformer increases when its magnetic core is made from amorphous electrical steel. Schemes of HTSC transformers with a localized magnetic field are given with cylindrical and disk symmetrical interleaved windings providing the cost-saving process of transfer of large electromagnetic energy at a high degree of its uniformity and improve the factor of nonuniformity of electromagnetic flux density.

  17. Electromagnetic Fields, Oxidative Stress, and Neurodegeneration

    PubMed Central

    Consales, Claudia; Merla, Caterina; Marino, Carmela; Benassi, Barbara

    2012-01-01

    Electromagnetic fields (EMFs) originating both from both natural and manmade sources permeate our environment. As people are continuously exposed to EMFs in everyday life, it is a matter of great debate whether they can be harmful to human health. On the basis of two decades of epidemiological studies, an increased risk for childhood leukemia associated with Extremely Low Frequency fields has been consistently assessed, inducing the International Agency for Research on Cancer to insert them in the 2B section of carcinogens in 2001. EMFs interaction with biological systems may cause oxidative stress under certain circumstances. Since free radicals are essential for brain physiological processes and pathological degeneration, research focusing on the possible influence of the EMFs-driven oxidative stress is still in progress, especially in the light of recent studies suggesting that EMFs may contribute to the etiology of neurodegenerative disorders. This review synthesizes the emerging evidences about this topic, highlighting the wide data uncertainty that still characterizes the EMFs effect on oxidative stress modulation, as both pro-oxidant and neuroprotective effects have been documented. Care should be taken to avoid methodological limitations and to determine the patho-physiological relevance of any alteration found in EMFs-exposed biological system. PMID:22991514

  18. Thermonuclear fusion in a strong laser field

    NASA Astrophysics Data System (ADS)

    Krainov, V. P.

    2014-08-01

    Thermonuclear fusion induced by the irradiation of solid deuterated cluster targets and foils with fields of strong femtosecond and picosecond laser pulses is discussed. The thermonuclear-fusion process D( d, n)3He in a collision of two deuterons at an energy of 50 to 100 keV in a deuterium cluster target irradiated with a strong laser pulse is discussed. A theory of thermonuclear fusion proceeding upon the irradiation of clusters formed by deuterium iodide (DI) molecules with the field of a superintense femtosecond laser pulse is developed. This theory is based on an above-barrier process in which the sequential multiple inner ionization of atomic ions within a cluster is accompanied by field-induced outer ionization. The yield of neutrons from thermonuclear fusion in a deuteron-deuteron collision after the completion of a laser pulse is calculated. The yield of neutrons is determined for the thermonuclear-fusion reaction proceeding in the interaction of an intense picosecond laser pulse with thin TiD2 foils. A multiple ionization of titanium atoms at the front edge of the laser pulse is considered. The heating of free electron occurs in induced inverse bremsstrahlung in the process of electron scattering on multiply charged titanium ions. The yield of alpha particles in the thermonuclear-fusion reaction involving protons and 11B nuclei that is induced in microdrops by a strong laser field is determined. Experimental data on laser-induced thermonuclear fusion are discussed.

  19. Anomalous electrodynamics of neutral pion matter in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Brauner, Tomáš; Kadam, Saurabh V.

    2017-03-01

    The ground state of quantum chromodynamics in sufficiently strong external magnetic fields and at moderate baryon chemical potential is a chiral soliton lattice (CSL) of neutral pions [1]. We investigate the interplay between the CSL structure and dynamical electromagnetic fields. Our main result is that in presence of the CSL background, the two physical photon polarizations and the neutral pion mix, giving rise to two gapped excitations and one gapless mode with a nonrelativistic dispersion relation. The nature of this mode depends on the direction of its propagation, interpolating between a circularly polarized electromagnetic wave [2] and a neutral pion surface wave, which in turn arises from the spontaneously broken translation invariance. Quite remarkably, there is a neutral-pion-like mode that remains gapped even in the chiral limit, in seeming contradiction to the Goldstone theorem. Finally, we have a first look at the effect of thermal fluctuations of the CSL, showing that even the soft nonrelativistic excitation does not lead to the Landau-Peierls instability. However, it leads to an anomalous contribution to pressure that scales with temperature and magnetic field as T 5/2( B/f π )3/2.

  20. Deterministic strong-field quantum control

    NASA Astrophysics Data System (ADS)

    Cavaletto, Stefano M.; Harman, Zoltán; Pfeifer, Thomas; Keitel, Christoph H.

    2017-04-01

    Strong-field quantum-state control is investigated, taking advantage of the full—amplitude and phase—characterization of the interaction between matter and intense ultrashort pulses via transient-absorption spectroscopy. As an example, we apply the method to a nondegenerate V -type three-level system modeling atomic Rb, and use a sequence of intense delayed pulses, whose parameters are tailored to steer the system into a desired quantum state. We show how to experimentally enable this optimization by retrieving all quantum features of the light-matter interaction from observable spectra. This provides a full characterization of the action of strong fields on the atomic system, including the dependence upon possibly unknown pulse properties and atomic structures. Precision and robustness of the scheme are tested, in the presence of surrounding atomic levels influencing the system's dynamics.

  1. Theory of a ring laser. [electromagnetic field and wave equations

    NASA Technical Reports Server (NTRS)

    Menegozzi, L. N.; Lamb, W. E., Jr.

    1973-01-01

    Development of a systematic formulation of the theory of a ring laser which is based on first principles and uses a well-known model for laser operation. A simple physical derivation of the electromagnetic field equations for a noninertial reference frame in uniform rotation is presented, and an attempt is made to clarify the nature of the Fox-Li modes for an open polygonal resonator. The polarization of the active medium is obtained by using a Fourier-series method which permits the formulation of a strong-signal theory, and solutions are given in terms of continued fractions. It is shown that when such a continued fraction is expanded to third order in the fields, the familiar small-signal ring-laser theory is obtained.

  2. Theory of a ring laser. [electromagnetic field and wave equations

    NASA Technical Reports Server (NTRS)

    Menegozzi, L. N.; Lamb, W. E., Jr.

    1973-01-01

    Development of a systematic formulation of the theory of a ring laser which is based on first principles and uses a well-known model for laser operation. A simple physical derivation of the electromagnetic field equations for a noninertial reference frame in uniform rotation is presented, and an attempt is made to clarify the nature of the Fox-Li modes for an open polygonal resonator. The polarization of the active medium is obtained by using a Fourier-series method which permits the formulation of a strong-signal theory, and solutions are given in terms of continued fractions. It is shown that when such a continued fraction is expanded to third order in the fields, the familiar small-signal ring-laser theory is obtained.

  3. Field-dressed orbitals in strong-field molecular ionization

    NASA Astrophysics Data System (ADS)

    Siemering, Robert; Njoya, Oumarou; Weinacht, Thomas; de Vivie-Riedle, Regina

    2015-10-01

    We demonstrate the importance of considering the shape of field-dressed molecular orbitals in interpreting angle-dependent measures of strong-field ionization from excited states. Our calculations of angle-dependent ionization for three homologous polyatomic molecules with very similar valence orbitals show that one has to take into account the shape of the field-dressed orbitals rather than the field-free orbitals in order to rationalize the experimental measurements.

  4. 78 FR 33654 - Reassessment of Exposure to Radiofrequency Electromagnetic Fields Limits and Policies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-04

    ... Electromagnetic Fields Limits and Policies AGENCY: Federal Communications Commission. ACTION: Proposed rule... 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...

  5. Interpreting marine controlled source electromagnetic field behaviour with streamlines

    NASA Astrophysics Data System (ADS)

    Pethick, A. M.; Harris, B. D.

    2013-10-01

    Streamlines represent particle motion within a vector field as a single line structure and have been used in many areas of geophysics. We extend the concept of streamlines to interactive three dimensional representations of the coupled vector fields generated during marine controlled source electromagnetic surveys. These vector fields have measurable amplitudes throughout many hundreds of cubic kilometres. Electromagnetic streamline representation makes electromagnetic interactions within complex geo-electrical setting comprehensible. We develop an interface to rapidly compute and interactively visualise the electric and magnetic fields as streamlines for 3D marine controlled source electromagnetic surveys. Several examples highlighting how interactive use has value in marine controlled source electromagnetic survey design, interpretation and teaching are provided. The first videos of electric, magnetic and Poynting vector field streamlines are provided along with the first published example of the airwave represented as streamlines. We demonstrate that the electric field airwave is a circulating vortex moving down and out from the air-water interface towards the ocean floor. The use of interactive streamlines is not limited to marine controlled source electromagnetic methods. Streamlines provides a high level visualisation tool for interpreting the electric and magnetic field behaviour generated by a wide range of electromagnetic survey configurations for complex 3D geo-electrical settings.

  6. Bound states in a strong magnetic field

    SciTech Connect

    Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G.; Ferreira Filho, L. G.

    2013-03-25

    We expect a strong magnetic field to be produced in the perpendicular direction to the reaction plane, in a noncentral heavy-ion collision . The strength of the magnetic field is estimated to be eB{approx}m{sup 2}{sub {pi}}{approx} 0.02 GeV{sup 2} at the RHIC and eB{approx} 15m{sup 2}{sub {pi}}{approx} 0.3 GeV{sup 2} at the LHC. We investigate the effects of the magnetic field on B{sup 0} and D{sup 0} mesons, focusing on the changes of the energy levels and of the mass of the bound states.

  7. [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.

  8. The van Cittert-Zernike theorem for electromagnetic fields.

    PubMed

    Ostrovsky, Andrey S; Martínez-Niconoff, Gabriel; Martínez-Vara, Patricia; Olvera-Santamaría, Miguel A

    2009-02-02

    The van Cittert-Zernike theorem, well known for the scalar optical fields, is generalized for the case of vector electromagnetic fields. The deduced theorem shows that the degree of coherence of the electromagnetic field produced by the completely incoherent vector source increases on propagation whereas the degree of polarization remains unchanged. The possible application of the deduced theorem is illustrated by an example of optical simulation of partially coherent and partially polarized secondary source with the controlled statistical properties.

  9. Coupled V-structured nano-antenna for electromagnetic field enhancement

    NASA Astrophysics Data System (ADS)

    Chen, Wanli; Zhang, Wanwan; Feng, Yuanming; Lin, Wang

    2017-05-01

    Nano-antennas play an important role in many areas of science and technology. It is desirable to achieve strong electric field enhancement by nano-antenna. In this paper, we simulate a symmetrical V-structured nano-antenna that is used to regulate the electromagnetic fields in the central gap region. We study the effects of structural parameters on the charge distribution and analyze the electric field enhancement factor in the central region of the nano-antenna. Then we use structural coupling methods to strengthen electromagnetic field intensity in the central region. Our results demonstrate that the charge distribution of the nano-antenna can be controlled by regulating the structural parameters, leading to the change of electromagnetic field intensity. In addition, electric field enhancement is achieved by coupling of multiple V structures. The multiple V structure could be used in surface-enhanced Raman scattering due to the electric field enhancement in its central region.

  10. Electromagnetic generation of sound in metals in a magnetic field

    NASA Astrophysics Data System (ADS)

    Aronov, I. E.; Fal'ko, V. L.

    1992-11-01

    A wide range of phenomena of the electromagnetic generation of sound in metals in a magnetic field is reviewed. All phenomena of mutual conversion of waves and of sound generation are due to the interaction of conduction electrons with phonons. A wide variety of resonance effects in a magnetic field determines numerous mechanisms for direct sound generation by an external microwave. The basic equations and boundary conditions for the problem of electron-phonon interaction in metals are presented in the quasiclassical approximation. In the low-temperature region under the conditions of the anomalous skin effect the wave conversion is caused, besides by inductive interaction, also by electron-phonon interaction via the deformation potential. The major conversion mechanism of an electromagnetic wave into sound results in various resonance effects in a magnetic field in conditions of strong spatial dispersion. We present an exact solution of the problem for an alkali metal in a magnetic field normal to the surface. We analyze the asymptotic approximations related with the skin-effect anomaly, the coupling of electromagnetic and acoustic waves in metals, and the role of surface scattering. We study the effect of resonance renormalization of electron-phonon interaction in metals with a complex dispersion law, which results in a partial compensation of resonance singularities and appears in Doppler-shifted cyclotron resonances. The doppleron-phonon resonance and its polarization effects are investigated. The electromagnetic generation of sound in metals in a magnetic field parallel to the surface is due to the additional mechanism of selecting “effective” electrons, where resonance effects are observed. We study geometric and cyclotron resonances, and the resonance coupling of a sound wave with a cyclotron wave. The amplitude and phase of the generated sound depend on the character of electron scattering on the metal boundary because in specular scattering a group of

  11. Algebraic structure of general electromagnetic fields and energy flow

    SciTech Connect

    Hacyan, Shahen

    2011-08-15

    Highlights: > Algebraic structure of general electromagnetic fields in stationary spacetime. > Eigenvalues and eigenvectors of the electomagnetic field tensor. > Energy-momentum in terms of eigenvectors and Killing vector. > Explicit form of reference frame with vanishing Poynting vector. > Application of formalism to Bessel beams. - Abstract: The algebraic structures of a general electromagnetic field and its energy-momentum tensor in a stationary space-time are analyzed. The explicit form of the reference frame in which the energy of the field appears at rest is obtained in terms of the eigenvectors of the electromagnetic tensor and the existing Killing vector. The case of a stationary electromagnetic field is also studied and a comparison is made with the standard short-wave approximation. The results can be applied to the general case of a structured light beams, in flat or curved spaces. Bessel beams are worked out as example.

  12. High-latitude electromagnetic and particle energy flux during an event with sustained strongly northward IMF

    NASA Astrophysics Data System (ADS)

    Korth, H.; Anderson, B. J.; Frey, H. U.; Waters, C. L.

    2005-06-01

    We present a case study of a prolonged interval of strongly northward orientation of the interplanetary magnetic field on 16 July 2000, 16:00-19:00 UT to characterize the energy exchange between the magnetosphere and ionosphere for conditions associated with minimum solar wind-magnetosphere coupling. With reconnection occurring tailward of the cusp under northward IMF conditions, the reconnection dynamo should be separated from the viscous dynamo, presumably driven by the Kelvin-Helmholtz (KH) instability. Thus, these conditions are also ideal for evaluating the contribution of a viscous interaction to the coupling process. We derive the two-dimensional distribution of the Poynting vector radial component in the northern sunlit polar ionosphere from magnetic field observations by the constellation of Iridium satellites together with drift meter and magnetometer observations from the Defense Meteorological Satellite Program (DMSP) F13 and F15 satellites. The electromagnetic energy flux is then compared with the particle energy flux obtained from auroral images taken by the far-ultraviolet (FUV) instrument on the Imager for Magnetopause to Aurora Global Exploration (IMAGE) spacecraft. The electromagnetic energy input to the ionosphere of 51 GW calculated from the Iridium/DMSP observations is eight times larger than the 6 GW due to particle precipitation all poleward of 78° MLAT. This result indicates that the energy transport is significant, particularly as it is concentrated in a small region near the magnetic pole, even under conditions traditionally considered to be quiet and is dominated by the electromagnetic flux. We estimate the contributions of the high and mid-latitude dynamos to both the Birkeland currents and electric potentials finding that high-latitude reconnection accounts for 0.8 MA and 45kV while we attribute <0.2MA and ~5kV to an interaction at lower latitudes having the sense of a viscous interaction. Given that these conditions are ideal for the

  13. Compton scattering in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Daugherty, Joseph K.; Harding, Alice K.

    1986-01-01

    The relativistic cross section for Compton scattering by electrons in strong magnetic fields is derived. The results confirm and extend earlier work which has treated only transitions to the lowest or first excited Landau levels. For the teragauss field strengths expected in neutron star magnetospheres, the relative rates for excited state transitions are found to be significant, especially for incident photon energies several times the cyclotron frequency. Since these transitions must result in the rapid emission of one or more cyclotron photons as well as the Compton-scattered photon, the scattering process actually becomes a photon 'splitting' mechanism which acts to soften hard photon spectra, and also provides a specific mechanism for populating higher Landau levels in the electron distribution function. The results should be significant for models of gamma-ray bursters and pulsating X-ray sources.

  14. Atoms and Molecules in Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Schmelcher, P.; Cederbaum, L. S.

    Selected topics on atoms and molecules in strong magnetic fields are reviewed. The enormous progress made for the hydrogen atom in a magnetic field and its impact on different areas like, for example, modern semi-classics and dynamics of non-integrable systems as well as laser spectroscopy are outlined. Due to the non-separability of the centre of mass and electronic motion of atoms/molecules in magnetic fields a variety of two-body phenomena can be observed in highly excited systems. Examples are the classical diffusion of the centre of mass and the giant dipole states for crossed fields. For ions energy transfer processes lead to the so-called self-ionisation process. Magnetically induced crossovers for the ground states of atoms are investigated. The increasing complexity of the ground state behaviour of magnetically dressed multi-electron atoms due to changes of the spin polarisation as well as spatial orbitals is demonstrated. For molecules, both fundamental aspects as well as the electronic structure of few-electron diatomics are reviewed.

  15. [Electromagnetic fields in melting divisions of nickel production].

    PubMed

    Nikitina, V N; Liashko, G G; Nikanov, A N; Nikitina, N Iu

    2004-01-01

    The authors evaluated electromagnetic situation in melting divisions, on transformer substation. Studies covered alternating electric and magnetic fields of industrial frequencies and direct magnetic fields in fire mode of nickel production on workplaces during working shifts. Results proved that induction of the magnetic fields varies widely. Magnetic fields influence is accidental and remains additional factor affecting human body.

  16. Quantum dynamics in strong fluctuating fields

    NASA Astrophysics Data System (ADS)

    Goychuk, Igor; Hänggi, Peter

    A large number of multifaceted quantum transport processes in molecular systems and physical nanosystems, such as e.g. nonadiabatic electron transfer in proteins, can be treated in terms of quantum relaxation processes which couple to one or several fluctuating environments. A thermal equilibrium environment can conveniently be modelled by a thermal bath of harmonic oscillators. An archetype situation provides a two-state dissipative quantum dynamics, commonly known under the label of a spin-boson dynamics. An interesting and nontrivial physical situation emerges, however, when the quantum dynamics evolves far away from thermal equilibrium. This occurs, for example, when a charge transferring medium possesses nonequilibrium degrees of freedom, or when a strong time-dependent control field is applied externally. Accordingly, certain parameters of underlying quantum subsystem acquire stochastic character. This may occur, for example, for the tunnelling coupling between the donor and acceptor states of the transferring electron, or for the corresponding energy difference between electronic states which assume via the coupling to the fluctuating environment an explicit stochastic or deterministic time-dependence. Here, we review the general theoretical framework which is based on the method of projector operators, yielding the quantum master equations for systems that are exposed to strong external fields. This allows one to investigate on a common basis, the influence of nonequilibrium fluctuations and periodic electrical fields on those already mentioned dynamics and related quantum transport processes. Most importantly, such strong fluctuating fields induce a whole variety of nonlinear and nonequilibrium phenomena. A characteristic feature of such dynamics is the absence of thermal (quantum) detailed balance.ContentsPAGE1. Introduction5262. Quantum dynamics in stochastic fields531 2.1. Stochastic Liouville equation531 2.2. Non-Markovian vs. Markovian discrete

  17. Manifestation of Symmetry Properties of Nucleon Structure in Strong and Electromagnetic Processes

    NASA Astrophysics Data System (ADS)

    Tomasi-Gustafsson, Egle; Rekalo, Michail P.

    2004-04-01

    In this contribution we present a specific application of a result obtained by Franco Iachello (in collaboration with R. Bijker and A. Leviatan), which concerns the inelastic electromagnetic form factors on the nucleons. In particular we show examples where symmetries inherent to the structure of the nucleon resonances can manifest in complicated processes of the strong interaction.

  18. [Computational radiofrequency electromagnetic field dosimetry in evaluation of biological effects].

    PubMed

    Perov, S Iu; Kudryashov, Iu B; Rubtsova, N B

    2012-01-01

    Given growing computational resources, radiofrequency electromagnetic field dosimetry is becoming more vital in the study of biological effects of non-ionizing electromagnetic radiation. The study analyzes numerical methods which are used in theoretical dosimetry to assess the exposure level and specific absorption rate distribution. The advances of theoretical dosimetry are shown. Advantages and disadvantages of different methods are analyzed in respect to electromagnetic field biological effects. The finite-difference time-domain method was implemented in detail; also evaluated were possible uncertainties of complex biological structure simulation for bioelectromagnetic investigations.

  19. Effects of Electromagnetic Fields on Fish and Invertebrates

    SciTech Connect

    Schultz, Irvin R.; Woodruff, Dana L.; Marshall, Kathryn E.; Pratt, William J.; Roesijadi, Guritno

    2010-10-13

    In this progress report, we describe the preliminary experiments conducted with three fish and one invertebrate species to determine the effects of exposure to electromagnetic fields. During fiscal year 2010, experiments were conducted with coho salmon (Onchrohychus kisutch), California halibut (Paralicthys californicus), Atlantic halibut (Hippoglossus hippoglossus), and Dungeness crab (Cancer magister). The work described supports Task 2.1.3: Effects on Aquatic Organisms, Subtask 2.1.3.1: Electromagnetic Fields.

  20. [Pulsed electromagnetic fields (PEMF)--results in evidence based medicine].

    PubMed

    Pieber, Karin; Schuhfried, Othmar; Fialka-Moser, Veronika

    2007-01-01

    Therapy with electromagnetic fields has a very old tradition in medicine. The indications are widespread, whereas little is known about the effects. Controlled randomizied studies with positive results for pulsed electromagnetic fields (PEMF) are available for osteotomies, the healing of skin wounds, and osteoarthritis. Comparison of the studies is difficult because of the different doses applied and intervals of therapy. Therefore recommendations regarding an optimal dosis and interval are, depending on the disease, quite variable.

  1. Magnetic field instability of a plasma in a beam of electromagnetic radiation

    NASA Astrophysics Data System (ADS)

    Gradov, O. M.; Stenflo, L.

    1980-04-01

    A beam of electromagnetic radiation can generate magnetic fields in plasmas. It is shown that those fields grow significantly when the incident radiation is sufficiently strong. We obtain expressions for the characteristic time of the growth of the fields as well as for their spatial distribution and point out a possible mechanism, which can lead to the formation of a quasi-stationary state. The maximum value of the magnetic field strength is estimated.

  2. Setting prudent public health policy for electromagnetic field exposures.

    PubMed

    Carpenter, David O; Sage, Cindy

    2008-01-01

    Electromagnetic fields (EMF) permeate our environment, coming both from such natural sources as the sun and from manmade sources like electricity, communication technologies and medical devices. Although life on earth would not be possible without sunlight, increasing evidence indicates that exposures to the magnetic fields associated with electricity and to communication frequencies associated with radio, television, WiFi technology, and mobile cellular phones pose significant hazards to human health. The evidence is strongest for leukemia from electricity-frequency fields and for brain tumors from communication-frequency fields, yet evidence is emerging for an association with other diseases as well, including neurodegenerative diseases. Some uncertainty remains as to the mechanism(s) responsible for these biological effects, and as to which components of the fields are of greatest importance. Nevertheless, regardless of whether the associations are causal, the strengths of the associations are sufficiently strong that in the opinion of the authors, taking action to reduce exposures is imperative, especially for the fetus and children. Inaction is not compatible with the Precautionary Principle, as enunciated by the Rio Declaration. Because of ubiquitous exposure, the rapidly expanding development of new EMF technologies and the long latency for the development of such serious diseases as brain cancers, the failure to take immediate action risks epidemics of potentially fatal diseases in the future.

  3. Electromagnetic Form Factors of Hadrons in Quantum Field Theories

    SciTech Connect

    Dominguez, C. A.

    2008-10-13

    In this talk, recent results are presented of calculations of electromagnetic form factors of hadrons in the framework of two quantum field theories (QFT), (a) Dual-Large N{sub c} QCD (Dual-QCD{sub {infinity}}) for the pion, proton, and {delta}(1236), and (b) the Kroll-Lee-Zumino (KLZ) fully renormalizable Abelian QFT for the pion form factor. Both theories provide a QFT platform to improve on naive (tree-level) Vector Meson Dominance (VMD). Dual-QCD{sub {infinity}} provides a tree-level improvement by incorporating an infinite number of zero-width resonances, which can be subsequently shifted from the real axis to account for the time-like behaviour of the form factors. The renormalizable KLZ model provides a QFT improvement of VMD in the framework of perturbation theory. Due to the relative mildness of the {rho}{pi}{pi} coupling, and the size of loop suppression factors, the perturbative expansion is well defined in spite of this being a strong coupling theory. Both approaches lead to considerable improvements of VMD predictions for electromagnetic form factors, in excellent agreement with data.

  4. Time delay in strong-field photoionization of a hydrogen atom

    SciTech Connect

    Ivanov, I. A.

    2011-02-15

    We study time delay for the process of photoionization of a hydrogen atom in a strong electromagnetic field. We compute this quantity by solving the time-dependent Schroedinger equation. We show that even a moderately strong field can have quite a considerable effect on the time delay. Analysis of the wave-packet motion performed by means of the Gabor transform shows that a simple semiclassical model can explain this phenomenon.

  5. Electromagnetic fields and potentials generated by massless charged particles

    SciTech Connect

    Azzurli, Francesco; Lechner, Kurt

    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 a 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.

  6. Strong-field ionization of lithium

    SciTech Connect

    Schuricke, Michael; Zhu Ganjun; Steinmann, Jochen; Simeonidis, Konstantinos; Dorn, Alexander; Ullrich, Joachim; Ivanov, Igor; Kheifets, Anatoli; Grum-Grzhimailo, Alexei N.; Bartschat, Klaus

    2011-02-15

    We report photoelectron energy spectra, momentum, and angular distributions for the strong-field single ionization of lithium by 30-fs laser pulses. For peak intensities between 10{sup 11} and 10{sup 14} W/cm{sup 2} at a central wavelength of 785 nm, the classical over-the-barrier intensity was reached well inside the multiphoton regime. The complete vector momenta of the ionization fragments were recorded by a reaction microscope with a magneto-optically trapped target (MOTREMI). On the theoretical side, the time-dependent Schroedinger equation was solved by two independent methods seeking the solution directly on a radial grid. Distinct differences between the results of both calculations and also in comparison with experiment point to a high sensitivity of this reaction with respect to small details, particularly in the description of the Li{sup +} core.

  7. Biological effects of prolonged exposure to ELF electromagnetic fields in rats: III. 50 Hz electromagnetic fields.

    PubMed

    Zecca, L; Mantegazza, C; Margonato, V; Cerretelli, P; Caniatti, M; Piva, F; Dondi, D; Hagino, N

    1998-01-01

    Groups of adult male Sprague Dawley rats (64 rats each) were exposed for 8 months to electromagnetic fields (EMF) of two different field strength combinations: 5microT - 1kV/m and 100microT - 5kV/m. A third group was sham exposed. Field exposure was 8 hrs/day for 5 days/week. Blood samples were collected for hematology determinations before the onset of exposure and at 12 week intervals. At sacrifice, liver, heart, mesenteric lymph nodes, bone marrow, and testes were collected for morphology and histology assessments, while the pineal gland and brain were collected for biochemical determinations. At both field strength combinations, no pathological changes were observed in animal growth rate, in morphology and histology of the collected tissue specimens (liver, heart, mesenteric lymph nodes, testes, bone marrow), and in serum chemistry. An increase in norepinephrine levels occurred in the pineal gland of rats exposed to the higher field strength. The major changes in the brain involved the opioid system in frontal cortex, parietal cortex, and hippocampus. From the present findings it may be hypothesized that EMF may cause alteration of some brain functions.

  8. [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.

  9. Electromagnetically induced transparency resonances inverted in magnetic field

    SciTech Connect

    Sargsyan, A.; Sarkisyan, D. E-mail: david@ipr.sci.am; Pashayan-Leroy, Y.; Leroy, C.; Cartaleva, S.; Wilson-Gordon, A. D.; Auzinsh, M.

    2015-12-15

    The phenomenon of electromagnetically induced transparency (EIT) is investigated in a Λ-system of the {sup 87}Rb D{sub 1} line in an external transverse magnetic field. Two spectroscopic cells having strongly different values of the relaxation rates γ{sub rel} are used: an Rb cell with antirelaxation coating (L ∼ 1 cm) and an Rb nanometric- thin cell (nanocell) with a thickness of the atomic vapor column L = 795 nm. For the EIT in the nanocell, we have the usual EIT resonances characterized by a reduction in the absorption (dark resonance (DR)), whereas for the EIT in the Rb cell with an antirelaxation coating, the resonances demonstrate an increase in the absorption (bright resonances (BR)). We suppose that such an unusual behavior of the EIT resonances (i.e., the reversal of the sign from DR to BR) is caused by the influence of an alignment process. The influence of alignment strongly depends on the configuration of the coupling and probe frequencies as well as on the configuration of the magnetic field.

  10. Nonlinear electromagnetic fields as a source of universe acceleration

    NASA Astrophysics Data System (ADS)

    Kruglov, S. I.

    2016-04-01

    A model of nonlinear electromagnetic fields with a dimensional parameter β is proposed. From PVLAS experiment the bound on the parameter β was obtained. Electromagnetic fields are coupled with the gravitation field and we show that the universe accelerates due to nonlinear electromagnetic fields. The magnetic universe is considered and the stochastic magnetic field is a background. After inflation the universe decelerates and approaches to the radiation era. The range of the scale factor, when the causality of the model and a classical stability take place, was obtained. The spectral index, the tensor-to-scalar ratio, and the running of the spectral index were estimated which are in approximate agreement with the Planck, WMAP, and BICEP2 data.

  11. 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

  12. 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.

  13. Basic Materials for Electromagnetic Field Standards

    DTIC Science & Technology

    2003-03-04

    choliner- gic processes // Labor Hygiene and Biological Effects of electromagnetic waves of ra- diofrequencies. Proceedings of 3rd All-Union Symposium...Microwave on Blood asparthate Amine transferase Enzymatic System. J. Radiation biology and ecol - ogy (Russian academy of sciences) 2001. Vol. 41. No.1...under Increased Temperature. J. Radiation biology and ecol - ogy (Russian academy of sciences) 2002. Vol. 42. No.1, pp. 191–193. 13. T.P. Semenova

  14. MESA: a new configuration for measuring electromagnetic field fluctuations.

    PubMed

    Harte, T M; Black, D L; Hollinshead, M T

    1999-11-01

    This paper describes how the multi-energy sensor array has been refitted to meet the needs of measuring geomagnetic and other types of electromagnetic phenomena in an environment. This portable laptop computer system was designed to measure the interaction of multiple frequencies with the psychological and physiological processes that underlie human exposure to electromagnetic fields across the spectra. New sensors and analytical software have been implemented in the new configuration.

  15. Strong-Field THz Interactions with Wavepackets

    NASA Astrophysics Data System (ADS)

    Bucksbaum, Philip H.

    1998-03-01

    Intense THz radiation from photoconducting antennas are particularly useful for manipulating the structure and dynamics of atomic and molecular Rydberg states. We have used sub-picosecond ``half-cycle'' field pulses to follow both the radial(C. Raman, C.W.S. Conover, C.I. Sukenik, and P. H. Bucksbaum, Physical Review Letters 76), 2436 (1996). and angular motion(C.S. Raman, T.C. Weinacht, and P.H. Bucksbaum, Physical Review A 55), R3995-8 (1997). of wavepackets. The impulse imparted to an atomic electron by these pulses can also be used to produce or alter wavepacket motion. The THz radiation can be shaped by modulating optical radiation which photo-excites the antenna.(A. S. Weling et al., Appl. Phys. Lett. 64), 137, 1994. In this way we have produced intense tunable narrow-band THz radiation, which was employed to study population transfer in strongly driven Rydberg systems.(C. Raman, M. F. DeCamp and P. H. Bucksbaum, Optics Express 1) 186 (1997). The same techniques is used to arbitrarily adjust the intensity envelope of the THz pulse, alter its central frequency over a wide range, and to produce and control dispersion. When combined with active pulse-shaping and adaptive feedback techniques, wavepacket shapes and dispersion properties can be controlled.

  16. Suppression and control of leakage field in electromagnetic helical microwiggler

    SciTech Connect

    Ohigashi, N.; Tsunawaki, Y.; Imasaki, K.

    1995-12-31

    Shortening the period of electromagnetic wiggler introduces both the radical increase of the leakage field and the decrease of the field in the gap region. The leakage field is severer problem in planar electromagnetic wiggler than in helical wiggler. Hence, in order to develop a short period electromagnetic wiggler, we have adopted {open_quotes}three poles per period{close_quotes} type electromagnetic helical microwiggler. In this work, we inserted the permanent magnet (PM) blocks with specific magnetized directions in the space between magnetic poles, for suppressing the leakage field flowing out from a pole face to the neighboring pole face. These PM-blocks must have higher intrinsic coersive force than saturation field of pole material. The gap field due to each pole is adjustable by controlling the leakage fields, that is, controlling the position of each iron screw set in each retainer fixing the PM-blocks. At present time, a test wiggler with period 7.8mm, periodical number 10 and gap length 4.6mm has been manufactured. Because the ratio of PM-block aperture to gap length is important parameter to suppress the leakage field, the parameter has been surveyed experimentally for PM-blocks with several dimensions of aperture. The field strength of 3-5kG (K=0.2-0.4) would be expected in the wiggler.

  17. Analytical model for electromagnetic cascades in rotating electric field

    SciTech Connect

    Nerush, E. N.; Bashmakov, V. F.; Kostyukov, I. Yu.

    2011-08-15

    Electromagnetic cascades attract a lot of attention as an important quantum electrodynamics effect that will reveal itself in various electromagnetic field configurations at ultrahigh intensities. We study cascade dynamics in rotating electric field analytically and numerically. The kinetic equations for the electron-positron plasma and gamma-quanta are formulated. The scaling laws are derived and analyzed. For the cascades arising far above the threshold the dependence of the cascade parameters on the field frequency is derived. The spectra of high-energy cascade particles are calculated. The analytical results are verified by numerical simulations.

  18. Electromagnetic Fields Produced by Inclined Return Stroke Channel

    NASA Astrophysics Data System (ADS)

    Nemamcha, Abdelmalek; Houabes, Mourad

    2014-05-01

    In this paper further theoretical investigations to understand and elucidate recently raised questions on the characteristics of lightning return-strokes curried out. Using Antenna Theory (AT) model, which is extended to take into account the channel inclination, the electromagnetic fields expressions for vertical dipole are completed, and an inclined channel is properly modeled, vertical electric and azimuthally magnetic fields are computed at different distances (close, intermediate and far distance ranges). The computations show that amplitudes and wave forms of the electromagnetic fields at close and intermediate lightning environment are considerably affected by the channel inclination.

  19. 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.

  20. 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…

  1. 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…

  2. External Field QED on Cauchy Surfaces for Varying Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Deckert, D.-A.; Merkl, F.

    2016-08-01

    The Shale-Stinespring Theorem (J Math Mech 14:315-322, 1965) together with Ruijsenaar's criterion (J Math Phys 18(4):720-737, 1977) provide a necessary and sufficient condition for the implementability of the evolution of external field quantum electrodynamics between constant-time hyperplanes on standard Fock space. The assertion states that an implementation is possible if and only if the spatial components of the external electromagnetic four-vector potential {A_μ} are zero. We generalize this result to smooth, space-like Cauchy surfaces and, for general {A_μ}, show how the second-quantized Dirac evolution can always be implemented as a map between varying Fock spaces. Furthermore, we give equivalence classes of polarizations, including an explicit representative, that give rise to those admissible Fock spaces. We prove that the polarization classes only depend on the tangential components of {A_μ} w.r.t. the particular Cauchy surface, and show that they behave naturally under Lorentz and gauge transformations.

  3. The effect of pulsed electromagnetic field therapy on food sensitivity.

    PubMed

    Monro, Jean A; Puri, Basant K

    2015-01-01

    Owing to the involvement of the immune system in the etiology of food sensitivity, and because pulsed electromagnetic field therapy is associated with beneficial immunologic changes, it was hypothesized that pulsed electromagnetic fields may have a beneficial effect on food sensitivity. A small pilot study was carried out in patients suffering from food sensitivity, with the antigen leukocyte antibody test being employed to index the degree of food sensitivity in terms of the number of foods to which each patient reacted. It was found that a 1-week course of pulsed electromagnetic field therapy, consisting of one hour's treatment per day, resulted in a reduction in the mean number of reactive foods of 10.75 (p < 0.05). On the basis of these results, a larger study is warranted.

  4. Electromagnetic Propulsion System for Spacecraft using Geomagnetic fields and Superconductors

    NASA Astrophysics Data System (ADS)

    Dadhich, Anang

    This thesis concentrates on developing an innovative method to generate thrust force for spacecraft in localized geomagnetic fields by various electromagnetic systems. The proposed electromagnetic propulsion system is an electromagnet, like normal or superconducting solenoid, having its own magnetic field which interacts with the planet's magnetic field to produce a reaction thrust force. The practicality of the system is checked by performing simulations in order the find the varying radius, velocity, and acceleration changes. The advantages, challenges, various optimization techniques, and viability of such a propulsion system in present day and future are discussed. The propulsion system such developed is comparable to modern MPD Thrusters and electric engines, and has various applications like spacecraft propulsion, orbit transfer and stationkeeping.

  5. 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

  6. 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.

  7. On electromagnetic fields and their applications in the early universe

    NASA Astrophysics Data System (ADS)

    Ahonen, Jarkko Tapani

    1998-07-01

    The field equations of the electromagnetic field, combined with models of the early universe, make it possible to study electromagnetic phenomena at the early stages of the universe. Electromagnetic fields provide us with a tool to estimate electrical conductivity and transport coefficients (heat conductivity and viscosity) in the primordial plasma of the hot early universe. Electrical conductivity plays an important role, for example, in the dissipation of the axion field (a weakly interacting dark matter candidate) and in the creation and dissipation of the primordial magnetic field. On the other hand, heat conductivity and shear viscosity are important, for example, in connection with primordial density perturbations, i.e., galaxy formation, early phase transitions, and primordial magnetic fields. First, in paper I, we derived the equations of motion for the axion field coupled with an electromagnetic field. It was found that energy from the axion field can be transferred to the electromagnetic field. Therefore the damping of the axion field depends on electrical conductivity but that the electromagnetic dissipation cannot, however, significantly damp the axion field. In paper II we developed the tools with which to estimate electrical conductivity in the primordial plasma. We used the Boltzmann collision equation to study how a beam of charged particles will be scattered in the early hot universe. We integrated the collision integral numerically by a simple Monte Carlo integration routine. We discovered that the charged leptons give the largest contribution to the electrical conductivity; the quark contribution was found to be negligible. In Paper III, we estimated with an Abelian Higgs model what kind of a primordial magnetic field can be created in first order phase transition bubble collisions. Assuming that the Abelian model reflects the properties of the full electroweak case, we found that the seed field created is of the right order of magnitude in order

  8. Extremely low frequency electromagnetic fields and cancer: the epidemiologic evidence.

    PubMed Central

    Bates, M N

    1991-01-01

    This paper reviews the epidemiologic evidence that low frequency electromagnetic fields generated by alternating current may be a cause of cancer. Studies examining residential exposures of children and adults and studies of electrical and electronics workers are reviewed. Using conventional epidemiologic criteria for inferring causal associations, including strength and consistency of the relationship, biological plausibility, and the possibility of bias as an explanation, it is concluded that the evidence is strongly suggestive that such radiation is carcinogenic. The evidence is strongest for brain and central nervous system cancers in electrical workers and children. Weaker evidence supports an association with leukemia in electrical workers. Some evidence also exists for an association with melanoma in electrical workers. Failure to find consistent evidence of a link between residential exposures and adult cancers may be attributable to exposure misclassification. Studies so far have used imperfect surrogates for any true biologically effective magnetic field exposure. The resulting exposure misclassification has produced relative risk estimates that understate any true risk. PMID:1821368

  9. Kinetic theory of plasma equilibrium in an electromagnetic field

    NASA Astrophysics Data System (ADS)

    Gorbunov, L. M.; Gradov, O. M.; Ziunder, D.; Ramazashvili, R. R.

    1981-04-01

    The present study examines the equilibrium of a direct-current-carrying plasma in an electromagnetic field under the assumption that the particles escaping from the plasma have a Maxwellian distribution. It is shown that an equilibrium state is possible only in the case of a definite relationship between the amplitude of the incident wave and the concentration of escaping particles. Attention is given to spatial variations of the electromagnetic field, and of the plasma density and flow velocity. The application of these effects in microwave devices is discussed.

  10. Radiation of de-excited electrons at large times in a strong electromagnetic plane wave

    SciTech Connect

    Kazinski, P.O.

    2013-12-15

    The late time asymptotics of the physical solutions to the Lorentz–Dirac equation in the electromagnetic external fields of simple configurations–the constant homogeneous field, the linearly polarized plane wave (in particular, the constant uniform crossed field), and the circularly polarized plane wave–are found. The solutions to the Landau–Lifshitz equation for the external electromagnetic fields admitting a two-parametric symmetry group, which include as a particular case the above mentioned field configurations, are obtained. Some general properties of the total radiation power of a charged particle are established. In particular, for a circularly polarized wave and constant uniform crossed fields, the total radiation power in the asymptotic regime is independent of the charge and the external field strength, when expressed in terms of the proper-time, and equals a half the rest energy of a charged particle divided by its proper-time. The spectral densities of the radiation power formed on the late time asymptotics are derived for a charged particle moving in the external electromagnetic fields of the simple configurations pointed above. This provides a simple method to verify experimentally that the charged particle has reached the asymptotic regime. -- Highlights: •Late time asymptotics of the solutions to the Lorentz–Dirac equation are studied. •General properties of the total radiation power of electrons are established. •The total radiation power equals a half the rest energy divided by the proper-time. •Spectral densities of radiation formed on the late time asymptotics are derived. •Possible experimental verification of the results is proposed.

  11. Near-field thermal electromagnetic transport: An overview

    NASA Astrophysics Data System (ADS)

    Edalatpour, Sheila; DeSutter, John; Francoeur, Mathieu

    2016-07-01

    A general near-field thermal electromagnetic transport formalism that is independent of the size, shape and number of heat sources is derived. The formalism is based on fluctuational electrodynamics, where fluctuating currents due to thermal agitation are added to Maxwell's curl equations, and is thus valid for heat sources in local thermodynamic equilibrium. Using a volume integral formulation, it is shown that the proposed formalism is a generalization of the classical electromagnetic scattering framework in which thermal emission is implicitly assumed to be negligible. The near-field thermal electromagnetic transport formalism is afterwards applied to a problem involving three spheres with size comparable to the wavelength, where all multipolar interactions are taken into account. Using the thermal discrete dipole approximation, it is shown that depending on the dielectric function, the presence of a third sphere slightly affects the spatial distribution of power absorbed compared to the two-sphere case. A transient analysis shows that despite a non-uniform spatial distribution of power absorbed, the sphere temperature remains spatially uniform at any instant due to the fact that the thermal resistance by conduction is much smaller than the resistance by radiation. The formalism proposed in this paper is general, and could be used as a starting point for adapting solution methods employed in traditional electromagnetic scattering problems to near-field thermal electromagnetic transport.

  12. The Electromagnetic Fields Under, On and Up Earth Surface As Precursor of Local Earthquake

    NASA Astrophysics Data System (ADS)

    Chterev Mavrodiev, Strachimir

    The analysis of accurasy measured Earth magnetic field gives a signal for near future near enîugh and strong enough eartquake. The correlation wit the tide gravitational potential derivatives permits to predict the day of the earthquake. It is formulated a Programm for electromagnetic field monitoring under on and up Earth surface and data analysis for investigation of possibilities for predicting the time, place, Magnitude and destractive power of future earthquake in Balkan and Black Sea region.

  13. Optimal control of electromagnetic field using metallic nanoclusters

    NASA Astrophysics Data System (ADS)

    Grigorenko, Ilya; Haas, Stephan; Balatsky, Alexander; Levi, A. F. J.

    2008-04-01

    The dielectric properties of metallic nanoclusters in the presence of an applied electromagnetic field are investigated using the non-local linear response theory. In the quantum limit we find a nontrivial dependence of the induced field and charge distributions on the spatial separation between the clusters and on the frequency of the driving field. Using a genetic algorithm, these quantum functionalities are exploited to custom-design sub-wavelength lenses with a frequency-controlled switching capability.

  14. Method for imaging with low frequency electromagnetic fields

    DOEpatents

    Lee, Ki H.; Xie, Gan Q.

    1994-01-01

    A method for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy and resolution. The imaging method includes the steps of placing one or more transmitters, at various positions in a plurality of transmitter holes, and placing a plurality of receivers in a plurality of receiver holes. The transmitters generate electromagnetic signals which diffuse through a medium, such as earth, toward the receivers. The measured diffusion field data H is then transformed into wavefield data U. The traveltimes corresponding to the wavefield data U, are then obtained, by charting the wavefield data U, using a different regularization parameter .alpha. for each transform. The desired property of the medium, such as conductivity, is then derived from the velocity, which in turn is constructed from the wavefield data U using ray tomography.

  15. Method for imaging with low frequency electromagnetic fields

    DOEpatents

    Lee, K.H.; Xie, G.Q.

    1994-12-13

    A method is described for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy and resolution. The imaging method includes the steps of placing one or more transmitters, at various positions in a plurality of transmitter holes, and placing a plurality of receivers in a plurality of receiver holes. The transmitters generate electromagnetic signals which diffuse through a medium, such as earth, toward the receivers. The measured diffusion field data H is then transformed into wavefield data U. The travel times corresponding to the wavefield data U, are then obtained, by charting the wavefield data U, using a different regularization parameter [alpha] for each transform. The desired property of the medium, such as conductivity, is then derived from the velocity, which in turn is constructed from the wavefield data U using ray tomography. 13 figures.

  16. Deformation methods in modelling of the inner magnetospheric electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Toivanen, P. K.

    2007-12-01

    Various deformation methods have been widely used in animation image processing. In common terms, they are mathematical presentations of deformations of an image drawn on an elastic material under stretching or compression of the material. Such a method has also been used in modelling of the magnetospheric magnetic fields, and recently been generalized to include also the electric fields. In this presentations, the theory of the deformation method and an application in a form of a new global magnetospheric electromagnetic field model are previewed. The main focus of the presentation is on the inner magnetospheric current systems and associated electromagnetic fields during quiet and disturbed periods. Finally, a short look at the modern deformation methods in image processing is taken. These methods include the Free Form Deformations and Moving Least Squares Deformations, and their future applications in magnetospheric field modelling are discussed.

  17. Ultracold atoms in strong synthetic magnetic fields

    NASA Astrophysics Data System (ADS)

    Ketterle, Wolfgang

    2015-03-01

    The Harper Hofstadter Hamiltonian describes charged particles in the lowest band of a lattice at high magnetic fields. This Hamiltonian can be realized with ultracold atoms using laser assisted tunneling which imprints the same phase into the wavefunction of neutral atoms as a magnetic field dose for electrons. I will describe our observation of a bosonic superfluid in a magnetic field with half a flux quantum per lattice unit cell, and discuss new possibilities for implementing spin-orbit coupling. Work done in collaboration with C.J. Kennedy, G.A. Siviloglou, H. Miyake, W.C. Burton, and Woo Chang Chung.

  18. On the scalar particle creation by electromagnetic fields in Robertson-Walker spacetime

    NASA Astrophysics Data System (ADS)

    Sogut, Kenan; Havare, Ali

    2015-12-01

    In the present paper, we obtained the scalar particle creation number density by using the Klein-Gordon equation coupled to the electromagnetic fields in the Robertson-Walker spacetime with the help of the Bogoliubov transformation method. We analyzed the resulting expression for the effect of a time-dependent electric field and a constant magnetic field on the particle production rate and found that the strong time-dependent electric field amplifies the particle creation and the magnetic field reduces the rate, in accordance with the previous findings.

  19. Dynamical equations and transport coefficients for the metals at high pulse electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Volkov, N. B.; Chingina, E. A.; Yalovets, A. P.

    2016-11-01

    We offer a metal model suitable for the description of fast electrophysical processes in conductors under influence of powerful electronic and laser radiation of femto- and picosecond duration, and also high-voltage electromagnetic pulses with picosecond front and duration less than 1 ns. The obtained dynamic equations for metal in approximation of one quasineutral liquid are in agreement with the equations received by other authors formerly. New wide-range expressions for the electronic conduction in strong electromagnetic fields are obtained and analyzed.

  20. Relativistic Particle in Electromagnetic Fields with a Generalized Uncertainty Principle

    NASA Astrophysics Data System (ADS)

    Merad, M.; Zeroual, F.; Falek, M.

    2012-05-01

    In this paper, we propose to solve the relativistic Klein-Gordon and Dirac equations subjected to the action of a uniform electromagnetic field with a generalized uncertainty principle in the momentum space. In both cases, the energy eigenvalues and their corresponding eigenfunctions are obtained. The limit case is then deduced for a small parameter of deformation.

  1. What Message Should Health Educators Give regarding Electromagnetic Fields?

    ERIC Educational Resources Information Center

    Al-Khamees, Nedaa A.

    2008-01-01

    The possibility of extremely low frequency electromagnetic fields (ELF EMF) causing a number of medical conditions and common symptoms remains a concern and presents somewhat of a quandary to health educators in view of conflicting results. This study investigated the relationship of a number of EMF sources to reported symptoms in an attempt to,…

  2. What Message Should Health Educators Give regarding Electromagnetic Fields?

    ERIC Educational Resources Information Center

    Al-Khamees, Nedaa A.

    2008-01-01

    The possibility of extremely low frequency electromagnetic fields (ELF EMF) causing a number of medical conditions and common symptoms remains a concern and presents somewhat of a quandary to health educators in view of conflicting results. This study investigated the relationship of a number of EMF sources to reported symptoms in an attempt to,…

  3. Electromagnetic Field in Lyra Manifold: A First Order Approach

    NASA Astrophysics Data System (ADS)

    Casana, R.; de Melo, C. A. M.; Pimentel, B. M.

    2005-12-01

    We discuss the coupling of the electromagnetic field with a curved and torsioned Lyra manifold using the Duffin-Kemmer-Petiau theory. We will show how to obtain the equations of motion and energy-momentum and spin density tensors by means of the Schwinger Variational Principle.

  4. Oscillator strength sum rules with an external electromagnetic field

    NASA Astrophysics Data System (ADS)

    Cabrera-Trujillo, R.; Sabin, John R.; Öhrn, Yngve; Oddershede, J.

    1998-04-01

    We demonstrate that the Bethe, and therefore the Thomas-Reiche-Kuhn, sum rule is unaffected by the presence of an applied external electromagnetic field in the exact case. We use the consequence that the first-order perturbation contribution must also vanish to derive a necessary condition for the completeness of computational one-electron basis sets.

  5. Does three-dimensional electromagnetic field inherit the spacetime symmetries?

    NASA Astrophysics Data System (ADS)

    Cvitan, M.; Dominis Prester, P.; Smolić, I.

    2016-04-01

    We prove that the electromagnetic field in a (1+2)-dimensional spacetime necessarily inherits the symmetries of the spacetime metric in a large class of generalized Einstein-Maxwell theories. The Lagrangians of the studied theories have general diff-covariant gravitational part and include both the gravitational and the gauge Chern-Simons terms.

  6. Three-dimensional electromagnetic strong turbulence: Dependence of the statistics and dynamics of strong turbulence on the electron to ion temperature ratio

    NASA Astrophysics Data System (ADS)

    Graham, D. B.; Cairns, Iver H.; Skjaeraasen, O.; Robinson, P. A.

    2012-02-01

    The temperature ratio Ti/Te of ions to electrons affects both the ion-damping rate and the ion-acoustic speed in plasmas. The effects of changing the ion-damping rate and ion-acoustic speed are investigated for electrostatic strong turbulence and electromagnetic strong turbulence in three dimensions. When ion damping is strong, density wells relax in place and act as nucleation sites for the formation of new wave packets. In this case, the density perturbations are primarily density wells supported by the ponderomotive force. For weak ion damping, corresponding to low Ti/Te, ion-acoustic waves are launched radially outwards when wave packets dissipate at burnout, thereby increasing the level of density perturbations in the system and thus raising the level of scattering of Langmuir waves off density perturbations. Density wells no longer relax in place so renucleation at recent collapse sites no longer occurs, instead wave packets form in background low density regions, such as superpositions of troughs of propagating ion-acoustic waves. This transition is found to occur at Ti/Te ≈ 0.1. The change in behavior with Ti/Te is shown to change the bulk statistical properties, scaling behavior, spectra, and field statistics of strong turbulence. For Ti/Te>rsim0.1, the electrostatic results approach the predictions of the two-component model of Robinson and Newman, and good agreement is found for Ti/Te>rsim0.15.

  7. Electromagnetic waves destabilized by runaway electrons in near-critical electric fields

    SciTech Connect

    Komar, A.; Pokol, G. I.; Fueloep, T.

    2013-01-15

    Runaway electron distributions are strongly anisotropic in velocity space. This anisotropy is a source of free energy that may destabilize electromagnetic waves through a resonant interaction between the waves and the energetic electrons. In this work, we investigate the high-frequency electromagnetic waves that are destabilized by runaway electron beams when the electric field is close to the critical field for runaway acceleration. Using a runaway electron distribution appropriate for the near-critical case, we calculate the linear instability growth rate of these waves and conclude that the obliquely propagating whistler waves are most unstable. We show that the frequencies, wave numbers, and propagation angles of the most unstable waves depend strongly on the magnetic field. Taking into account collisional and convective damping of the waves, we determine the number density of runaways that is required to destabilize the waves and show its parametric dependences.

  8. Effects of pulsed electromagnetic fields on benign prostate hyperplasia.

    PubMed

    Giannakopoulos, Xenophon K; Giotis, Christos; Karkabounas, Spyridon Ch; Verginadis, Ioannis I; Simos, Yannis V; Peschos, Dimitrios; Evangelou, Angelos M

    2011-12-01

    Benign prostate hyperplasia (BPH) has been treated with various types of electromagnetic radiation methods such as transurethral needle ablation (TUNA), interstitial laser therapy (ILC), holmium laser resection (HoLRP). In the present study, the effects of a noninvasive method based on the exposure of patients with BPH to a pulsative EM Field at radiofrequencies have been investigated. Twenty patients with BPH, aging 68-78 years old (y.o), were enrolled in the study. Patients were randomly divided into two groups: the treatment group (10 patients, 74.0 ± 5.7 y.o) treated with the α-blocker Alfusosin, 10 mg/24 h for at least 4 weeks, and the electromagnetic group (10 patients, 73.7 ± 6.3 y.o) exposed for 2 weeks in a very short wave duration, pulsed electromagnetic field at radiofrequencies generated by an ion magnetic inductor, for 30 min daily, 5 consecutive days per week. Patients of both groups were evaluated before and after drug and EMF treatment by values of total PSA and prostatic PSA fraction, acid phosphate, U/S estimation of prostate volume and urine residue, urodynamic estimation of urine flow rate, and International Prostate Symptom Score (IPSS). There was a statistically significant decrease before and after treatment of IPSS (P < 0.02), U/S prostate volume (P < 0.05), and urine residue (P < 0.05), as well as of mean urine flow rate (P < 0.05) in patients of the electromagnetic group, in contrast to the treatment group who had only improved IPSS (P < 0.05). There was also a significant improvement in clinical symptoms in patients of the electromagnetic group. Follow-up of the patients of this group for one year revealed that results obtained by EMFs treatment are still remaining. Pulsed electromagnetic field at radiofrequencies may benefit patients with benign prostate hyperplasia treated by a non-invasive method.

  9. Association between electromagnetic field exposure and abortion in pregnant women living in Tehran

    PubMed Central

    Abad, Masoumeh; Malekafzali, Hossein; Simbar, Masoumeh; Seyed Mosaavi, Hassan; Merghati Khoei, Effat

    2016-01-01

    Background: Health-related quality of life is affected by electromagnetic field exposure in each person everyday life. However, this is extremely controversial issue. Objective: Investigation of the associations between electromagnetic field exposure and miscarriage among women of Tehran. Materials and Methods: In this longitudinal study, 462 pregnant women with gestational age <12 wks from seven main regions of Tehran city in Iran with similar social and cultural status were participated. Women were interviewed face-to face to collect data. Reproductive information was collected using medical file recorded in those hospitals the subjects had delivery. The measuring device measured electromagnetic waves, Narda safety test solutions with valid calibration date at the entrance door of their houses. Results: A significant likelihood of miscarriage in women who exposed to significant level of electromagnetic wave. However, this association was not confirmed by Wald test. Conclusion: This study may not provide strong or consistent evidence that electromagnetic field exposure is associated or cause miscarriage. This issue may be due to small sample size in this study. PMID:27326421

  10. Spin generation by strong inhomogeneous electric fields

    NASA Astrophysics Data System (ADS)

    Finkler, Ilya; Engel, Hans-Andreas; Rashba, Emmanuel; Halperin, Bertrand

    2007-03-01

    Motivated by recent experiments [1], we propose a model with extrinsic spin-orbit interaction, where an inhomogeneous electric field E in the x-y plane can give rise, through nonlinear effects, to a spin polarization with non-zero sz, away from the sample boundaries. The field E induces a spin current js^z= z x(αjc+βE), where jc=σE is the charge current, and the two terms represent,respectively, the skew scattering and side-jump contributions. [2]. The coefficients α and β are assumed to be E- independent, but conductivity σ is field dependent. We find the spin density sz by solving the equation for spin diffusion and relaxation with a source term ∇.js^z. For sufficiently low fields, jc is linear in E, and the source term vanishes, implying that sz=0 away from the edges. However, for large fields, σ varies with E. Solving the diffusion equation in a T-shaped geometry, where the electric current propagates along the main channel, we find spin accumulation near the entrance of the side channel, similar to experimental findings [1]. Also, we present a toy model where spin accumulation away from the boundary results from a nonlinear and anisotropic conductivity. [1] V. Sih, et al, Phys. Rev. Lett. 97, 096605 (2006). [2] H.-A. Engel, B.I. Halperin, E.I.Rashba, Phys. Rev. Lett. 95, 166605 (2005).

  11. QED effective action in magnetic field backgrounds and electromagnetic duality

    NASA Astrophysics Data System (ADS)

    Kim, Sang Pyo

    2011-09-01

    In the in-out formalism we advance a method of the inverse scattering matrix for calculating effective actions in pure magnetic field backgrounds. The one-loop effective actions are found in a localized magnetic field of Sauter type and approximately in a general magnetic field by applying the uniform semiclassical approximation. The effective actions exhibit the electromagnetic duality between a constant electric field and a constant magnetic field and between E(x)=Esech2(x/L) and B(x)=Bsech2(x/L).

  12. Electromagnetic fields from mobile phone base station - variability analysis.

    PubMed

    Bienkowski, Pawel; Zubrzak, Bartlomiej

    2015-09-01

    The article describes the character of electromagnetic field (EMF) in mobile phone base station (BS) surroundings and its variability in time with an emphasis on the measurement difficulties related to its pulse and multi-frequency nature. Work also presents long-term monitoring measurements performed recently in different locations in Poland - small city with dispersed building development and in major polish city - dense urban area. Authors tried to determine the trends in changing of EMF spectrum analyzing daily changes of measured EMF levels in those locations. Research was performed using selective electromagnetic meters and also EMF meter with spectrum analysis.

  13. [Clinical monitoring in areas of exposure to radiofrequency electromagnetic fields].

    PubMed

    Suvorov, I M

    2013-01-01

    Clinical syndromes induced by high intensity radiofrequency electromagnetic field chronic exposure are described. Persons injured by occupational exposure have been observed central nervous system changes in diencephalic syndrome form, cardio-vascular system changes revealed in atherosclerosis, isch(a)emic heart disease and coronary insufficiency rapid progressive expansion. General public living in territory of radar station exposure zone different functional disorders have been identified: vegetative dystonia (asthenovegetative syndrome), thrombocytopenia, decrease of blood coagulation index, and thyroid gland function changes. Observed diseases clinical variability may be determined by electromagnetic exposure characteristics.

  14. Topology, Magnetic Field, and Strongly Interacting Matter

    DOE PAGES

    Kharzeev, Dmitri E.

    2015-06-05

    Gauge theories with compact symmetry groups possess topologically nontrivial configurations of gauge field. This characteristic has dramatic implications for the vacuum structure of quantum chromodynamics (QCD) and for the behavior of QCD plasma, as well as for condensed matter systems with chiral quasi-particles. Here, I review the current status of this problem with an emphasis both on the interplay between chirality and a background magnetic field and on the observable manifestations of topology in heavy-ion collisions, Dirac semimetals, neutron stars, and the early Universe.

  15. Fundamental emission via wave advection from a collapsing wave packet in electromagnetic strong plasma turbulence

    SciTech Connect

    Jenet, F. A.; Melatos, A.; Robinson, P. A.

    2007-10-15

    Zakharov simulations of nonlinear wave collapse in continuously driven two-dimensional, electromagnetic strong plasma turbulence with electron thermal speeds v{>=}0.01c show that for v < or approx. 0.1c, dipole radiation occurs near the plasma frequency, mainly near arrest, but for v > or approx. 0.1c, a new mechanism applies in which energy oscillates between trapped Langmuir and transverse modes until collapse is arrested, after which trapped transverse waves are advected into incoherent interpacket turbulence by an expanding annular density well, where they detrap. The multipole structure, Poynting flux, source current, and radiation angular momentum are computed.

  16. Vacuum polarization in a strong external field

    NASA Technical Reports Server (NTRS)

    Soff, Gerhard; Mohr, Peter J.

    1988-01-01

    Vacuum polarization in the field of a high-Z finite-size nucleus is examined, and the polarization charge density in coordinate space of order alpha(Z alpha)exp n not less than 3 is calculated. Energy-level shifts of K- and L-shell electrons in hydrogenlike systems are given.

  17. Vacuum polarization in a strong external field

    NASA Technical Reports Server (NTRS)

    Soff, Gerhard; Mohr, Peter J.

    1988-01-01

    Vacuum polarization in the field of a high-Z finite-size nucleus is examined, and the polarization charge density in coordinate space of order alpha(Z alpha)exp n not less than 3 is calculated. Energy-level shifts of K- and L-shell electrons in hydrogenlike systems are given.

  18. Gravitational mass and energy gradient in the ultra-strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Weng, Zi-Hua

    2017-07-01

    The paper aims to apply the complex octonion to explore the influence of the energy gradient on the Eötvös experiment, impacting the gravitational mass in the ultra-strong magnetic fields. Until now the Eötvös experiment has never been validated under the ultra-strong magnetic field. It is aggravating the existing serious qualms about the Eötvös experiment. According to the electromagnetic and gravitational theory described with the complex octonions, the ultra-strong magnetic field must result in a tiny variation of the gravitational mass. The magnetic field with the gradient distribution will generate the energy gradient. These influencing factors will exert an influence on the state of equilibrium in the Eötvös experiment. That is, the gravitational mass will depart from the inertial mass to a certain extent, in the ultra-strong magnetic fields. Only under exceptional circumstances, especially in the case of the weak field strength, the gravitational mass may be equal to the inertial mass approximately. The paper appeals intensely to validate the Eötvös experiment in the ultra-strong electromagnetic strengths. It is predicted that the physical property of gravitational mass will be distinct from that of inertial mass.

  19. Numerical Analysis of Electromagnetic Fields in Multiscale Model

    NASA Astrophysics Data System (ADS)

    Ma, Ji; Fang, Guang-You; Ji, Yi-Cai

    2015-04-01

    Modeling technique for electromagnetic fields excited by antennas is an important topic in computational electromagnetics, which is concerned with the numerical solution of Maxwell's equations. In this paper, a novel hybrid technique that combines method of moments (MoM) with finite-difference time-domain (FDTD) method is presented to handle the problem. This approach employed Huygen's principle to realize the hybridization of the two classical numerical algorithms. For wideband electromagnetic data, the interpolation scheme is used in the MoM based on the dyadic Green's function. On the other hand, with the help of equivalence principle, the scattered electric and magnetic fields on the Huygen's surface calculated by MoM are taken as the sources for FDTD. Therefore, the electromagnetic fields in the environment can be obtained by employing finite-difference time-domain method. Finally, numerical results show the validity of the proposed technique by analyzing two canonical samples. Supported in part by China Postdoctoral Science Foundation under Grant No. 201M550839, and in part by the Key Research Program of the Chinese Academy of Sciences under Grant No. KGZD-EW-603

  20. Heavy meson spectroscopy under strong magnetic field

    NASA Astrophysics Data System (ADS)

    Yoshida, Tetsuya; Suzuki, Kei

    2016-10-01

    Spectra of the neutral heavy mesons, ηc(1 S ,2 S ), J /ψ , ψ (2 S ), ηb(1 S ,2 S ,3 S ), ϒ (1 S ,2 S ,3 S ) , D , D*, B , B*, Bs and Bs*, in a homogeneous magnetic field are analyzed by using a potential model with constituent quarks. To obtain anisotropic wave functions and the corresponding eigenvalues, the cylindrical Gaussian expansion method is applied, where the wave functions for transverse and longitudinal directions in the cylindrical coordinate are expanded by the Gaussian bases separately. Energy level structures in the wide range of magnetic fields are obtained and the deformation of the wave functions is shown, which reflects effects of the spin mixing, the Zeeman splitting and quark Landau levels. The contribution from the magnetic catalysis in heavy-light mesons is discussed as a change of the light constituent quark mass.

  1. Electromagnetic Field Effects in Semiconductor Crystal Growth

    NASA Technical Reports Server (NTRS)

    Dulikravich, George S.

    1996-01-01

    This proposed two-year research project was to involve development of an analytical model, a numerical algorithm for its integration, and a software for the analysis of a solidification process under the influence of electric and magnetic fields in microgravity. Due to the complexity of the analytical model that was developed and its boundary conditions, only a preliminary version of the numerical algorithm was developed while the development of the software package was not completed.

  2. 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.

  3. Meson spectrum in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Andreichikov, M. A.; Kerbikov, B. O.; Orlovsky, V. D.; Simonov, Yu. A.

    2013-05-01

    We study the relativistic quark-antiquark system embedded in a magnetic field (MF). The Hamiltonian containing confinement, one gluon exchange, and spin-spin interaction is derived. We analytically follow the evolution of the lowest meson states as a function of MF strength. Calculating the one gluon exchange interaction energy ⟨VOGE⟩ and spin-spin contribution ⟨aSS⟩ we have observed that these corrections remain finite at large MF, preventing the vanishing of the total ρ meson mass at some Bcrit, as previously thought. We display the ρ masses as functions of the MF in comparison with recent lattice data.

  4. Dynamics of ionisation and entanglement in the 'atom + quantum electromagnetic field' system

    SciTech Connect

    Sharapova, P R; Tikhonova, O V

    2012-03-31

    The dynamics of a model Rydberg atom in a strong nonclassical electromagnetic field is investigated. The field-induced transitions to the continuum involving different numbers of photons (with intermediate states in the discrete spectrum) are taken into account and the specific features of ionisation in 'squeezed' field states are considered in comparison with the case of classical light. A significant decrease in the ionisation rate is found, which is caused by the interference stabilisation of the atomic system. The entanglement of the atomic and field subsystems, the temporal dynamics of the correlations found, and the possibility of measuring them are analysed.

  5. Exposure to electromagnetic fields from laptop use of "laptop" computers.

    PubMed

    Bellieni, C V; Pinto, I; Bogi, A; Zoppetti, N; Andreuccetti, D; Buonocore, G

    2012-01-01

    Portable computers are often used at tight contact with the body and therefore are called "laptop." The authors measured electromagnetic fields (EMFs) laptop computers produce and estimated the induced currents in the body, to assess the safety of laptop computers. The authors evaluated 5 commonly used laptop of different brands. They measured EMF exposure produced and, using validated computerized models, the authors exploited the data of one of the laptop computers (LTCs) to estimate the magnetic flux exposure of the user and of the fetus in the womb, when the laptop is used at close contact with the woman's womb. In the LTCs analyzed, EMF values (range 1.8-6 μT) are within International Commission on Non-Ionizing Radiation (NIR) Protection (ICNIRP) guidelines, but are considerably higher than the values recommended by 2 recent guidelines for computer monitors magnetic field emissions, MPR II (Swedish Board for Technical Accreditation) and TCO (Swedish Confederation of Professional Employees), and those considered risky for tumor development. When close to the body, the laptop induces currents that are within 34.2% to 49.8% ICNIRP recommendations, but not negligible, to the adult's body and to the fetus (in pregnant women). On the contrary, the power supply induces strong intracorporal electric current densities in the fetus and in the adult subject, which are respectively 182-263% and 71-483% higher than ICNIRP 98 basic restriction recommended to prevent adverse health effects. Laptop is paradoxically an improper site for the use of a LTC, which consequently should be renamed to not induce customers towards an improper use.

  6. Proton Radiography as an electromagnetic field and density perturbation diagnostic

    SciTech Connect

    Mackinnon, A; Patel, P; Town, R; Edwards, M; Phillips, T; Lerner, S; Price, D; Hicks, D; Key, M; Hatchett, S; Wilks, S; King, J; Snavely, R; Freeman, R; Boehlly, T; Koenig, M; Martinolli, E; Lepape, S; Benuzzi-Mounaix, A; Audebert, P; Gauthier, J; Borghesi, M; Romagnani, L; Toncian, T; Pretzler, G; Willi, O

    2004-04-15

    Laser driven proton beams have been used to diagnose transient fields and density perturbations in laser produced plasmas. Grid deflectometry techniques have been applied to proton radiography to obtain precise measurements of proton beam angles caused by electromagnetic fields in laser produced plasmas. Application of proton radiography to laser driven implosions has demonstrated that density conditions in compressed media can be diagnosed with MeV protons. This data has shown that proton radiography can provide unique insight into transient electromagnetic fields in super critical density plasmas and provide a density perturbation diagnostics in compressed matter . PACS numbers: 52.50.Jm, 52.40.Nk, 52.40.Mj, 52.70.Kz

  7. Momentum of the electromagnetic field in transparent dielectric media

    NASA Astrophysics Data System (ADS)

    Mansuripur, Masud

    2007-09-01

    We present arguments in favor of the proposition that the momentum of light inside a transparent dielectric medium is the arithmetic average of the Minkowski and Abraham momenta. Using the Lorentz transformation of the fields (and of the coordinates) from a stationary to a moving reference frame, we show the consistent transformation of electromagnetic energy and momentum between the two frames. We also examine the momentum of static (i.e., time-independent) electromagnetic fields, and show that the close connection that exists between the Poynting vector and the momentum density extends all the way across the frequency spectrum to this zero-frequency limit. In the specific example presented in this paper, the static field inside a non-absorbing dielectric material turns out to have the Minkowski momentum.

  8. Beta Decay in the Field of an Electromagnetic Wave and Experiments on Measuring the Neutrino Mass

    SciTech Connect

    Dorofeev, O.F.; Lobanov, A.E.

    2005-06-01

    Investigations of the effect of an electromagnetic wave field on the beta-decay process are used to analyze the tritium-decay experimental data on the neutrino mass. It is shown that the electromagnetic wave can distort the beta spectrum, shifting the end point to the higher energy region. This phenomenon is purely classical and it is associated with the electron acceleration in the radiation field. Since strong magnetic fields exist in setups for precise measurement of the neutrino mass, the indicated field can appear owing to the synchrotron radiation mechanism. The phenomenon under consideration can explain the experimentally observed anomalies in the spectrum of the decay electrons; in particular, the effect of the 'negative square of the neutrino mass'.

  9. Strong terahertz field generation, detection, and application

    SciTech Connect

    Kim, Ki-Yong

    2016-05-22

    This report describes the generation and detection of high-power, broadband terahertz (THz) radiation with using femtosecond terawatt (TW) laser systems. In particular, this focuses on two-color laser mixing in gases as a scalable THz source, addressing both microscopic and macroscopic effects governing its output THz yield and radiation profile. This also includes the characterization of extremely broad THz spectra extending from microwaves to infrared frequencies. Experimentally, my group has generated high-energy (tens of microjoule), intense (>8 MV/cm), and broadband (0.01~60 THz) THz radiation in two-color laser mixing in air. Such an intense THz field can be utilized to study THz-driven extremely nonlinear phenomena in a university laboratory.

  10. Strong terahertz field generation, detection, and application

    SciTech Connect

    Kim, Ki-Yong

    2016-05-15

    This report describes the generation and detection of high-power, broadband terahertz (THz) radiation with using femtosecond terawatt (TW) laser systems. In particular, this focuses on two-color laser mixing in gases as a scalable THz source, addressing both microscopic and macroscopic effects governing its output THz yield and radiation profile. This also includes the characterization of extremely broad THz spectra extending from microwaves to infrared frequencies. Experimentally, my group has generated high-energy (tens of microjoule), intense (>8 MV/cm), and broadband (0.01~60 THz) THz radiation in two-color laser mixing in air. Such an intense THz field can be utilized to study THz-driven extremely nonlinear phenomena in a university laboratory.

  11. Controlling Electromagnetic Field by Graded Meta-materials

    NASA Astrophysics Data System (ADS)

    Sun, Lei

    Metamaterials , i.e. artificial materials with electromagnetic properties not readily available in nature, have become a major research topic in both scientific and engineering communities. Being different from conventional materials, metamaterials possess peculiar electromagnetic properties, e.g. negative refractive index, depending on their structures. In particular, metamaterials form a basis for achieving cloaking device that makes an object invisible or transparency to the probing electromagnetic wave. This topic has significant impact on various fields ranging from optics, medicine, biology to nanotechnology. Several cloaking techniques have been proposed by different research groups, namely, anomalous localized resonance, transformation optics, and scattering cancellation, etc. Each of them has its own advantages and disadvantages. For instance, the limitation in working frequency is a primary disadvantage of them. This thesis is concentrated on controlling electromagnetic field by graded metamaterials, i.e, metamaterials with graded structures, with the objective to realize the broadband electromagnetic transparency by extending the working frequency. Regarding the limitations of existing cloaking techniques, we propose the graded model based on the scattering cancellation technique, because it does not rely on resonant phenomena, and is fairly robust to relatively high variations of the shape and electromagnetic properties of the cloaked object. We modify the original Mie theory and Rayleigh scattering theory to deal with the graded metamaterial structures, and calculate the scattering cross section of graded isotropic and anisotropic spherical structures, an alytically and numerically. For the graded isotropic spherical structure, we achieve the exact analytic expressions for both full-wave and Rayleigh scattering cross sections, within our modified Mie theory and Rayleigh scattering theory. The numerical studies on the scattering cross sections clearly

  12. Consequences of Coupled Electromagnetic-Gravitational Fields

    NASA Technical Reports Server (NTRS)

    Smalley, Larry

    2002-01-01

    In the late 1980s there was a flurry of activities involving the newly discovered high Tc superconductors in the development of new devices such as more efficient current transmission, transformers, generators, and motors. One such developmental project by Podkletnov in 1992 noted some small, anomalous gravitational behaviors. A following unpublished paper by Podkletnov 1995 provided data with larger effects using a larger (approx. 25 cm) superconducting disk. Unfortunately this disk was extremely fragile and was broken beyond repair. To date, these experiments have not been successfully repeated because of the difficulties of producing stable, durable (and fired) superconducting disks. This problem with firing these disks has been solved by Li. What remains is to install the disk in "motor", at superconducting temperatures in the presence of appropriately tailored magnetic fields.

  13. Influence of 400, 900, and 1900 MHz electromagnetic fields on Lemna minor growth and peroxidase activity.

    PubMed

    Tkalec, Mirta; Malarić, Kresimir; Pevalek-Kozlina, Branka

    2005-04-01

    Increased use of radio and microwave frequencies requires investigations of their effects on living organisms. Duckweed (Lemna minor L.) has been commonly used as a model plant for environmental monitoring. In the present study, duckweed growth and peroxidase activity was evaluated after exposure in a Gigahertz Transversal Electromagnetic (GTEM) cell to electric fields of frequencies 400, 900, and 1900 MHz. The growth of plants exposed for 2 h to the 23 V/m electric field of 900 MHz significantly decreased in comparison with the control, while an electric field of the same strength but at 400 MHz did not have such effect. A modulated field at 900 MHz strongly inhibited the growth, while at 400 MHz modulation did not influence the growth significantly. At both frequencies a longer exposure mostly decreased the growth and the highest electric field (390 V/m) strongly inhibited the growth. Exposure of plants to lower field strength (10 V/m) for 14 h caused significant decrease at 400 and 1900 MHz while 900 MHz did not influence the growth. Peroxidase activity in exposed plants varied, depending on the exposure characteristics. Observed changes were mostly small, except in plants exposed for 2 h to 41 V/m at 900 MHz where a significant increase (41%) was found. Our results suggest that investigated electromagnetic fields (EMFs) might influence plant growth and, to some extent, peroxidase activity. However, the effects of EMFs strongly depended on the characteristics of the field exposure.

  14. Dynamics of liquid metal droplets and jets influenced by a strong axial magnetic field

    NASA Astrophysics Data System (ADS)

    Hernández, D.; Karcher, Ch

    2017-07-01

    Non-contact electromagnetic control and shaping of liquid metal free surfaces is crucial in a number of high-temperature metallurgical processes like levitation melting and electromagnetic sealing, among others. Other examples are the electromagnetic bending or stabilization of liquid metal jets that frequently occur in casting or fusion applications. Within this context, we experimentally study the influence of strong axial magnetic fields on the dynamics of falling metal droplets and liquid metal jets. GaInSn in eutectic composition is used as test melt being liquid at room temperature. In the experiments, we use a cryogen-free superconducting magnet (CFM) providing steady homogeneous fields of up to 5 T and allowing a tilt angle between the falling melt and the magnet axis. We vary the magnetic flux density, the tilt angle, the liquid metal flow rate, and the diameter and material of the nozzle (electrically conducting/insulating). Hence, the experiments cover a parameter range of Hartmann numbers Ha, Reynolds numbers Re, and Weber numbers We within 0 < Ha < 440, 340 < Re < 4500, and 0.09 < We < 12.1. As major results we find that under the influence of the strong magnetic field, droplet rotation ceases and the droplets are stretched in the field direction. Moreover, we observe that the jet breakup into droplets (spheroidization) is suppressed, and in the case of electrically conducting nozzles and tilt, the jets are bent towards the field axis.

  15. Electromagnetic field distributions in waveguide-based axial-type microwave plasma source

    NASA Astrophysics Data System (ADS)

    Nowakowska, H.; Jasiński, M.; Mizeraczyk, J.

    2009-08-01

    We present results from simulations of 2D distributions of the electromagnetic field inside a waveguide-based axial-type microwave plasma source (MPS) used for hydrogen production via methane reforming. The studies are aimed at optimization of discharge processes and hydrogen production. We derive equations for determining electromagnetic field distributions and next determine the electromagnetic field distributions for two cases - without and with plasma inside the MPS. For the first case, we examine the influence of the length of the inner conductor of the coaxial line on electromagnetic field distributions. We have obtained standing wave patterns along the coaxial line and found resonances for certain positions of the coaxial line inner conductor. For the case with plasma inside the MPS, we perform calculations assuming that distributions of plasma parameters are known. Simulations are done for several values of maximum electron density. We have found that for values of electron density greater than 3× 10^{18} m^{-3} strong skin effect in the plasma is observed. Consequently, plasma may be treated as an extension of the inner conductor of the coaxial line. We have used FlexPDE software for the calculations.

  16. Designing localized electromagnetic fields in a source-free space.

    PubMed

    Borzdov, George N

    2002-06-01

    An approach to characterizing and designing localized electromagnetic fields, based on the use of differentiable manifolds, differentiable mappings, and the group of rotation, is presented. By way of illustration, novel families of exact time-harmonic solutions to Maxwell's equations in the source-free space--localized fields defined by the rotation group--are obtained. The proposed approach provides a broad spectrum of tools to design localized fields, i.e., to build-in symmetry properties of oscillating electric and magnetic fields, to govern the distributions of their energy densities (both size and form of localization domains), and to set the structure of time-average energy fluxes. It is shown that localized fields can be combined as constructive elements to obtain a complex field structure with desirable properties, such as one-, two-, or three-dimensional field gratings. The proposed approach can be used in designing localized electromagnetic fields to govern motion and state of charged and neutral particles. As an example, motion of relativistic electrons in one-dimensional and three-dimensional field gratings is treated.

  17. Radiotelephone with reduced electromagnetic field in human head

    NASA Astrophysics Data System (ADS)

    King, Ronold W. P.

    1995-01-01

    The quarter-wave monopole base driven over a circular ground plane with a finite radius has applications in over-the-horizon radar and on surveillance aircraft. A new use, for which the analysis is given in this paper, is as an over-the-head-mounted antenna for cellular telephones. With this design, the electromagnetic field in the head and the associated specific absorption rate of electromagnetic energy are greatly reduced when compared with the conventional hand-held transceiver. A complete analysis is carried out of the electromagnetic field on the surface of the head and throughout its interior when the head is modeled as a cylinder with the electrical properties of the brain enclosed in a wall with the thickness and electrical properties of the skull. Graphs and tables are provided that give the field in the air on the surface of the head and in the skull and brain. The far field is also determined. The results are compared with those obtained with the hand-held radiotelephone (King, 1995).

  18. Electromagnetic fields in the exterior of an oscillating relativistic star - II. Electromagnetic damping

    NASA Astrophysics Data System (ADS)

    Rezzolla, Luciano; Ahmedov, Bobomurat J.

    2016-07-01

    An important issue in the asteroseismology of compact and magnetized stars is the determination of the dissipation mechanism which is most efficient in damping the oscillations when these are produced. In a linear regime and for low-multipolarity modes, these mechanisms are confined to either gravitational-wave or electromagnetic losses. We here consider the latter and compute the energy losses in the form of Poynting fluxes, Joule heating and Ohmic dissipation in a relativistic oscillating spherical star with a dipolar magnetic field in vacuum. While this approach is not particularly realistic for rapidly rotating stars, it has the advantage that it is fully analytic and that it provides expressions for the electric and magnetic fields produced by the most common modes of oscillation both in the vicinity of the star and far away from it. In this way, we revisit and extend to a relativistic context the classical estimates of McDermott et al. Overall, we find that general-relativistic corrections lead to electromagnetic damping time-scales that are at least one order of magnitude smaller than in Newtonian gravity. Furthermore, with the only exception of g (gravity) modes, we find that f (fundamental), p (pressure), i (interface) and s (shear) modes are suppressed more efficiently by gravitational losses than by electromagnetic ones.

  19. [New mechanisms of biological effects of electromagnetic fields].

    PubMed

    Buchachenko, A L; Kuznetsov, D A; Berdinskiĭ, V L

    2006-01-01

    The production of ATP in mitochondria depends on the magnesium nuclear spin and magnetic moment of a Mg2+ ion in creatine kinase and ATPase. This suggests that enzymatic synthesis of ATP is an ion-radical process and thus depends on the external magnetic field (magnetobiology originates from this fact) and microwave fields, which control the spin states of ion-radical pairs and affect the ATP synthesis. The chemical mechanism of ATP synthesis and the origin of biological effects of electromagnetic (microwave) fields are discussed.

  20. Invariant superoscillatory electromagnetic fields in 3D-space

    NASA Astrophysics Data System (ADS)

    Makris, K. G.; Papazoglou, D. G.; Tzortzakis, S.

    2017-01-01

    We derive exact solutions of Maxwell’s equations based on superoscillatory superpositions of vectorial Bessel beams. These novel beams are diffraction-free and can support subwavelength features in their transverse electromagnetic fields, without the presence of any evanescent waves. These features can be propagated into the far field. Approximate solutions in closed form are also derived based on asymptotic expansions of Bessel functions for simple prescribed subwavelength patterns. The superoscillatory characteristics of both electric, magnetic field components (transverse and longitudinal), and the Poynting vector, as well as, the effect of nonparaxiality are systematically investigated.

  1. Neutron stars in a perturbative f(R) gravity model with strong magnetic fields

    SciTech Connect

    Cheoun, Myung-Ki; Deliduman, Cemsinan; Güngör, Can; Keleş, Vildan; Ryu, C.Y.; Kajino, Toshitaka; Mathews, Grant J. E-mail: cemsinan@msgsu.edu.tr E-mail: kelesvi@itu.edu.tr E-mail: kajino@nao.ac.jp

    2013-10-01

    In Kaluza-Klein electromagnetism it is natural to associate modified gravity with strong electromagnetic fields. Hence, in this paper we investigate the combined effects of a strong magnetic field and perturbative f(R) gravity on the structure of neutron stars. The effect of an interior strong magnetic field of about 10{sup 17−18} G on the equation of state is derived in the context of a quantum hadrodynamics (QHD) equation of state (EoS) including effects of the magnetic pressure and energy along with occupied Landau levels. Adopting a random orientation of interior field domains, we solve the modified spherically symmetric hydrostatic equilibrium equations derived for a gravity model with f(R) = R+αR{sup 2}. Effects of both the finite magnetic field and the modified gravity are detailed for various values of the magnetic field and the perturbation parameter α along with a discussion of their physical implications. We show that there exists a parameter space of the modified gravity and the magnetic field strength, in which even a soft equation of state can accommodate a large ( > 2 M{sub s}un) maximum neutron star mass.

  2. Effects of noise and electromagnetic fields on reproductive outcomes.

    PubMed Central

    Meyer, R E; Aldrich, T E; Easterly, C E

    1989-01-01

    Much public health research has been directed to studies of cancer risks due to chemical agents. Recently, increasing attention has been given to adverse reproductive outcomes as another, shorter-term biologic indicator of public health impact. Further, several low-level ubiquitous physical agents have been implicated recently as possibly affecting human health. These physical factors (noise and electromagnetic fields) represent difficult topics for research with epidemiologic study methods. This paper provides a brief review of the published data related to the risk of adverse reproductive outcomes and exposure to noise or electromagnetic fields. The discussion includes ideas for possible biologic mechanisms, considerations for exposure assessment, and suggestions for epidemiologic research. PMID:2667980

  3. Soft hairs on isolated horizon implanted by electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Mao, Pujian; Wu, Xiaoning; Zhang, Hongbao

    2017-03-01

    Inspired by the recent proposal of soft hair on black holes in Hawking et al (2016 Phys. Rev. Lett. 116 231301), we have shown that an isolated horizon carries soft hairs implanted by electromagnetic fields. The solution space and the asymptotic symmetries of Einstein–Maxwell theory have been worked out explicitly near the isolated horizon. The conserved current has been computed and an infinite number of near horizon charges have been introduced from the electromagnetic fields associated with the asymptotic U(1) symmetry near the horizon, which indicates the fact that the isolated horizon carries a large amount of soft electric hairs. The soft electric hairs, i.e. asymptotic U(1) charges, are shown to be equivalent to the electric multipole moments of isolated horizons. It is further argued that the isolated horizon supertranslation is from the ambiguity of its foliation and an analogue of memory effect on horizon can be expected.

  4. Acoustic effect of an electromagnetic pulsed UHF field

    SciTech Connect

    Kapyrin, Yu.V.; Moiseev, V.I.; Petrenko, V.V.

    1988-06-01

    During the course of studies on the Fakel linear accelerator it was found that the metal structures of the electrodynamic components of the accelerator are subjected to ultrasonic vibrations, the intensity and spectral composition of which depend on the operating regimes of its high-frequency system and on the conditions of resonance energy exchange between the electromagnetic field and the particle beam. From the results of calculations and measurements, the authors of this paper propose, without ruling out the contribution of other sources, that the ultrasonic signals observed in the irises and regular square waveguides of an accelerator can be attributed to the A ponderomotive effect of powerful pulses of the high-frequency electromagnetic field.

  5. Asseleration of ions in turbulent electromagnetic field during dipolarization events

    NASA Astrophysics Data System (ADS)

    Zhukova, Elena; Popov, Victor

    2017-04-01

    In spite of the long time interest for the acceleration of hight energetic ions in the Earth's magnetotail, considerable uncertainty remains as to the quantitative influence of different acceleration mechanism and their modifications. Both theoretical and numerical studies predict a hardening of the energy spectra of the particles wandering into the current sheet. Such energetic ion fluxes in the near-Earth tail were usually observed during magnetic dipolarizations or presence of turbulent electromagnetic field in the central region of current sheet that can effectively interact with the charged particles and energize them. The results demonstrate particle acceleration by separate two mechanisms and by their joint action. Both acceleration mechanisms lead to the formation of powered tails in proton distribution functions. Generally acceleration on magnetic dipolarization can be more effective in comparison with turbulent electromagnetic field.

  6. Immunorehabilitating effect of ultrahigh frequency electromagnetic fields in immunocompromised animals.

    PubMed

    Pershin, S B; Bobkova, A S; Derevnina, N A; Sidorov, V D

    2013-06-01

    We observed immunorehabilitation effects of ultrahigh frequency electromagnetic fields (microwaves) in immunocompromised animals. It was shown that microwave irradiation of the thyroid gland area could abolish actinomycin D- and colchicine-induced immunosuppression and did not affect immunosuppression caused by 5-fluorouracil. These findings suggest that changes in the hormonal profile of the organism during microwave exposure can stimulate the processes of transcription and mitotic activity of lymphoid cells.

  7. Immune Response to Electromagnetic Fields through Cybernetic Modeling

    SciTech Connect

    Godina-Nava, J. J.; Segura, M. A. Rodriguez; Cadena, S. Reyes; Sierra, L. C. Gaitan

    2008-08-11

    We study the optimality of the humoral immune response through a mathematical model, which involves the effect of electromagnetic fields over the large lymphocytes proliferation. Are used the so called cybernetic variables in the context of the matching law of microeconomics or mathematical psychology, to measure the large lymphocytes population and to maximize the instantaneous antibody production rate in time during the immunologic response in order to most efficiently inactivate the antigen.

  8. Systemic Effects of Electromagnetic Fields in Patients with Myocardial Infarction

    NASA Astrophysics Data System (ADS)

    Cañedo-Dorantes, L.; Valle, L.; Uruchurtu, E.; Medel, A.; García-Mayen, F.; Serrano-Luna, G.

    2003-09-01

    Healing of acute myocardial infarction (AMI) is associated with inflammatory response, which promotes healing and scar formation. Activation of a local inflammatory response in patients with sequel of AMI could have an important role to enhance angiogenesis and regeneration of hibernating myocardial tissue. Chronic arterial leg ulcers have a similar etiology, and healing has been promoted by exposure to extremely low frequency electromagnetic fields (ELF). We report the evolution of three AMI patients with sequel of AMI that were exposed to ELF.

  9. Immune Response to Electromagnetic Fields through Cybernetic Modeling

    NASA Astrophysics Data System (ADS)

    Godina-Nava, J. J.; Segura, M. A. Rodríguez; Cadena, S. Reyes; Sierra, L. C. Gaitán

    2008-08-01

    We study the optimality of the humoral immune response through a mathematical model, which involves the effect of electromagnetic fields over the large lymphocytes proliferation. Are used the so called cybernetic variables in the context of the matching law of microeconomics or mathematical psychology, to measure the large lymphocytes population and to maximize the instantaneous antibody production rate in time during the immunologic response in order to most efficiently inactivate the antigen.

  10. Low-frequency electromagnetic field in a Wigner crystal

    SciTech Connect

    Stupka, Anton

    2013-03-15

    Long-wave low-frequency oscillations are described in a Wigner crystal by generalization of the reverse continuum model for the case of electronic lattice. The internal self-consistent long-wave electromagnetic field is used to describe the collective motions in the system. The eigenvectors and eigenvalues of the obtained system of equations are derived. The velocities of longitudinal and transversal sound waves are found.

  11. Effects of Pulsed Electromagnetic Fields on Osteoporosis Model

    NASA Astrophysics Data System (ADS)

    Xiaowei, Yang; Liming, Wang; Guan, Z. C.; Yaou, Zhang; Xiangpeng, Wang

    The purpose of this paper was to investigate the preventive effects and long term effects of extremely low frequency pulsed electromagnetic fields (PEMFs), generated by circular coils and pulsed electromagnetic fields stimulators, on osteoporosis in bilaterally ovariectomized rats. In preventive experiment, thirty three-month old female Sprague-Dawley rats were randomly divided into three different groups: sham (SHAM), ovariectomy (OVX), PEMFs stimulation (PEMFs). All rats were subjected to bilaterally ovariectomy except those in SHAM group. The PEMFs group was exposed to pulsed electromagnetic fields with frequency 15 Hz, peak magnetic induction density 2.2mT and exposure time 2 hours per day. The bone mineral density (BMD) of vertebra and left femur were measured by dual energy X-ray absorptiometry at eighth week, twelfth week and sixteenth week after surgery. In long term effects experiment, forty four rats were randomly divided into sham (14 rats, SHAM), ovariectomy group (10 rats, OVX), 15Hz PEMFs group(10 rats, 15Hz) and 30Hz PEMFs group(10 rats, 30Hz) at twenty-sixth week after surgery. Rats in PEMFs groups were stimulated sixteen weeks. In preventive experiment, the Corrected BMD of vertebra and femur was significantly higher than that of OVX group after 16 weeks (P<0.001, P<0.001 respectively). In long term effects experiment, the vertebral BMD of 15Hz PEMFs group and 30Hz PEMFs group was significantly higher than that of OVX groups (P<0.01, P<0.05 respectively). The experimental results demonstrated that extremely low intensity, low frequency, single pulsed electromagnetic fields significantly slowed down the loss of corrected vertebral and femoral BMD in bilaterally ovariectomized rats and suggest that PEMFs may be beneficial in the treatment of osteoporosis.

  12. Electron Dynamics in Nanostructures in Strong Laser Fields

    SciTech Connect

    Kling, Matthias

    2014-09-11

    The goal of our research was to gain deeper insight into the collective electron dynamics in nanosystems in strong, ultrashort laser fields. The laser field strengths will be strong enough to extract and accelerate electrons from the nanoparticles and to transiently modify the materials electronic properties. We aimed to observe, with sub-cycle resolution reaching the attosecond time domain, how collective electronic excitations in nanoparticles are formed, how the strong field influences the optical and electrical properties of the nanomaterial, and how the excitations in the presence of strong fields decay.

  13. 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

  14. Electromagnetic field interacting with a semi-infinite plasma.

    PubMed

    Apostol, M; Vaman, G

    2009-07-01

    Plasmon and polariton modes are derived for an ideal semi-infinite (half-space) plasma by using a general, unifying procedure based on the equation of motion of the polarization and the electromagnetic potentials. Known results are reproduced in a much more direct manner, and new ones are derived. The approach consists of representing the charge disturbances by a displacement field in the positions of the moving particles (electrons). The propagation of an electromagnetic wave in this plasma is treated by using the retarded electromagnetic potentials. The resulting integral equations are solved, and the reflected and refracted fields are computed, as well as the reflection coefficient. Generalized Fresnel relations are thereby obtained for any incidence angle and polarization. Bulk and surface plasmon-polariton modes are identified. As is well known, the field inside the plasma is either damped (evanescent) or propagating (transparency regime), and the reflection coefficient exhibits an abrupt enhancement on passing from the propagating regime to the damped one (total reflection).

  15. Offshore windmills and the effects of electromagnetic fields on fish.

    PubMed

    Ohman, Marcus C; Sigray, Peter; Westerberg, Håkan

    2007-12-01

    With the large scale developments of offshore windpower the number of underwater electric cables is increasing with various technologies applied. A wind farm is associated with different types of cables used for intraturbine, array-to-transformer, and transformer-to-shore transmissions. As the electric currents in submarine cables induce electromagnetic fields there is a concern of how they may influence fishes. Studies have shown that there are fish species that are magneto-sensitive using geomagnetic field information for the purpose of orientation. This implies that if the geomagnetic field is locally altered it could influence spatial patterns in fish. There are also physiological aspects to consider, especially for species that are less inclined to move as the exposure could be persistent in a particular area. Even though studies have shown that magnetic fields could affect fish, there is at present limited evidence that fish are influenced by the electromagnetic fields that underwater cables from windmills generate. Studies on European eel in the Baltic Sea have indicated some minor effects. In this article we give an overview on the type of submarine cables that are used for electric transmissions in the sea. We also describe the character of the magnetic fields they induce. The effects of magnetic fields on fish are reviewed and how this may relate to the cables used for offshore wind power is discussed.

  16. Risk assessment of electromagnetic fields exposure with metallic orthopedic implants: a cadaveric study.

    PubMed

    Crouzier, D; Selek, L; Martz, B-A; Dabouis, V; Arnaud, R; Debouzy, J-C

    2012-02-01

    Metallic materials are well known to strongly interact with electromagnetic fields. While biological effects of such field have been extensively studied, only few works dealt with the interactions of electromagnetic waves with passive metallic device implanted in biological system. Hence only several numerical and phantom simulation studies were focusing on this aspect, whereas no in situ anatomic experiment has been previously performed. In this study the effect of electromagnetic waves on eight different orthopaedic medical devices (six plates from 55 to 318mm length, a total knee and a total hip prosthesis) were explored on six human cadavers. To mimic a random environmental exposure resulting from the most common frequencies band used in domestic environment and medical applications (TV and radio broadcasting, cell phone communication, MRI, diathermy treatment), a multifrequency generator emitting in VHF, UHF, GSM and GCS frequency bands was used. The different medical devices were exposed to an electromagnetic field at 50W/m(2) and 100W/m(2). After 6min exposure, the temperature was measured on three points close to each medical device, and the induced currents were estimated. No significant temperature increase (<0.2°C) was finally detected; beside, a slight induced tension (up to 1.1V) was recorded but would appear too low to induce any biological side effect. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  17. Physics in Strong Magnetic Fields Near Neutron Stars.

    ERIC Educational Resources Information Center

    Harding, Alice K.

    1991-01-01

    Discussed are the behaviors of particles and energies in the magnetic fields of neutron stars. Different types of possible research using neutron stars as a laboratory for the study of strong magnetic fields are proposed. (CW)

  18. Physics in Strong Magnetic Fields Near Neutron Stars.

    ERIC Educational Resources Information Center

    Harding, Alice K.

    1991-01-01

    Discussed are the behaviors of particles and energies in the magnetic fields of neutron stars. Different types of possible research using neutron stars as a laboratory for the study of strong magnetic fields are proposed. (CW)

  19. Electromagnetic fields in medicine - The state of art.

    PubMed

    Pasek, Jarosław; Pasek, Tomasz; Sieroń-Stołtny, Karolina; Cieślar, Grzegorz; Sieroń, Aleksander

    2016-01-01

    Intense development of methods belonging to physical medicine has been noted recently. There are treatment methods, which in many cases lead to reduction treatment time and positively influence on quality of life treatment patients. The present physical medicine systematically extends their therapeutic possibilities. This above applies to illnesses and injuries of locomotor system, diseases affecting of soft tissues, as well as chronic wounds. The evidence on this are the results of basic and clinical examinations relating the practical use of electromagnetic fields in medicine. In this work the authors introduced the procedure using the current knowledge relating to physical characteristic and biological effects of the magnetic fields. In the work the following methods were used: static magnetic fields, spatial magnetic fields, the variable magnetic fields both with laser therapy (magnetolaserotherapy) and variable magnetic fields both with light optical non-laser (magnetoledtherapy) talked.

  20. Strong-field ionization via a high-order Coulomb-corrected strong-field approximation

    NASA Astrophysics Data System (ADS)

    Klaiber, Michael; Daněk, Jiří; Yakaboylu, Enderalp; Hatsagortsyan, Karen Z.; Keitel, Christoph H.

    2017-02-01

    Signatures of the Coulomb corrections in the photoelectron momentum distribution during laser-induced ionization of atoms or ions in tunneling and multiphoton regimes are investigated analytically in the case of a one-dimensional problem. A high-order Coulomb-corrected strong-field approximation is applied, where the exact continuum state in the S matrix is approximated by the eikonal Coulomb-Volkov state including the second-order corrections to the eikonal. Although without high-order corrections our theory coincides with the known analytical R -matrix (ARM) theory, we propose a simplified procedure for the matrix element derivation. Rather than matching the eikonal Coulomb-Volkov wave function with the bound state as in the ARM theory to remove the Coulomb singularity, we calculate the matrix element via the saddle-point integration method by time as well as by coordinate, and in this way avoiding the Coulomb singularity. The momentum shift in the photoelectron momentum distribution with respect to the ARM theory due to high-order corrections is analyzed for tunneling and multiphoton regimes. The relation of the quantum corrections to the tunneling delay time is discussed.

  1. Optimization of an electromagnetic generator for strong shocks in low pressure gas

    NASA Astrophysics Data System (ADS)

    Larour, Jean; Singh, Raj Laxmi; Stehlé, Chantal; Ciardi, Andrea; Chaulagain, Uddhab; Suzuki-Vidal, Francisco

    2015-12-01

    In this paper, we present the design and optimization of an electromagnetic generator, able to produce strong shocks in noble gases, relevant to astrophysical conditions. It is a powerful accelerating device which ejects a quasi-planar plasma sheath out of a set of coaxial conical electrodes where a pulsed 100-kA current is passing. A simple model is used to optimize the operation parameters. Preliminary experiments show that the generator is capable of launching supersonic shocks in Argon, in the form of a thin plasma layer with the speed of ∼1-30 km/s. A three-dimension MHD simulation gives a description consistent with the model and with the observations.

  2. Studying the interplay of strong and electromagnetic forces in heavy-ion collisions with NICA

    NASA Astrophysics Data System (ADS)

    Rybicki, A.; Szczurek, A.; Kłusek-Gawenda, M.; Sputowska, I.

    2016-08-01

    In the following we stress the advantages of the NICA research programme in the context of studying the spectator-induced electromagnetic phenomena present in heavy-ion collisions. We point at the specific interest of using these phenomena as a new, independent source of information on the space-time evolution of the reaction and of the non-perturbative process of particle production. We propose an extended series of measurements of well-defined observables to be performed in different types of nuclear reactions and in the whole range of collision energies available to NICA. We expect these measurements to bring very valuable new insight into the mechanism of non-perturbative strong interactions, complementary to the studies made at the SPS at CERN, RHIC at BNL, and the LHC.

  3. PREFACE: International Seminar on Strong and Electromagnetic Interactions in High Energy Collisions 2012

    NASA Astrophysics Data System (ADS)

    Giardina, Giorgio; Sandorfi, Andrew; Pedroni, Paolo

    2013-03-01

    The International Seminar 'Strong and Electromagnetic Interaction in High Energy Collisions' was held in the Conference Hall 'Ettore Majorana' of the Department of Physics in Messina, Italy on October 12, 2012. The Seminar was organized by the University of Messina and 'Fondazione Bonino-Pulejo', with the aim of presenting and discussing the results of the current experiments and also new plans involving research at INFN-LNF (Italy), JLAB (USA), LHC-CERN, ELSA (Bonn), MAMI (Mainz). The main purpose of this Seminar was to deal with aspects of electromagnetic and strong forces by meson photoproduction and the electron-positron collider, and to search for dark energy. The recent results on hadron contributions to the muon anomalous magnetic moment and kaon interferometry at the DAFNE facility were also discussed. Editors: Giorgio Giardina (University of Messina), Andrew M Sandorfi (Thomas Jefferson National Accelerator Facility, Newport News, USA), Paolo Pedroni (INFN 'Sezione di Pavia') Organizing Committee: Chairman: G Giardina (Messina - Italy) Co-Chairman: A M Sandorfi (Newport News, USA) Co-Chairman: P Pedroni (Pavia - Italy) Scientific Secretary: G Mandaglio (University of Messina - Italy) Organizing Institutions: University of Messina Fondazione Bonino-Pulejo (Messina) Topics: Meson photoproduction and baryon resonances Muon anomaly (g-2) Recent results in experiments at the Large Hadron Collider Kaon interferometry Local Organizing Committee: F Curciarello, V De Leo, G Fazio, G Giardina, G Mandaglio, M Romaniuk Sponsored by: University of Messina, Fondazione Bonino-Pulejo (Messina), INFN Sezione di Catania Web-Site: http://newcleo.unime.it/IntSem2012

  4. Reconstruction of velocity fields in electromagnetic flow tomography

    PubMed Central

    Lehtikangas, Ossi; Karhunen, Kimmo

    2016-01-01

    Electromagnetic flow meters (EMFMs) are the gold standard in measuring flow velocity in process industry. The flow meters can measure the mean flow velocity of conductive liquids and slurries. A drawback of this approach is that the velocity field cannot be determined. Asymmetric axial flows, often encountered in multiphase flows, pipe elbows and T-junctions, are problematic and can lead to serious systematic errors. Recently, electromagnetic flow tomography (EMFT) has been proposed for measuring velocity fields using several coils and a set of electrodes attached to the surface of the pipe. In this work, a velocity field reconstruction method for EMFT is proposed. The method uses a previously developed finite-element-based computational forward model for computing boundary voltages and a Bayesian framework for inverse problems. In the approach, the vz-component of the velocity field along the longitudinal axis of the pipe is estimated on the pipe cross section. Different asymmetric velocity fields encountered near pipe elbows, solids-in-water flows in inclined pipes and in stratified or multiphase flows are tested. The results suggest that the proposed reconstruction method could be used to estimate velocity fields in complicated pipe flows in which the conventional EMFMs have limited accuracy. This article is part of the themed issue ‘Supersensing through industrial process tomography’. PMID:27185961

  5. Reconstruction of velocity fields in electromagnetic flow tomography.

    PubMed

    Lehtikangas, Ossi; Karhunen, Kimmo; Vauhkonen, Marko

    2016-06-28

    Electromagnetic flow meters (EMFMs) are the gold standard in measuring flow velocity in process industry. The flow meters can measure the mean flow velocity of conductive liquids and slurries. A drawback of this approach is that the velocity field cannot be determined. Asymmetric axial flows, often encountered in multiphase flows, pipe elbows and T-junctions, are problematic and can lead to serious systematic errors. Recently, electromagnetic flow tomography (EMFT) has been proposed for measuring velocity fields using several coils and a set of electrodes attached to the surface of the pipe. In this work, a velocity field reconstruction method for EMFT is proposed. The method uses a previously developed finite-element-based computational forward model for computing boundary voltages and a Bayesian framework for inverse problems. In the approach, the vz-component of the velocity field along the longitudinal axis of the pipe is estimated on the pipe cross section. Different asymmetric velocity fields encountered near pipe elbows, solids-in-water flows in inclined pipes and in stratified or multiphase flows are tested. The results suggest that the proposed reconstruction method could be used to estimate velocity fields in complicated pipe flows in which the conventional EMFMs have limited accuracy. This article is part of the themed issue 'Supersensing through industrial process tomography'.

  6. Spectrum of classes of point emitters of electromagnetic wave fields.

    PubMed

    Castañeda, Román

    2016-09-01

    The spectrum of classes of point emitters has been introduced as a numerical tool suitable for the design, analysis, and synthesis of non-paraxial optical fields in arbitrary states of spatial coherence. In this paper, the polarization state of planar electromagnetic wave fields is included in the spectrum of classes, thus increasing its modeling capabilities. In this context, optical processing is realized as a filtering on the spectrum of classes of point emitters, performed by the complex degree of spatial coherence and the two-point correlation of polarization, which could be implemented dynamically by using programmable optical devices.

  7. Electromagnetic field properties in the vicinity of a massive wormhole

    SciTech Connect

    Novikov, I. D.; Shatskiy, A. A.

    2011-12-15

    It is proved that not only massless but also traversable massive wormholes can have electromagnetic 'hair.' An analysis is also presented of the passage from a traversable wormhole to the limit of a Reissner-Nordstroem black hole, with the corresponding disappearance of 'hair.' A general method is developed for solving stationary axisymmetric Maxwell's equations in the field of a massive, spherically symmetric wormhole. As a particular example of application of the method, a solution is found to the axisymmetric magnetostatic problem for a current loop in the field of the Bronnikov-Ellis-Morris-Thorne wormhole.

  8. Electromagnetic field redistribution in hybridized plasmonic particle-film system

    NASA Astrophysics Data System (ADS)

    Fang, Yurui; Huang, Yingzhou

    2013-04-01

    Combining simulation and experiment, we demonstrate that a metal nanoparticle dimer on a gold film substrate can confine more energy in the particle/film gap because of the hybridization of the dimer resonant lever and the continuous state of the film. The hybridization may even make the electric field enhancement in the dimer/film gap stronger than in the gap between particles. The resonant peak can be tuned by varying the size of the particles and the film thickness. This electromagnetic field redistribution has tremendous applications in sensor, photocatalysis and solar cell, etc., especially considering ultrasensitive detection of tracing molecule on substrates.

  9. Electromagnetic Field Quantization in Time-Dependent Linear Media

    SciTech Connect

    Pedrosa, I. A.; Rosas, Alexandre

    2009-07-03

    We present a quantization scheme for the electromagnetic field in time-dependent homogeneous nondispersive conducting and nonconducting linear media without sources. Using the Coulomb gauge, we demonstrate this quantization can be mapped into a damped (attenuated) time-dependent quantum harmonic oscillator. Remarkably, we find that the time dependence of the permittivity, for epsilon>0, gives rise to an attenuation of the radiation field. Afterwards, we obtain the exact wave functions for this problem and consider an exponential time accretion of the permittivity as a particular case.

  10. On a remarkable electromagnetic field in the Einstein Universe

    NASA Astrophysics Data System (ADS)

    Kopiński, Jarosław; Natário, José

    2017-06-01

    We present a time-dependent solution of the Maxwell equations in the Einstein universe, whose electric and magnetic fields, as seen by the stationary observers, are aligned with the Clifford parallels of the 3-sphere S^3. The conformal equivalence between Minkowski's spacetime and (a region of) the Einstein cylinder is then exploited in order to obtain a knotted, finite energy, radiating solution of the Maxwell equations in flat spacetime. We also discuss similar electromagnetic fields in expanding closed Friedmann models, and compute the matter content of such configurations.

  11. Electromagnetic field occupational exposure: non-thermal vs. thermal effects.

    PubMed

    Israel, M; Zaryabova, V; Ivanova, M

    2013-06-01

    There are a variety of definitions for "non-thermal effects" included in different international standards. They start by the simple description that they are "effects of electromagnetic energy on a body that are not heat-related effects", passing through the very general definition related to low-level effects: "biological effects ascribed to exposure to low-level electric, magnetic and electromagnetic fields, i.e. at or below the corresponding dosimetric reference levels in the frequency range covered in this standard (0 Hz-300 GHz)", and going to the concrete definition of "the stimulation of muscles, nerves, or sensory organs, vertigo or phosfenes". Here, we discuss what kind of effect does the non-thermal one has on human body and give data of measurements in different occupations with low-frequency sources of electromagnetic field such as electric power distribution systems, transformers, MRI systems and : video display units (VDUs), whereas thermal effects should not be expected. In some of these workplaces, values above the exposure limits could be found, nevertheless that they are in the term "non-thermal effects" on human body. Examples are workplaces in MRI, also in some power plants. Here, we will not comment on non-thermal effects as a result of RF or microwave exposure because there are not proven evidence about the existance of such effects and mechanisms for them are not clear.

  12. Synergistic health effects between chemical pollutants and electromagnetic fields.

    PubMed

    Ledoigt, Gérard; Sta, Chaima; Goujon, Eric; Souguir, Dalila; El Ferjani, Ezzeddine

    2015-01-01

    Humans and ecosystems are exposed to highly variable and unknown cocktail of chemicals and radiations. Although individual chemicals are typically present at low concentrations, they can interact with each other resulting in additive or potentially synergistic mixture effects. This was also observed with products obtained by radiation actions such as sunlight or electromagnetic fields that can change the effects of chemicals, such as pesticides, and metal trace elements on health. Concomitant presence of various pesticides and their transformation products adds further complexity to chemical risk assessment since chronic inflammation is a key step for cancer promotion. Degradation of a parent molecule can produce several by-products which can trigger various toxic effects with different impacts on health and environment. For instance, the cocktail of sunlight irradiated sulcotrione pesticide has a greater cytotoxicity and genotoxicity than parent molecule, sulcotrione, and questions about the impact of photochemical process on environment. Adjuvants were shown to modify the biological features of pesticides. Addition of other elements, metals or biological products, can differently enhance cell toxicity of pesticides or electromagnetic radiations suggesting a synergy in living organisms. Electromagnetic fields spreading, pesticide by-products and mixtures monitoring become greater for environmental contamination evaluations.

  13. Noise induced calcium oscillations in a cell exposed to electromagnetic fields.

    PubMed

    Zhang, Yuhong; Zhao, Yongli; Chen, Yafei; Yuan, Changqing; Zhan, Yong

    2015-01-01

    The effects of noise on the calcium oscillations in a cell exposed to electromagnetic fields are described by a dynamic model. Noise is a very important factor to be considered in the dynamic research on the calcium oscillations in a cell exposed to electromagnetic fields. Some meaningful results have been obtained here based on the discussion. The results show that the pattern of intracellular calcium oscillations exposure to electromagnetic fields can be influenced by noise. Furthermore, the intracellular calcium oscillations exposure to electromagnetic fields can also be induced by noise. And the work has also studied the relationships between the voltage sensitive calcium channel's open probability and electromagnetic field. The result can provide new insights into constructive roles and potential applications of selecting appropriate electromagnetic field frequency during the research of biological effect of electromagnetic field.

  14. Damping of Sound Waves in Strong Centrifugal Field

    NASA Astrophysics Data System (ADS)

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    A method for numerical calculation of the sound wave damping and dispersion law in a strong centrifugal field of the order of 106 g is considered. The damping is defined from the width of the resonance peak for different wave vectors. In the strong centrifugal field damping of the sound waves essentially exceeds the damping in the quiescent gas.

  15. Plasma effects in electromagnetic field interaction with biological tissue

    NASA Astrophysics Data System (ADS)

    Sharma, R. P.; Batra, Karuna; Excell, Peter S.

    2011-02-01

    Theoretical analysis is presented of the nonlinear behavior of charge carriers in biological tissue under the influence of varying low-intensity electromagnetic (EM) field. The interaction occurs because of the nonlinear force arising due to the gradient of the EM field intensity acting on free electrons in the conduction band of proteins in metabolically active biological cell membrane receptors leading to a redistribution of charge carriers. Field dependence of the resulting dielectric constant is investigated by a suitable modification to include an additional electronic contribution term to the three-term Debye model. The exogenous EM field propagating in this nonlinear cellular medium satisfies the nonlinear Schrödinger equation and can be affected significantly. Resulting field effect can be substantially augmented and effective rectification/demodulation can occur. Possible implications of this modification on biological processes in white and grey matter are discussed.

  16. Effects of Bluetooth device electromagnetic field on hearing: pilot study.

    PubMed

    Balachandran, R; Prepageran, N; Prepagaran, N; Rahmat, O; Zulkiflee, A B; Hufaida, K S

    2012-04-01

    The Bluetooth wireless headset has been promoted as a 'hands-free' device with a low emission of electromagnetic radiation. To evaluate potential changes in hearing function as a consequence of using Bluetooth devices, by assessing changes in pure tone audiography and distortion production otoacoustic emissions. Prospective study. Thirty adult volunteers were exposed to a Bluetooth headset device (1) on 'standby' setting for 6 hours and (2) at full power for 10 minutes. Post-exposure hearing was evaluated using pure tone audiography and distortion production otoacoustic emission testing. There were no statistically significant changes in hearing, as measured above, following either exposure type. Exposure to the electromagnetic field emitted by a Bluetooth headset, as described above, did not decrease hearing thresholds or alter distortion product otoacoustic emissions.

  17. Work and energy for particles in electromagnetic field

    NASA Astrophysics Data System (ADS)

    Babajanyan, S. G.

    2017-07-01

    Defining the energy and work for particles interacting with electromagnetic field (EMF) is an open problem, because—due to the gauge-freedom—there exist various non-equivalent possibilities. It is argued that a consistent definition can be provided via the Lorenz gauge. To this end, I work out a system of two electromagnetically coupled classical particles. One of them is much heavier and models the source of work. The definition of energy in the Lorenz gauge is causal and consistent, because it leads to an approximate conservation law due to which the work done by the heavy particle (source of work) can be defined either via the kinetic energy of the heavy particle, or via the full time-dependent energy (kinetic + potential in the Lorenz gauge) of the light particle.

  18. Evaluation of Electromagnetic Fields in a Hospital for Safe Use of Electronic Medical Equipment.

    PubMed

    Ishida, Kai; Fujioka, Tomomi; Endo, Tetsuo; Hosokawa, Ren; Fujisaki, Tetsushi; Yoshino, Ryoji; Hirose, Minoru

    2016-03-01

    Establishment of electromagnetic compatibility is important in use of electronic medical equipment in hospitals. To evaluate the electromagnetic environment, the electric field intensity induced by electromagnetic radiation in broadcasting spectra coming from outside the hospital was measured in a new hospital building before any patients visited the hospital and 6 months after the opening of the hospital. Various incoming radio waves were detected on the upper floors, with no significant difference in measured levels before and after opening of the hospital. There were no cellphone terminal signals before the hospital opened, but these signals were strongly detected at 6 months thereafter. Cellphone base stations signals were strongly detected on the upper floors, but there were no signals at most locations in the basement and in the center of the building on the lower floors. A maximum electrical intensity of 0.28 V/m from cellphone base stations (2.1 GHz) was detected at the south end of the 2nd floor before the hospital opened. This value is lower than the EMC marginal value for general electronic medical equipment specified in IEC 60601-1-2 (3 V/m). Therefore, electromagnetic interference with electronic medical equipment is unlikely in this situation. However, cellphone terminal signals were frequently detected in non-base station signal areas. This is a concern, and understanding signal strength from cellphone base stations at a hospital is important for promotion of greater safety.

  19. Atomic processes in strong bichromatic elliptically polarized laser fields

    SciTech Connect

    Odžak, S. Hasović, E.; Gazibegović-Busuladžić, A.; Čerkić, A. Fetić, B.; Kramo, A.; Busuladžić, M.; Milošević, D. B.

    2016-03-25

    Nonlinear quantum-mechanical phenomena in strong laser fields, such as high-order harmonic generation (HHG) and above-threshold ionization (ATI) are significantly modified if the applied laser field is bichromatic and/or elliptically polarized. Numerical results obtained within the strong-field approximation are presented for two special cases. We show results for HHG by plasma ablation in a bichromatic linearly polarized laser field. We also consider the ATI process in bicircular field which consists of two coplanar counter-rotating circularly polarized fields.

  20. Biological effects from electromagnetic field exposure and public exposure standards.

    PubMed

    Hardell, Lennart; Sage, Cindy

    2008-02-01

    During recent years there has been increasing public concern on potential health risks from power-frequency fields (extremely low frequency electromagnetic fields; ELF) and from radiofrequency/microwave radiation emissions (RF) from wireless communications. Non-thermal (low-intensity) biological effects have not been considered for regulation of microwave exposure, although numerous scientific reports indicate such effects. The BioInitiative Report is based on an international research and public policy initiative to give an overview of what is known of biological effects that occur at low-intensity electromagnetic fields (EMFs) exposure. Health endpoints reported to be associated with ELF and/or RF include childhood leukaemia, brain tumours, genotoxic effects, neurological effects and neurodegenerative diseases, immune system deregulation, allergic and inflammatory responses, breast cancer, miscarriage and some cardiovascular effects. The BioInitiative Report concluded that a reasonable suspicion of risk exists based on clear evidence of bioeffects at environmentally relevant levels, which, with prolonged exposures may reasonably be presumed to result in health impacts. Regarding ELF a new lower public safety limit for habitable space adjacent to all new or upgraded power lines and for all other new constructions should be applied. A new lower limit should also be used for existing habitable space for children and/or women who are pregnant. A precautionary limit should be adopted for outdoor, cumulative RF exposure and for cumulative indoor RF fields with considerably lower limits than existing guidelines, see the BioInitiative Report. The current guidelines for the US and European microwave exposure from mobile phones, for the brain are 1.6 W/Kg and 2 W/Kg, respectively. Since use of mobile phones is associated with an increased risk for brain tumour after 10 years, a new biologically based guideline is warranted. Other health impacts associated with exposure to

  1. The universal C*-algebra of the electromagnetic field II. Topological charges and spacelike linear fields

    NASA Astrophysics Data System (ADS)

    Buchholz, Detlev; Ciolli, Fabio; Ruzzi, Giuseppe; Vasselli, Ezio

    2017-02-01

    Conditions for the appearance of topological charges are studied in the framework of the universal C*-algebra of the electromagnetic field, which is represented in any theory describing electromagnetism. It is shown that non-trivial topological charges, described by pairs of fields localised in certain topologically non-trivial spacelike separated regions, can appear in regular representations of the algebra only if the fields depend non-linearly on the mollifying test functions. On the other hand, examples of regular vacuum representations with non-trivial topological charges are constructed, where the underlying field still satisfies a weakened form of "spacelike linearity". Such representations also appear in the presence of electric currents. The status of topological charges in theories with several types of electromagnetic fields, which appear in the short distance (scaling) limit of asymptotically free non-abelian gauge theories, is also briefly discussed.

  2. Effects of electromagnetic fields on fecundity in the chicken.

    PubMed

    Krueger, W F; Giarola, A J; Bradley, J W; Shrekenhamer, A

    1975-02-28

    Egg production was reduced when young laying hens were kept in contact with metal cages while being continuously exposed to the following cw fields: a vhf field at a frequency of 260 MHz, with an incident power that decreased from 100 to 4mW during the experiment; a uhf field at a frequency of 915 MHz, with an incident power of 800 mW during the first 2.5 weeks, zero during the following week, and 200 mW for the remainder of the experiment; a uhf field at 2.435 GHz, with an incident power of 800 mW; an elf electric field at a frequency of 60 Hz, with a calculated value of field strength of 1600 V/m; an elf magnetic field at 60 Hz, with a value of magnetic flux density of 1.4G. With the exception of the hens exposed to the uhf field at 915 MHz, all other treated groups laid significantly less eggs than the controls (p smaller than or equal to 0.01). This reduction (similar 15% less than the controls) began with the first 4-week production period. The egg production curves for the hens exposed to the vhf field at 260 MHz and to the uhf field at 2.435 GHz were approximately the same beginning with the sixth week of production, and they maintained comparable production levels for the remainder of the experiment. An 8% total drop in production also was experienced in the group of birds exposed to the 915-MHz field, which pulsed because of equipment failure. Egg production rate curves for the birds in the elf electric and magnetic fields were substantially different from those exhibited by birds in the other electromagnetic fields. The birds in the E-field regained a production level comparable to the controls after 11 weeks production, whereas those in the B-field dropped to 31% production, which was approximately 40% poorer than the controls by the twelfth week of production. Fertility of cocks and hens was not affected by continuous low-power vhf and uhf near-zone electromagnetic exposure or elf electric or magnetic field treatment. Fertility was exceptionally good

  3. 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.…

  4. 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.…

  5. Scattering of strong electromagnetic wave by relativistic electrons: Thomson and Compton regimes

    NASA Astrophysics Data System (ADS)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.

    2017-04-01

    The processes of the nonlinear Compton and the nonlinear Thomson scattering in a field of intense plane electromagnetic wave in terms of photon yield have been considered. The quantum consideration of the Compton scattering process allows us to calculate the probability of a few successive collisions k of an electron with laser photons accompanied by the absorption of n photons (nonlinear regime) when the number of collisions and the number of absorbed photons are of random quantities. The photon spectrum of the nonlinear Thomson scattering process was obtained from the classical formula for intensity using the Planck's law. The conditions for which the difference between the classical and the quantum regimes is manifested was obtained. Such a condition is determined by a discrete quantum radiation mechanism, namely, by the mean number of photons k bar emitted by an electron passing through the laser pulse.

  6. Chromosomal damage in human diploid fibroblasts by intermittent exposure to extremely low-frequency electromagnetic fields.

    PubMed

    Winker, Robert; Ivancsits, Sabine; Pilger, Alexander; Adlkofer, Franz; Rüdiger, H W

    2005-08-01

    Environmental exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) has been implicated in the development of cancer in humans. An important basis for assessing a potential cancer risk due to ELF-EMF exposure is knowledge of biological effects on human cells at the chromosomal level. Therefore, we investigated in the present study the effect of intermittent ELF electromagnetic fields (50 Hz, sinusoidal, 5'field-on/10'field-off, 2-24 h, 1 mT) on the induction of micronuclei (MN) and chromosomal aberrations in cultured human fibroblasts. ELF-EMF radiation resulted in a time-dependent increase of micronuclei, which became significant after 10 h of intermittent exposure at a flux density of 1 mT. After approximately 15 h a constant level of micronuclei of about three times the basal level was reached. In addition, chromosomal aberrations were increased up to 10-fold above basal levels. Our data strongly indicate a clastogenic potential of intermittent low-frequency electromagnetic fields, which may lead to considerable chromosomal damage in dividing cells.

  7. Influence of ELF sinusoidal electromagnetic fields on proliferation and metabolite yield of fungi.

    PubMed

    Berg, Albrecht; Berg, Hermann

    2006-01-01

    The response of mycelium proliferation in 12 strains of fungi were tested by sinusoidal ELF 50 Hz electromagnetic field treatment in the range B = 0.6-10 mT over 10 days. The ratio of experiment/control indicated three types of proliferation changes: a) no significant change, b) a strong decrease down to E/C = 0.2, c) a maximization of mycelium diameter by treatment at 5-7 mT. According to these results, effects can be produced noninvasively by varying either magnetic intensities or time of treatment. As yet, systematic bioelectromagnetic research using sinusoidal electromagnetic fields (SEMF)-on fermentation of fungi is still in its initial stages.

  8. Growth and differentiation of PC6 cells: the effects of pulsed electromagnetic fields (PEMF).

    PubMed

    Shah, J P; Midkiff, P; Brandt, P C; Sisken, B F

    2001-05-01

    Previous studies in our laboratory showed that neurite outgrowth in vitro and nerve regeneration in vivo were stimulated by 2 Hz, 0.3 mT (3 G) pulsed electromagnetic fields (PEMF). To learn more about the effects of PEMF on nerve cells, we exposed PC6 cells, a standard neuronal-like cell model, to the same pulsed electromagnetic fields for 2 h/day for 2 days and asked whether two different cell processes, proliferation and differentiation, were affected. The cells were also treated with a differentiating agent, nerve growth factor (NGF), to further define any interactive effects. We found that proliferation was unaffected by either PEMF or NGF alone or in combination. Differentiation, expressed as neurite outgrowth, was strongly upregulated with NGF, but this NGF response was significantly depressed in cells treated with PEMF. Copyright 2001 Wiley-Liss, Inc.

  9. Electromagnetic field of a charge traveling into an anisotropic medium.

    PubMed

    Galyamin, Sergey N; Tyukhtin, Andrey V

    2011-11-01

    We analyze the electromagnetic field generated by a point charge intersecting the interface between vacuum and a nonmagnetic anisotropic medium with a plasma-type dispersion of the dielectric permittivity tensor. After penetrating the medium, the charge moves along its main axis. The total field is presented as a sum of a self-field (i.e., a charge field in a corresponding unbounded medium) and a scattered field associated with the boundary influence. We show that the self-field in the considered anisotropic medium is divided into a quasistatic field and a wave field (the so-called "plasma trace" is absent in the case under consideration). Under certain conditions, the Vavilov-Cherenkov radiation generated in the medium is reversed (i.e., the energy flux density vector forms an obtuse angle with the direction of the charge motion). Accordingly, so-called reversed Cherenkov-transition radiation (RCTR) can be generated. We analytically and numerically investigate both the scattered field and the total one, and we show that RCTR exists in the vacuum region if the charge velocity exceeds a certain threshold value associated with total internal reflection. Computations of the Fourier harmonics of the field as well as the total field itself demonstrate that RCTR in vacuum can be a dominant effect. Some properties of RCTR can be useful for diagnostics of particle bunches and determination of medium characteristics.

  10. Electromagnetic field of a charge traveling into an anisotropic medium

    NASA Astrophysics Data System (ADS)

    Galyamin, Sergey N.; Tyukhtin, Andrey V.

    2011-11-01

    We analyze the electromagnetic field generated by a point charge intersecting the interface between vacuum and a nonmagnetic anisotropic medium with a plasma-type dispersion of the dielectric permittivity tensor. After penetrating the medium, the charge moves along its main axis. The total field is presented as a sum of a self-field (i.e., a charge field in a corresponding unbounded medium) and a scattered field associated with the boundary influence. We show that the self-field in the considered anisotropic medium is divided into a quasistatic field and a wave field (the so-called “plasma trace” is absent in the case under consideration). Under certain conditions, the Vavilov-Cherenkov radiation generated in the medium is reversed (i.e., the energy flux density vector forms an obtuse angle with the direction of the charge motion). Accordingly, so-called reversed Cherenkov-transition radiation (RCTR) can be generated. We analytically and numerically investigate both the scattered field and the total one, and we show that RCTR exists in the vacuum region if the charge velocity exceeds a certain threshold value associated with total internal reflection. Computations of the Fourier harmonics of the field as well as the total field itself demonstrate that RCTR in vacuum can be a dominant effect. Some properties of RCTR can be useful for diagnostics of particle bunches and determination of medium characteristics.

  11. Electromagnetic field of a charge traveling into an anisotropic medium

    SciTech Connect

    Galyamin, Sergey N.; Tyukhtin, Andrey V.

    2011-11-15

    We analyze the electromagnetic field generated by a point charge intersecting the interface between vacuum and a nonmagnetic anisotropic medium with a plasma-type dispersion of the dielectric permittivity tensor. After penetrating the medium, the charge moves along its main axis. The total field is presented as a sum of a self-field (i.e., a charge field in a corresponding unbounded medium) and a scattered field associated with the boundary influence. We show that the self-field in the considered anisotropic medium is divided into a quasistatic field and a wave field (the so-called 'plasma trace' is absent in the case under consideration). Under certain conditions, the Vavilov-Cherenkov radiation generated in the medium is reversed (i.e., the energy flux density vector forms an obtuse angle with the direction of the charge motion). Accordingly, so-called reversed Cherenkov-transition radiation (RCTR) can be generated. We analytically and numerically investigate both the scattered field and the total one, and we show that RCTR exists in the vacuum region if the charge velocity exceeds a certain threshold value associated with total internal reflection. Computations of the Fourier harmonics of the field as well as the total field itself demonstrate that RCTR in vacuum can be a dominant effect. Some properties of RCTR can be useful for diagnostics of particle bunches and determination of medium characteristics.

  12. Momentum transport in strongly coupled anisotropic plasmas in the presence of strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Finazzo, Stefano Ivo; Critelli, Renato; Rougemont, Romulo; Noronha, Jorge

    2016-09-01

    We present a holographic perspective on momentum transport in strongly coupled, anisotropic non-Abelian plasmas in the presence of strong magnetic fields. We compute the anisotropic heavy quark drag forces and Langevin diffusion coefficients and also the anisotropic shear viscosities for two different holographic models, namely, a top-down deformation of strongly coupled N =4 super-Yang-Mills theory triggered by an external Abelian magnetic field, and a bottom-up Einstein-Maxwell-dilaton (EMD) model which is able to provide a quantitative description of lattice QCD thermodynamics with (2 +1 ) flavors at both zero and nonzero magnetic fields. We find that, in general, energy loss and momentum diffusion through strongly coupled anisotropic plasmas are enhanced by a magnetic field being larger in transverse directions than in the direction parallel to the magnetic field. Moreover, the anisotropic shear viscosity coefficient is smaller in the direction of the magnetic field than in the plane perpendicular to the field, which indicates that strongly coupled anisotropic plasmas become closer to the perfect fluid limit along the magnetic field. We also present, in the context of the EMD model, holographic predictions for the entropy density and the crossover critical temperature in a wider region of the (T , B ) phase diagram that has not yet been covered by lattice simulations. Our results for the transport coefficients in the phenomenologically realistic magnetic EMD model could be readily used as inputs in numerical codes for magnetohydrodynamics.

  13. Instability-driven electromagnetic fields in coronal plasmas

    SciTech Connect

    Manuel, M. J.-E.; Li, C. K.; Seguin, F. H.; Sinenian, N.; Frenje, J. A.; Casey, D. T.; Petrasso, R. D.; Hager, J. D.; Betti, R.; Hu, S. X.; Delettrez, J.; Meyerhofer, D. D.

    2013-04-15

    Filamentary electromagnetic fields previously observed in the coronae of laser-driven spherical targets [F. H. S eguin et al., Phys. Plasma. 19, 012701 (2012)] have been further investigated in laser irradiated plastic foils. Face-on proton-radiography provides an axial view of these filaments and shows coherent cellular structure regardless of initial foil-surface conditions. The observed cellular fields are shown to have an approximately constant scale size of 210 lm throughout the plasma evolution. A discussion of possible field-generation mechanisms is provided and it is demonstrated that the likely source of the cellular field structure is the magnetothermal instability. Using predicted temperature and density profiles, the fastest growing modes of this instability were found to be slowly varying in time and consistent with the observed cellular size.

  14. Instability-driven electromagnetic fields in coronal plasmas

    DOE PAGES

    Manuel, M. J.-E.; Li, C. K.; Seguin, F. H.; ...

    2013-04-15

    Filamentary electromagnetic fields previously observed in the coronae of laser-driven spherical targets [F. H. S eguin et al., Phys. Plasma. 19, 012701 (2012)] have been further investigated in laser irradiated plastic foils. Face-on proton-radiography provides an axial view of these filaments and shows coherent cellular structure regardless of initial foil-surface conditions. The observed cellular fields are shown to have an approximately constant scale size of 210 lm throughout the plasma evolution. A discussion of possible field-generation mechanisms is provided and it is demonstrated that the likely source of the cellular field structure is the magnetothermal instability. Using predicted temperature andmore » density profiles, the fastest growing modes of this instability were found to be slowly varying in time and consistent with the observed cellular size.« less

  15. Human disease resulting from exposure to electromagnetic fields.

    PubMed

    Carpenter, David O

    2013-01-01

    Electromagnetic fields (EMFs) include everything from cosmic rays through visible light to the electric and magnetic fields associated with electricity. While the high frequency fields have sufficient energy to cause cancer, the question of whether there are human health hazards associated with communication radiofrequency (RF) EMFs and those associated with use of electricity remains controversial. The issue is more important than ever given the rapid increase in the use of cell phones and other wireless devices. This review summarizes the evidence stating that excessive exposure to magnetic fields from power lines and other sources of electric current increases the risk of development of some cancers and neurodegenerative diseases, and that excessive exposure to RF radiation increases risk of cancer, male infertility, and neurobehavioral abnormalities. The relative impact of various sources of exposure, the great range of standards for EMF exposure, and the costs of doing nothing are also discussed.

  16. ELECTRON HOLOGRAPHY OF ELECTROMAGNETIC FIELDS - RECENT THEORETICAL ADVANCES.

    SciTech Connect

    BELEGGIA,M.; POZZI, G.; TONOMURA, A.

    2007-01-01

    It has been shown in this work that the Fourier space approach can be fruitfully applied to the calculation of the fields and the associated electron optical phase shift of several magnetic and electrostatic structures, like superconducting vortices in conventional and high-T{sub c} superconductors, reverse biased p-n junctions, magnetic domains and nanoparticles. In all these cases, this novel approach has led to unexpected but extremely interesting results, very often expressed in analytical form, which allow the quantitative and reliable interpretation of the experimental data collected by means of electron holography or of more conventional Lorentz microscopy techniques. Moreover, it is worth recalling that whenever long-range electromagnetic fields are involved, a physical model of the object under investigation is necessary in order to take into account correctly the perturbation of the reference wave induced by the tail of the field protruding into the vacuum. For these reasons, we believe that the Fourier space approach for phase computations we have introduced and discussed in this chapter will represent an invaluable tool for the investigation of electromagnetic fields at the meso- and nano-scale.

  17. Cosmological magnetic fields from inflation in extended electromagnetism

    SciTech Connect

    Beltran Jimenez, Jose; Maroto, Antonio L.

    2011-01-15

    In this work we consider an extended electromagnetic theory in which the scalar state which is usually eliminated by means of the Lorenz condition is allowed to propagate. This state has been shown to generate a small cosmological constant in the context of standard inflationary cosmology. Here we show that the usual Lorenz gauge-breaking term now plays the role of an effective electromagnetic current. Such a current is generated during inflation from quantum fluctuations and gives rise to a stochastic effective charge density distribution. Because of the high electric conductivity of the cosmic plasma after inflation, the electric charge density generates currents which give rise to both vorticity and magnetic fields on sub-Hubble scales. Present upper limits on vorticity coming from temperature anisotropies of the CMB are translated into lower limits on the present value of cosmic magnetic fields. We find that, for a nearly scale invariant vorticity spectrum, magnetic fields B{sub {lambda}>}10{sup -12} G are typically generated with coherence lengths ranging from subgalactic scales up to the present Hubble radius. Those fields could act as seeds for a galactic dynamo or even account for observations just by collapse and differential rotation of the protogalactic cloud.

  18. Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals.

    PubMed

    Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong

    2017-03-03

    We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 10^{4}  s. This uncertainty can be suppressed by a factor of ∼10^{10}, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ-ray bursts and fast radio bursts.

  19. Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals

    NASA Astrophysics Data System (ADS)

    Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong

    2017-03-01

    We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 1 04 s . This uncertainty can be suppressed by a factor of ˜1 010, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ -ray bursts and fast radio bursts.

  20. A review on Electromagnetic fields (EMFs) and the reproductive system

    PubMed Central

    Asghari, Ali; Khaki, Amir Afshin; Rajabzadeh, Asghar; Khaki, Arash

    2016-01-01

    Environmental factors, such as electromagnetic waves, induce biological and genetic effects. One of the most important physiological systems involved with electromagnetic fields (EMFs) is the genital system. This paper reviews the effects of EMFs on human reproductive organs, female animals, fetus development and the importance of two types of natural antioxidants, i.e., vitamin E and fennel. The studies presented in this review referred to the effects of different exposures to EMFs on the reproductive system, and we tried to show the role of natural antioxidants in reducing the effects of the exposures. Many studies have been done on the effects of ionizing and non-ionizing electromagnetic waves on the cell line of spermatogenesis, sexual hormones, and the structure of the testes. Also, about the hormonal cycle, folliculogenesis and female infertility related to EMF have been given more consideration. In particular, attention is directed to pregnant women due to the importance of their fetuses. However, in addition to the studies conducted on animals, further epidemiological research should be conducted. PMID:27648194

  1. A review on Electromagnetic fields (EMFs) and the reproductive system.

    PubMed

    Asghari, Ali; Khaki, Amir Afshin; Rajabzadeh, Asghar; Khaki, Arash

    2016-07-01

    Environmental factors, such as electromagnetic waves, induce biological and genetic effects. One of the most important physiological systems involved with electromagnetic fields (EMFs) is the genital system. This paper reviews the effects of EMFs on human reproductive organs, female animals, fetus development and the importance of two types of natural antioxidants, i.e., vitamin E and fennel. The studies presented in this review referred to the effects of different exposures to EMFs on the reproductive system, and we tried to show the role of natural antioxidants in reducing the effects of the exposures. Many studies have been done on the effects of ionizing and non-ionizing electromagnetic waves on the cell line of spermatogenesis, sexual hormones, and the structure of the testes. Also, about the hormonal cycle, folliculogenesis and female infertility related to EMF have been given more consideration. In particular, attention is directed to pregnant women due to the importance of their fetuses. However, in addition to the studies conducted on animals, further epidemiological research should be conducted.

  2. Dynamics of Cometary Dust Particles in Electromagnetic Radiation Fields

    NASA Astrophysics Data System (ADS)

    Herranen, Joonas; Markkanen, Johannes; Penttilä, Antti; Muinonen, Karri

    2016-10-01

    The formation of cometary dust tails and comae is based on solar radiation pressure. The pressure effects of electromagnetic radiation were originally conceptualized in Kepler's observations of the tails of comets and formulated mathematically by Maxwell in 1873. Today, the dynamics of cometary dust are known to be governed by gravity, electromagnetic forces, drag, solar wind, and solar radiation pressure.Solar radiation pressure has its roots in absorption, emission, and scattering of electromagnetic radiation. Due to modern advances in so-called integral equation methods in electromagnetics, a new approach of studying the effect of radiation pressure on cometary dust dynamics can be constructed. We solve the forces and torques due to radiation pressure for an arbitrarily shaped dust particle using volume integral equation methods.We then present a framework for solving the equations of motion of cometary dust particles due to radiative interactions. The solution is studied in a simplified cometary environment, where the radiative effects are studied at different orbits. The rotational and translational equations of motion are solved directly using a quaternion-based integrator. The rotational and translational equations of motion affect dust particle alignment and concentration. This is seen in the polarization of the coma. Thus, our direct dynamical approach can be used in modelling the observed imaging photo-polarimetry of the coma.In future studies, the integrator can be further extended to an exemplary comet environment, taking into account the drag, and the electric and magnetic fields. This enables us to study the dynamics of a single cometary dust particle based on fundamental physics.Acknowledgments. Research supported, in part, bythe European Research Council (ERC, grant Nr. 320773).

  3. Atomic excitation and acceleration in strong laser fields

    NASA Astrophysics Data System (ADS)

    Zimmermann, H.; Eichmann, U.

    2016-10-01

    Atomic excitation in the tunneling regime of a strong-field laser-matter interaction has been recently observed. It is conveniently explained by the concept of frustrated tunneling ionization (FTI), which naturally evolves from the well-established tunneling picture followed by classical dynamics of the electron in the combined laser field and Coulomb field of the ionic core. Important predictions of the FTI model such as the n distribution of Rydberg states after strong-field excitation and the dependence on the laser polarization have been confirmed in experiments. The model also establishes a sound basis to understand strong-field acceleration of neutral atoms in strong laser fields. The experimental observation has become possible recently and initiated a variety of experiments such as atomic acceleration in an intense standing wave and the survival of Rydberg states in strong laser fields. Furthermore, the experimental investigations on strong-field dissociation of molecules, where neutral excited fragments after the Coulomb explosion of simple molecules have been observed, can be explained. In this review, we introduce the subject and give an overview over relevant experiments supplemented by new results.

  4. An Optimization of Pulsed ElectroMagnetic Fields Study

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas J.

    2006-01-01

    To date, in our research we have focused on the use of normal human neuronal progenitor (NHNP) cells because of their importance in human nervous system regeneration, development and maintenance, but we have developed 2-D and 3-D bioreactors that can accommodate any cell line. In this Project, we will include the use of tissues important for physiological regeneration: Human osteoblasts or chondrocytes, and vascular cells. Our initial results with the NHNP cells were quite startling using extremely low-level electromagnetic fields (5 microtesla at 10Hz; 6mA). The low-amplitude, rapidly time-varying electromagnetic fields exert a very potent effect on the proliferation, morphology, and gene expression of the cells in culture, both in standard 2-dimensional culture plates as well as cells organized into 3-dimensional tissue-like assemblies (TLAs) in a 3D bioreactor. We have replicated our preliminary results many, many times, have analyzed the gene expression using gene arrays (followed by Luminex analysis for protein production), and have monitored cell proliferation, orientation, morphology, and glucose metabolism, and we are confident that we have a stable and reliable model to study the control of high-level cellular processes by application of low-amplitude, time varying electromagnetic fields (TVEMF) (1, 2). In additional studies at the University of Michigan, we have been able to generate functional in vitro engineered mammalian skeletal muscle, and have employed nerve-muscle co-culture techniques to promote axonal sprouting. We believe that nearly all tissues, in particular, neural, are susceptible to the influences of low-level TVEMF.

  5. An Optimization of Pulsed ElectroMagnetic Fields Study

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas J.

    2006-01-01

    To date, in our research we have focused on the use of normal human neuronal progenitor (NHNP) cells because of their importance in human nervous system regeneration, development and maintenance, but we have developed 2-D and 3-D bioreactors that can accommodate any cell line. In this Project, we will include the use of tissues important for physiological regeneration: Human osteoblasts or chondrocytes, and vascular cells. Our initial results with the NHNP cells were quite startling using extremely low-level electromagnetic fields (5 microtesla at 10Hz; 6mA). The low-amplitude, rapidly time-varying electromagnetic fields exert a very potent effect on the proliferation, morphology, and gene expression of the cells in culture, both in standard 2-dimensional culture plates as well as cells organized into 3-dimensional tissue-like assemblies (TLAs) in a 3D bioreactor. We have replicated our preliminary results many, many times, have analyzed the gene expression using gene arrays (followed by Luminex analysis for protein production), and have monitored cell proliferation, orientation, morphology, and glucose metabolism, and we are confident that we have a stable and reliable model to study the control of high-level cellular processes by application of low-amplitude, time varying electromagnetic fields (TVEMF) (1, 2). In additional studies at the University of Michigan, we have been able to generate functional in vitro engineered mammalian skeletal muscle, and have employed nerve-muscle co-culture techniques to promote axonal sprouting. We believe that nearly all tissues, in particular, neural, are susceptible to the influences of low-level TVEMF.

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

    PubMed

    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.

  7. 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

  8. Electromagnetic Confined Plasma Target for Interaction Studies with Intense Laser Fields

    SciTech Connect

    Zielbauer, B; Ursescu, U; Trotsenko, S; Spillmann, U; Schuch, R; Stohlker, T; Kuhl, T; Borneis, S; Schenkel, T; McDonald, J; Schneider, D

    2006-08-09

    The paper describes a novel application of an electron beam ion trap as a plasma target facility for intense laser-plasma interaction studies. The low density plasma target ({approx}10{sup 13}/cm{sup 3}) is confined in a mobile cryogenic electromagnetic charged particle trap, with the magnetic confinement field of 1-3T maintained by a superconducting magnet. Ion plasmas for a large variety of ion species and charge states are produced and maintained within the magnetic field and the space charge of an energetic electron beam in the ''Electron Beam Ion Trap'' (EBIT) geometry. Intense laser beams (optical lasers, x-ray lasers and upcoming ''X-Ray Free Electron Lasers'' (XFEL)) provide strong time varying electromagnetic fields (>10{sup 12} V/cm in femto- to nano-sec pulses) for interactions with electromagnetically confined neutral/non-neutral plasmas. The experiments are aimed to gain understanding of the effects of intense photon fields on ionization/excitation processes, the ionization balance, as well as photon polarization effects. First experimental scenarios and tests with an intense laser that utilize the ion plasma target are outlined.

  9. RF Electromagnetic Field Treatment of Tetragonal Kesterite CZTSSe Light Absorbers.

    PubMed

    Semenenko, Mykola O; Babichuk, Ivan S; Kyriienko, Oleksandr; Bodnar, Ivan V; Caballero, Raquel; Leon, Maximo

    2017-12-01

    In this work, we propose a method to improve electro-optical and structural parameters of light-absorbing kesterite materials. It relies on the application of weak power hydrogen plasma discharges using electromagnetic field of radio frequency range, which improves homogeneity of the samples. The method allows to reduce strain of light absorbers and is suitable for designing solar cells based on multilayered thin film structures. Structural characteristics of tetragonal kesterite Cu2ZnSn(S, Se)4 structures and their optical properties were studied by Raman, infrared, and reflectance spectroscopies. They revealed a reduction of the sample reflectivity after RF treatment and a modification of the energy band structure.

  10. Accuracy Improvement in Magnetic Field Modeling for an Axisymmetric Electromagnet

    NASA Technical Reports Server (NTRS)

    Ilin, Andrew V.; Chang-Diaz, Franklin R.; Gurieva, Yana L.; Il,in, Valery P.

    2000-01-01

    This paper examines the accuracy and calculation speed for the magnetic field computation in an axisymmetric electromagnet. Different numerical techniques, based on an adaptive nonuniform grid, high order finite difference approximations, and semi-analitical calculation of boundary conditions are considered. These techniques are being applied to the modeling of the Variable Specific Impulse Magnetoplasma Rocket. For high-accuracy calculations, a fourth-order scheme offers dramatic advantages over a second order scheme. For complex physical configurations of interest in plasma propulsion, a second-order scheme with nonuniform mesh gives the best results. Also, the relative advantages of various methods are described when the speed of computation is an important consideration.

  11. RF Electromagnetic Field Treatment of Tetragonal Kesterite CZTSSe Light Absorbers

    NASA Astrophysics Data System (ADS)

    Semenenko, Mykola O.; Babichuk, Ivan S.; Kyriienko, Oleksandr; Bodnar, Ivan V.; Caballero, Raquel; Leon, Maximo

    2017-06-01

    In this work, we propose a method to improve electro-optical and structural parameters of light-absorbing kesterite materials. It relies on the application of weak power hydrogen plasma discharges using electromagnetic field of radio frequency range, which improves homogeneity of the samples. The method allows to reduce strain of light absorbers and is suitable for designing solar cells based on multilayered thin film structures. Structural characteristics of tetragonal kesterite Cu2ZnSn(S, Se)4 structures and their optical properties were studied by Raman, infrared, and reflectance spectroscopies. They revealed a reduction of the sample reflectivity after RF treatment and a modification of the energy band structure.

  12. Phenomenological local field enhancement factor distributions around electromagnetic hot spots

    NASA Astrophysics Data System (ADS)

    Le Ru, E. C.; Etchegoin, P. G.

    2009-05-01

    We propose a general phenomenological description of the enhancement factor distribution for surface-enhanced Raman scattering (SERS) and other related phenomena exploiting large local field enhancements at hot spots. This description extends naturally the particular case of a single (fixed) hot spot, and it is expected to be "universal" for many classes of common SERS substrates containing a collection of electromagnetic hot spots with varying geometrical parameters. We further justify it from calculations with generalized Mie theory. The description studied here provides a useful starting point for a qualitative (and semiquantitative) understanding of experimental data and, in particular, the analysis of the statistics of single-molecule SERS events.

  13. Healing of Chronic Wounds through Systemic Effects of Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Cañedo, L.; Trigos, I.; García-Cantú, R.; Godina-Nava, J. J.; Serrano, G.

    2002-08-01

    Extremely low frequency electromagnetic fields (ELF) were configured to interact with peripheral blood mononuclear cells (PBMC). These ELF were applied in the arm to five patients with chronic wounds resistant to medical and surgical treatment. Wound healing began in all patients during the first two weeks after ELF exposure permiting their previously unresponsive chronic wounds to function as internal controls. All lesions were cured or healed >70% in less than four months. Systemic effects were explained by ELF activation of PBMC and their transportation through the blood to the affected site. This therapy is effective in selected patients with chronic wounds.

  14. Basics of quantum field theory of electromagnetic interaction processes in single-layer graphene

    NASA Astrophysics Data System (ADS)

    Hieu Nguyen, Van

    2016-09-01

    The content of this work is the study of electromagnetic interaction in single-layer graphene by means of the perturbation theory. The interaction of electromagnetic field with Dirac fermions in single-layer graphene has a peculiarity: Dirac fermions in graphene interact not only with the electromagnetic wave propagating within the graphene sheet, but also with electromagnetic field propagating from a location outside the graphene sheet and illuminating this sheet. The interaction Hamiltonian of the system comprising electromagnetic field and Dirac fermions fields contains the limits at graphene plane of electromagnetic field vector and scalar potentials which can be shortly called boundary electromagnetic field. The study of S-matrix requires knowing the limits at graphene plane of 2-point Green functions of electromagnetic field which also can be shortly called boundary 2-point Green functions of electromagnetic field. As the first example of the application of perturbation theory, the second order terms in the perturbative expansions of boundary 2-point Green functions of electromagnetic field as well as of 2-point Green functions of Dirac fermion fields are explicitly derived. Further extension of the application of perturbation theory is also discussed.

  15. Electromagnetic field tapering using all-dielectric gradient index materials

    PubMed Central

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-01-01

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes. PMID:27464989

  16. Conserved currents for electromagnetic fields in the Kerr spacetime

    NASA Astrophysics Data System (ADS)

    Grant, Alexander; Flanagan, Eanna

    2017-01-01

    For any classical linear Lagrangian field theory, the symplectic product provides a conserved current that is bilinear on the space of solutions. Given a linear mapping from the space of solutions into itself, a ``symmetry operator'', one can therefore generate quadratic conserved currents for any linear classical field theory. We apply this procedure to the case of electromagnetism on a Kerr background, showing that this procedure can generate the conserved currents given by Andersson, Bäckdahl, and Blue, as well as two new conserved currents. These currents reduce to the sum of (positive powers of) the Carter constants of the photons in the geometric optics limit, and generalize the current for scalar fields discovered by Carter. We furthermore show that the fluxes of these new currents through null infinity and the horizon are finite.

  17. Electromagnetic field tapering using all-dielectric gradient index materials.

    PubMed

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-07-28

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes.

  18. Electromagnetic field tapering using all-dielectric gradient index materials

    NASA Astrophysics Data System (ADS)

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-07-01

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes.

  19. Time dependent electromagnetic fields and 4-dimensional Stokes' theorem

    NASA Astrophysics Data System (ADS)

    Andosca, Ryan; Singleton, Douglas

    2016-11-01

    Stokes' theorem is central to many aspects of physics—electromagnetism, the Aharonov-Bohm effect, and Wilson loops to name a few. However, the pedagogical examples and research work almost exclusively focus on situations where the fields are time-independent so that one need only deal with purely spatial line integrals (e.g., ∮ A . d x ) and purely spatial area integrals (e.g., ∫ ( ∇ × A ) . d a = ∫ B . d a ). Here, we address this gap by giving some explicit examples of how Stokes' theorem plays out with time-dependent fields in a full 4-dimensional spacetime context. We also discuss some unusual features of Stokes' theorem with time-dependent fields related to gauge transformations and non-simply connected topology.

  20. Weak scattering of scalar and electromagnetic random fields

    NASA Astrophysics Data System (ADS)

    Tong, Zhisong

    This dissertation encompasses several studies relating to the theory of weak potential scattering of scalar and electromagnetic random, wide-sense statistically stationary fields from various types of deterministic or random linear media. The proposed theory is largely based on the first Born approximation for potential scattering and on the angular spectrum representation of fields. The main focus of the scalar counterpart of the theory is made on calculation of the second-order statistics of scattered light fields in cases when the scattering medium consists of several types of discrete particles with deterministic or random potentials. It is shown that the knowledge of the correlation properties for the particles of the same and different types, described with the newly introduced pair-scattering matrix, is crucial for determining the spectral and coherence states of the scattered radiation. The approach based on the pair-scattering matrix is then used for solving an inverse problem of determining the location of an "alien" particle within the scattering collection of "normal" particles, from several measurements of the spectral density of scattered light. Weak scalar scattering of light from a particulate medium in the presence of optical turbulence existing between the scattering centers is then approached using the combination of the Born's theory for treating the light interaction with discrete particles and the Rytov's theory for light propagation in extended turbulent medium. It is demonstrated how the statistics of scattered radiation depend on scattering potentials of particles and the power spectra of the refractive index fluctuations of turbulence. This theory is of utmost importance for applications involving atmospheric and oceanic light transmission. The second part of the dissertation includes the theoretical procedure developed for predicting the second-order statistics of the electromagnetic random fields, such as polarization and linear momentum

  1. Quark matter under strong magnetic fields in chiral models

    SciTech Connect

    Rabhi, Aziz; Providencia, Constanca

    2011-05-15

    The chiral model is used to describe quark matter under strong magnetic fields and is compared to other models, the MIT bag model and the two-flavor Nambu-Jona-Lasinio model. The effect of vacuum corrections due to the magnetic field is discussed. It is shown that if the magnetic-field vacuum corrections are not taken into account explicitly, the parameters of the models should be fitted to low-density meson properties in the presence of the magnetic field.

  2. Quasi-TEM electromagnetic modes of a plasma waveguide with a nonsimply connected cross section in an external magnetic field

    SciTech Connect

    Kartashov, I. N. Kuzelev, M. V.

    2014-12-15

    Electromagnetic modes of a plasma waveguide with a nonsimply connected cross section in an external magnetic field are investigated. The existence of quasi-TEM modes in a finite-strength magnetic field is demonstrated. It is shown that, in the limits of infinitely strong and zero magnetic fields, this mode transforms into a true TEM mode. The possibility of excitation of such modes by an electron beam in the regime of the anomalous Doppler effect is analyzed.

  3. Robust multiscale field-only formulation of electromagnetic scattering

    NASA Astrophysics Data System (ADS)

    Sun, Qiang; Klaseboer, Evert; Chan, Derek Y. C.

    2017-01-01

    We present a boundary integral formulation of electromagnetic scattering by homogeneous bodies that are characterized by linear constitutive equations in the frequency domain. By working with the Cartesian components of the electric E and magnetic H fields and with the scalar functions (r .E ) and (r .H ) where r is a position vector, the problem can be cast as having to solve a set of scalar Helmholtz equations for the field components that are coupled by the usual electromagnetic boundary conditions at material boundaries. This facilitates a direct solution for the surface values of E and H rather than having to work with surface currents or surface charge densities as intermediate quantities in existing methods. Consequently, our formulation is free of the well-known numerical instability that occurs in the zero-frequency or long-wavelength limit in traditional surface integral solutions of Maxwell's equations and our numerical results converge uniformly to the static results in the long-wavelength limit. Furthermore, we use a formulation of the scalar Helmholtz equation that is expressed as classically convergent integrals and does not require the evaluation of principal value integrals or any knowledge of the solid angle. Therefore, standard quadrature and higher order surface elements can readily be used to improve numerical precision for the same number of degrees of freedom. In addition, near and far field values can be calculated with equal precision, and multiscale problems in which the scatterers possess characteristic length scales that are both large and small relative to the wavelength can be easily accommodated. From this we obtain results for the scattering and transmission of electromagnetic waves at dielectric boundaries that are valid for any ratio of the local surface curvature to the wave number. This is a generalization of the familiar Fresnel formula and Snell's law, valid at planar dielectric boundaries, for the scattering and transmission

  4. Thermoelectric effects in organic conductors in a strong magnetic field

    SciTech Connect

    Kirichenko, O. V.; Peschanskii, V. G. Hasan, R. A.

    2007-07-15

    The linear response of the electron system of a layered conductor to the temperature gradient in this system in a strong magnetic field is investigated theoretically. Thermoelectric emf is studied as a function of the magnitude and orientation of a strong external magnetic field; the experimental investigation of this function, combined with the study of the electric and thermal resistance, allows one to completely determine the structure of the energy spectrum of charge carriers.

  5. Low-energy structures in strong-field ionization

    NASA Astrophysics Data System (ADS)

    Ivanov, I. A.; Nam, Chang Hee; Kim, Kyung Taec

    2016-04-01

    We show that the Gabor transform provides a convenient tool allowing one to study the origin of the low-energy structures (LES) in the process of the strong-field ionization. The classical trajectories associated with the stationary points of the Gabor transform enable us to explicate the role of the forward scattering process in forming LES. Our approach offers a fully quantum mechanical description of LES, which can also be applied for other strong-field processes.

  6. Mean-field descriptions of collective migration with strong adhesion.

    PubMed

    Johnston, Stuart T; Simpson, Matthew J; Baker, Ruth E

    2012-05-01

    Random walk models based on an exclusion process with contact effects are often used to represent collective migration where individual agents are affected by agent-to-agent adhesion. Traditional mean-field representations of these processes take the form of a nonlinear diffusion equation which, for strong adhesion, does not predict the averaged discrete behavior. We propose an alternative suite of mean-field representations, showing that collective migration with strong adhesion can be accurately represented using a moment closure approach.

  7. Ionization and dissociation dynamics of molecules in strong laser fields

    NASA Astrophysics Data System (ADS)

    Lai, Wei

    The fast advancement of ultrashort-pulsed high-intensity laser technology allows for generating an electric field equivalent to the Coulomb field inside an atom or a molecule (e.g., EC=5.14x109 V/cm at the 1s orbit radius a0=0.0529 nm of the hydrogen atom, which corresponds to an intensity of 3.54x1016 W/cm2). Atoms and molecules exposed in such a field will easily be ionized, as the external field is strong enough to remove the electrons from the core. This is usually referred to "strong field". Strong fields provide a new tool for studying the interaction of atoms and molecules with light in the nonlinear nonperturbative regime. During the past three decades, significant progress has been made in the strong field science. Today, most phenomena involving atoms in strong fields have been relatively well understood by the single-active-electron (SAE) approximation. However, the interpretation of these responses in molecules has encountered great difficulties. Not like atoms that only undergo excitation and ionization, various dissociation channels accompanying excitation and ionization can occur in molecules during the laser pulse interaction, which imparts further complexity to the study of molecules in strong fields. Previous studies have shown that molecules can behave significantly different from rare gas atoms in phenomena as simple as single and double ionization. Molecular dissociation following ionization also presents challenges in strong fields compared to what we have learned in the weak-field regime. This dissertation focuses on experimental studies on ionization and dissociation of some commonly-seen small molecules in strong laser fields. Previous work of molecules in strong fields will be briefly reviewed, particularly on some open questions about multiple dissociation channels, nonsequential double ionization, enhanced ionization and molecular alignment. The identification of various molecular dissociation channels by recent experimental technical

  8. High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED.

    PubMed

    Ullmann, Johannes; Andelkovic, Zoran; Brandau, Carsten; Dax, Andreas; Geithner, Wolfgang; Geppert, Christopher; Gorges, Christian; Hammen, Michael; Hannen, Volker; Kaufmann, Simon; König, Kristian; Litvinov, Yuri A; Lochmann, Matthias; Maaß, Bernhard; Meisner, Johann; Murböck, Tobias; Sánchez, Rodolfo; Schmidt, Matthias; Schmidt, Stefan; Steck, Markus; Stöhlker, Thomas; Thompson, Richard C; Trageser, Christian; Vollbrecht, Jonas; Weinheimer, Christian; Nörtershäuser, Wilfried

    2017-05-16

    Electrons bound in highly charged heavy ions such as hydrogen-like bismuth (209)Bi(82+) experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron-nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth (209)Bi(82+,80+) with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7-σ discrepancy compared with the theoretical prediction.

  9. High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED

    NASA Astrophysics Data System (ADS)

    Ullmann, Johannes; Andelkovic, Zoran; Brandau, Carsten; Dax, Andreas; Geithner, Wolfgang; Geppert, Christopher; Gorges, Christian; Hammen, Michael; Hannen, Volker; Kaufmann, Simon; König, Kristian; Litvinov, Yuri A.; Lochmann, Matthias; Maaß, Bernhard; Meisner, Johann; Murböck, Tobias; Sánchez, Rodolfo; Schmidt, Matthias; Schmidt, Stefan; Steck, Markus; Stöhlker, Thomas; Thompson, Richard C.; Trageser, Christian; Vollbrecht, Jonas; Weinheimer, Christian; Nörtershäuser, Wilfried

    2017-05-01

    Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209Bi82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron-nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209Bi82+,80+ with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7-σ discrepancy compared with the theoretical prediction.

  10. High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED

    PubMed Central

    Ullmann, Johannes; Andelkovic, Zoran; Brandau, Carsten; Dax, Andreas; Geithner, Wolfgang; Geppert, Christopher; Gorges, Christian; Hammen, Michael; Hannen, Volker; Kaufmann, Simon; König, Kristian; Litvinov, Yuri A.; Lochmann, Matthias; Maaß, Bernhard; Meisner, Johann; Murböck, Tobias; Sánchez, Rodolfo; Schmidt, Matthias; Schmidt, Stefan; Steck, Markus; Stöhlker, Thomas; Thompson, Richard C.; Trageser, Christian; Vollbrecht, Jonas; Weinheimer, Christian; Nörtershäuser, Wilfried

    2017-01-01

    Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209Bi82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron–nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209Bi82+,80+ with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7-σ discrepancy compared with the theoretical prediction. PMID:28508892

  11. Warm and dense stellar matter under strong magnetic fields

    SciTech Connect

    Rabhi, A.; Panda, P. K.; Providencia, C.

    2011-09-15

    We investigate the effects of strong magnetic fields on the equation of state of warm stellar matter as it may occur in a protoneutron star. Both neutrino-free and neutrino-trapped matter at a fixed entropy per baryon are analyzed. A relativistic mean-field nuclear model, including the possibility of hyperon formation, is considered. A density-dependent magnetic field with a magnitude of 10{sup 15} G at the surface and not more than 3x10{sup 18} G at the center is considered. The magnetic field gives rise to a neutrino suppression, mainly at low densities, in matter with trapped neutrinos. It is shown that a hybrid protoneutron star will not evolve into a low-mass black hole if the magnetic field is strong enough and the magnetic field does not decay. However, the decay of the magnetic field after cooling may give rise to the formation of a low-mass black hole.

  12. Radio frequency electromagnetic fields: cancer, mutagenesis, and genotoxicity.

    PubMed

    Heynick, Louis N; Johnston, Sheila A; Mason, Patrick A

    2003-01-01

    We present critiques of epidemiologic studies and experimental investigations, published mostly in peer-reviewed journals, on cancer and related effects from exposure to nonionizing electromagnetic fields in the nominal frequency range of 3 kHz to 300 GHz of interest to Subcommittee 4 (SC4) of the International Committee on Electromagnetic Safety (ICES). The major topics discussed are presented under the headings Epidemiologic and Other Findings on Human Exposure, Mammals Exposed In Vivo, Mammalian Live Tissues and Cell Preparations Exposed In Vitro, and Mutagenesis and Genotoxicity in Microorganisms and Fruit Flies. Under each major topic, we present minireviews of papers on various specific endpoints investigated. The section on Epidemiologic and Other Findings on Human Exposure is divided into two subsections, the first on possible carcinogenic effects of exposure from emitters not in physical contact with the populations studied, for example, transmitting antennas and other devices. Discussed in the second subsection are studies of postulated carcinogenic effects from use of mobile phones, with prominence given to brain tumors from use of cellular and cordless telephones in direct physical contact with an ear of each subject. In both subsections, some investigations yielded positive findings, others had negative findings, including papers directed toward experimentally verifying positive findings, and both were reported in a few instances. Further research on various important aspects may resolve such differences. Overall, however, the preponderance of published epidemiologic and experimental findings do not support the supposition that in vivo or in vitro exposures to such fields are carcinogenic.

  13. Quantum Mechanics Action of ELF Electromagnetic Fields on Living Organisms

    NASA Astrophysics Data System (ADS)

    Godina-Nava, J. J.

    2010-10-01

    There is presently an intense discussion if extremely low frequency electromagnetic field (ELF-EMF) exposure has consequences for human health. This include exposure to structures and appliances from this range of frequency in the electromagnetic (EM) spectrum. Biological effects of such exposures have been noted frequently, although the implications for specific health effects is not that clear. The basic interactions mechanisms between such fields and living matter is unknown. Numerous hypotheses have been suggested, although none is convincingly supported by experimental data. Various cellular components, processes, and systems can be affected by EMF exposure. Since it is unlikely that EMF can induce DNA damage directly, most studies have examined EMF effects on the cell membrane level, general and specific gene expression, and signal transduction pathways. Even more, a large number of studies have been performed regarding cell proliferation, cell cycle regulation, cell differentiation, metabolism, and various physiological characteristics of cells. The aim of this letter is present the hypothesis of a possible quantum mechanic effect generated by the exposure of ELF EMF, an event which is compatible with the multitude of effects observed after exposure. Based on an extensive literature review, we suggest that ELF EMF exposure is able to perform such activation restructuring the electronic level of occupancy of free radicals in molecules interacting with DNA structures.

  14. Pulsed Electromagnetic Field Assisted in vitro Electroporation: A Pilot Study

    NASA Astrophysics Data System (ADS)

    Novickij, Vitalij; Grainys, Audrius; Lastauskienė, Eglė; Kananavičiūtė, Rūta; Pamedytytė, Dovilė; Kalėdienė, Lilija; Novickij, Jurij; Miklavčič, Damijan

    2016-09-01

    Electroporation is a phenomenon occurring due to exposure of cells to Pulsed Electric Fields (PEF) which leads to increase of membrane permeability. Electroporation is used in medicine, biotechnology, and food processing. Recently, as an alternative to electroporation by PEF, Pulsed ElectroMagnetic Fields (PEMF) application causing similar biological effects was suggested. Since induced electric field in PEMF however is 2-3 magnitudes lower than in PEF electroporation, the membrane permeabilization mechanism remains hypothetical. We have designed pilot experiments where Saccharomyces cerevisiae and Candida lusitaniae cells were subjected to single 100-250 μs electrical pulse of 800 V with and without concomitant delivery of magnetic pulse (3, 6 and 9 T). As expected, after the PEF pulses only the number of Propidium Iodide (PI) fluorescent cells has increased, indicative of membrane permeabilization. We further show that single sub-millisecond magnetic field pulse did not cause detectable poration of yeast. Concomitant exposure of cells to pulsed electric (PEF) and magnetic field (PMF) however resulted in the increased number PI fluorescent cells and reduced viability. Our results show increased membrane permeability by PEF when combined with magnetic field pulse, which can explain electroporation at considerably lower electric field strengths induced by PEMF compared to classical electroporation.

  15. Electromagnetic dissipation during asymmetric reconnection with a moderate guide field

    NASA Astrophysics Data System (ADS)

    Genestreti, Kevin; Burch, James; Cassak, Paul; Torbert, Roy; Phan, Tai; Ergun, Robert; Giles, Barbara; Russell, Chris; Wang, Shan; Akhavan-Tafti, Mojtaba; Varsani, Ali

    2017-04-01

    We calculate the work done on the plasma by the electromagnetic (EM) field, ⃗Jṡ⃗E', and analyze the related electron currents and electric fields, focusing on a single asymmetric guide field electron diffusion region (EDR) event observed by MMS on 8 December 2015. For this event, each of the four MMS spacecraft observed dissipation of EM energy at the in-plane magnetic null point, though large-scale generation/dissipation was observed inconsistently on the magnetospheric side of the boundary. The current at the null was carried by a beam-like population of magnetosheath electrons traveling anti-parallel to the guide field, whereas the current on the Earthward side of the boundary was carried by crescent-shaped electron distributions. We also analyze the terms in Ohm's law, finding a large residual electric field throughout the EDR, inertial and pressure divergence fields at the null, and pressure divergence fields at the magnetosphere-side EDR. Our analysis of the terms in Ohm's law suggests that the EDR had significant three-dimensional structure.

  16. Pulsed Electromagnetic Field Assisted in vitro Electroporation: A Pilot Study

    PubMed Central

    Novickij, Vitalij; Grainys, Audrius; Lastauskienė, Eglė; Kananavičiūtė, Rūta; Pamedytytė, Dovilė; Kalėdienė, Lilija; Novickij, Jurij; Miklavčič, Damijan

    2016-01-01

    Electroporation is a phenomenon occurring due to exposure of cells to Pulsed Electric Fields (PEF) which leads to increase of membrane permeability. Electroporation is used in medicine, biotechnology, and food processing. Recently, as an alternative to electroporation by PEF, Pulsed ElectroMagnetic Fields (PEMF) application causing similar biological effects was suggested. Since induced electric field in PEMF however is 2–3 magnitudes lower than in PEF electroporation, the membrane permeabilization mechanism remains hypothetical. We have designed pilot experiments where Saccharomyces cerevisiae and Candida lusitaniae cells were subjected to single 100–250 μs electrical pulse of 800 V with and without concomitant delivery of magnetic pulse (3, 6 and 9 T). As expected, after the PEF pulses only the number of Propidium Iodide (PI) fluorescent cells has increased, indicative of membrane permeabilization. We further show that single sub-millisecond magnetic field pulse did not cause detectable poration of yeast. Concomitant exposure of cells to pulsed electric (PEF) and magnetic field (PMF) however resulted in the increased number PI fluorescent cells and reduced viability. Our results show increased membrane permeability by PEF when combined with magnetic field pulse, which can explain electroporation at considerably lower electric field strengths induced by PEMF compared to classical electroporation. PMID:27634482

  17. Magnetic field induced by strong transverse plasmons in ultra-relativistic electron-positron plasmas

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Li, X. Q.; Liu, S. Q.

    2012-08-01

    Context. We investigated the generation of localized magnetic fields in an ultra-relativistic non-isothermal electron-positron plasma by strong electromagnetic plasmons. Aims: The results obtained can be used to explain the origin of small-scale magnetic fields in the internal shock region of gamma-ray bursts with ultra-relativistic electron positron plasmas. Methods: The generation of magnetic fields was investigated with kinetic Vlasov Maxwell equations. Results: The self-generated magnetic field will collapse for modulation instability, leading to spatially highly intermittent magnetic fluxes, whose characteristic scale is much larger than relativistic plasma skin depth, which in turn is conducive to the generation of the long-life small-scale magnetic fields in the internal shock region of gamma-ray bursts.

  18. Resonance fluorescence from an asymmetric quantum dot dressed by a bichromatic electromagnetic field

    NASA Astrophysics Data System (ADS)

    Kryuchkyan, G. Yu.; Shahnazaryan, V.; Kibis, O. V.; Shelykh, I. A.

    2017-01-01

    We present the theory of resonance fluorescence from an asymmetric quantum dot driven by a two-component electromagnetic field with two different frequencies, polarizations, and amplitudes (bichromatic field) in the regime of strong light-matter coupling. It follows from the elaborated theory that the broken inversion symmetry of the driven quantum system and the bichromatic structure of the driving field result in unexpected features of the resonance fluorescence, including the infinite set of Mollow triplets, the quench of fluorescence peaks induced by the dressing field, and the oscillating behavior of the fluorescence intensity as a function of the dressing field amplitude. These quantum phenomena are of general physical nature and, therefore, can take place in various double-driven quantum systems with broken inversion symmetry.

  19. Electromagnetic field triggered drug and chemical delivery via liposomes

    DOEpatents

    Liburdy, Robert P.

    1993-01-01

    The present invention relates to a system and to a method of delivering a drug to a preselected target body site of a patient, comprising the steps of encapsulating the chemical agent within liposomes, essentially temperature insensitive, i.e. not having a specific predetermined phase transition temperature within the specific temperature range of drug administration; administering the liposomes to the target body site; and subjecting the target body site to nonionizing electromagnetic fields in an area of the preselected target body in order to release said chemical agent from the liposomes at a temperature of between about +10 and 65.degree. C. The invention further relates to the use of said liposomes to bind to the surface of or to enter target tissue or an organ in a living system, and, when subjected to a nonionizing field, to release a drug from the liposomes into the target site.

  20. The dielectric response to the magnetic field of electromagnetic radiation

    NASA Astrophysics Data System (ADS)

    Mukherjee, Shouvik; Mukhopadhyay, Sourabh; Datta, Prasanta Kumar

    2017-04-01

    Light-matter interaction in transparent dielectrics is revisited, including the magnetic force on bound charges in the Lorentz oscillator model. The parameter ranges of incident radiation and the medium on which the magnetic field of the electromagnetic radiation will have a significant effect are traced using Floquet theory. The analysis reveals that the threshold intensity for a significant response of the magnetic field of the radiation at the second harmonic of the incident radiation can be reduced to {10}12 {{W}}{{cm}}-2 for off resonant and even lower for resonant interaction. This phenomenon has already been observed indirectly in experiments [1, 2]. Induced magnetizing current due to the magnetic force is shown to originate from a modified dielectric response, which may be useful in future magneto-optic devices, solar energy harvesting, and studying the ultrafast dynamics in doped dielectrics.

  1. Acceleration of adiabatic quantum dynamics in electromagnetic fields

    SciTech Connect

    Masuda, Shumpei; Nakamura, Katsuhiro

    2011-10-15

    We show a method to accelerate quantum adiabatic dynamics of wave functions under electromagnetic field (EMF) by developing the preceding theory [Masuda and Nakamura, Proc. R. Soc. London Ser. A 466, 1135 (2010)]. Treating the orbital dynamics of a charged particle in EMF, we derive the driving field which accelerates quantum adiabatic dynamics in order to obtain the final adiabatic states in any desired short time. The scheme is consolidated by describing a way to overcome possible singularities in both the additional phase and driving potential due to nodes proper to wave functions under EMF. As explicit examples, we exhibit the fast forward of adiabatic squeezing and transport of excited Landau states with nonzero angular momentum, obtaining the result consistent with the transitionless quantum driving applied to the orbital dynamics in EMF.

  2. Electromagnetic field limits set by the V-Curve.

    SciTech Connect

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Hudson, Howard Gerald

    2014-07-01

    When emitters of electromagnetic energy are operated in the vicinity of sensitive components, the electric field at the component location must be kept below a certain level in order to prevent the component from being damaged, or in the case of electro-explosive devices, initiating. The V-Curve is a convenient way to set the electric field limit because it requires minimal information about the problem configuration. In this report we will discuss the basis for the V-Curve. We also consider deviations from the original V-Curve resulting from inductive versus capacitive antennas, increases in directivity gain for long antennas, decreases in input impedance when operating in a bounded region, and mismatches dictated by transmission line losses. In addition, we consider mitigating effects resulting from limited antenna sizes.

  3. Photon merging and splitting in electromagnetic field inhomogeneities

    NASA Astrophysics Data System (ADS)

    Gies, Holger; Karbstein, Felix; Seegert, Nico

    2016-04-01

    We investigate photon merging and splitting processes in inhomogeneous, slowly varying electromagnetic fields. Our study is based on the three-photon polarization tensor following from the Heisenberg-Euler effective action. We put special emphasis on deviations from the well-known constant field results, also revisiting the selection rules for these processes. In the context of high-intensity laser facilities, we analytically determine compact expressions for the number of merged/split photons as obtained in the focal spots of intense laser beams. For the parameter range of typical petawatt class laser systems as pump and probe, we provide estimates for the numbers of signal photons attainable in an actual experiment. The combination of frequency upshifting, polarization dependence and scattering off the inhomogeneities renders photon merging an ideal signature for the experimental exploration of nonlinear quantum vacuum properties.

  4. Geometric entropy and edge modes of the electromagnetic field

    NASA Astrophysics Data System (ADS)

    Donnelly, William; Wall, Aron C.

    2016-11-01

    We calculate the vacuum entanglement entropy of Maxwell theory in a class of curved spacetimes by Kaluza-Klein reduction of the theory onto a two-dimensional base manifold. Using two-dimensional duality, we express the geometric entropy of the electromagnetic field as the entropy of a tower of scalar fields, constant electric and magnetic fluxes, and a contact term, whose leading-order divergence was discovered by Kabat. The complete contact term takes the form of one negative scalar degree of freedom confined to the entangling surface. We show that the geometric entropy agrees with a statistical definition of entanglement entropy that includes edge modes: classical solutions determined by their boundary values on the entangling surface. This resolves a long-standing puzzle about the statistical interpretation of the contact term in the entanglement entropy. We discuss the implications of this negative term for black hole thermodynamics and the renormalization of Newton's constant.

  5. Near-field electromagnetic theory for thin solar cells.

    PubMed

    Niv, A; Gharghi, M; Gladden, C; Miller, O D; Zhang, X

    2012-09-28

    Current methods for evaluating solar cell efficiencies cannot be applied to low-dimensional structures where phenomena from the realm of near-field optics prevail. We present a theoretical approach to analyze solar cell performance by allowing rigorous electromagnetic calculations of the emission rate using the fluctuation-dissipation theorem. Our approach shows the direct quantification of the voltage, current, and efficiency of low-dimensional solar cells. This approach is demonstrated by calculating the voltage and the efficiency of a GaAs slab solar cell for thicknesses from several microns down to a few nanometers. This example highlights the ability of the proposed approach to capture the role of optical near-field effects in solar cell performance.

  6. Electromagnetic field triggered drug and chemical delivery via liposomes

    DOEpatents

    Liburdy, R.P.

    1993-03-02

    The present invention relates to a system and to a method of delivering a drug to a preselected target body site of a patient, comprising the steps of encapsulating the chemical agent within liposomes, essentially temperature insensitive, i.e. not having a specific predetermined phase transition temperature within the specific temperature range of drug administration; administering the liposomes to the target body site; and subjecting the target body site to nonionizing electromagnetic fields in an area of the preselected target body in order to release the chemical agent from the liposomes at a temperature of between about +10 and 65 C. The invention further relates to the use of the liposomes to bind to the surface of or to enter target tissue or an organ in a living system, and, when subjected to a nonionizing field, to release a drug from the liposomes into the target site.

  7. Interaction of extremely-low-frequency electromagnetic fields with humans

    SciTech Connect

    Tenforde, T.S.

    1991-07-01

    At a macroscopic level, the effects of extremely low frequency (ELF) electromagnetic fields on humans are well understood based on fundamental physical principles, but far less is known about the nature of the interactions at a cellular or molecular level. Current evidence suggests the effects of ELF on cellular biochemistry are due to interactions with the cell membrane. Elucidation of the mechanism that underlies this transmembrane signaling is critical for a molecular-level understanding of ELF field effects. Further research is also required to clarify a possible link between ELF exposure and increased cancer risk, since estimated ELF exposure in occupational or residential settings is much lower that the levels used in laboratory studies. There is a clear need for additional epidemiological research in which qualitative dosimetry is used to characterize ELF exposure and careful attention is given to possible effects of confounding variables. 24 refs.

  8. Relativistic particle acceleration by obliquely propagating electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Villalón, Elena; Burke, William J.

    1987-12-01

    The relativistic equations of motion are analyzed for charged particles in a magnetized plasma and externally imposed electromagnetic fields (ω, k), which have wave vectors k that are at arbitrary angles. The particle energy is obtained from a set of nonlinear differential equations, as a function of time, initial conditions, and cyclotron harmonic numbers. For a given cyclotron resonance, the energy oscillates in time within the limits of a potential well; stochastic acceleration occurs if the widths of different Hamiltonian potentials overlap. The net energy gain for a given harmonic increase with the angle of propagation, and decreases as the magnitude of the wave magnetic field increases. Potential applications of these results to the acceleration of ionsopheric electrons are presented.

  9. Electromagnetic fields and the induction of DNA strand breaks.

    PubMed

    Ruiz-Gómez, Miguel J; Martínez-Morillo, Manuel

    2009-01-01

    The International Agency for Research on Cancer (IARC) has classified the extremely low-frequency (ELF) electromagnetic fields (EMF) as "possible carcinogenic" based on the reported effects. The purpose of this work is to review and compare the recent findings related to the induction of DNA strand breaks (DNA-SB) by magnetic field (MF) exposure. We found 29 studies (genotoxic and epigenetic) about the induction of DNA-SB by MF. 50% showed effect of MF and 50% showed no DNA-SB. Nevertheless, considering only genotoxic or only epigenetic studies, 37.5% and 69.2% found induction of DNA-SB by MF, respectively. In relation to these data it seems that MF could act as a co-inductor of DNA damage rather than as a genotoxic agent per se. Nevertheless, the published results, in some cases conflicting with negative findings, do not facilitate to obtain a common consensus about MF effects and biophysical interaction mechanisms.

  10. Electromagnetic plasma wave emissions from the auroral field lines

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.

    1977-01-01

    The most important types of auroral radio emissions are reviewed, both from a historical perspective as well as considering the latest results. Particular emphasis is placed on four types of electromagnetic emissions which are directly associated with the plasma on the auroral field lines. These emissions are (1) auroral hiss, (2) saucers, (3) ELF noise bands, and (4) auroral kilometric radiation. Ray tracing and radio direction finding measurements indicate that both the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances from about 2.5 to 5 R sub e. For the auroral hiss the favored mechanism appears to be amplified Cerenkov radiation. For the auroral kilometric radiation several mechanisms have been proposed, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.

  11. Electron cyclotron maser instability (ECMI) in strong magnetic guide field reconnection

    NASA Astrophysics Data System (ADS)

    Treumann, Rudolf A.; Baumjohann, Wolfgang

    2017-08-01

    The ECMI model of electromagnetic radiation from electron holes is shown to be applicable to spontaneous magnetic reconnection. We apply it to reconnection in strong current-aligned magnetic guide fields. Such guide fields participate only passively in reconnection, which occurs in the antiparallel components to both sides of the guide-field-aligned current sheets with current carried by kinetic Alfvén waves. Reconnection generates long (the order of hundreds of electron inertial scales) electron exhaust regions at the reconnection site X point, which are extended perpendicular to the current and the guide fields. Exhausts contain a strongly density-depleted hot electron component and have properties similar to electron holes. Exhaust electron momentum space distributions are highly deformed, exhibiting steep gradients transverse to both the reconnecting and guide fields. Such properties suggest application of the ECMI mechanism with the fundamental ECMI X-mode emission beneath the nonrelativistic guide field cyclotron frequency in localized source regions. An outline of the mechanism and its prospects is given. Potential applications are the kilometric radiation (AKR) in auroral physics, solar radio emissions during flares, planetary emissions and astrophysical scenarios (radiation from stars and compact objects) involving the presence of strong magnetic fields and field-aligned currents. Drift of the exhausts along the guide field maps the local field and plasma properties. Escape of radiation from the exhaust and radiation source region still poses a problem. The mechanism can be studied in 2-D particle simulations of strong guide field reconnection which favours 2-D, mapping the deformation of the electron distribution perpendicular to the guide field, and using it in the numerical calculation of the ECMI growth rate. The mechanism suggests also that reconnection in general may become a source of the ECMI with or without guide fields. This is of particular

  12. Assessment of the Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields

    DTIC Science & Technology

    2003-06-01

    the Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5d. TASK NUMBER 6. AUTHOR(S) Dr... Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields (EMFs) (From 1 June 2002 to 31 May 2003 for 12 months) Nikolai Konstantinovich Chemeris...International Science and Technology Center (ISTC), Moscow. 2 ISTC 2350 Assessment of the Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields

  13. A. A. Ukhtomskii's dominance principle of brain activity in the perception of electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Kholodov, Yu. A.

    1994-01-01

    Preliminary instruction of the subject plays an important role in the perception of weak electromagnetic fields acting on the hand. Active attention to a potential effect amplifies a brain state that can be called caution dominance and arises spontaneously with a “placebo” or an electromagnetic field. The radar principle of brain operation is discussed among the physiological mechanisms through which electromagnetic fields act on an organism.

  14. A. A. Ukhtomskii`s dominance principle of brain activity in the perception of electromagnetic fields

    SciTech Connect

    Kholodov, Yu.A.

    1994-07-01

    Preliminary instruction of the subject plays an important role in the perception of weak electromagnetic fields acting on the hand. Active attention to a potential effect amplifies a brain state that can be called caution dominance and arises spontaneously with a {open_quotes}placebo{close_quotes} or an electromagnetic field. The radar principle of brain operation is discussed among the physiological mechanisms through which electromagnetic fields act on an organism.

  15. Cell membrane thermal gradients induced by electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Garner, Allen L.; Deminsky, Maxim; Bogdan Neculaes, V.; Chashihin, V.; Knizhnik, Andrey; Potapkin, Boris

    2013-06-01

    While electromagnetic fields induce structural changes in cell membranes, particularly electroporation, much remains to be understood about membrane level temperature gradients. For instance, microwaves induce cell membrane temperature gradients (∇T) and bioeffects with little bulk temperature change. Recent calculations suggest that nanosecond pulsed electric fields (nsPEFs) may also induce such gradients that may additionally impact the electroporation threshold. Here, we analytically and numerically calculate the induced ∇T as a function of pulse duration and pulse repetition rate. We relate ∇T to the thermally induced cell membrane electric field (Em) by assuming the membrane behaves as a thermoelectric such that Em ˜ ∇T. Focusing initially on applying nsPEFs to a uniform membrane, we show that reducing pulse duration and increasing pulse repetition rate (or using higher frequency for alternating current (AC) fields) maximizes the magnitude and duration of ∇T and, concomitantly, Em. The maximum ∇T initially occurs at the interface between the cell membrane and extracellular fluid before becoming uniform across the membrane, potentially enabling initial molecular penetration and subsequent transport across the membrane. These results, which are equally applicable to AC fields, motivate further studies to elucidate thermoelectric behavior in a model membrane system and the coupling of the Em induced by ∇T with that created directly by the applied field.

  16. Simultaneous Electromagnetic Tracking and Calibration for Dynamic Field Distortion Compensation.

    PubMed

    Sadjadi, Hossein; Hashtrudi-Zaad, Keyvan; Fichtinger, Gabor

    2016-08-01

    Electromagnetic (EM) tracking systems are highly susceptible to field distortion. The interference can cause measurement errors up to a few centimeters in clinical environments, which limits the reliability of these systems. Unless corrected for, this measurement error imperils the success of clinical procedures. It is therefore fundamental to dynamically calibrate EM tracking systems and compensate for measurement error caused by field distorting objects commonly present in clinical environments. We propose to combine a motion model with observations of redundant EM sensors and compensate for field distortions in real time. We employ a simultaneous localization and mapping technique to accurately estimate the pose of the tracked instrument while creating the field distortion map. We conducted experiments with six degrees-of-freedom motions in the presence of field distorting objects in research and clinical environments. We applied our approach to improve the EM tracking accuracy and compared our results to a conventional sensor fusion technique. Using our approach, the maximum tracking error was reduced by 67% for position measurements and by 64% for orientation measurements. Currently, clinical applications of EM trackers are hampered by the adverse distortion effects. Our approach introduces a novel method for dynamic field distortion compensation, independent from preoperative calibrations or external tracking devices, and enables reliable EM navigation for potential applications.

  17. Attosecond Electron Wave Packet Dynamics in Strong Laser Fields

    SciTech Connect

    Johnsson, P.; Remetter, T.; Varju, K.; L'Huillier, A.; Lopez-Martens, R.; Valentin, C.; Balcou, Ph.; Kazamias, S.; Mauritsson, J.; Gaarde, M. B.; Schafer, K. J.; Mairesse, Y.; Wabnitz, H.; Salieres, P.

    2005-07-01

    We use a train of sub-200 attosecond extreme ultraviolet (XUV) pulses with energies just above the ionization threshold in argon to create a train of temporally localized electron wave packets. We study the energy transfer from a strong infrared (IR) laser field to the ionized electrons as a function of the delay between the XUV and IR fields. When the wave packets are born at the zero crossings of the IR field, a significant amount of energy ({approx}20 eV) is transferred from the field to the electrons. This results in dramatically enhanced above-threshold ionization in conditions where the IR field alone does not induce any significant ionization. Because both the energy and duration of the wave packets can be varied independently of the IR laser, they are valuable tools for studying and controlling strong-field processes.

  18. Pion Production from Proton Synchrotron Radiation in Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Maruyama, Tomoyuki; Cheoun, Myung-Ki; Kajino, Toshitaka; Mathews, Grant J.

    We study pion production by proton synchrotron radiation in the presence of a strong magnetic field. In this study we find that the decay width satisfies a robust scaling relation. This scaling implies that one can infer the decay width in more realistic magnetic fields of 1015 G, where ni,f ˜ 1012-1013, from the results for ni,f ˜ 104-105. Then, we present the resultant pion intensity and angular distributions for realistic magnetic field strengths.

  19. Effects of Pulse Electromagnetic Field on Corrosion Resistance of Al-5 % Cu Alloy

    NASA Astrophysics Data System (ADS)

    Wang, B.; Tang, L. D.; Qi, J. G.; Wang, J. Z.

    2013-03-01

    It was investigated that corrosion resistance of Al-5 % Cu alloy was influenced by pulse electromagnetic field (PEMF). The morphologies were observed by scanning election microscopy (SEM). The corrosion behaviors were investigated by potentiodynamic polarization tests and immersion tests. The results indicated that corrosion resistance of samples could be increased by using pulse electromagnetic field, moreover, the optimum parameter of pulse electromagnetic field in this experiment was showed as follows: 500 V, 3 Hz, 30 s. Decreasing the quantity of eutectic in grain boundaries and refining the grains were main causations for increasing corrosion resistance of Al-5 % Cu alloy with pulse electromagnetic field.

  20. Low-frequency, motionally induced electromagnetic fields in the ocean. 1. Theory

    NASA Astrophysics Data System (ADS)

    Chave, Alan D.; Luther, Douglas S.

    1990-05-01

    The theory of electromagnetic induction by motional sources in the ocean is examined from a first principles point of view. The electromagnetic field is expanded mathematically in poloidal and toroidal magnetic modes based on the Helmholtz decomposition. After deriving a set of Green functions for the modes in an unbounded ocean of constant depth and conductivity underlain by an arbitrary one-dimensional conducting earth, a set of exact integral equations are obtained which describe the induction process in an ocean of vertically varying conductivity. Approximate solutions are constructed for the low-frequency (subinertial) limit where the horizontal length scale of the flow is large compared to the water depth, the effect of self induction is weak, and the vertical velocity is negligible, explicitly yielding complex relationships between the vertically-integrated, conductivity-weighted horizontal water velocity and the horizontal electric and three component magnetic fields and accounting for interactions with the conductive earth. After introducing geophysically reasonable models for the conductivity structures of the ocean and earth, these reduce to a spatially smoothed proportionality between the electromagnetic field components and the vertically-integrated, conductivity-weighted horizontal water velocity. An upper bound of a few times the water depth for the lateral averaging scale of the horizontal electric field is derived, and its constant of proportionality is shown to be nearly 1 for most of the deep ocean based on geophysical arguments. The magnetic field is shown to have a similar form but is a relatively weak, larger-scale average of the velocity field. Because vertical variations in the conductivity of seawater largely reflect its thermal structure and are weak beneath the thermocline, the horizontal electric field is a spatially filtered version of the true water velocity which strongly attenuates the influence of baroclinicity and accentuates the

  1. Bragg scattering of light in vacuum structured by strong periodic fields.

    PubMed

    Kryuchkyan, Gagik Yu; Hatsagortsyan, Karen Z

    2011-07-29

    Elastic scattering of laser radiation due to vacuum polarization by spatially modulated strong electromagnetic fields is considered. The Bragg interference arising at a specific impinging direction of the probe wave concentrates the scattered light in specular directions. The interference maxima are enhanced with respect to the usual vacuum polarization effect proportional to the square of the number of modulation periods within the interaction region. The Bragg scattering can be employed to detect the vacuum polarization effect in a setup of multiple crossed superstrong laser beams with parameters envisaged in the future Extreme Light Infrastructure.

  2. Quantum diffusion of electromagnetic fields of ultrarelativistic spin-half particles

    NASA Astrophysics Data System (ADS)

    Peroutka, Balthazar; Tuchin, Kirill

    2017-10-01

    We compute electromagnetic fields created by a relativistic charged spin-half particle in empty space at distances comparable to the particle Compton wavelength. The particle is described as a wave packet evolving according to the Dirac equation. It produces the electromagnetic field that is essentially different from the Coulomb field due to the quantum diffusion effect.

  3. Probing intergalactic magnetic fields with simulations of electromagnetic cascades

    NASA Astrophysics Data System (ADS)

    Alves Batista, Rafael; Saveliev, Andrey; Sigl, Günter; Vachaspati, Tanmay

    2016-10-01

    We determine the effect of intergalactic magnetic fields on the distribution of high-energy gamma rays by performing three-dimensional Monte Carlo simulations of the development of gamma-ray-induced electromagnetic cascades in the magnetized intergalactic medium. We employ the so-called "Large Sphere Observer" method to efficiently simulate blazar gamma ray halos. We study magnetic fields with a Batchelor spectrum and with maximal left- and right-handed helicities. We also consider the case of sources whose jets are tilted with respect to the line of sight. We verify the formation of extended gamma ray halos around the source direction, and observe spiral-like patterns if the magnetic field is helical. We apply the Q -statistics to the simulated halos to extract their spiral nature and also propose an alternative method, the S -statistics. Both methods provide a quantitative way to infer the helicity of the intervening magnetic fields from the morphology of individual blazar halos for magnetic field strengths B ≳10-15 G and magnetic coherence lengths Lc≳100 Mpc . We show that the S -statistics has a better performance than the Q -statistics when assessing magnetic helicity from the simulated halos.

  4. [Methods of dosimetry in evaluation of electromagnetic fields' biological action].

    PubMed

    Rubtsova, N B; Perov, S Iu

    2012-01-01

    Theoretical and experimental dosimetry can be used for adequate evaluation of the effects of radiofrequency electromagnetic fields. In view of the tough electromagnetic environment in aircraft, pilots' safety is of particular topicality. The dosimetric evaluation is made from the quantitative characteristics of the EMF interaction with bio-objects depending on EM energy absorption in a unit of tissue volume or mass calculated as a specific absorbed rate (SAR) and measured in W/kg. Theoretical dosimetry employs a number of computational methods to determine EM energy, as well as the augmented method of boundary conditions, iterative augmented method of boundary conditions, moments method, generalized multipolar method, finite-element method, time domain finite-difference method, and hybrid methods combining several decision plans modeling the design philosophy of navigation, radiolocation and human systems. Because of difficulties with the experimental SAR estimate, theoretical dosimetry is regarded as the first step in analysis of the in-aircraft conditions of exposure and possible bio-effects.

  5. Strong superchiral field in hot spots and its interaction with chiral molecules

    NASA Astrophysics Data System (ADS)

    Liu, Yineng

    We have found that strong superchiral fields created by surface plasmon resonance exist in hot spots of nonchiral plasmonic structure, which showed a chiral density greater than that of circularly polarized light by hundreds of times. We have demonstrated a direct correlation between the chirality of the local field and the circular dichroism (CD) response at the plasmon resonance bands induced by chiral molecules in the hot spots. Our results reveal that the wavelength-dependent superchiral fields in the hot spots can play a crucial role in the determination of the plasmonic CD effect. This finding is in contrast to the currently accepted physical model in which the electromagnetic field intensity in hot spots is a key factor to determine the peak intensity of the plasmonic CD spectrum. Some related experimental phenomena have been explained by using our theoretical analysis. The work was supported by the China National Natural Science Foundation (Grant No. 11504306).

  6. Slowing the probe field in the second window of double-double electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Alotaibi, Hessa M. M.; Sanders, Barry C.

    2015-04-01

    For Doppler-broadened media operating under double-double electromagnetically induced transparency (EIT) conditions, we devise a scheme to control and reduce the probe-field group velocity at the center of the second transparency window. We derive numerical and approximate analytical solutions for the width of EIT windows and for the group velocities of the probe field at the two distinct transparency windows, and we show that the group velocities of the probe field can be lowered by judiciously choosing the physical parameters of the system. Our modeling enables us to identify three signal-field strength regimes (with a signal-field strength always higher than the probe-field strength), quantified by the Rabi frequency, for slowing the probe field. These three regimes correspond to a weak signal field, with the probe-field group velocity and transparency-window width both smaller for the second window compared to the first window, a medium-strength signal field, with a probe-field group velocity smaller in the second window than in the first window but with larger transparency-window width for the second window, and the strong signal field, with both group velocity and transparency-window width larger for the second window. Our scheme exploits the fact that the second transparency window is sensitive to a temperature-controlled signal-field nonlinearity, whereas the first transparency window is insensitive to this nonlinearity.

  7. Electromagnetic field strength levels surrounding electronic article surveillance (EAS) systems.

    PubMed

    Harris, C; Boivin, W; Boyd, S; Coletta, J; Kerr, L; Kempa, K; Aronow, S

    2000-01-01

    Electronic article surveillance (EAS) is used in many applications throughout the world to prevent theft. EAS systems produce electromagnetic (EM) energy around exits to create an EM interrogation zone through which protected items must pass before leaving the establishment. Specially designed EAS tags are attached to these items and must either be deactivated or removed prior to passing through the EAS EM interrogation zone to prevent the alarm from sounding. Recent reports in the scientific literature have noted the possibility that EM energy transmitted by EAS systems may interfere with the proper operation of sensitive electronic medical devices. The Food and Drug Administration has the regulatory responsibility to ensure the safety and effectiveness of medical devices. Because of the possibility of electromagnetic interference (EMI) between EAS systems and electronic medical devices, in situ measurements of the electric and magnetic fields were made around various types of EAS systems. Field strength levels were measured around four types of EAS systems: audio frequency magnetic, pulsed magnetic resonant, radio frequency, and microwave. Field strengths from these EAS systems varied with magnetic fields as high as 1073.6 Am(-1) (in close proximity to the audio frequency magnetic EAS system towers), and electric fields up to 23.8 Vm(-1) (in close proximity to the microwave EAS system towers). Medical devices are only required to withstand 3 Vm(-1) by the International Electrotechnical Commission's current medical device standards. The modulation scheme of the signal transmitted by some types of EAS systems (especially the pulsed magnetic resonant) has been shown to be more likely to cause EMI with electronic medical devices. This study complements other work in the field by attaching specific characteristics to EAS transmitted EM energy. The quantitative data could be used to relate medical device EMI with specific field strength levels and signal waveforms

  8. Airborne electromagnetics supporting salinity and natural resource management decisions at the field scale in Australia

    NASA Astrophysics Data System (ADS)

    Cresswell, Richard G.; Mullen, Ian C.; Kingham, Rob; Kellett, Jim; Dent, David L.; Jones, Grant L.

    2007-05-01

    Airborne geophysics has been used at the catchment scale to map salt stores, conduits and soil variability, but few studies have evaluated its usefulness as a land management tool at the field scale. We respond to questions posed by land managers with: (1) comparison of airborne and ground-based electromagnetic surveys in the Lower Balonne catchment, Queensland, and (2) comparison with historical and anecdotal knowledge of landscape response in the country around Jamestown in mid-South Australia. In the Lower Balonne, direct comparison between ground electromagnetic survey (EM) and airborne electromagnetics (AEM) showed a strong relationship for both the absolute values and spatial patterns of conductivity. The penetration of AEM to greater than 100 m is valuable in defining hydrological barriers. In the Jamestown area, AEM conductivity corresponded well with specific outbreaks of salinity and observed variability in crop response; local inconsistencies at the ground surface could be resolved when sub-surface data were considered. AEM can provide valuable information at the field scale that is relevant to salinity management. Farmers can have confidence in any of these techniques (historical information, EM and AEM) and they may directly compare or integrate the results.

  9. Effects of strong and electromagnetic correlations on neutrino interactions in dense matter

    SciTech Connect

    Reddy, S.; Prakash, M.; Lattimer, J.M.; Reddy, S.; Pons, J.A.

    1999-05-01

    An extensive study of the effects of correlations on both charged and neutral current weak interaction rates in dense matter is performed. Both strong and electromagnetic correlations are considered. The propagation of particle-hole interactions in the medium plays an important role in determining the neutrino mean free paths. The effects due to Pauli blocking and density, spin, and isospin correlations in the medium significantly reduce the neutrino cross sections. As a result of the lack of experimental information at high density, these correlations are necessarily model dependent. For example, spin correlations in nonrelativistic models are found to lead to larger suppressions of neutrino cross sections compared to those of relativistic models. This is due to the tendency of the nonrelativistic models to develop spin instabilities. Notwithstanding the above caveats, and the differences between nonrelativistic and relativistic approaches such as the spin- and isospin-dependent interactions and the nucleon effective masses, suppressions of order 2{endash}3, relative to the case in which correlations are ignored, are obtained. Neutrino interactions in dense matter are especially important for supernova and early neutron star evolution calculations. The effects of correlations for protoneutron star evolution are calculated. Large effects on the internal thermodynamic properties of protoneutron stars, such as the temperature, are found. These translate into significant early enhancements in the emitted neutrino energies and fluxes, especially after a few seconds. At late times, beyond about 10 s, the emitted neutrino fluxes decrease more rapidly compared to simulations without the effects of correlations, due to the more rapid onset of neutrino transparency in the protoneutron star. {copyright} {ital 1999} {ital The American Physical Society}

  10. Strings: A possible alternative explanation for the Unification of Gravitation Field and Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Rivera, Susana

    Throughout the last century, since the last decades of the XIX century, until present day, there had been many attempts to achieve the unification of the Forces of Nature. First unification was done by James Clerk Maxwell, with his Electromagnetic Theory. Then Max Plank developed his Quantum Theory. In 1905, Albert Einstein gave birth to the Special Relativity Theory, and in 1916 he came out with his General Relativity Theory. He noticed that there was an evident parallelism between the Gravitational Force, and the Electromagnetic Force. So, he tried to unify these forces of Nature. But Quantum Theory interposed on his way. On the 1940’s it had been developed the Quantum Electrodynamics (QED), and with it, the unified field theory had an arise interest. On the 60’s and 70’s there was developed the Quantum Chromodynamics (QCD). Along with these theories came the discovery of the strong interaction force and weak interaction force. And though there had been many attempts to unify all these forces of the nature, it could only be achieved the Unification of strong interaction, weak interaction and Electromagnetic Force. On the late 80”s and throughout the last two decades, theories such as “super-string theory”, “or the “M-theory”, among others, groups of Scientists, had been doing grand efforts and finally they came out with the unification of the forces of nature, being the only limitation the use of more than 11 dimensions. Using an ingenious mathematical tool known as the super symmetries, based on the Kaluza - Klein work, they achieve this goal. The strings of these theories are in the rank of 10-33 m. Which make them undetectable. There are many other string theories. The GEUFT theory is based on the existence of concentrated energy lines, which vibrates, expands and contracts, submitting and absorbing energy, matter and antimatter, and which yields a determined geometry, that gives as a result the formation of stars, galaxies, nebulae, clusters

  11. Simulation Study of Magnetic Fields Generated by the Electromagnetic Filamentation Instability

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Ramirez-Ruiz, E.; Hardee, P.; Hededal, C. B.; Mizuno, Y.; Fishman, G. J.

    2007-01-01

    We have investigated the effects of plasma instabilities driven by rapid e(sup plus or minus) pair cascades, which arise in the environment of GRB sources as a result of back-scattering of a seed fraction of the original spectrum. The injection of e(sup plus or minus) pairs induces strong streaming motions in the ambient medium. One therefore expects the pair-enriched medium ahead of the forward shock to be strongly sheared on length scales comparable to the radiation front thickness. Using three-dimensional particle-in-cell simulations, we show that plasma instabilities driven by these streaming e(sup plus or minus) pairs are responsible for the excitation of near-equipartition, turbulent magnetic fields. Our results reveal the importance of the electromagnetic filamentation instability in ensuring an effective coupling between e(sup plus or minus) pairs and ions, and may help explain the origin of large upstream fields in GRB shocks.

  12. [Effects of radiofrequency electromagnetic fields on mammalian spermatogenesis].

    PubMed

    Susa, Martina; Pavicić, Ivan

    2007-12-01

    This article reviews studies about the effects of radiofrequency electromagnetic (RF EM) fields on male reproductive system and reproductive health in mammals. According to current data, there are almost 4 million active mobile phone lines in Croatia while this number has risen to 2 billion in the world. Increased use of mobile technology raises scientific and public concern about possible hazardous effects of RF fields on human health. The effects of radiofrequencies on reproductive health and consequences for the offspring are still mainly unknown. A number of in vivo and in vitro studies indicated that RF fields could interact with charged intracellular macromolecular structures. Results of several laboratory studies on animal models showed how the RF fields could affect the mammalian reproductive system and sperm cells. Inasmuch as, in normal physiological conditions spermatogenesis is a balanced process of division, maturation and storage of cells, it is particularly vulnerable to the chemical and physical environmental stimuli. Especially sensitive could be the cytoskeleton, composed of charged proteins; actin, intermedial filaments and microtubules. Cytoskeleton is a functional and structural part of the cell that has important role in the sperm motility, and is actively involved in the morphologic changes that occur during mammalian spermiogenesis.

  13. Equations of a moving mirror and the electromagnetic field

    NASA Astrophysics Data System (ADS)

    Octavio Castaños, Luis; Weder, Ricardo

    2015-06-01

    We consider a system composed of a mobile slab and the electromagnetic field. We assume that the slab is made of a material that has the following properties when it is at rest: it is linear, isotropic, non-magnetizable, and ohmic with zero free charge density. Using instantaneous Lorentz transformations, we deduce the set of self-consistent equations governing the dynamics of the system and we obtain approximate equations to first order in the velocity and the acceleration of the slab. As a consequence of the motion of the slab, the field must satisfy a wave equation with damping and slowly varying coefficients plus terms that are small when the time-scale of the evolution of the mirror is much larger than that of the field. Also, the motion of the slab and its interaction with the field introduce two effects in the slab’s equation of motion. The first one is a position- and time-dependent mass related to the effective mass taken in phenomenological treatments of this type of systems. The second one is a velocity-dependent force that can give rise to friction and that is related to the much sought cooling of mechanical objects.

  14. Could Radiotherapy Effectiveness Be Enhanced by Electromagnetic Field Treatment?

    PubMed Central

    Francisco, Artacho-Cordón; del Mar, Salinas-Asensio María; Irene, Calvente; Sandra, Ríos-Arrabal; Josefa, León; Elisa, Román-Marinetto; Nicolás, Olea; Isabel, Núñez María

    2013-01-01

    One of the main goals in radiobiology research is to enhance radiotherapy effectiveness without provoking any increase in toxicity. In this context, it has been proposed that electromagnetic fields (EMFs), known to be modulators of proliferation rate, enhancers of apoptosis and inductors of genotoxicity, might control tumor recruitment and, thus, provide therapeutic benefits. Scientific evidence shows that the effects of ionizing radiation on cellular compartments and functions are strengthened by EMF. Although little is known about the potential role of EMFs in radiotherapy (RT), the radiosensitizing effect of EMFs described in the literature could support their use to improve radiation effectiveness. Thus, we hypothesized that EMF exposure might enhance the ionizing radiation effect on tumor cells, improving the effects of RT. The aim of this paper is to review reports of the effects of EMFs in biological systems and their potential therapeutic benefits in radiotherapy. PMID:23867611

  15. Coherent electromagnetic field imaging through Fourier transform heterodyne

    SciTech Connect

    Cooke, B.J.; Laubscher, B.E.; Olivas, N.L.; Goeller, R.M.; Cafferty, M.; Briles, S.D.; Galbraith, A.E. |; Grubler, A.C. |

    1998-12-31

    The authors present a detection process capable of directly imaging the transverse amplitude, phase, and if desired, Doppler shift of coherent electromagnetic fields. Based on coherent detection principles governing conventional heterodyned RADAR/LIDAR systems, Fourier Transform Heterodyne (FTH) incorporates transverse spatial encoding of the local oscillator for image capture. Appropriate selection of spatial encoding functions, or basis set, allows image retrieval by way of classic Fourier manipulations. Of practical interest: (1) imaging is accomplished on a single element detector requiring no additional scanning or moving components, and (2) a wide variety of appropriate spatial encoding functions exist that may be adaptively configured in real-time for applications requiring optimal detection. In this paper, they introduce the underlying principles governing FTH imaging, followed by demonstration of concept via a simple experimental setup based on a HeNe laser and a 69 element spatial phase modulator.

  16. Finite element modeling of electromagnetic fields and waves using NASTRAN

    NASA Technical Reports Server (NTRS)

    Moyer, E. Thomas, Jr.; Schroeder, Erwin

    1989-01-01

    The various formulations of Maxwell's equations are reviewed with emphasis on those formulations which most readily form analogies with Navier's equations. Analogies involving scalar and vector potentials and electric and magnetic field components are presented. Formulations allowing for media with dielectric and conducting properties are emphasized. It is demonstrated that many problems in electromagnetism can be solved using the NASTRAN finite element code. Several fundamental problems involving time harmonic solutions of Maxwell's equations with known analytic solutions are solved using NASTRAN to demonstrate convergence and mesh requirements. Mesh requirements are studied as a function of frequency, conductivity, and dielectric properties. Applications in both low frequency and high frequency are highlighted. The low frequency problems demonstrate the ability to solve problems involving media inhomogeneity and unbounded domains. The high frequency applications demonstrate the ability to handle problems with large boundary to wavelength ratios.

  17. Electromagnetic field-induced stimulation of Bruton's tyrosine kinase.

    PubMed

    Kristupaitis, D; Dibirdik, I; Vassilev, A; Mahajan, S; Kurosaki, T; Chu, A; Tuel-Ahlgren, L; Tuong, D; Pond, D; Luben, R; Uckun, F M

    1998-05-15

    Here we present evidence that exposure of DT40 lymphoma B-cells to low energy electromagnetic fields (EMF) results in activation of phospholipase C-gamma 2 (PLC-gamma2), leading to increased inositol phospholipid turnover. PLC-gamma2 activation in EMF-stimulated cells is mediated by stimulation of the Bruton's tyrosine kinase (BTK), a member of the Src-related TEC family of protein tyrosine kinases, which acts downstream of LYN kinase and upstream of PLC-gamma2. B-cells rendered BTK-deficient by targeted disruption of the btk gene did not show enhanced PLC-gamma2 activation in response to EMF exposure. Introduction of the wild-type (but not a kinase domain mutant) human btk gene into BTK-deficient B-cells restored their EMF responsiveness. Thus, BTK exerts a pivotal and mandatory function in initiation of EMF-induced signaling cascades in B-cells.

  18. Electromagnetic field energy density in homogeneous negative index materials.

    PubMed

    Shivanand; Webb, Kevin J

    2012-05-07

    An exact separation of both electric and magnetic energies into stored and lost energies is shown to be possible in the special case when the wave impedance is independent of frequency. A general expression for the electromagnetic energy density in such a dispersive medium having a negative refractive index is shown to be accurate in comparison with numerical results. Using an example metamaterial response that provides a negative refractive index, it is shown that negative time-averaged stored energy can occur. The physical meaning of this negative energy is explained as the energy temporarily borrowed by the field from the material. This observation for negative index materials is of interest when approaching properties for a perfect lens. In the broader context, the observation of negative stored energy is of consequence in the study of dispersive materials.

  19. Electromagnetic pulse (EMP), Part I: Effects on field medical equipment

    SciTech Connect

    Vandre, R.H.; Klebers, J.; Tesche, F.M.; Blanchard, J.P. )

    1993-04-01

    The electromagnetic pulse (EMP) from a high-altitude nuclear detonation has the potential to cover an area as large as the continental United States with damaging levels of EMP radiation. In this study, two of seven items of medical equipment were damaged by an EMP simulator. Computer circuit analysis of 17 different items showed that 11 of the 17 items would be damaged by current surges on the power cords, while two would be damaged by current surges on external leads. This research showed that a field commander can expect approximately 65% of his electronic medical equipment to be damaged by a single nuclear detonation as far as 2,200 km away.

  20. Annals of conflicting results: looking back on electromagnetic field research.

    PubMed

    Schoen, D

    1996-11-15

    Few environmental health issues are as contentious as the question of whether exposure to electromagnetic fields (EMFs) from power lines increases cancer risk. Among the many actors in this controversy, epidemiologists have played the leading role in raising the question and motivating research. Epidemiologic studies of the effects of exposure to power-line EMFs include the investigation by Dr. Gilles Thériault and colleagues into incidence rates of cancer among electric-utility workers in Quebec, Ontario and France. With the development of personal dosimeters to measure exposure to electric, magnetic and pulsed EMFs, occupational studies in the 1990s have made an important methodologic advance. But, as Thériault explains, improvements in assessing exposure have not yet translated into clear and consistent findings.

  1. Human exposure to radiofrequency electromagnetic fields. Final rule.

    PubMed

    2013-06-04

    This document resolves several issues regarding compliance with the Federal Communications Commission's (FCC's) regulations for conducting environmental reviews under the National Environmental Policy Act (NEPA) as they relate to the guidelines for human exposure to RF electromagnetic fields. More specifically, the Commission clarifies evaluation procedures and references to determine compliance with its limits, including specific absorption rate (SAR) as a primary metric for compliance, consideration of the pinna (outer ear) as an extremity, and measurement of medical implant exposure. The Commission also elaborates on mitigation procedures to ensure compliances with its limits, including labeling and other requirements for occupational exposure classification, clarification of compliance responsibility at multiple transmitter sites, and labeling of fixed consumer transmitters.

  2. Near-field thermal radiation between homogeneous dual uniaxial electromagnetic metamaterials

    SciTech Connect

    Chang, Jui-Yung; Basu, Soumyadipta; Yang, Yue; Wang, Liping

    2016-06-07

    Recently, near-field thermal radiation has attracted much attention in several fields since it can exceed the Planck blackbody limit through the coupling of evanescent waves. In this work, near-field radiative heat transfer between two semi-infinite dual uniaxial electromagnetic metamaterials with two different material property sets is theoretically analyzed. The near-field radiative heat transfer is calculated using fluctuational electrodynamics incorporated with anisotropic wave optics. The underlying mechanisms, namely, magnetic hyperbolic mode, magnetic surface polariton, electrical hyperbolic mode, and electrical surface polariton, between two homogeneous dual uniaxial electromagnetic metamaterials are investigated by examining the transmission coefficient and the spectral heat flux. The effect of vacuum gap distance is also studied, which shows that the enhancement at smaller vacuum gap is mainly due to hyperbolic mode and surface plasmon polariton modes. In addition, the results show that the contribution of s-polarized waves is significant and should not be excluded due to the strong magnetic response regardless of vacuum gap distances. The fundamental understanding and insights obtained here will facilitate the finding and application of novel materials for near-field thermal radiation.

  3. Paternal occupational exposure to electromagnetic fields and neuroblastoma in offspring

    SciTech Connect

    Wilkins, J.R. 3d.; Hundley, V.D. )

    1990-06-01

    Investigators in Texas have reported an association between paternal employment in jobs linked with exposure to electromagnetic fields and risk of neuroblastoma in offspring. In an attempt to replicate this finding, the authors conducted a case-control study in Ohio. A total of 101 incident cases of neuroblastoma were identified through the Columbus (Ohio) Children's Hospital Tumor Registry. All cases were born sometime during the period 1942-1967. From a statewide roster of birth certificates, four controls were selected for each case, with individual matching on the case's year of birth, race, and sex, and the mother's county of residence at the time of the (index) child's birth. Multiple definitions were employed to infer the potential for paternal occupational exposure to electromagnetic fields from the industry/occupation statements on the birth certificates. Case-control comparisons revealed adjusted odds ratios ranging in magnitude from 0.5 to 1.9. For two of the exposure definitions employed--both of which are similar to one used by the Texas investigators--the corresponding odds ratios were modestly elevated (odds ratios = 1.6 and 1.9). Notably, the magnitude of these odds ratios is not inconsistent with the Texas findings, where the exposure definition referred to yielded an odds ratio of 2.1. Because the point estimates in this study are imprecise, and because the biologic plausibility of the association is uncertain, the results reported here must be interpreted cautiously. However, the apparent consistency between two independent studies suggests that future evaluation of the association is warranted.

  4. Exit point in the strong field ionization process

    PubMed Central

    Ivanov, I. A.; Nam, Chang Hee; Kim, Kyung Taec

    2017-01-01

    We analyze the process of strong field ionization using the Bohmian approach. This allows retention of the concept of electron trajectories. We consider the tunnelling regime of ionization. We show that, in this regime, the coordinate distribution for the ionized electron has peaks near the points in space that can be interpreted as exit points. The interval of time during which ionization occurs is marked by a quick broadening of the coordinate distribution. The concept of the exit point in the tunneling regime, which has long been assumed for the description of strong field ionization, is justified by our analysis. PMID:28057938

  5. Metallization of nanofilms in strong adiabatic electric fields.

    PubMed

    Durach, Maxim; Rusina, Anastasia; Kling, Matthias F; Stockman, Mark I

    2010-08-20

    We introduce an effect of metallization of dielectric nanofilms by strong, adiabatically varying electric fields. The metallization causes optical properties of a dielectric film to become similar to those of a plasmonic metal (strong absorption and negative permittivity at low optical frequencies). This is a quantum effect, which is exponentially size-dependent, occurring at fields on the order of 0.1 V/Å and pulse durations ranging from ∼1 fs to ∼10 ns for a film thickness of 3-10 nm.

  6. Metallization of Nanofilms in Strong Adiabatic Electric Fields

    NASA Astrophysics Data System (ADS)

    Durach, Maxim; Rusina, Anastasia; Kling, Matthias F.; Stockman, Mark I.

    2010-08-01

    We introduce an effect of metallization of dielectric nanofilms by strong, adiabatically varying electric fields. The metallization causes optical properties of a dielectric film to become similar to those of a plasmonic metal (strong absorption and negative permittivity at low optical frequencies). This is a quantum effect, which is exponentially size-dependent, occurring at fields on the order of 0.1V/Å and pulse durations ranging from ˜1fs to ˜10ns for a film thickness of 3-10 nm.

  7. Exit point in the strong field ionization process

    NASA Astrophysics Data System (ADS)

    Ivanov, I. A.; Nam, Chang Hee; Kim, Kyung Taec

    2017-01-01

    We analyze the process of strong field ionization using the Bohmian approach. This allows retention of the concept of electron trajectories. We consider the tunnelling regime of ionization. We show that, in this regime, the coordinate distribution for the ionized electron has peaks near the points in space that can be interpreted as exit points. The interval of time during which ionization occurs is marked by a quick broadening of the coordinate distribution. The concept of the exit point in the tunneling regime, which has long been assumed for the description of strong field ionization, is justified by our analysis.

  8. 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.

  9. Strongly enhanced field-dependent single-molecule electroluminescence

    NASA Astrophysics Data System (ADS)

    Lee, Tae-Hee; Gonzalez, Jose I.; Dickson, Robert M.

    2002-08-01

    Individual, strongly electroluminescent Agn molecules (n = 28 atoms) have been electrically written within otherwise nonemissive silver oxide films. Exhibiting characteristic single-molecule behavior, these individual room-temperature molecules exhibit extreme electroluminescence enhancements (>104 vs. bulk and dc excitation on a per molecule basis) when excited with specific ac frequencies. Occurring through field extraction of electrons with subsequent reinjection and radiative recombination, single-molecule electroluminescence is enhanced by a general mechanism that avoids slow bulk material response. Thus, while we detail strong electroluminescence from single, highly fluorescent Agn molecules, this mechanism also yields strong ac-excited electroluminescence from similarly prepared, but otherwise nonemissive, individual Cu nanoclusters.

  10. Anomaly-Induced Dynamical Refringence in Strong-Field QED

    NASA Astrophysics Data System (ADS)

    Mueller, N.; Hebenstreit, F.; Berges, J.

    2016-08-01

    We investigate the impact of the Adler-Bell-Jackiw anomaly on the nonequilibrium evolution of strong-field quantum electrodynamics (QED) using real-time lattice gauge theory techniques. For field strengths exceeding the Schwinger limit for pair production, we encounter a highly absorptive medium with anomaly induced dynamical refractive properties. In contrast to earlier expectations based on equilibrium properties, where net anomalous effects vanish because of the trivial vacuum structure, we find that out-of-equilibrium conditions can have dramatic consequences for the presence of quantum currents with distinctive macroscopic signatures. We observe an intriguing tracking behavior, where the system spends longest times near collinear field configurations with maximum anomalous current. Apart from the potential relevance of our findings for future laser experiments, similar phenomena related to the chiral magnetic effect are expected to play an important role for strong QED fields during initial stages of heavy-ion collision experiments.

  11. Anomaly-Induced Dynamical Refringence in Strong-Field QED.

    PubMed

    Mueller, N; Hebenstreit, F; Berges, J

    2016-08-05

    We investigate the impact of the Adler-Bell-Jackiw anomaly on the nonequilibrium evolution of strong-field quantum electrodynamics (QED) using real-time lattice gauge theory techniques. For field strengths exceeding the Schwinger limit for pair production, we encounter a highly absorptive medium with anomaly induced dynamical refractive properties. In contrast to earlier expectations based on equilibrium properties, where net anomalous effects vanish because of the trivial vacuum structure, we find that out-of-equilibrium conditions can have dramatic consequences for the presence of quantum currents with distinctive macroscopic signatures. We observe an intriguing tracking behavior, where the system spends longest times near collinear field configurations with maximum anomalous current. Apart from the potential relevance of our findings for future laser experiments, similar phenomena related to the chiral magnetic effect are expected to play an important role for strong QED fields during initial stages of heavy-ion collision experiments.

  12. Localization from near-source quasi-static electromagnetic fields

    SciTech Connect

    Mosher, John Compton

    1993-09-01

    A wide range of research has been published on the problem of estimating the parameters of electromagnetic and acoustical sources from measurements of signals measured at an array of sensors. In the quasi-static electromagnetic cases examined here, the signal variation from a point source is relatively slow with respect to the signal propagation and the spacing of the array of sensors. As such, the location of the point sources can only be determined from the spatial diversity of the received signal across the array. The inverse source localization problem is complicated by unknown model order and strong local minima. The nonlinear optimization problem is posed for solving for the parameters of the quasi-static source model. The transient nature of the sources can be exploited to allow subspace approaches to separate out the signal portion of the spatial correlation matrix. Decomposition techniques are examined for improved processing, and an adaptation of MUtiple SIgnal Characterization (MUSIC) is presented for solving the source localization problem. Recent results on calculating the Cramer-Rao error lower bounds are extended to the multidimensional problem here. This thesis focuses on the problem of source localization in magnetoencephalography (MEG), with a secondary application to thunderstorm source localization. Comparisons are also made between MEG and its electrical equivalent, electroencephalography (EEG). The error lower bounds are examined in detail for several MEG and EEG configurations, as well as localizing thunderstorm cells over Cape Canaveral and Kennedy Space Center. Time-eigenspectrum is introduced as a parsing technique for improving the performance of the optimization problem.

  13. Development of a strong field helicon plasma source

    SciTech Connect

    Shinohara, Shunjiro; Mizokoshi, Hiroshi

    2006-03-15

    We developed a high-density helicon plasma source with a very strong field of up to 10 kG. Using a double-loop antenna wound around a quartz tube, 9.5 cm in inner diameter and 90 cm in axial length, initial plasmas with a high density more than 10{sup 13} cm{sup -3} were successfully produced with a radio frequency power less than a few kilowatts, and with changing magnetic fields, fill pressures, and gas species.

  14. Ionizing gas breakdown waves in strong electric fields.

    NASA Technical Reports Server (NTRS)

    Klingbeil, R.; Tidman, D. A.; Fernsler, R. F.

    1972-01-01

    A previous analysis by Albright and Tidman (1972) of the structure of an ionizing potential wave driven through a dense gas by a strong electric field is extended to include atomic structure details of the background atoms and radiative effects, especially, photoionization. It is found that photoionization plays an important role in avalanche propagation. Velocities, electron densities, and temperatures are presented as a function of electric field for both negative and positive breakdown waves in nitrogen.

  15. Do the standard expressions for the electromagnetic field momentum need any modifications?

    NASA Astrophysics Data System (ADS)

    Singal, Ashok K.

    2016-10-01

    We investigate here the question raised in the literature about the correct expression for the electromagnetic field momentum, especially when static or stationary fields are involved. For this, we examine a couple of simple but intriguing cases. First, we consider a system configuration in which electromagnetic field momentum is present even though the system is stationary. We trace the electromagnetic momentum to be present in the form of a continuous transport of electromagnetic energy from one part of the system to another, without causing any net change in the energy of the system. In a second case, we show that the electromagnetic momentum is zero irrespective of whether the charged system is static or in motion, even though the electromagnetic energy is present throughout. We demonstrate that the conventional formulation of electromagnetic field momentum describes the systems consistently without any real contradictions. Here, we also make exposition of a curiosity where electromagnetic energy decreases when the charged system gains velocity. Then we discuss the more general question that has been raised: Are the conventional formulas for energy-momentum of electromagnetic fields valid for all cases? Specifically, in the case of so-called "bound fields," do we need to change to some modified definitions? We show that in all cases it is only the conventional formulas that lead to results consistent with the rest of physics, including the special theory of relativity, and that any proposed modifications are thus superfluous.

  16. Hydrogen molecule in a strong parallel magnetic field

    NASA Astrophysics Data System (ADS)

    Kravchenko, Yu. P.; Liberman, M. A.

    1998-05-01

    We investigate the hydrogen molecule in a strong parallel magnetic field using a fully numerical Hartree-Fock approach. We find that for magnetic fields below 4.2×104 T the ground state of H2 is the strongly bound singlet state 1Σg, for magnetic fields stronger than 3×106 T the ground state of the molecule is the strongly bound triplet 3Πu, and for magnetic fields between 4.2×104 T and 3×106 T the symmetry of the ground state is the triplet state 3Σu, which is characterized by repulsion at intermediate internuclear distances and by a weak quadrupole-quadrupole interaction between atoms at large internuclear separation. In this region of magnetic field strength the hydrogen molecule is bound weakly, if at all; the hydrogen atoms behave like a weakly nonideal gas of Bose particles and can form a superfluid phase predicted in earlier works [Korolev and Liberman, Phys. Rev. Lett. 72, 270 (1994)]. For magnetic fields between ~3×105 T and 3×106 T the triplet state 3Πu is found to be metastable. This state may be responsible for an unknown excitonic line observed experimentally [Timofeev and Chernenko, JETP Lett. 61, 617 (1995)].

  17. Particle diffusion in strong field-guided magnetohydrodynamic turbulence

    NASA Astrophysics Data System (ADS)

    Tsang, Yue-Kin; Joanne Mason Collaboration

    2015-11-01

    We consider three-dimensional incompressible magnetohydrodynamic turbulence in the presence of a strong mean background magnetic field. We examine the Lagrangian statistics and characterize the transport properties of the system by numerically tracking a large number of passive massless particles. Previous studies demonstrated that in two dimensions, the presence of a weak background guiding field can suppress turbulent transport in the field-perpendicular direction. The situation in three dimensions is less clear. Here, we measure the single-particle diffusion along different directions with respect to the background magnetic field. By varying the background field strength, we quantify the effect of such guiding field on turbulent diffusion and interpret the results in terms of the Lagrangian velocity function. This work is supported by the UK EPSRC Grant EP/M004546/1.

  18. Electromagnetic field and cylindrical compact objects in modified gravity

    NASA Astrophysics Data System (ADS)

    Yousaf, Z.; Bhatti, M. Zaeem ul Haq

    2016-05-01

    In this paper, we have investigated the role of different fluid parameters particularly electromagnetic field and f(R) corrections on the evolution of cylindrical compact object. We have explored the modified field equations, kinematical quantities and dynamical equations. An expression for the mass function has been found in comparison with the Misner-Sharp formalism in modified gravity, after which different mass-radius diagrams are drawn. The coupled dynamical transport equation have been formulated to discuss the role of thermoinertial effects on the inertial mass density of the cylindrical relativistic interior. Finally, we have presented a framework, according to which all possible solutions of the metric f(R)-Maxwell field equations coupled with static fluid can be written through set of scalar functions. It is found that modified gravity induced by Lagrangians f(R) = αR2, f(R) = αR2 - βR and f(R)=α R^2-β R/1+γ R are likely to host more massive cylindrical compact objects with smaller radii as compared to general relativity.

  19. Analyzing Exposures to Electromagnetic Fields in an Intensive Care Unit

    PubMed Central

    Gökmen, Necati; Erdem, Sabri; Toker, Kadir Atilla; Öçmen, Elvan; Gökmen, Başak Ilgım; Özkurt, Ahmet

    2016-01-01

    Objective In this study, we conducted a numerical analysis of exposure to electromagnetic fields (EMFs) in a hospital’s intensive care unit that is one of the most crucial one in terms of hazardous areas among all service units. This is a new study for measuring exposure to EMFs in an intensive care unit as well as other healthcare services in Turkey. Methods We measured the EMFs in the intensive care unit with a SRM-3006 (selective radiation metre), which was used for measurement of the absolute and the limit values of high frequency EMFs. The measurement points were chosen to represent the highest levels of exposure to which a person might be subjected. We obtained a dataset that included 5929 observations, with 96 extreme values, through measuring the magnetic field in terms of V/m. Results The measurements show the frequency varies from 47 MHz to 2.5 GHz as 17 frequency ranges at the measurement point as well. According to these findings, the referenced maximum safety limit was not exceeded. However, it was also found that mobile telecommunication was the most critical cause of magnetic fields. Conclusion Further studies need to be performed with different frequency antennas to assess the EMFs in intensive care units. PMID:27909603

  20. Mesoscopic fluctuations of the population of a qubit in a strong alternating field

    SciTech Connect

    Denisenko, M. V. Satanin, A. M.

    2016-12-15

    Fluctuations of the population of a Josephson qubit in an alternating field, which is a superposition of electromagnetic pulses with large amplitudes, are studied. It is shown that the relative phase of pulses is responsible for the rate of Landau–Zener transitions and, correspondingly, for the frequency of transitions between adiabatic states. The durations of pulses incident on the qubit are controlled with an accuracy of the field period, which results in strong mesoscopic fluctuations of the population of the qubit. Similar to the magnetic field in mesoscopic physics, the relative phase of pulses can destroy the interference pattern of the population of the qubit. The influence of the duration of the pulse and noise on the revealed fluctuation effects is studied.

  1. Mesoscopic fluctuations of the population of a qubit in a strong alternating field

    NASA Astrophysics Data System (ADS)

    Denisenko, M. V.; Satanin, A. M.

    2016-12-01

    Fluctuations of the population of a Josephson qubit in an alternating field, which is a superposition of electromagnetic pulses with large amplitudes, are studied. It is shown that the relative phase of pulses is responsible for the rate of Landau-Zener transitions and, correspondingly, for the frequency of transitions between adiabatic states. The durations of pulses incident on the qubit are controlled with an accuracy of the field period, which results in strong mesoscopic fluctuations of the population of the qubit. Similar to the magnetic field in mesoscopic physics, the relative phase of pulses can destroy the interference pattern of the population of the qubit. The influence of the duration of the pulse and noise on the revealed fluctuation effects is studied.

  2. Singularities in the Transverse Fields of Electromagnetic Waves. II. Observations on the Electric Field

    NASA Astrophysics Data System (ADS)

    Hajnal, J. V.

    1987-12-01

    Electromagnetic waves propagating in free space contain three kinds of singularities called C lines, S surfaces and disclinations. The paper describes observations of these singularities in two different monochromatic microwave fields. The observations confirm all the theoretically predicted properties of the singularities that could be tested. As expected, the singularities were found to be prominent structural features of the fields and in consequence to provide an economical means of characterizing their structure. A notable result is the observation of both right-hand and left-hand C lines in a field that is nominally uniformly left-hand circularly polarized. This is in agreement with the previous assertion that, in general, electromagnetic wavefields contain both right-hand and left-hand polarized regions.

  3. Quantum Theory of a Strongly-Dissipative Scalar Field

    NASA Astrophysics Data System (ADS)

    Jafari, Marjan; Kheirandish, Fardin

    2017-04-01

    The properties of a quantum dissipative scalar field is analyzed by Caldeira-Leggett model in strong-coupling regime. The Lagrangian of the total system is canonically quantized and the full Hamiltonian is diagonalized using Fano technique. A mode-dependent probability density is introduced. The steady state energy and correlation functions at finite temperature are calculated in terms of the probability density.

  4. Semiclassical approximation for strong-laser-field processes

    NASA Astrophysics Data System (ADS)

    Milošević, D. B.

    2017-08-01

    The exact time-evolution operator of an atom in the presence of a strong laser field is expressed using the phase-space path integral. Presenting this result in the form of a perturbative expansion in the effective interaction of the electron with the rest of the atom enables straightforward derivation of the well-known strong-field approximation and its higher-order corrections. Alternatively, one can use this exact result to obtain a semiclassical approximation by expansion in powers of small fluctuations around the classical trajectories. We present a derivation of such a semiclassical approximation. The obtained result for the momentum-space matrix element of the total time-evolution operator can be useful for studying various processes in strong-field physics. Using the example of above-threshold ionization, it is shown how this approximation can be applied to laser-induced processes. More attention is devoted to the laser-assisted scattering. Using the example of few-cycle laser-pulse-assisted electron-atom potential scattering, we show similarities and differences between the semiclassical and the strong-field approximations. For low energies, the semiclassical scattering cross section is modified and there are trajectories along which the electron is temporarily captured by the atomic potential. Applying stationary-phase method to the integral over the scattering time, we clearly identified relevant semiclassical electron trajectories.

  5. The Reaction of Dissociative Recombination in a Strong Light Field

    SciTech Connect

    Golubkov, M. G.; Golubkov, G. V.; Adamson, S. O.; Ryabinkin, I. G.; Apukhtina, N. V.; Dementiev, A. I.

    2008-10-22

    The DR theory of slow electrons with molecular ions in strong monochromatic light field is developed. The potential energy curves of the oxygen molecule O{sub 2}** dissociative states are calculated. Classification of all possible transitions and reaction mechanisms are presented.

  6. Orbital alignment in photodissociation probed using strong field ionization

    SciTech Connect

    Lin Yunfei; Yan Lu; Lee, Suk Kyoung; Herath, Thushani; Li Wen

    2011-12-21

    The photodissociation of molecules often produces atomic fragments with polarized electronic angular momentum, and the atomic alignment, for example, can provide valuable information on the dynamical pathways of chemical reactions unavailable by other means. In this work, we demonstrate for the first time that orbital polarization in chemical reactions can be measured with great sensitivity using strong field ionization by exploiting its extreme nonlinearity.

  7. The use of the rotating electromagnetic field for hardening treatment of details

    NASA Astrophysics Data System (ADS)

    Lebedev, V. A.; Kochubey, A. A.; Kiricheck, A. V.

    2017-02-01

    The article discusses energy aspects of details’ hardening with convective flows of freely moving indenters under the conditions of the rotating electromagnetic field. Results of theoretical studies of the kinetics of the movement of the ferromagnetic indenters are presented and the energy model of the state of the rotating magnetic liquefied layer is proposed, formed under the influence of the rotating electromagnetic field.

  8. Spontaneous topological transitions of electromagnetic fields in spatially inhomogeneous C P -odd domains

    NASA Astrophysics Data System (ADS)

    Tuchin, Kirill

    2016-12-01

    Metastable C P -odd domains of the hot QCD matter are coupled to QED via the chiral anomaly. The topology of electromagnetic field in these domains is characterized by magnetic helicity. It is argued, using the Maxwell-Chern-Simons model, that spatial inhomogeneity of the domains induces spontaneous transitions of electromagnetic field between the opposite magnetic helicity states.

  9. A strong electroweak phase transition from the inflaton field

    SciTech Connect

    Tenkanen, Tommi; Tuominen, Kimmo; Vaskonen, Ville

    2016-09-22

    We study a singlet scalar extension of the Standard Model. The singlet scalar is coupled non-minimally to gravity and assumed to drive inflation, and also couple sufficiently strongly with the SM Higgs field in order to provide for a strong first order electroweak phase transition. Requiring the model to describe inflation successfully, be compatible with the LHC data, and yield a strong first order electroweak phase transition, we identify the regions of the parameter space where the model is viable. We also include a singlet fermion with scalar coupling to the singlet scalar to probe the sensitivity of the constraints on additional degrees of freedom and their couplings in the singlet sector. We also comment on the general feasibility of these fields to act as dark matter.

  10. Breakdown of the Strong-Field Approximation for Transverse Electron Momentum Distributions in Strong-Field Ionization

    NASA Astrophysics Data System (ADS)

    Sang, Robert; Calvert, J. E.; Goodall, S.; Wang, X.; Xu, H.; Palmer, A. J.; Ivanov, I. A.; Kheifets, A. S.; Kielpinski, D.; Litvinyuk, I. V.

    2015-05-01

    We investigated the transverse electron momentum distributions for the strong field ionization of atoms by laser pulses with varying ellipticity. We investigated two ionization regimes; tunelling and over the barrier ionization regimes. The over the barrier regime was accessed by using neon atoms in excited atomic metastable states and is the first such strong-field experiment to use such an atomic species. We will show that the transverse momentum distributions evolve in qualitatively different when the ellipticity of the driving laser pulses is varied. email: R.Sang@griffith.edu.au

  11. Vesicle deformation and poration under strong dc electric fields

    NASA Astrophysics Data System (ADS)

    Sadik, Mohamed M.; Li, Jianbo; Shan, Jerry W.; Shreiber, David I.; Lin, Hao

    2011-06-01

    When subject to applied electric pulses, a lipid membrane exhibits complex responses including electrodeformation and electroporation. In this work, the electrodeformation of giant unilamellar vesicles under strong dc electric fields was investigated. Specifically, the degree of deformation was quantified as a function of the applied field strength and the electrical conductivity ratio of the fluids inside and outside of the vesicles. The vesicles were made from L-α-phosphatidylcholine with diameters ranging from 14 to 30 μm. Experiments were performed with field strengths ranging from 0.9 to 2.0 kV/cm, and intra-to-extra-vesicular conductivity ratios varying between 1.92 and 53.0. With these parametric configurations, the vesicles exhibited prolate elongations along the direction of the electric field. The degree of deformation was, in general, significant. In some cases, the aspect ratio of a deformed vesicle exceeded 10, representing a strong-deformation regime previously not explored. The aspect ratio scaled quadratically with the field strength, and increased asymptotically to a maximum value at high conductivity ratios. Appreciable area and volumetric changes were observed both during and after pulsation, indicating the concurrence of electroporation. A theoretical model is developed to predict these large deformations in the strongly permeabilized limit, and the results are compared with the experimental data. Both agreements and discrepancies are found, and the model limitations and possible extensions are discussed.

  12. Synchrotron radiation in strongly coupled conformal field theories

    SciTech Connect

    Athanasiou, Christiana; Chesler, Paul M.; Liu, Hong; Rajagopal, Krishna; Nickel, Dominik

    2010-06-15

    Using gauge/gravity duality, we compute the energy density and angular distribution of the power radiated by a quark undergoing circular motion in strongly coupled N=4 supersymmetric Yang-Mills theory. We compare the strong coupling results to those at weak coupling, finding them to be very similar. In both regimes, the angular distribution of the radiated power is in fact similar to that of synchrotron radiation produced by an electron in circular motion in classical electrodynamics: the quark emits radiation in a narrow beam along its velocity vector with a characteristic opening angle {alpha}{approx}1/{gamma}. To an observer far away from the quark, the emitted radiation appears as a short periodic burst, just like the light from a lighthouse does to a ship at sea. Our strong coupling results are valid for any strongly coupled conformal field theory with a dual classical gravity description.

  13. Exact Classical and Quantum Dynamics in Background Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Heinzl, Tom; Ilderton, Anton

    2017-03-01

    Analytic results for (Q)ED processes in external fields are limited to a few special cases, such as plane waves. However, the strong focusing of intense laser fields implies a need to go beyond the plane wave model. By exploiting Poincaré symmetry and superintegrability we show how to construct, and solve without approximation, new models of laser-matter interactions. We illustrate the method with a model of a radially polarized (TM) laser beam, for which we exactly determine the classical orbits and quantum wave functions. Including in this way the effects of transverse field structure should improve predictions and analyses for experiments at intense laser facilities.

  14. Modeling of interactions of electromagnetic fields with human bodies

    NASA Astrophysics Data System (ADS)

    Caputa, Krzysztof

    Interactions of electromagnetic fields with the human body have been a subject of scientific interest and public concern. In recent years, issues in power line field effects and those of wireless telephones have been in the forefront of research. Engineering research compliments biological investigations by quantifying the induced fields in biological bodies due to exposure to external fields. The research presented in this thesis aims at providing reliable tools, and addressing some of the unresolved issues related to interactions with the human body of power line fields and fields produced by handheld wireless telephones. The research comprises two areas, namely development of versatile models of the human body and their visualisation, and verification and application of numerical codes to solve selected problems of interest. The models of the human body, which are based on the magnetic resonance scans of the body, are unique and differ considerably from other models currently available. With the aid of computer software developed, the models can be arranged to different postures, and medical devices can be accurately placed inside them. A previously developed code for modeling interactions of power line fields with biological bodies has been verified by rigorous, quantitative inter-laboratory comparison for two human body models. This code has been employed to model electromagnetic interference (EMI) of the magnetic field with implanted cardiac pacemakers. In this case, the correct placement and representation of the pacemaker leads are critical, as simplified computations have been shown to result in significant errors. In modeling interactions of wireless communication devices, the finite difference time domain technique (FDTD) has become a de facto standard. The previously developed code has been verified by comparison with the analytical solution for a conductive sphere. While previously researchers limited their verifications to principal axes of the sphere

  15. GEMS (Gravity Electro-Magnetism Strong) SU(5) Theory and The Prediction of Exchange Boson Masses

    NASA Astrophysics Data System (ADS)

    Brandenburg, John

    2012-10-01

    The GEMS SU(5) [1] theory includes short range Nuclear Forces in the GEM unification theory [2], where the importance of the square root of the proton-electron mass ratio: σ = 42.8503 was found. The creation of mass by a Higgs field coupling must, by the Equivalence Principle, be viewed in the context of General Relativity. This is done here using Kaluza-Klein theory in a Feynman-Hawkings path integral formalism. GEM theory, quantum concepts of virtual particles, and ZPF (Zero Point Fluctuation) allow understanding of the Strong Force and Weak forces as the extension of electrodynamics in the quantum limit. The Strong and Weak forces are found to be associated with EM models of the electron and proton as finite sized structures respectively. Higher order Mie resonances off the EM ``mass at a distance'' structures associated with the electron, proton and fifth dimension generate the quanta with masses of the pion mπ = 2 me /α 140.0 MeV and Z boson: mZ = 2σ mp = 80.4 GeV. The ηc meson mη = 2980 GeV is identified with the 5^th dimension compactification force mediated by the Radion field. Another particle associated with this mass inducing field is the ``Radion'' or Higgs scattering quanta off the fifth dimension with a mass σmη 128.6 GeV which is the Higgs Boson. A GEMS SU(5) Georgi-Glashow model, is proposed, where the unification energy is now the Planck energy.[0pt] [1] Brandenburg, J.E. (2012)., STAIF II Conference Albuquerque NM[0pt] [2] Brandenburg, J.E. (2007). IEEE Transactions On Plasma Science, Vol. 35, No. 4., p845.

  16. Idiopathic environmental intolerance attributed to electromagnetic fields (formerly 'electromagnetic hypersensitivity'): An updated systematic review of provocation studies.

    PubMed

    Rubin, G James; Nieto-Hernandez, Rosa; Wessely, Simon

    2010-01-01

    Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF; formerly 'electromagetic hypersensitivity') is a medically unexplained illness in which subjective symptoms are reported following exposure to electrical devices. In an earlier systematic review, we reported data from 31 blind provocation studies which had exposed IEI-EMF volunteers to active or sham electromagnetic fields and assessed whether volunteers could detect these fields or whether they reported worse symptoms when exposed to them. In this article, we report an update to that review. An extensive literature search identified 15 new experiments. Including studies reported in our earlier review, 46 blind or double-blind provocation studies in all, involving 1175 IEI-EMF volunteers, have tested whether exposure to electromagnetic fields is responsible for triggering symptoms in IEI-EMF. No robust evidence could be found to support this theory. However, the studies included in the review did support the role of the nocebo effect in triggering acute symptoms in IEI-EMF sufferers. Despite the conviction of IEI-EMF sufferers that their symptoms are triggered by exposure to electromagnetic fields, repeated experiments have been unable to replicate this phenomenon under controlled conditions. A narrow focus by clinicians or policy makers on bioelectromagnetic mechanisms is therefore, unlikely to help IEI-EMF patients in the long-term.

  17. 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.

  18. The effect of strong static magnetic field on lymphocytes.

    PubMed

    Aldinucci, Carlo; Garcia, Julian Blanco; Palmi, Mitri; Sgaragli, Gianpietro; Benocci, Alberto; Meini, Antonella; Pessina, Federica; Rossi, Claudio; Bonechi, Claudia; Pessina, Gian Paolo

    2003-02-01

    We investigated whether static electromagnetic fields (EMFs) at a flux density of 4.75 T, generated by an NMR apparatus (NMRF), could promote movements of Ca2+, cell proliferation, and the eventual production of proinflammatory cytokines in human peripheral blood mononuclear cells (PBMC) as well as in Jurkat cells, after exposure to the field for 1 h. The same study was also performed after activation of cells with 5 mg/ml phytohaemagglutinin (PHA). Our results clearly demonstrate that static NMRF exposure has neither proliferative, nor activating, nor proinflammatory effects on both normal and PHA activated PBMC. Moreover, the concentration of interleukin-1beta, interleukin-2, interleukin-6, interferon, and tumour necrosis factor alpha (TNFalpha) remained unvaried in exposed cells. Exposure of Jurkat cells statistically decreased the proliferation and the proliferation indexes, which 24 and 48 h after exposure were 0.7 +/- 0.29 and 0.87 +/- 0.12, respectively. Moreover, in Jurkat cells the [Ca2+]i was higher than in PBMC and was reduced significantly to about one half after exposure. This is consistent with the decrease of proliferation and with the low levels of IL-2 measured. On the whole, our data suggest that NMRF exposure failed to affect the physiologic behaviour of normal lymphomonocytes. Instead in Jurkat cells, by changing the properties of cell membranes, NMRF can influence Ca2+ transport processes, and hence Ca2+ homeostasis with improvement of proliferation.

  19. Nerve excitation and recovery processes under strong static magnetic fields

    NASA Astrophysics Data System (ADS)

    Eguchi, Yawara; Ueno, Shoogo; Tatsuoka, Hozumi

    2003-05-01

    The membrane excitation and refractory processes of nerve fibers exposed to strong static magnetic fields of 8 T were studied. Sciatic nerve bundles of frogs were electrically excited by a pair of pulses with varying interpulse intervals, and the compound action potentials were measured under magnetic field exposures. Our experimental results show that the conduction velocity was not affected by 8 T magnetic fields; however, the membrane excitation during the recovery process in the relative refractory period was enhanced by 10% of maximal peak of nerve excitation by magnetic field exposure for 3 h. In this study, the optimal time interval for increased membrane excitation during the recovery process was between 1.0 and 1.1 ms. In other words, membrane excitation during the recovery process in the relative refractory period was affected by the magnetic fields just after Na+ channels were inactivated.

  20. Generation of strong electric fields in an ice film capacitor.

    PubMed

    Shin, Sunghwan; Kim, Youngsoon; Moon, Eui-seong; Lee, Du Hyeong; Kang, Hani; Kang, Heon

    2013-08-21

    We present a capacitor-type device that can generate strong electrostatic field in condensed phase. The device comprises an ice film grown on a cold metal substrate in vacuum, and the film is charged by trapping Cs(+) ions on the ice surface with thermodynamic surface energy. Electric field within the charged film was monitored through measuring the film voltage using a Kelvin work function probe and the vibrational Stark effect of acetonitrile using IR spectroscopy. These measurements show that the electric field can be increased to ∼4 × 10(8) V m(-1), higher than that achievable by conventional metal plate capacitors. In addition, the present device may provide several advantages in studying the effects of electric field on molecules in condensed phase, such as the ability to control the sample composition and structure at molecular scale and the spectroscopic monitoring of the sample under electric field.

  1. Strong magnetic fields in normal galaxies at high redshift.

    PubMed

    Bernet, Martin L; Miniati, Francesco; Lilly, Simon J; Kronberg, Philipp P; Dessauges-Zavadsky, Miroslava

    2008-07-17

    The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It was recently demonstrated that field strengths as traced by rotation measures of distant (and hence ancient) quasars are comparable to those seen today, but it was unclear whether the high fields were in the unusual environments of the quasars themselves or distributed along the lines of sight. Here we report high-resolution spectra that demonstrate that the quasars with strong Mg II absorption lines are unambiguously associated with larger rotation measures. Because Mg ii absorption occurs in the haloes of normal galaxies along the sightlines to the quasars, this association requires that organized fields of surprisingly high strengths are associated with normal galaxies when the Universe was only about one-third of its present age.

  2. Three-dimensional electromagnetic breathers in carbon nanotubes with the field inhomogeneity along their axes

    NASA Astrophysics Data System (ADS)

    Zhukov, Alexander V.; Bouffanais, Roland; Fedorov, Eduard G.; Belonenko, Mikhail B.

    2013-10-01

    We study the propagation of extremely short electromagnetic three-dimensional bipolar pulses in an array of semiconductor carbon nanotubes. The heterogeneity of the pulse field along the axis of the nanotubes is accounted for the first time. The evolution of the electromagnetic field and the charge density of the sample are described by Maxwell's equations supplemented by the continuity equation. Our analysis reveals for the first time the possibility of propagation of three-dimensional electromagnetic breathers in CNTs arrays. Specifically, we found that the propagation of short electromagnetic pulse induces a redistribution of the electron density in the sample.

  3. Wavelength Dependent Strong Field Interactions with Atoms and Molecules

    NASA Astrophysics Data System (ADS)

    Szafruga, Urszula Bozena

    In the regime of strong-field physics the electric field of a laser begins to strongly rival the binding potential of an atomic or molecular species. During these interactions an ionized electron can be driven away and then back towards its parent ion by the strong laser field and undergo rescattering before being detected. The amount of energy an electron can acquire during propagation is proportional to the laser intensity and the square of the wavelength. Recent improvements in laser technology have allowed us to push strong-field studies from visible/near-infrared wavelengths to the mid-infrared regime and thereby greatly increase the electron's maximum recollision energy. These high energy scattering events imprint target dependent structural information on the electron angular distribution from which we can extract atomic and molecular specific properties. Further, Keldysh invariance suggests that we can control the dominant ionization mechanism (multiphoton absorption versus tunneling through the field modified potential) by choosing an appropriate laser wavelength, laser intensity and target atom. Exploratory investigations in strong-field physics have produced many fascinating results which have led to production of attosecond duration laser pulses and atomic/molecular imaging techniques. As technological improvements continue we are able to gain further insights into these interesting physical phenomena. In this work we examine photoelectron spectra and ion yields in order to gain a deeper understanding of the fundamental processes that underlie atomic and molecular strong field interactions. Alkali metal atoms at mid-infrared wavelengths possess similar Keldysh parameter values as noble gas atoms at near-infrared wavelengths, which have received much more investigative attention. Therefore, by examining alkali metal atoms at longer wavelengths we hope to expand on our understanding of the global, Keldysh invariant, and atom specific ionization features

  4. Electromagnetic fluid drift turbulence in static ergodic magnetic fields

    SciTech Connect

    Reiser, D.; Scott, B.

    2005-12-15

    Numerical simulations of three-dimensional nonlinear electromagnetic fluid drift turbulence in a tokamak plasma with externally applied stochastic magnetic-field perturbations are presented. The contributions to the radial particle transport due to nonlinearities arising from ExB advection and magnetic flutter are investigated for perturbation fields of varying strengths in the cases of low and high collisionalities. The perturbation strength is varied to study the physics for Chirikov parameters above 1. In all the cases considered a significant increase of ExB transport is found. A static contribution in the density and velocity perturbations contributes significantly to the total radial ExB transport. For low collisionality, the external perturbation leads to enhanced density and velocity fluctuations over a broad range in the toroidal wave-number spectrum, resulting in an enhanced turbulent flux. For high collisionality, the density fluctuations stay roughly the same and the velocity fluctuations are increased in an intermediate range of the toroidal wave number spectrum, separated from the maximum of the density fluctuations, thus leaving the turbulent flux almost unchanged.

  5. Adaptive framework for uncertainty analysis in electromagnetic field measurements.

    PubMed

    Prieto, Javier; Alonso, Alonso A; de la Rosa, Ramón; Carrera, Albano

    2015-04-01

    Misinterpretation of uncertainty in the measurement of the electromagnetic field (EMF) strength may lead to an underestimation of exposure risk or an overestimation of required measurements. The Guide to the Expression of Uncertainty in Measurement (GUM) has internationally been adopted as a de facto standard for uncertainty assessment. However, analyses under such an approach commonly assume unrealistic static models or neglect relevant prior information, resulting in non-robust uncertainties. This study proposes a principled and systematic framework for uncertainty analysis that fuses information from current measurements and prior knowledge. Such a framework dynamically adapts to data by exploiting a likelihood function based on kernel mixtures and incorporates flexible choices of prior information by applying importance sampling. The validity of the proposed techniques is assessed from measurements performed with a broadband radiation meter and an isotropic field probe. The developed framework significantly outperforms GUM approach, achieving a reduction of 28% in measurement uncertainty. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Electromagnetic cascades and the depletion of intense fields

    NASA Astrophysics Data System (ADS)

    Bulanov, Stepan; Seipt, Daniel; Heinzl, Thomas; Marklund, Mattias; Ji, Qing; Steinke, Sven; Schroeder, Carl; Esarey, Eric; Leemans, Wim P.

    2016-10-01

    The interaction of electrons, positrons, and photons with intense electromagnetic fields gives rise to multi-photon Compton and Breit-Wheeler processes. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution. Moreover the multi-photon nature of Compton and Breit-Wheeler processes implies the absorption of a significant number of photons. As a result, the interaction of a highly charged electron bunch with an intense laser pulse can lead to a significant depletion of the laser pulse energy, thus rendering the external field approximation invalid. The relevance of these results to the proposed BELLA-i beamline at BELLA center at LBNL is discussed. We acknowledge support from the Office of Science of the US DOE under Contract No. DE-AC02-05CH11231.

  7. Error sources affecting thermocouple thermometry in RF electromagnetic fields.

    PubMed

    Chakraborty, D P; Brezovich, I A

    1982-03-01

    Thermocouple thermometry errors in radiofrequency (typically 13, 56 MHZ) electromagnetic fields such as are encountered in hyperthermia are described. RF currents capacitatively or inductively coupled into the thermocouple-detector circuit produce errors which are a combination of interference, i.e., 'pick-up' error, and genuine rf induced temperature changes at the junction of the thermocouple. The former can be eliminated by adequate filtering and shielding; the latter is due to (a) junction current heating in which the generally unequal resistances of the thermocouple wires cause a net current flow from the higher to the lower resistance wire across the junction, (b) heating in the surrounding resistive material (tissue in hyperthermia), and (c) eddy current heating of the thermocouple wires in the oscillating magnetic field. Low frequency theories are used to estimate these errors under given operating conditions and relevant experiments demonstrating these effects and precautions necessary to minimize the errors are described. It is shown that at 13.56 MHz and voltage levels below 100 V rms these errors do not exceed 0.1 degrees C if the precautions are observed and thermocouples with adequate insulation (e.g., Bailey IT-18) are used. Results of this study are being currently used in our clinical work with good success.

  8. Electromagnetic fluid drift turbulence in static ergodic magnetic fields

    NASA Astrophysics Data System (ADS)

    Reiser, D.; Scott, B.

    2005-12-01

    Numerical simulations of three-dimensional nonlinear electromagnetic fluid drift turbulence in a tokamak plasma with externally applied stochastic magnetic-field perturbations are presented. The contributions to the radial particle transport due to nonlinearities arising from E ×B advection and magnetic flutter are investigated for perturbation fields of varying strengths in the cases of low and high collisionalities. The perturbation strength is varied to study the physics for Chirikov parameters above 1. In all the cases considered a significant increase of E ×B transport is found. A static contribution in the density and velocity perturbations contributes significantly to the total radial E ×B transport. For low collisionality, the external perturbation leads to enhanced density and velocity fluctuations over a broad range in the toroidal wave-number spectrum, resulting in an enhanced turbulent flux. For high collisionality, the density fluctuations stay roughly the same and the velocity fluctuations are increased in an intermediate range of the toroidal wave number spectrum, separated from the maximum of the density fluctuations, thus leaving the turbulent flux almost unchanged.

  9. Convective heat transfer in engine coolers influenced by electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Karcher, C.; Kühndel, J.

    2017-08-01

    In engine coolers of off-highway vehicles, convective heat transfer at the coolant side limits both efficiency and performance density of the apparatus. Here, due to restrictions in construction and design, backwater areas and stagnation regions cannot be avoided. Those unwanted changes in flow characteristics are mainly triggered by flow deflections and sudden cross-sectional expansions. In application, mixtures of water and glysantine are used as appropriate coolants. Such coolants typically show an electrical conductivity of a few S/m. Coolant flow and convective heat transfer can then be controlled using Lorentz forces. These body forces are generated within the conducting fluid by the interactions of an electrical current density and a localized magnetic field, both of which are externally superimposed. In future application, this could be achieved by inserting electrodes in the cooler wall and a corresponding arrangement of permanent magnets. In this paper we perform numerical simulations of such magnetohydrodynamic flow in three model geometries that frequently appear in engine cooling applications: Carnot-Borda diffusor, 90° bend, and 180° bend. The simulations are carried out using the software package ANSYS Fluent. The present study demonstrates that, depending on the electromagnetic interaction parameter and the specific geometric arrangement of electrodes and magnetic field, Lorentz forces are suitable to break up eddy waters and separation zones and thus significantly increase convective heat transfer in these areas. Furthermore, the results show that hydraulic pressure losses can be reduced due to the pumping action of the Lorentz forces.

  10. Strong-field and attosecond physics in solids

    NASA Astrophysics Data System (ADS)

    Ghimire, Shambhu; Ndabashimiye, Georges; DiChiara, Anthony D.; Sistrunk, Emily; Stockman, Mark I.; Agostini, Pierre; DiMauro, Louis F.; Reis, David A.

    2014-10-01

    We review the status of strong-field and attosecond processes in bulk transparent solids near the Keldysh tunneling limit. For high enough fields and low-frequency excitations, the optical and electronic properties of dielectrics can be transiently and reversibly modified within the applied pulse. In Ghimire et al (2011 Phys. Rev. Lett. 107 167407) non-parabolic band effects were seen in photon-assisted tunneling experiments in ZnO crystals in a strong mid-infrared field. Using the same ZnO crystals, Ghimire et al (2011 Nat. Phys. 7 138-41) reported the first observation of non-pertubative high harmonics, extending well above the bandgap into the vacuum ultraviolet. Recent experiments by Schubert et al (2014 Nat. Photonics 8 119-23) showed a carrier envelope phase dependence in the harmonic spectrum in strong-field 30 THz driven GaSe crystals which is the most direct evidence yet of the role of sub-cycle electron dynamics in solid-state harmonic generation. The harmonic generation mechanism is different from the gas phase owing to the high density and periodicity of the crystal. For example, this results in a linear dependence of the high-energy cutoff with the applied field in contrast to the quadratic dependence in the gas phase. Sub-100 attosecond pulses could become possible if the harmonic spectrum can be extended into the extreme ultraviolet (XUV). Here we report harmonics generated in bulk MgO crystals, extending to ˜ 26 eV when driven by ˜35 fs, 800 nm pulses focused to a ˜1 VÅ-1 peak field. The fundamental strong-field and attosecond response also leads to Wannier-Stark localization and reversible semimetallization as seen in the sub-optical cycle behavior of XUV absorption and photocurrent experiments on fused silica by Schiffrin et al (2013 Nature 493 70-4) and Schultze et al (2013 Nature 493 75-8). These studies are advancing our understanding of fundamental strong-field and attosecond physics in solids with potential applications for compact

  11. Strong-field and attosecond physics in solids

    DOE PAGES

    Ghimire, Shambhu; Ndabashimiye, Georges; DiChiara, Anthony D.; ...

    2014-10-08

    We review the status of strong-field and attosecond processes in bulk transparent solids near the Keldysh tunneling limit. For high enough fields and low-frequency excitations, the optical and electronic properties of dielectrics can be transiently and reversibly modified within the applied pulse. In Ghimire et al (2011 Phys. Rev. Lett. 107 167407) non-parabolic band effects were seen in photon-assisted tunneling experiments in ZnO crystals in a strong mid-infrared field. Using the same ZnO crystals, Ghimire et al (2011 Nat. Phys. 7 138–41) reported the first observation of non-pertubative high harmonics, extending well above the bandgap into the vacuum ultraviolet. Recent experiments by Schubert et al (2014 Nat. Photonics 8 119–23) showed a carrier envelope phase dependence in the harmonic spectrum in strong-field 30 THz driven GaSe crystals which is the most direct evidence yet of the role of sub-cycle electron dynamics in solid-state harmonic generation. The harmonic generation mechanism is different from the gas phase owing to the high density and periodicity of the crystal. For example, this results in a linear dependence of the high-energy cutoff with the applied field in contrast to the quadratic dependence in the gas phase. Sub-100 attosecond pulses could become possible if the harmonic spectrum can be extended into the extreme ultraviolet (XUV). Here we report harmonics generated in bulk MgO crystals, extending tomore » $$\\sim 26$$ eV when driven by ~35 fs, 800 nm pulses focused to a ~1 VÅ$$^{-1}$$ peak field. The fundamental strong-field and attosecond response also leads to Wannier–Stark localization and reversible semimetallization as seen in the sub-optical cycle behavior of XUV absorption and photocurrent experiments on fused silica by Schiffrin et al (2013 Nature 493 70–4) and Schultze et al (2013 Nature 493 75–8). These studies are advancing our understanding of fundamental strong-field and attosecond physics in solids with potential

  12. Globally strong geomagnetic field intensity circa 3000 years ago

    NASA Astrophysics Data System (ADS)

    Hong, Hoabin; Yu, Yongjae; Lee, Chan Hee; Kim, Ran Hee; Park, Jingyu; Doh, Seong-Jae; Kim, Wonnyon; Sung, Hyongmi

    2013-12-01

    High-fidelity geomagnetic field intensity determination was carried out using 191 baked fragments collected from 20 kilns or hearths with ages ranging between ∼1200 BC and ∼AD 1725 in South Korea. Geomagnetic field intensity variation displayed three narrow minima at ∼800-700 BC, ∼AD 700, and ∼AD 1600 and two maxima at ∼1200-1100 BC and ∼AD 1000-1100. In most time intervals, virtual axial dipole moment (VADM) variation is confined within 20% of the present VADM. However, geomagnetic field intensity circa 3000 yr ago is nearly 40% larger than the present value. Such high VADMs circa 3000 yr ago are in phase with those in other longitudinal bands in northern hemisphere centered at 5E (France), 30E (the Middle East) and 200E (Hawaii). Although strong geomagnetic field intensity circa 3000 yr ago is globally synchronous, the highest VADM occurs at slightly different time intervals in different locations. Hence it is possible that the globally strong geomagnetic field intensity circa 3000 yr ago reflects the migration of persistent hemispheric flux in northern hemisphere or an episode of geomagnetic field hemispheric asymmetry.

  13. Strong parallel magnetic field effects on the hydrogen molecular ion

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Li, Baiwen; Taylor, K. T.

    2003-09-01

    Equilibrium distances, binding energies and dissociation energies for the ground and low-lying states of the hydrogen molecular ion in a strong magnetic field parallel to the internuclear axis are calculated and refined, by using the two-dimensional pseudospectral method. High-precision results are presented for the binding energies over a wider field regime than already given in the literature (Kravchenko and Liberman 1997 Phys. Rev. A 55 2701). The present work removes a long-standing discrepancy for the Req value in the 1sigmau state at a field strength of 1.0 × 106 T. The dissociation energies of the antibonding 1pig state induced by magnetic fields are determined accurately. We have also observed that the antibonding 1pig potential energy curve develops a minimum if the field is sufficiently strong. Some unreliable results in the literature are pointed out and discussed. A way to efficiently treat vibrational processes and coupling between the nuclear and the electronic motions in magnetic fields is also suggested within a three-dimensional pseudospectral scheme.

  14. Observability of atomic line features in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Wunner, G.; Ruder, H.; Herold, H.; Truemper, J.

    1981-01-01

    The physical properties of atoms in superstrong magnetic fields, characteristic of neutron stars, and the possibility of detecting magnetically strongly shifted atomic lines in the spectra of magnetized X-ray pulsars are discussed. It is suggested that it is recommendable to look for magnetically strongly shifted Fe 26 Lyman lines in rotating neutron stars of not too high luminosity using spectrometers working in the energy range 10 - 20 keV, with sensitivities to minus 4 power photons per sq cm and second, and resolution E/delta E approx. 10-100.

  15. Growth inhibition of Staphylococcus aureus induced by low-frequency electric and electromagnetic fields.

    PubMed

    Obermeier, Andreas; Matl, Florian Dominik; Friess, Wolfgang; Stemberger, Axel

    2009-05-01

    Magnetic field therapy is an established technique in the treatment of pseudarthrosis. In cases of osteomylitis, palliation is also observed. This study focuses on the impact of different electric and electromagnetic fields on the growth of Staphylococcus aureus by in vitro technologies. Cultures of Staphylococcus aureus in fluid and gel-like medium were exposed to a low-frequency electromagnetic field, an electromagnetic field combined with an additional electric field, a sinusoidal electric field and a static electric field. In gel-like medium no significant difference between colony-forming units of exposed samples and non-exposed references was detected. In contrast, Staphylococcus aureus concentrations in fluid medium could clearly be reduced under the influence of the four different applied fields within 24 h of experiment. The strongest effects were observed for the direct current electric field which could decrease CFU/ml of 37%, and the low-frequency electromagnetic field with additional induced electric alternating field with a decrease of Staphylococci concentration by 36%. The effects of the electromagnetic treatment on Staphylococci within fluid medium are significantly higher than in gel-like medium. The application of low-frequency electromagnetic fields corroborates clinical situations of bone infections during magnetic field therapy. Copyright 2009 Wiley-Liss, Inc.

  16. Electromagnetic Near-Field Computations for a Broadcast Monopole Using Numerical Electromagnetics Code (NEC).

    DTIC Science & Technology

    1983-09-01

    Electromagnetic Near-FEjeid Computazions for a Broadcast Mono~ole using ’Vimerical El.ectromagnetics Code (NEC) by David Duerr T-homson Li’~enntCommander... Poggio of Lawrence Livermore Laboratory, January 1981. 3. Schelkuncff, S.A. and Friis, H.T., Antennas Theory -and ?ractice, Wiley, 1952. 4. Jordan...Virginia 22314 2. Library, Code 0142 2 Naval Postgraduate School Monterey, California 93943 3. LCDR David D. Thomson (Code 33n9)2Naval Weapons Center

  17. Localized electron heating by strong guide-field magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Guo, Xuehan; Inomoto, Michiaki; Sugawara, Takumichi; Yamasaki, Kotaro; Ushiki, Tomohiko; Ono, Yasushi

    2015-10-01

    Localized electron heating of magnetic reconnection was studied under strong guide-field using two merging spherical tokamak plasmas in the University of Tokyo Spherical Tokamak experiment. Our new slide-type two-dimensional Thomson scattering system is documented for the first time the electron heating localized around the X-point. Shape of the high electron temperature area does not agree with that of energy dissipation term Et.jt . If we include a guide-field effect term Bt/(Bp+αBt) for Et.jt , the energy dissipation area becomes localized around the X-point, suggesting that the electrons are accelerated by the reconnection electric field parallel to the magnetic field and thermalized around the X-point.

  18. Electromagnetic Radiation System (EMRS) for Susceptibility Testing.

    DTIC Science & Technology

    ELECTROMAGNETIC COMPATIBILITY, *ELECTROMAGNETIC SUSCEPTIBILITY, COMMUNICATION EQUIPMENT, ELECTRONIC EQUIPMENT, ELECTROMAGNETIC RADIATION , ANTENNAS, ELECTROMAGNETIC INTERFERENCE, RADAR SIGNALS, RADIO SIGNALS, FIELD INTENSITY.

  19. Coherent Dynamics Following Strong Field Ionization of Polyatomic Molecules

    NASA Astrophysics Data System (ADS)

    Konar, Arkaprabha; Shu, Yinan; Lozovoy, Vadim; Jackson, James; Levine, Benjamin; Dantus, Marcos

    2015-03-01

    Molecules, as opposed to atoms, present confounding possibilities of nuclear and electronic motion upon strong field ionization. The dynamics and fragmentation patterns in response to the laser field are structure sensitive; therefore, a molecule cannot simply be treated as a ``bag of atoms'' during field induced ionization. We consider here to what extent molecules retain their molecular identity and properties under strong laser fields. Using time-of-flight mass spectrometry in conjunction with pump-probe techniques we study the dynamical behavior of these molecules, monitoring ion yield modulation caused by intramolecular motions post ionization. The delay scans show that among positional isomers the variations in relative energies, amounting to only a few hundred meVs, influence the dynamical behavior of the molecules despite their having experienced such high fields (V/Å). Ab initio calculations were performed to predict dynamics along with single and multiphoton resonances in the neutral and ionic states. We propose that single electron ionization occurs within an optical cycle with the electron carrying away essentially all of the energy, leaving behind little internal energy in the cation. Evidence for this observation comes from coherent vibrational motion governed by the potential energy surface of the ground state of the cation. Subsequent fragmentation of the cation takes place as a result of further photon absorption modulated by one- and two-photon resonances, which provide sufficient energy to overcome the dissociation energy.

  20. Pair annihilation into neutrinos in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Among the processes that are of primary importance for the thermal history of a neutron star is electron-positron annihilation into neutrinos and photoneutrinos. These processes are computed in the presence of a strong magnetic field typical of neutron stars, and the results are compared with the zero-field case. It is shown that the neutrino luminosity Q(H) is greater than Q(O) for temperatures up to T about equal to 3 x 10 to the 8th power K and densities up to 1,000,000 g/cu cm.

  1. Doubly Dressed Bosons: Exciton Polaritons in a Strong Terahertz Field

    NASA Astrophysics Data System (ADS)

    Pietka, B.; Bobrovska, N.; Stephan, D.; Teich, M.; Król, M.; Winnerl, S.; Pashkin, A.; Mirek, R.; Lekenta, K.; Morier-Genoud, F.; Schneider, H.; Deveaud, B.; Helm, M.; Matuszewski, M.; Szczytko, J.

    2017-08-01

    We demonstrate the existence of a novel quasiparticle, an exciton in a semiconductor doubly dressed with two photons of different wavelengths: a near infrared cavity photon and terahertz (THz) photon, with the THz coupling strength approaching the ultrastrong coupling regime. This quasiparticle is composed of three different bosons, being a mixture of a matter-light quasiparticle. Our observations are confirmed by a detailed theoretical analysis, treating quantum mechanically all three bosonic fields. The doubly dressed quasiparticles retain the bosonic nature of their constituents, but their internal quantum structure strongly depends on the intensity of the applied terahertz field.

  2. Pair annihilation into neutrinos in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Among the processes that are of primary importance for the thermal history of a neutron star is electron-positron annihilation into neutrinos and photoneutrinos. These processes are computed in the presence of a strong magnetic field typical of neutron stars, and the results are compared with the zero-field case. It is shown that the neutrino luminosity Q(H) is greater than Q(O) for temperatures up to T about equal to 3 x 10 to the 8th power K and densities up to 1,000,000 g/cu cm.

  3. Mott scattering of polarized electrons in a strong laser field

    SciTech Connect

    Manaut, B.; Taj, S.; Attaourti, Y.

    2005-04-01

    We present analytical and numerical results of the relativistic calculation of the transition matrix element S{sub fi} and differential cross sections for Mott scattering of initially polarized Dirac particles (electrons) in the presence of a strong laser field with linear polarization. We use exact Dirac-Volkov wave functions to describe the dressed electrons and the collision process is treated in the first Born approximation. The influence of the laser field on the degree of polarization of the scattered electron is reported.

  4. Pair production in strong SU(2) background fields

    NASA Astrophysics Data System (ADS)

    Jia, Mo-Ran; Li, Zi-Liang; Lv, Chong; Wan, Feng; Xie, Bai-Song

    2017-10-01

    Fermion particle pair production in strong SU(2)-gauge chromoelectric fields is studied using the Boltzmann-Vlasov equation in a classical way. The existence of a preproduction process in a classical description is shown using the distribution evolution of non-Abelian particle production. It is interesting to find that the distribution of the particle number density is centered on two islands and shows a split on the color charge sphere as it evolves, ultimately reaching a steady state that is related to the amplitude and variation of the field.

  5. Possibility of sounding Earth by using electromagnetic field of sea current

    NASA Astrophysics Data System (ADS)

    Smagin, V. P.; Fonarev, G. A.; Savchenko, V. N.

    1985-06-01

    The possibilities of determining the conductivity of bottom rocks by measuring different combinations of components of the electromagnetic field of a current on the ocean floor are analyzed. It is shown that the sea current induces an electromagnetic field in the geomagnetic field. Then a formula is derived for the magnetic component B. After determining B it is possible to find the electric field in sea water and in rocks beneath the ocean layer. The parameter epsilon is introduced which makes it possible to ascertain the vertical gradient of the magnetic field in bottom rocks; a function is derived which characterizes the magnetic field in the bottom rocks. Formulas are derived which can be used in estimating the width of a current by an electromagnetic method. It is shown, therefore, that with electromagnetic sounding in the fields of sea currents it is possible to make a simple interpretation of the experimental data within the framework of an exponential model of ocean floor conductivity.

  6. [ASSESSMENT OF OCCUPATIONAL EXPOSURE TO RADIO FREQUENCY ELECTROMAGNETIC FIELDS].

    PubMed

    Aniołczyk, Halina; Mariańska, Magda; Mamrot, Paweł

    2015-01-01

    European Union Directive 2013/35/UE provides for the implementation of EU regulations into national legislation. Our aim is to assess actual health hazards from radiofrequency eldctromagnetic field (RF EMF) (range: 100 kHz - 300 GHz) and indicate workplaces with the highest risk to employee health. Data from measurements of RF EMF performed by the Laboratory of Electromagnetic Hazards in Nofer Institute of Occupational Medicine (Łódź, Poland) were analyzed. The analysis covered the results of electric field intensity (E) for over 450 selected items. The ranges of protection zones and the extent to which maximum admissible intensity (MAI) values were also analyzed. The determinations and'measurements of EMF in the work environment met the requirements of Polish Standard, while Polish regulations on the MAI values were used as the criterion for the assessment of the exposure. The highest values of E field intensity at workplaces were measured for: electrosurgery, to 400 V/m, and short-wave diathermy units, to 220 V/m, dielectric welders to 240 V/m, within the FM radio antenna systems, to 180 V/m. The widest protection zones were noted for prototype research instruments, short-wave diathermy units, and dielectric welders. The most excessive (up to 12-fold MAI) values were recorded for dielectric welders, short-wave diathermy units (up to 11-fold) and microwave diathermy units (up to 8-fold). Our results have confirmed the high RF EMF values for physiotherapists, operators of dielectric welders, and mast maintenance workers in radio com munication facilities (especially radio and TV broadcasting stations).

  7. Molecules and chains in a strong magnetic field - Statistical treatment

    NASA Technical Reports Server (NTRS)

    Abrahams, Andrew M.; Shapiro, Stuart L.

    1991-01-01

    A Thomas-Fermi-Dirac-Weizsaecker statistical model is developed and employed to investigate diatomic molecules and infinite molecular chains in strong magnetic fields. The standard magnetic Thomas-Fermi-Dirac kinetic, potential, and exchange energy functionals are supplemented by a gradient correction to the kinetic energy. The numerical method used for solving this system in two spatial dimensions is detailed. Numerical solutions for a wide range of magnetic strengths and elements are presented to demonstrate the robustness, as well as the limitations, of the statistical approach. These calculations qualitatively reproduce many of the results of detailed quantum mechanical treatments. For example, the fractional binding energy is greatest for low atomic numbers and for strong magnetic fields.

  8. Strongly interacting photons in a synthetic magnetic field

    NASA Astrophysics Data System (ADS)

    Roushan, Pedram; Neill, C.; Megrant, A.; Chen, Y.; Barends, R.; Cambell, B.; Chen, Z.; Chiaro, B.; Dunsworth, A.; Fowler, A.; Jeffrey, E.; Kelly, J.; Lucero, E.; Mutus, J.; O'Malley, P.; Neeley, M.; Quintana, C.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T.; Kapit, E.; Martinis, J.

    Interacting electrons in the presence of magnetic fields exhibit some of the most fascinating phases in condensed matter systems. Realizing these phases in an engineered platform could provide deeper insight into their. Using three superconducting qubits, we synthesize artificial magnetic fields by modulating the inter-qubit coupling. In the closed loop formed by the qubits, we observe the directional circulation of a microwave photon as well as chiral groundstate currents, the signatures of broken time-reversal symmetry. The existence of strong interactions in our system is seen via the creation of photon vacancies, or ''holes'', which circulate in the opposite direction from the photons. Our work demonstrates an experimental approach for engineering quantum phases of strongly interacting bosons.

  9. Consequences of rotating off-centred dipolar electromagnetic field in vacuum around Pulsars

    NASA Astrophysics Data System (ADS)

    Kundu, A.; Pétri, J.

    2016-12-01

    Studying the electromagnetic field of pulsars is one of the key themes in neutron star physics. While most of the works assume a standard central dipolar electromagnetic field model, recently some efforts had been made in explaining how inclusion of higher field components produces drastic consequences in our understanding of these objects. We put forward the effects of a unique recently presented approach in which the magnetic axis is shifted off from the centre. It is found that the rotating off-centred dipolar electromagnetic field itself reveals the presence of the higher components within. The consequences of this approach on the shape of the polar caps and the emission diagrams are discussed.

  10. Effects of pulsed electromagnetic field frequencies on the osteogenic differentiation of human mesenchymal stem cells.

    PubMed

    Luo, Fei; Hou, Tianyong; Zhang, Zehua; Xie, Zhao; Wu, Xuehui; Xu, Jianzhong

    2012-04-01

    The purpose of this study was to evaluate the effect of different frequencies of pulsed electromagnetic fields on the osteogenic differentiation of human mesenchymal stem cells. Third-generation human mesenchymal stem cells were irradiated with different frequencies of pulsed electromagnetic fields, including 5, 25, 50, 75, 100, and 150 Hz, with a field intensity of 1.1 mT, for 30 minutes per day for 21 days. Changes in human mesenchymal stem cell morphology were observed using phase contrast microscopy. Alkaline phosphatase activity and osteocalcin expression were also determined to evaluate human mesenchymal stem cell osteogenic differentiation.Different effects were observed on human mesenchymal stem cell osteoblast induction following exposure to different pulsed electromagnetic field frequencies. Levels of human mesenchymal stem cell differentiation increased when the pulsed electromagnetic field frequency was increased from 5 hz to 50 hz, but the effect was weaker when the pulsed electromagnetic field frequency was increased from 50 Hz to 150 hz. The most significant effect on human mesenchymal stem cell differentiation was observed at of 50 hz.The results of the current study show that pulsed electromagnetic field frequency is an important factor with regard to the induction of human mesenchymal stem cell differentiation. Furthermore, a pulsed electromagnetic field frequency of 50 Hz was the most effective at inducing human mesenchymal stem cell osteoblast differentiation in vitro.

  11. Estimation of the Lithospheric Component Share in the Earth Natural Pulsed Electromagnetic Field Structure

    NASA Astrophysics Data System (ADS)

    Malyshkov, S. Y.; Gordeev, V. F.; Polyvach, V. I.; Shtalin, S. G.; Pustovalov, K. N.

    2017-04-01

    Article describes the results of the atmosphere and Earth’s crust climatic and ecological parameters integrated monitoring. The estimation is made for lithospheric component share in the Earth natural pulsed electromagnetic field structure. To estimate lithospheric component we performed a round-the-clock monitoring of the Earth natural pulsed electromagnetic field background variations at the experiment location and measured the Earth natural pulsed electromagnetic field under electric shields. Natural materials in a natural environment were used for shielding, specifically lakes with varying parameters of water conductivity. Skin effect was used in the experiment - it is the tendency of electromagnetic waves amplitude to decrease with greater depths in the conductor. Atmospheric and lithospheric component the Earth natural pulsed electromagnetic field data recorded on terrain was compared against the recorded data with atmosphere component decayed by an electric shield. In summary we have demonstrated in the experiment that thunderstorm discharge originating electromagnetic field decay corresponds to the decay calculated using Maxwell equations. In the absence of close lightning strikes the ratio of field intensity recorded on terrain to shielded field intensity is inconsistent with the ratio calculated for atmospheric sources, that confirms there is a lithospheric component present to the Earth natural pulsed electromagnetic field.

  12. Hig Resolution Seismometer Insensitive to Extremely Strong Magnetic Fields

    SciTech Connect

    Abramovich, Igor A

    2009-07-14

    A highly sensitive broadband seismic sensor has been developed successfully to be used in beam focusing systems of particale accelerators. The sensor is completely insensitive to extremely strong magnetic fields and to hard radiation conditions that exist at the place of their installation. A unique remote sensor calibration method has been invented and implemented. Several such sensors were sold to LAPP (LAPP-IN2P3/CNRS-Université de Savoie; Laboratoire d'Annecy-le-Vieux de Physique des Particules)

  13. Interference stabilisation of Rydberg atoms in a strong laser field

    SciTech Connect

    Fedorov, Mikhail V

    1999-07-31

    A review is given of the published theoretical and experimental investigations of the interference stabilisation of Rydberg atoms by a strong optical field. The physical nature of the effect, the models used to describe it, the alternative stabilisation mechanisms, and the extent to which the theoretical results match the published experimental data are discussed. (this issue is dedicated to the memory of s a akhmanov)

  14. Extended virtual detector theory for strong-field atomic ionization.

    PubMed

    Wang, Xu; Tian, Justin; Eberly, J H

    2013-06-14

    For time-dependent strong-field atomic ionization a new theoretical approach is described that combines the numerical time-dependent Schrödinger equation (TDSE) and the numerical time-dependent Newtonian equation (TDNE). This approach keeps both the accuracy of quantum calculations and the speed of classical calculations. It does not use approximate tunneling formulas. It is applied to a recent experimental result, and we show its successful comparison to extensive TDSE calculations made under exactly the same conditions.

  15. Strong field radio-frequency measurements using Rydberg states in a vapor cell

    NASA Astrophysics Data System (ADS)

    Miller, Stephanie; Anderson, David; Raithel, Georg

    2016-05-01

    There has been a growing interest in using electromagnetically induced transparency with Rydberg atoms in a room-temperature vapor cell as an all-optical readout method for measuring microwave electric fields. We present results from RF-modulating the 60S1 / 2 and 58D5 / 2 Rydberg states of rubidium with 50 MHz and 100 MHz fields, respectively. Weak RF fields AC Stark-shifts the Rydberg states. As the field strength is increased, sidebands appear at even multiples of the driving frequency. When strong fields are applied, the nearby hydrogenic manifold begins to intersect with the shifted levels. Similar investigations have been performed in cesium. Due to the significant amount of state mixing and level structure, Floquet theory is required to describe the level shifts and mixing. By comparing the calculation with the experimental data, we obtain an absolute determination of the RF electric field reaching a maximum field of 296 V/m to within +/- 0 . 35 % . Additionally, we estimate the shielding of DC fields within the vapor cell.

  16. Modelling laser-atom interactions in the strong field regime

    NASA Astrophysics Data System (ADS)

    Galstyan, Alexander; Popov, Yuri V.; Mota-Furtado, Francisca; O'Mahony, Patrick F.; Janssens, Noël; Jenkins, Samuel D.; Chuluunbaatar, Ochbadrakh; Piraux, Bernard

    2017-04-01

    We consider the ionisation of atomic hydrogen by a strong infrared field. We extend and study in more depth an existing semi-analytical model. Starting from the time-dependent Schrödinger equation in momentum space and in the velocity gauge we substitute the kernel of the non-local Coulomb potential by a sum of N separable potentials, each of them supporting one hydrogen bound state. This leads to a set of N coupled one-dimensional linear Volterra integral equations to solve. We analyze the gauge problem for the model, the different ways of generating the separable potentials and establish a clear link with the strong field approximation which turns out to be a limiting case of the present model. We calculate electron energy spectra as well as the time evolution of electron wave packets in momentum space. We compare and discuss the results obtained with the model and with the strong field approximation and examine in this context the role of excited states. Contribution to the Topical Issue "Many Particle Spectroscopy of Atoms, Molecules, Clusters and Surfaces", edited by A.N. Grum-Grzhimailo, E.V. Gryzlova, Yu V. Popov, and A.V. Solov'yov.

  17. STRONG FIELD EFFECTS ON PULSAR ARRIVAL TIMES: GENERAL ORIENTATIONS

    SciTech Connect

    Wang Yan; Creighton, Teviet; Price, Richard H.; Jenet, Frederick A.

    2009-11-10

    A pulsar beam passing close to a black hole can provide a probe of very strong gravitational fields even if the pulsar itself is not in a strong field region. In the case that the spin of the hole can be ignored, we have previously shown that all strong field effects on the beam can be understood in terms of two 'universal' functions: F(phi{sub in}) and T(phi{sub in}) of the angle of beam emission phi{sub in}; these functions are universal in that they depend only on a single parameter, the pulsar/black hole distance from which the beam is emitted. Here we apply this formalism to general pulsar-hole-observer geometries, with arbitrary alignment of the pulsar spin axis and arbitrary pulsar beam direction and angular width. We show that the analysis of the observational problem has two distinct elements: (1) the computation of the location and trajectory of an observer-dependent 'keyhole' direction of emission in which a signal can be received by the observer; and (2) the determination of an annulus that represents the set of directions containing beam energy. Examples of each are given along with an example of a specific observational scenario.

  18. Plasma waves in a relativistic, strongly anisotropic plasma propagated along a strong magnetic field

    NASA Technical Reports Server (NTRS)

    Onishchenko, O. G.

    1980-01-01

    The dispersion properties of plasma waves in a relativistic homogeneous plasma propagated along a strong magnetic field are studied. It is shown that the non-damping plasma waves exist in the frequency range omega sub p or = omega or = omega sub L. The values of omega sub p and omega sub L are calculated for an arbitrary homogeneous relativistic function of the particle distribution. In the case of a power ultrarelativistic distribution, it is shown that, if the ultrarelativistic tail of the distribution drops very rapidly, slightly damping plasma waves are possible with the phase velocity (omega/K)c.

  19. Detection and processing of electromagnetic and near-field acoustic signals in elasmobranch fishes.

    PubMed Central

    Kalmijn, A D

    2000-01-01

    The acoustic near field of quietly moving underwater objects and the bio-electric field of aquatic animals exhibit great similarity, as both are predominantly governed by Laplace's equation. The acoustic and electrical sensory modalities thus may, in directing fishes to their prey, employ analogous processing algorithms, suggesting a common evolutionary design, founded on the salient physical features shared by the respective stimulus fields. Sharks and rays are capable of orientating to the earth's magnetic field and, hence, have a magnetic sense. The electromagnetic theory of orientation offers strong arguments for the animals using the electric fields induced by ocean currents and by their own motions in the earth's magnetic field. In the animal's frame of reference, in which the sense organs are at rest, the classical concept of motional electricity must be interpreted in relativistic terms. In the ampullae of Lorenzini, weak electric fields cause the ciliated apical receptor-cell membranes to produce graded, negative receptor currents opposite in direction to the fields applied. The observed currents form part of a positive-feedback mechanism, supporting the generation of receptor potentials much larger than the input signal. Acting across the basal cell membranes, the receptor potentials control the process of synaptic transmission. PMID:11079385

  20. Molecular Strong Field Ionization viewed with Photoelectron Velocity Map Imaging

    NASA Astrophysics Data System (ADS)

    Sandor, Peter

    In this thesis, work is presented on molecular strong-field ionization, during which an electron is removed from polyatomic molecules in the presence of strong laser fields. This is a process which is the basis of a number of experimental techniques to uncover electronic dynamics in atoms and molecules on the femtosecond and attosecond timescale. 'Strong' refers to an electric field strength which leads to a response from the system which can not be modeled perturbatively. These fields can be easily produced in the focus of femtosecond laser radiation, as is done in this work. With the use of velocity map imaging of the photoelectron in coincidence with the fragment ion, multiple ionization--dissociation pathways can be distinguished. It is shown that as opposed to early attempts to model the process, multiple low-lying states are populated in the ion, and also the signatures of multielectron dynamics are revealed. By changing the laser pulse duration from 30 fs to below 10 fs, control is demonstrated over which quantum states of the ion are populated. It is also shown that for pulses shorter than 10 fs (which is a timescale below the shortest vibrational period in molecules), ionization pathways that involve motion of the nuclei are almost completely shut off. Finally, the origin of electrons with <1 meV kinetic energy is discussed. A two-step model is proposed for creating the electrons: the first step is population transfer to high-lying excited states of the neutral molecule by the laser field; the second step is ionization. Different ionization mechanisms are examined and their viability is checked against available data.

  1. Effects of pulsed electromagnetic fields on postmenopausal osteoporosis.

    PubMed

    Zhu, Siyi; He, Hongchen; Zhang, Chi; Wang, Haiming; Gao, Chengfei; Yu, Xijie; He, Chengqi

    2017-09-01

    Postmenopausal osteoporosis (PMOP) is considered to be a well-defined subject that has caused high morbidity and mortality. In elderly women diagnosed with PMOP, low bone mass and fragile bone strength have been proven to significantly increase risk of fragility fractures. Currently, various anabolic and anti-resorptive therapies have been employed in an attempt to retain healthy bone mass and strength. Pulsed electromagnetic fields (PEMFs), first applied in treating patients with delayed fracture healing and nonunions, may turn out to be another potential and effective therapy for PMOP. PEMFs can enhance osteoblastogenesis and inhibit osteoclastogenesis, thus contributing to an increase in bone mass and strength. However, accurate mechanisms of the positive effects of PEMFs on PMOP remain to be further elucidated. This review attempts to summarize recent advances of PEMFs in treating PMOP based on clinical trials, and animal and cellular studies. Possible mechanisms are also introduced, and the future possibility of application of PEMFs on PMOP are further explored and discussed. Bioelectromagnetics. 38:406-424, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. Electromagnetic fields in neonatal incubators: the reasons for an alert.

    PubMed

    Bellieni, Carlo Valerio; Nardi, Valentina; Buonocore, Giuseppe; Di Fabio, Sandra; Pinto, Iole; Verrotti, Alberto

    2017-10-08

    Neonatal incubators are important tools for sick newborns in the first few days of life. Nevertheless, their electric engine, often very close to the newborn's body, emits electromagnetic fields (EMF) to which newborns are exposed. Aim of this paper is to review the available literature on EMF exposure in incubators, and the effects of such exposures on newborns that have been investigated. We carried out a systematic review of studies about EMF emissions produced by incubators, using Medline and Embase databases from 1993 to 2017. We retrieved 15 papers that described the EMF exposure in incubators and their biological effects on babies. EMF levels in incubators appear to be between 2 and 100 mG, depending on the distance of the mattress from the electric engine. In some cases they exceed this range. These values interfere with melatonin production or with vagal tone. Even caregivers are exposed to high EMF, above 200 mG, when working at close contact with the incubators. EMF have been described as potentially hazardous for human health, and values reported in this review are an alert to prevent babies' and caregivers' exposure when close to the incubators. A precautionary approach should be adopted in future incubator design, to prevent high exposures of newborns in incubators and of caregivers as well.

  3. The role of electromagnetic fields in neurological disorders.

    PubMed

    Terzi, Murat; Ozberk, Berra; Deniz, Omur Gulsum; Kaplan, Suleyman

    2016-09-01

    In the modern world, people are exposed to electromagnetic fields (EMFs) as part of their daily lives; the important question is "What is the effect of EMFs on human health?" Most previous studies are epidemiological, and we still do not have concrete evidence of EMF pathophysiology. Several factors may lead to chemical, morphological, and electrical alterations in the nervous system in a direct or indirect way. It is reported that non-ionizing EMFs have effects on animals and cells. The changes they bring about in organic systems may cause oxidative stress, which is essential for the neurophysiological process; it is associated with increased oxidization in species, or a reduction in antioxidant defense systems. Severe oxidative stress can cause imbalances in reactive oxygen species, which may trigger neurodegeneration. This review aims to detail these changes. Special attention is paid to the current data regarding EMFs' effects on neurological disease and associated symptoms, such as headache, sleep disturbances, and fatigue. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Effect of cyclophosphamide and electromagnetic fields on mouse bone marrow

    SciTech Connect

    Cadossi, R.; Zucchini, P.; Emilia, G.; Torelli, G. )

    1990-02-26

    The authors have previously shown that the exposure to low frequency pulsing electromagnetic fields (PEMF) of mice X-ray irradiated resulted in an increased damage to the bone marrow. The series of experiments here reported were designed to investigate the effect of PEMF exposure after intraperitoneum injection of 200mg/kg of cyclophosphamide (CY). Control mice were CY injected only; experimental mice were CY injected and then exposed to PEMF. Exposure to PEMF (24 hours/day) increased the rate of decline of white blood cells in peripheral blood. Spleen weight was statistically higher among control mice than among mice exposed to PEMF at day 6, 8 and 10 after CY injection. Spleen autoradiography proved to be higher among PEMF exposed mice than among controls at day 8 and 9 after CY injection. The grafting efficiency of the bone marrow obtained from control mice was higher than the grafting efficiency of the bone marrow recovered from mice exposed to PEMF. All these data indicate that the exposure to PEMF increases the cytotoxic effect of CY.

  5. Effect of electromagnetic field exposure on the reproductive system

    PubMed Central

    Park, Chan Jin

    2012-01-01

    The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has become a public health issue. To date, many in vivo and in vitro studies have revealed that EMF exposure can alter cellular homeostasis, endocrine function, reproductive function, and fetal development in animal systems. Reproductive parameters reported to be altered by EMF exposure include male germ cell death, the estrous cycle, reproductive endocrine hormones, reproductive organ weights, sperm motility, early embryonic development, and pregnancy success. At the cellular level, an increase in free radicals and [Ca2+]i may mediate the effect of EMFs and lead to cell growth inhibition, protein misfolding, and DNA breaks. The effect of EMF exposure on reproductive function differs according to frequency and wave, strength (energy), and duration of exposure. In the present review, the effects of EMFs on reproductive function are summarized according to the types of EMF, wave type, strength, and duration of exposure at cellular and organism levels. PMID:22563544

  6. Effect of extremely low frequency electromagnetic fields on bacterial membrane.

    PubMed

    Oncul, Sule; Cuce, Esra M; Aksu, Burak; Inhan Garip, Ayse

    2016-01-01

    The effect of extremely low frequency electromagnetic fields (ELF-EMF) on bacteria has attracted attention due to its potential for beneficial uses. This research aimed to determine the effect of ELF-EMF on bacterial membrane namely the membrane potential, surface potential, hydrophobicity, respiratory activity and growth. Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli were subjected to ELF-EMF, 50 Hz, 1 mT for 2 h. Membrane potential was determined by fluorescence spectroscopy with or without EDTA (Ethylenediaminetetraacetic acid) with DisC3(5) (3,3-dipropylthiacarbocyanine iodide), zeta potential measurements were performed by electrophoretic mobility, hydrophobicity of the membrane was measured with MATH (Microbial Adhesion to Hydrocarbons) test, respiratory activity was determined with CTC (5-Cyano-2,3-ditolyl tetrazolium chloride), colony forming unit (CFU) and DAPI (4',6-diamidino-2-phenylindole, dihydrochloride) was used for growth determinations. ELF-EMF caused changes in physicochemical properties of both Gram-positive and Gram-negative bacteria. Hyperpolarization was seen in S. aureus and EDTA-treated E. coli. Surface potential showed a positive shift in S. aureus contrariwise to the negative shift seen in EDTA-untreated E. coli. Respiratory activity increased in both bacteria. A slight decrease in growth was observed. These results show that ELF-EMF affects the crucial physicochemical processes in both Gram-positive and Gram-negative bacteria which need further research.

  7. Effects of Electromagnetic Fields on Automated Blood Cell Measurements.

    PubMed

    Vagdatli, Eleni; Konstandinidou, Vasiliki; Adrianakis, Nikolaos; Tsikopoulos, Ioannis; Tsikopoulos, Alexios; Mitsopoulou, Kyriaki

    2014-08-01

    The aim of this study is to investigate whether the electromagnetic fields associated with mobile phones and/or laptops interfere with blood cell counts of hematology analyzers. Random blood samples were analyzed on an Aperture Impedance hematology analyzer. The analysis was performed in four ways: (A) without the presence of any mobile phone or portable computer in use, (B) with mobile phones in use (B1: one mobile, B4: four mobiles), (C) with portable computers (laptops) in use (C1: one laptop, C3: three laptops), and (D) with four mobile phones and three laptops in use simultaneously. The results obtained demonstrated a statistically significant decrease in neutrophil, erythrocyte, and platelet count and an increase in lymphocyte count, mean corpuscular volume, and red blood cell distribution width, notably in the B4 group. Despite this statistical significance, in clinical practice, only the red blood cell reduction could be taken into account, as the mean difference between the A and B4 group was 60,000 cells/µL. In group D, the analyzer gave odd results after 11 measurements and finally stopped working. The combined and multiple use of mobile phones and computers affects the function of hematology analyzers, leading to false results. Consequently, the use of such electronic devices must be avoided.

  8. Spectroscopy of cesium Rydberg atoms in strong radio-frequency fields

    NASA Astrophysics Data System (ADS)

    Jiao, Yuechun; Han, Xiaoxuan; Yang, Zhiwei; Li, Jingkui; Raithel, Georg; Zhao, Jianming; Jia, Suotang

    2016-08-01

    We study Rydberg atoms modulated by strong radio-frequency (rf) fields with a frequency of 70 MHz. The Rydberg atoms are prepared in a room-temperature cesium cell, and their level structure is probed using electromagnetically induced transparency (EIT). As the rf field increases from the weak- into the strong-field regime, the range of observed rf-induced phenomena progresses from ac level shifts through increasingly pronounced and numerous rf modulation sidebands to complex state mixing and level crossings with high - l hydrogenlike states. Weak anharmonic admixtures in the rf field generate clearly visible modifications in the Rydberg EIT spectra. A Floquet analysis is employed to model the Rydberg spectra, and good agreement with the experimental observations is found. Our results show that all-optical spectroscopy of Rydberg atoms in vapor cells can serve as an antenna-free, atom-based, and calibration-free technique to measure rf electric fields and to analyze their higher-harmonic contents.

  9. Electromagnetic induction in New Zealand: analogue model and field results

    NASA Astrophysics Data System (ADS)

    Chen, J.; Dosso, H. W.; Ingham, M.

    The behaviour of electric and magnetic variations over North Island (New Zealand) is studied with the aid of a laboratory analogue model. The source field frequencies used in the analogue modelling simulate naturally occurring geomagnetic variations of 5-120 min periods. In-phase and quadrature magnetic and electric fields for a selection of traverses for the modelled region of North Island are presented. Since North Island is of a relatively narrow cross-section, the field responses, even for inland locations, are expected to show strongly the effects of the surrounding ocean. The irregular coastlines, as well as the strait between North and South Islands, lead to coastal and inland field anomalies due to induced currents being deflected and channelled to produce localized current densities. The comparison of model results with field station measurements obtained earlier individually by Ingham and by Midha for sites in the northeastern, central, and southern (near Cook Strait) regions of North Island demonstrates the large role the ocean has in the observed field responses. Differences in the model and field results at some sites are expected and should reflect the effects of the local geology and the conductive substructure related to the complex tectonics of the region not simulated in the model.

  10. [On the mechanisms of stimulation and inhibition during germination of wheat seeds in extremely low frequency electromagnetic fields].

    PubMed

    Aksenov, S I; Grunina, T Iu; Goriachev, S N

    2007-01-01

    It has been shown that the effects of stimulation of germination of wheat seeds by electromagnetic field depend on the degree of membrane tension during imbibition of seeds in sucrose solutions. This provides further confirmation of the influence of electromagnetic fields on the release of proteins from the bound state on the membranes. The prolonged treatment with electromagnetic fields during the imbibition of seeds leads not only to the inhibition of germination of sprouts but also to a decrease in their germinability, which can be as strong as twofold for seeds with the initial low germinability. This is related to the desynchronization of germination processes, caused by the stimulation of the release of proteins and inhibition of another stage during the cell division, the assembly of complex structures. It is noted that the activation of the release of proteins and inhibition of their binding by the action of electromagnetic fields must elevate the cell excitability. The presumably, the excitability of cells determines the effects of magnetic storms and high solar activity on the physiological state of organisms.

  11. Bacterial growth rates are influenced by cellular characteristics of individual species when immersed in electromagnetic fields.

    PubMed

    Tessaro, Lucas W E; Murugan, Nirosha J; Persinger, Michael A

    2015-03-01

    Previous studies have shown that exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) have negative effects on the rate of growth of bacteria. In the present study, two Gram-positive and two Gram-negative species were exposed to six magnetic field conditions in broth cultures. Three variations of the 'Thomas' pulsed frequency-modulated pattern; a strong-static "puck" magnet upwards of 5000G in intensity; a pair of these magnets rotating opposite one another at ∼30rpm; and finally a strong dynamic magnetic field generator termed the 'Resonator' with an average intensity of 250μT were used. Growth rate was discerned by optical density (OD) measurements every hour at 600nm. ELF-EMF conditions significantly affected the rates of growth of the bacterial cultures, while the two static magnetic field conditions were not statistically significant. Most interestingly, the 'Resonator' dynamic magnetic field increased the rates of growth of three species (Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli), while slowing the growth of one (Serratia marcescens). We suggest that these effects are due to individual biophysical characteristics of the bacterial species. Copyright © 2015 Elsevier GmbH. All rights reserved.

  12. Dual-Scattering Near-Field Microscope for Correlative Nanoimaging of SERS and Electromagnetic Hotspots.

    PubMed

    Kusch, Patryk; Mastel, Stefan; Mueller, Niclas S; Morquillas Azpiazu, Nieves; Heeg, Sebastian; Gorbachev, Roman; Schedin, Fredrik; Hübner, Uwe; Pascual, Jose I; Reich, Stephanie; Hillenbrand, Rainer

    2017-04-12

    Surface-enhanced Raman spectroscopy (SERS) enables sensitive chemical studies and materials identification, relying on electromagnetic (EM) and chemical-enhancement mechanisms. Here we introduce a tool for the correlative nanoimaging of EM and SERS hotspots, areas of strongly enhanced EM fields and Raman scattering, respectively. To that end, we implemented a grating spectrometer into a scattering-type scanning near-field optical microscope (s-SNOM) for mapping of both the elastically and inelastically (Raman) scattered light from the near-field probe, that is, a sharp silicon tip. With plasmon-resonant gold dimers (canonical SERS substrates) we demonstrate with nanoscale spatial resolution that the enhanced Raman scattering from the tip is strongly correlated with its enhanced elastic scattering, the latter providing access to the EM-field enhancement at the illumination frequency. Our technique has wide application potential in the correlative nanoimaging of local-field enhancement and SERS efficiency as well as in the investigation and quality control of novel SERS substrates.

  13. Influence of different types of electromagnetic fields on skin reparatory processes in experimental animals.

    PubMed

    Matic, Milan; Lazetic, Bogosav; Poljacki, Mirjana; Djuran, Verica; Matic, Aleksandra; Gajinov, Zorica

    2009-05-01

    Wound healing is a very complex process, some phases of which have only recently been explained. Magnetic and electromagnetic fields can modulate this process in a non-thermal way. The aim of this research was to compare the influence of constant and pulsed electromagnetic fields and low-level laser therapy (LLLT) on wound healing in experimental animals. The experiment was conducted on 120 laboratory rats divided into four groups of 30 animals each (constant electromagnetic field, pulsed electromagnetic field, LLLT and control group). It lasted for 21 days. Under the influence of the constant electromagnetic field the healing of the skin defect was accelerated in comparison with the control group. The difference was statistically significant in all the weeks of the experiment at the P < 0.01 level. Accelerated healing was also observed under the influence of the pulsed electromagnetic field (P < 0.05). In the group of animals exposed to LLLT, the healing of the skin defect was faster than in the control group. The statistical significance was at the P < 0.05 level. Different types of electromagnetic fields have a promoting effect on the wound healing process.

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

    PubMed

    Elgohary, Hany M; Tantawy, Sayed A

    2017-08-01

    [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.

  15. Occupational exposure to electromagnetic fields and acute leukaemia: analysis of a case-control study

    PubMed Central

    Willett, E; McKinney, P; Fear, N; Cartwright, R; Roman, E

    2003-01-01

    Aims: To investigate whether the risk of acute leukaemia among adults is associated with occupational exposure to electromagnetic fields. Methods: Probable occupational exposure to electromagnetic fields at higher than typical residential levels was investigated among 764 patients diagnosed with acute leukaemia during 1991–96 and 1510 sex and age matched controls. A job exposure matrix was applied to the self reported employment histories to determine whether or not a subject was exposed to electromagnetic fields. Risks were assessed using conditional logistic regression for a matched analysis. Results: Study subjects considered probably ever exposed to electromagnetic fields at work were not at increased risk of acute leukaemia compared to those considered never exposed. Generally, no associations were observed on stratification by sex, leukaemia subtype, number of years since exposure stopped, or occupation; there was no evidence of a dose-response effect using increasing number of years exposed. However, relative to women considered never exposed, a significant excess of acute lymphoblastic leukaemia was observed among women probably exposed to electromagnetic fields at work that remained increased irrespective of time prior to diagnosis or job ever held. Conclusion: This large population based case-control study found little evidence to support an association between occupational exposure to electromagnetic fields and acute leukaemia. While an excess of acute lymphoblastic leukaemia among women was observed, it is unlikely that occupational exposure to electromagnetic fields was responsible, given that increased risks remained during periods when exposure above background levels was improbable. PMID:12883018

  16. Colliding-wind Binaries with Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Kissmann, R.; Reitberger, K.; Reimer, O.; Reimer, A.; Grimaldo, E.

    2016-12-01

    The dynamics of colliding-wind binary (CWB) systems and conditions for efficient particle acceleration therein have attracted multiple numerical studies in recent years. These numerical models seek an explanation of the thermal and nonthermal emission of these systems as seen by observations. In the nonthermal regime, radio and X-ray emission is observed for several of these CWBs, while gamma-ray emission has so far only been found in η Carinae and possibly in WR 11. Energetic electrons are deemed responsible for a large fraction of the observed high-energy photons in these systems. Only in the gamma-ray regime might there be, depending on the properties of the stars, a significant contribution of emission from neutral pion decay. Thus, studying the emission from CWBs requires detailed models of the acceleration and propagation of energetic electrons. This in turn requires a detailed understanding of the magnetic field, which will affect not only the energy losses of the electrons but also, in the case of synchrotron emission, the directional dependence of the emissivity. In this study we investigate magnetohydrodynamic simulations of different CWB systems with magnetic fields that are strong enough to have a significant effect on the winds. Such strong fields require a detailed treatment of the near-star wind acceleration zone. We show the implementation of such simulations and discuss results that demonstrate the effect of the magnetic field on the structure of the wind collision region.

  17. RF breakdown of 805 MHz cavities in strong magnetic fields

    SciTech Connect

    Bowring, D.; Stratakis, D.; Kochemirovskiy, A.; Leonova, M.; Moretti, A.; Palmer, M.; Peterson, D.; Yonehara, K.; Freemire, B.; Lane, P.; Torun, Y.; Haase, A.

    2015-05-03

    Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures in the presence of strong magnetic fields. We have measured the breakdown rate in several RF cavities operating at several frequencies. Cavities operating within solenoidal magnetic fields B > 0.25 T show an increased RF breakdown rate at lower gradients compared with similar operation when B = 0 T. Ultimately, this breakdown behavior limits the maximum safe operating gradient of the cavity. Beyond ionization cooling, this issue affects the design of photoinjectors and klystrons, among other applications. We have built an 805 MHz pillbox-type RF cavity to serve as an experimental testbed for this phenomenon. This cavity is designed to study the problem of RF breakdown in strong magnetic fields using various cavity materials and surface treatments, and with precise control over sources of systematic error. We present results from tests in which the cavity was run with all copper surfaces in a variety of magnetic fields.

  18. Anisotropic magnetohydrodynamic turbulence in a strong external magnetic field

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Turner, L.

    1981-01-01

    A strong external dc magnetic field introduces a basic anisotropy in incompressible MHD turbulence. The modifications that this is likely to produce in the properties of the turbulence are investigated for high Reynolds numbers. It is found that the turbulent spectrum splits into two parts: (1) an essentially two-dimensional spectrum with both the velocity field and the magnetic fluctuations perpendicular to the dc magnetic field, and (2) a generally weaker and more nearly isotropic spectrum of Alfven waves. These results are discussed in relation to measurements from the Culham-Harwell Zeta pinch device and the UCLA Macrorotor tokamak, as well as in relation to measurements of MHD turbulence in the solar wind.

  19. Anisotropic magnetohydrodynamic turbulence in a strong external magnetic field

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Turner, L.

    1981-01-01

    A strong external dc magnetic field introduces a basic anisotropy into incompressible magnetohydrodynamic turbulence. The modifications that this is likely to produce in the properties of the turbulence are explored for the high Reynolds number case. The conclusion is reached that the turbulent spectrum splits into two parts: an essentially two dimensional spectrum with both the velocity field and magnetic fluctuations perpendicular to the dc magnetic field, and a generally weaker and more nearly isotropic spectrum of Alfven waves. A minimal characterization of the spectral density tensors is given. Similarities to measurements from the Culham-Harwell Zeta pinch device and the UCLA Macrotor Tokamak are remarked upon, as are certain implications for the Belcher and Davis measurements of magnetohydrodynamic turbulence in the solar wind.

  20. Probabilistic Motion Planning of Balloons in Strong, Uncertain Wind Fields

    NASA Technical Reports Server (NTRS)

    Wolf, Michael T.; Blackmore, Lars; Kuwata, Yoshiaki; Fathpour, Nanaz; Elfes, Alberto; Newman, Claire

    2010-01-01

    This paper introduces a new algorithm for probabilistic motion planning in arbitrary, uncertain vector fields, with emphasis on high-level planning for Montgolfiere balloons in the atmosphere of Titan. The goal of the algorithm is to determine what altitude--and what horizontal actuation, if any is available on the vehicle--to use to reach a goal location in the fastest expected time. The winds can vary greatly at different altitudes and are strong relative to any feasible horizontal actuation, so the incorporation of the winds is critical for guidance plans. This paper focuses on how to integrate the uncertainty of the wind field into the wind model and how to reach a goal location through the uncertain wind field, using a Markov decision process (MDP). The resulting probabilistic solutions enable more robust guidance plans and more thorough analysis of potential paths than existing methods.