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Magnetodynamic waves in the air
Abstract
The paper describes experiments to search for a variable magnetic field close to a rechargeable conductive flat plate and a ball in the air, as well as an experiment looking for a variable electric field near a rotating permanent magnet. It has been found that variable electric and magnetic fields do not induce each other within the measurement error. It means that rotary Maxwell's equations are not applicable in the near-field zone and the classical concept of displacement current in vacuum (air) has no physical meaning. A conclusion is made on the existence of transverse magnetodynamic waves. Statics and dynamics of the magnetic field near the permanent magnet rod are investigated experimentally. The methods to compute magnetodynamic waves from any source are presented. Four types of polarization of these waves are identified: linear, circular, toroidal and mixed. Concentration and deflection of magnetodynamic waves are observed on introducing inhomogeneity in the form of a ferrite rod into their propagation way, which is similar to diffraction in optics. Secondary magnetodynamic waves from the induced magnetic moments in atoms of ferrite are registered near its surface, which is like reflection in optics. Some ideas for observation of effects similar to dispersion and interference are presented for magnetodynamic waves. The structure and properties of electrodynamic, magnetodynamic and electromagnetic waves are discussed. The ideas of experiments to search for their unknown properties are described. In conclusion, technical applications of magnetodynamic waves such as magnetography, magnetic tomography and other are considered.
... In view of the fact that the photon mass is extremely small, even a high power beam will provide a very weak thrust (~ 1 μN for P = 300 W). In the technique, an electric and magnetic dynamic fields (electrodynamic and magnetodynamic waves [6]) are used to transfer energy (and momentum) of high power to within short distances. In the cores of high-voltage power transformers, for example, magnetodynamic waves transfer power ~ 1 MW and more. ...
... Streamlines slipping and rotation of these flows can be characterized by the distribution of v B velocity and, if necessary, by acceleration of a B at any time. At periodic movements it can be said about the expansion of "magnetodynamic waves" [13]. ...
The motional EMF in segments of the copper wire with magnetic shielding is
found according to the voltage lack in two coils with partial shielding moving
relative to the magnetic field lines. The first coil moved across the Earth’s
magnetic field lines. The second one was located near the end face of the rotating
disk magnet with an axial magnetization. Permalloy foil wound around
a part of turns containing wire was used for shielding. The experiments result
reveals the penetrating ability of the magnetic field through the ferromagnetic
shield and shows the physical nature of the superposition principle. With this
in mind, a universal method for calculating EMF induced in a conductive
body has been provided as well as the concepts of magnetic field lines velocity
and acceleration have been introduced.
... Multitude of photons in vicinity form large electromagnetic wave. Besides the electromagnetic photons, electrodynamic and magnetodynamic [7] ones, as parts of corresponding varying fields (flows), can be distinguished. It is difficult to create more accurate theory of photon until its structure is not known vaguely, and its basic physical parameters, such as mass, amplitude, size and, of course, energy, are not measured. ...
The article considers physical properties of photon as a quantum of electromagnetic wave in luminiferous medium. An experimental evaluation method for its energy and mass based on radiation pressure effect was presented. The of " photon amplitude " concept was introduced, through which energy is represented similarly to quantum (phonon) energy of elastic mechanical wave. A model of photon as a wave packet in the medium was considered, which based its volume evaluation. The resulting equation for energy corresponds to commonly known, regarding the first degree frequency proportionality, while it is more informative.
... However, the electric and magnetic fields in a real conductor differ from these in transverse electromagnetic wave in vacuum and they depend on the conductor charges and its material. As well as it is shown in [11] the variable magnetic field can propagate independently of the variable electrical one. Thus, the transfer from (4) to (3) is not correct. ...
Experimental validation of the Faraday's law of electromagnetic induction
(EMI) is performed when an electromotive force is generated in thin copper
turns, located inside a large magnetic coil. It has been established that the
electromotive force (emf) value should be dependent not only on changes of the
magnetic induction flux through a turn and on symmetry of its crossing by
magnetic power lines also. The law of EMI is applicable in sufficient
approximation in case of the changes of the magnetic field near the turn are
symmetrical. Experimental study of the induced emf in arcs and a direct section
of the conductor placed into the variable field has been carried out. Linear
dependence of the induced emf on the length of the arc has been ascertained in
case of the magnetic field distribution symmetry about it. Influence of the
magnetic field symmetry on the induced emf in the arc has been observed. The
curve of the induced emf in the direct section over period of current pulse is
similar to this one for the turns and arcs. The general law of EMI for a
curvilinear conductor has been deduced. Calculation of the induced emf in the
turns wrapped over it and comparison with the experimental data has been made.
The proportionality factor has been ascertained for the law. Special conditions
have been described, when the induced emf may not exist in the presence of
inductive current. Theoretical estimation of the inductive current has been
made at a induced low voltage in the turn. It has been noted the necessity to
take into account the concentration of current carriers in calculation of the
induced emf in semiconductors and ionized conductors.
By combining four parallel rows of permanent magnet blocks, a magnet device that can produce variable high magnetic field in three dimensions has been designed. In this device, the magnetic field direction and strength can be varied by shifting the four rows along their longitudinal direction and by varying the magnet gap between the top and bottom rows. With a magnet gap of 10 mm, the magnetic field strength at the center of the device is about 1.4 T along the longitudinal and two transverse directions. This device can be utilized in X-ray magnetic circular dichroism and X-ray magnetic linear dichroism experiments as well as in other applications where a variable high magnetic field in three dimensions is needed.
A simple one-band model of the electronic structure of a ferromagnetic metal is examined to determine the existence and properties of polar spin-wave states, i.e., "optical" spin waves due to the finite range of the electron-electron interaction. The model Hamiltonian is an extension of the Hubbard Hamiltonian, including Coulomb interaction between electrons occupying neighboring-site Wannier functions. The equation-of-motion method is used in the random-phase approximation to determine the various spin-wave collective excitations. For a finite-range Coulomb interaction, the equations can be transformed into the equations of the Koster-Slater impurity problem with nearest-neighbor-potential matrix elements. Polar spin waves are found to exist for a wide range of band occupancies, tending to merge with the continuum with decreasing occupancy of the spin-up band. It is found that near wave vector q=0, inelastic neutron scattering by the acoustic spin-wave mode dominates scattering by all other spin-wave and Stoner modes; however, a finite polar-mode scattering cross section does exist away from q=0. Since polar spin waves carry an electric moment, Raman scattering of light from polar spin waves is also examined as a possible way of observing these states. A procedure is described for identifying the various Raman lines corresponding to various polar spin-wave states.
A superconducting octupole magnet capable of producing a variable high magnetic field in three dimensions has been designed and constructed. Eight cone-shape superconducting coils are arranged octahedrally to form four independent dipole pairs, facilitating five 30° conic bore holes and a 210° slit opening for large angle photon-in–photon-out experiments. To achieve high magnetic field and liquid-helium-free operation, holmium pole pieces, HTS (high Tc superconducting) current leads, and a GM-type cryocooler are employed. The maximum magnetic field and the full current excitation time are measured to be 3.65T and 20min, respectively. A relay circuit for switching the magnet field along different major directions is also presented.
We present a new device for estimating the spectrum of a time variable magnetic field of frequency down to 5 kHz. It has a linear response with a sensitivity of about 1 mVnT in the range from 0 to 300 Hz. Over this range the sensitivity decreases and a correction factor is necessary.
1. Electrostatics: charges and fields; 2. The electric potential; 3.
Electric field around conductors; 4. Electric currents; 5. The fields of
moving charges; 6. The magnetic field; 7. Electromagnetic induction; 8.
Alternating-current circuits; 9. Maxwell's equations and electromagnetic
waves; 10. Electric fields in matter; 11. Magnetic fields in matter;
Appendixes; Index.
Theoretically scalar potential Φ waves with a longitudinal electric field in the direction of propagation must exist. A centrally fed ball antenna, 6 cm diameter, producing a pulsating 433.59 MHz spherical source charge, generated such a wave, that was detected by an identical ball antenna. The longitudinality of was demonstrated by intervening a cubic array of 9 half-wavelength wires, that absorbed the wave when the wires were parallel (but not when perpendicular) to the direction of propagation. The signal from the ball antenna source, placed 4.0 m above ground and receiver 4.4 m above ground, was measured as a function of distance, yielding satisfactory agreement with theory, including 2 expected interference minima produced by an image source induced in the Earth. Only waves can yield such an interference and can be reflected from the Earth's surface and vary as the inverse square of distance.
(1) The most obvious mechanical phenomenon in electrical and magnetical experiments is the mutual action by which bodies in certain states set each other in motion while still at a sensible distance from each other. The first step, therefore, in reducing these phenomena into scientific form, is to ascertain the magnitude and direction of the force acting between the bodies, and when it is found that this force depends in a certain way upon the relative position of the bodies and on their electric or magnetic condition, it seems at first sight natural to explain the facts by assuming the existence of something either at rest or in motion in each body, constituting its electric or magnetic state, and capable of acting at a distance according to mathematical laws. In this way mathematical theories of statical electricity, of magnetism, of the mechanical action between conductors carrying currents, and of the induction of currents have been formed. In these theories the force acting between the two bodies is treated with reference only to the condition of the bodies and their relative position, and without any express consideration of the surrounding medium.
A Chua‐type magnetization model is derived by means of a Fourier series while the magnetic flux density is sinusoidally varying with time. It is shown that this Chua‐type model is well suited for practical computations of magnetodynamic field. A geometrical duality between the Delaunay triangles and associated Voronoi polygons is utilized to implement a dual energy finite element approach. As an example, the magnetodynamic fields in a toroidal reactor including the effects of transients, eddy currents, and hysteresis are computed.
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