共查询到20条相似文献,搜索用时 15 毫秒
1.
Robert E. Var 《Foundations of Physics》1975,5(3):407-431
It is shown by means of general principles and specific examples that, contrary to a long-standing misconception, the modern mathematical physics of compressible fluid dynamics provides a generally consistent and efficient language for describing many seemingly fundamental physical phenomena. It is shown to be appropriate for describing electric and gravitational force fields, the quantized structure of charged elementary particles, the speed of light propagation, relativistic phenomena, the inertia of matter, the expansion of the universe, and the physical nature of time. New avenues and opportunities for fundamental theoretical research are thereby illuminated. 相似文献
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Simon J. BENDING 《物理学进展》2013,62(4):449-535
Investigations of the magnetic properties of high temperature superconductors (HTSs) have revealed the existence of striking new vortex phenomena due, in part, to their strong crystalline anisotropy, very short coherence lengths and the much larger thermal energies available at high temperatures. Some of these phenomena, for example vortex lattice 'melting', pose serious problems for technological applications of the most anisotropic HTS materials and a fuller understanding of them is of considerable importance. The most direct information regarding vortex structures and dynamics is obtained through local measurement of the magnetic field within or at the surface of a superconducting sample. A detailed review of such local magnetic probes is presented here including Lorentz microscopy, magnetic force microscopy, Bitter decoration, scanning Hall probe microscopy, magneto-optical imaging, and scanning superconducting quantum interference device microscopy. In each case the principles underpinning the technique are described together with the factors that limit the magnetic field and the spatial and temporal resolution. A range of examples will be given, emphasizing applications in the area of HTSs. In addition the ways in which the existing techniques can be expected to develop over the next few years will be discussed and new approaches that seem likely to be successful described. 相似文献
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Demosthenes Kivotides 《Physics letters. A》2019,383(14):1601-1606
Interactions between magnetic and vortex rings are studied over a wide interval of interaction parameter values ranging from negligible magnetic effects on vorticity structure, to very strong effects. The employed interaction parameter measures the strength of the Lorentz force in units of the inertial force. At small interaction parameters, the vortex ring shapes part of the magnetic ring into a dissipative, curved, magnetic sheet structure. At high interaction parameters, the Lorentz force acts as an agent of proliferation of vortex rings, since it generates two vortex rings adjacent to the original magnetic structure, one of which is pulled (together with the advected magnetic field) into the wake of the original vortex ring, while the other escapes, ready to interact with another magnetic ring. Once within the initial vortex ring wake, both magnetic and vorticity structures are stretched into spirals, whilst the Lorentz force continuously generates new, intense vorticity at high magnetic field sites. 相似文献
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本文认为在感生电场的情况下,磁场的强弱变化可以引起磁场自身的横向运动,使得线圈中电子相对于磁场发生运动,从而等效为一个动生电场,受到洛伦兹力的作用.借助磁感线模拟磁场的运动方式,得到圆形回路中任意一点与磁场相对运动速度的表达式,进而推得该"等效动生电场"中的洛伦兹力.以螺线管为例,验证该方法可以解释感生电场所满足的规律.将感生电场与动生电场的产生原因统一为导体中电子与磁场的相对运动,相应电动势的非静电力统一为洛伦兹力. 相似文献
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V. M. Mekhitarian 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2016,51(2):108-126
The Faraday law of electromagnetic induction for an arbitrarily moving charge is generalized and the expression for the force acting on the charge in an alternating magnetic field is obtained. It is shown that besides the Lorentz force perpendicular to the velocity of the particle, the Faraday force parallel to the particle velocity and proportional to it is acting on the charge, too. The equations of motion of the charged particle and the magnetic moment are obtained in the time-varying magnetic field. The problems of induction acceleration of charged particles (betatron) and induction heating of medium (plasma, plasma betatron) are considered. 相似文献
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基于洛伦兹电子论和洛伦兹磁力,否定法拉第定律和相对论电磁学,暨揭示广义洛伦兹磁力的科学研究之五:相对论的协变场是荒唐。本文基于洛伦兹电子论和洛伦兹磁力,论证表明:协变换出来的磁力线成为直线,它违背客观事实;协变换出来的环形电力线更荒唐;协变换出来的电磁场成为无穷大,广义洛伦兹磁力才是真谛;两电荷对撞时协变换出来的排斥力成为虚数,它违背客观事。 相似文献
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Nitter T. Aslaksen T.K. Melandso F. Havnes O. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1994,22(2):159-172
Examines the dynamics of a collection of charged dust particles in the plasma sheath above a large body in a fully ionized space plasma when the radius of the large body is much larger than the sheath thickness. The dust particles are charged by the plasma, and the forces on the dust particles are assumed to be from the electric field in the sheath and from gravitation only. These forces will often act in opposite directions and may balance, making dust suspension and collection possible. The dust particles are supplied by injection or by electrostatic levitation. The ability of the sheath to collect dust particles, will be optimal for a certain combination of gravitation and plasma and dust particle parameters. In a dense dust sheath, the charges on the dust particles contribute significantly to the total space charge, and collective effects become important. These effects will reduce the magnitude of the sheath electric field strength and the charge on the dust particles. As dust particles are collected, the dust sheath is stretched and the largest dust particles may drop out, because the sheath is no longer able to suspend them. In a tenuous dust sheath, the inner layer, from the surface and about one Debye length thick, will be unstable for dust particle motion, and dust will not collect there. In a dense dust sheath, collective effects will decrease the thickness of this inner dust-free layer, making dust collection closer to the surface possible. By linearization of the force and current equations, the necessary and sufficient conditions for a stable dust sheath are found. The authors consider conditions which resemble those of planetary system bodies, but the results may also be of relevance to some laboratory plasmas 相似文献
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Valery P. Dmitriyev 《Central European Journal of Physics》2008,6(3):711-716
The centripetal and Coriolis accelerations experienced by a cart traveling over a rotating turntable are usually calculated
proceeding from the known kinematics of the problem. Respective forces can be regarded as due to the entrainment of the cart
in the moving solid environs. We extend the approach to the general case of a particle entrained in the flow of the surrounding
medium. The expression for the driving force on the particle obtained from the kinematics of the entrainment prescribed appears
to be isomorphic to the Lorentz and Coulomb force on a positive electric charge. The inverse direction of the electromagnetic
force on a negative charge implies that a growing applied flow induces the upstream motion of the particle. A possible microscopic
mechanism for it may be the Magnus force dynamics of a kink in a vortex tangle. The loop on a straight vortex filament can
be taken as a model of the electron, the loop with a cavitation models the positron. The Lorentz force is concerned with the
Coriolis acceleration. The Coulomb interaction is due to the centripetal or centrifugal force that arises in the turbophoresis
of the kink in the perturbation field generated in the medium by the center of pressure.
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We have studied the physics of atoms with permanent electric dipole moment and nonvanishing magnetic moment interacting with an electric field and inhomogeneous magnetic field. This system can be demonstrated as the atomic analogue of Landau quantization of charged particles in a uniform magnetic field. This Landau-like atomic problem is also studied with space-space noncommutative coordinates. 相似文献
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Electrodynamic phenomena related to vortices in superconductors have been studied since their prediction by Abrikosov, and seem to hold no fundamental mysteries. However, most of the effects are treated separately, with no guiding principles.We demonstrate that the relativistic vortex worldsheet in spacetime is the object that naturally conveys all electric and magnetic information, for which we obtain simple and concise equations. Breaking Lorentz invariance leads to down-to-earth Abrikosov vortices, and special limits of these equations include for instance dynamic Meissner screening and the AC Josephson relation. On a deeper level, we explore the electrodynamics of two-form sources in the absence of electric monopoles, in which the electromagnetic field strength itself acquires the characteristics of a gauge field. This novel framework leaves room for unexpected surprises. 相似文献
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V. M. Sorokin 《Russian Journal of Physical Chemistry B, Focus on Physics》2007,1(2):138-170
The paper presents a physical model of the electrodynamic effect on the ionosphere of natural and artificial processes that occur in the near-Earth atmospheric layer and are accompanied by the transfer of charged aerosols in the atmosphere. These processes include the preparation of earthquakes and typhoons, dust storms, and nuclear accidents. The model is based experimentally on satellite and ground-based records of plasma and electromagnetic perturbations, measurements of the injection of soil gases into the atmosphere, and atmospheric radioactivity data. The ionosphere is subject to actions of the conduction electric current flowing in the atmosphere-ionosphere circuit. Its source is an extraneous current formed by vertical turbulent transfer of charged aerosols and their interaction with atmospheric ions during the injection of radioactive substances and modification of atmospheric conductivity. Changes in the electric field of the ionosphere induce the development of plasma and electromagnetic phenomena. The model suggested relates ionospheric and electromagnetic perturbations to the dynamics of charged aerosols in the lower atmosphere. 相似文献
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An accelerator is proposed in which a TE-mode wave is used to drive charged particles in contrast to the usual linear accelerators in which longitudinal electric fields or TM-mode waves are supposed to be utilized. The principle of the acceleration is based on the Vp × B acceleration of a dynamo force acceleration. That is, a charged particle trapped in a transverse wave feels a constant electric field (Faraday induction field) and subsequently is accelerated when an appropriate magnetic field is externally applied in the direction perpendicular to the wave propagation. A pair of dielectric plates is used to produce a slow TE mode. Discussions will be given on what the conditions of the particle trapping are and how to stabilize the particle orbit. 相似文献
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A simulation method for trajectories of charged particles in the real magnetic fields is introduced for the forward spectrometer in experiments of high energy physics.By using the numerical integrations to the Lorentz equation,simulation tracks with good accuracy have been obtained. 相似文献
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This study presents a new model to simulate the electric behaviour of one-dimensional ionised flames and to predict the electric currents in these flames. The model utilises Poisson’s equation to compute the electric potential. A multi-component diffusion model, including the influence of an electric field, is used to model the diffusion of neutral and charged species. The model is incorporated into the existing CHEM1D flame simulation software. A comparison between the computed electric currents and experimental values from the literature shows good qualitative agreement for the voltage–current characteristic. Physical phenomena, such as saturation and the diodic effect, are captured by the model. The dependence of the saturation current on the equivalence ratio is also captured well for equivalence ratios between 0.6 and 1.2. Simulations show a clear relation between the saturation current and the total number of charged particles created. The model shows that the potential at which the electric field saturates is strongly dependent on the recombination rate and the diffusivity of the charged particles. The onset of saturation occurs because most created charged particles are withdrawn from the flame and because the electric field effects start dominating over mass based diffusion. It is shown that this knowledge can be used to optimise ionisation chemistry mechanisms. It is shown numerically that the so-called diodic effect is caused primarily by the distance the heavier cations have to travel to the cathode. 相似文献
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介绍了虚构的法拉第定律与电子感应加速器不合理,用完整洛伦兹磁力解释电子感应加速器合理有效。 相似文献