scholarly journals Shock waves and Cerenkov radiation in electromagnetic substratum

1991 ◽  
Vol 14 (4) ◽  
pp. 769-788 ◽  
Author(s):  
H. E. Wilhelm
Keyword(s):  
Shock Waves ◽  
Relative Velocity ◽  
Maxwell Equations ◽  
Rest Frame ◽  
Charged Particles ◽  
Cerenkov Radiation ◽  
Physical Vacuum ◽  
Inertial Frames ◽  
Theoretical Predictions

TheEMfields of charged particles moving with velocityvin a physical vacuum with wave carrier (substratum) are determined by means of the generalized, Galilei covariant Maxwell equations for inertial frames∑. with substratum floww. In this Galilean approach, all velocities have absolute meaning relative to the substratum rest frame∑o, and the relative velocity of material particles is given by the linear Galilean relationvG=v1−v2, permitting in principle superluminal relative velocities|vG|>co. Inter alias, the possibility ofEMshock waves and Cerenkov radiation in the vacuum substratum is discussed. Experiments are proposed to test the theoretical predictions.

scholarly journals Quantitative Experimental and Theoretical Investigations on the Interaction of Shock Waves with Magnetic Fields

1969 ◽  
Vol 24 (10) ◽  
pp. 1449-1457
Author(s):  
H. Klingenberg ◽  
F. Sardei ◽  
W. Zimmermann
Keyword(s):  
Magnetic Fields ◽  
Shock Waves ◽  
Physical Model ◽  
Spectroscopic Method ◽  
Experimental Results ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Theoretical Investigations ◽  
Theoretical Predictions ◽  
Interaction Of Shock Waves

Abstract In continuation of the work on interaction between shock waves and magnetic fields 1,2 the experiments reported here measured the atomic and electron densities in the interaction region by means of an interferometric and a spectroscopic method. The transient atomic density was also calculated using a one-dimensional theory based on the work of Johnson3 , but modified to give an improved physical model. The experimental results were compared with the theoretical predictions.

Lorentz Transformation as a Galilei Transformation with Physical Length and Time Contractions

1988 ◽  
Vol 43 (10) ◽  
pp. 859-864
Author(s):  
H. E. Wilhelm
Keyword(s):  
Rest Frame ◽  
Lorentz Transformations ◽  
Speed Of Light ◽  
Analogous Structure ◽  
Galilean Relativity ◽  
Symmetry Properties ◽  
Inertial Frames ◽  
Ether Frame ◽  
Light Signals ◽  
Time Variables

Abstract The Lorentz transformations between the space-time coordinates of a point in two inertial frames with arbitrary relative velocity, are reformulated as Galilei transformations with length and time contractions, by introducing the ether rest frame (in which light signals propagate isotropically with the vacuum speed of light). The generalized Galilei transformations for the (longitudinal) space coordinates (x1,2) and the time variables (t1,2) of a point in two inertial frames ∑1,2 are not only of analogous structure, but have remarkable symmetry properties, too. The appearing length and time contractions are absolute effects in the sense of Lorentz-Fitzgerald, i.e., a rod has its largest length and a clock its fastest rate when at rest in the ether frame ∑0. Thus, an analytical reformulation and a physical interpretation of the Lorentz transformations within Galilean relativity physics is achieved.

The interaction of pulsar winds with old supernova remnants

2000 ◽  
Vol 177 ◽  
pp. 513-514
Author(s):  
Eric van der Swaluw ◽  
Abraham Achterberg ◽  
Yves A. Gallant
Keyword(s):  
Cosmic Rays ◽  
Shock Waves ◽  
Radio Emission ◽  
Supernova Remnants ◽  
Charged Particles ◽  
Simple Problem ◽  
Relativistic Electrons ◽  
First Case ◽  
Pulsar Wind ◽  
Pulsar Winds

Shock waves in young supernova remnants (SNR) are generally considered to be the places where production and acceleration of charged particles (relativistic electrons and cosmic rays) take place. Older remnants can be re-energised if an active pulsar catches up with the shell of the remnant (Shull, Fesen, & Saken 1989). In that case a pulsar-driven wind can inject energetic particles into the shell, resulting into a rejuvenation of the radio emission of the old remnant due to the presence of additional relativistic electrons.Radio observations of CTB80 (Angerhofer et al. 1981) and G5.4-1.2 (Frail & Kulkarni 1991) give evidence for the importance of the presence of an active pulsar close to the old shell of the remnants. In the first case the pulsar is believed to be inside the SNR. In the second case the pulsar is thought to have penetrated the shell of the SNR, and resides in the interstellar medium (ISM). We intend to investigate the physics which are connected with these kind of systems. One expects new effects resulting from the interaction of the three different shocks; the SNR shock, the bowshock bounding the pulsar wind nebula (PWN) and the (pulsar) wind termination shock. The dynamics of the system is described by a hydrodynamics code. We use the results from the hydrodynamics code to investigate the process of acceleration and transport of particles which are advected by the flow and diffuse with respect to the flow. We have applied the latter to a simple problem, the case of a spherically expanding SNR.

Existence conditions for collisionless hydromagnetic shock waves along the magnetic field

1971 ◽  
Vol 6 (3) ◽  
pp. 467-493 ◽  
Author(s):  
Yusuke Kato† ◽  
Masayoshi Tajiri ◽  
Tosiya Taniuti
Keyword(s):  
Magnetic Field ◽  
Shock Waves ◽  
Flow Velocity ◽  
Maxwell Equations ◽  
Collisionless Plasma ◽  
Electrostatic Waves ◽  
Pressure Anisotropy ◽  
Existence Conditions ◽  
Upstream Flow ◽  
The Magnetic Field

This paper is concerned with existence conditions for steady hydromagnetic shock waves propagating in a collisionless plasma along an applied magnetic field. The electrostatic waves are excluded. The conditions are based on the requirement that solutions of the Vlasov-Maxwell equations deviate from a uniform state ahead of a wave. They are given as the conditions on the upstream flow velocity in the wave frame (i.e. in the form of inequalities among the upstream flow velocity and some critical velocities). The conditions crucially depend on the pressure anisotropy, and demonstrate possibilities of exacting collisionless shock waves for high β plasmas.

Energy Dissipation in Normal Elastoplastic Impact Between Two Spheres

2009 ◽  
Vol 76 (6) ◽  
Author(s):  
Yanchen Du ◽  
Shulin Wang
Keyword(s):  
Relative Velocity ◽  
Elastoplastic Deformation ◽  
Mass Density ◽  
Finite Element Analyses ◽  
Vibration System ◽  
Lower Yield ◽  
Theoretical Predictions ◽  
Lower Yield Strength ◽  
Three Stages ◽  
The Impact

Elastoplastic deformation occurs widely in engineering impact. Although many empirical solutions of elastoplastic impact between two spheres have been obtained, the analytical solution, verified by means of other methods, to the impact model has not been put forward. This paper proposes a dynamic pattern of elastoplastic impact for two spheres with low relative velocity, in which three stages are introduced and elastic and plastic regions are both considered. Finite element analyses with various parameters are carried out to validate the above model. The numerical results prove to agree with the theoretical predictions very well. Based on this model, the dissipation nature of elastoplastic impact are then analyzed, and the conclusion can be drawn that materials with lower yield strength, higher elastic modulus, and higher mass density have better attenuation and dissipation effects. The study provides a basis to predict the particle impact damping containing plastic deformation and to model the impact damped vibration system enrolling microparticles as a damping agent.

scholarly journals A Model of Magnetic Monopoles

1997 ◽  
Vol 12 (40) ◽  
pp. 3153-3159 ◽  
Author(s):  
Rainer W. Kühne
Keyword(s):  
Electric Charge ◽  
Quantum Electrodynamics ◽  
Maxwell Equations ◽  
Rest Frame ◽  
Electromagnetic Interaction ◽  
Magnetic Monopoles ◽  
Relativity Principle ◽  
Electric And Magnetic Fields ◽  
Physical Effects ◽  
Field Theoretical Model

The possibility of the existence of magnetic charges is one of the greatest unsolved issues of the physics of this century. The concept of magnetic monopoles has at least two attractive features: (i) Electric and magnetic fields can be described equivalently. (ii) In contrast to quantum electrodynamics, models of monopoles are able to explain the quantization of electric charge. We suggest a quantum field theoretical model of the electromagnetic interaction that describes electricity and magnetism as equivalent as possible. This model requires the cross-section of Salam's "magnetic photon" to depend on the absolute motion of the electric charge with which it interacts. We suggest a tabletop experiment to verify this magnetic photon. Its discovery by the predicted effect would have far-reaching consequences: (i) Evidence for a new gauge boson and a new kind of radiation which may find applications in medicine. (ii) Evidence for symmetrized Maxwell equations. (iii) Evidence for an absolute rest frame that gives rise to local physical effects and violation of Einstein's relativity principle.

Rankine–Hugoniot-Berechnungen für Nichtgleichgewichts-Plasmen

1966 ◽  
Vol 21 (11) ◽  
pp. 1960-1963
Author(s):  
J. Artmann
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Pressure Ratio ◽  
Density Ratio ◽  
Charged Particles ◽  
Strong Shock ◽  
Ion Temperature ◽  
Saha Equation ◽  
Wave Parameters ◽  
Strong Shock Waves

In optically thin plasmas produced by strong shock waves the SAHA equation is no longer valid to describe the conditions directly behind the shock wave. Photoionisation may be neglected in the balance of production and recombination of charged particles. For the case of nonequilibrium a calculation assuming various ratios of electron to ion temperature (ϑ= TeT) shows that the shock wave parameters are described sufficiently well by the Korona-equation. Temperature, density ratio and electron density are increased with increasing ϑ whereas the pressure ratio is independent of the kind of equilibrium and ϑ.

2. Motion and inertia

2021 ◽  
pp. 23-41
Author(s):  
David Wallace
Keyword(s):  
Rest Frame ◽  
Constant Speed ◽  
Absolute Space ◽  
Theory Of Relativity ◽  
Relativity Principle ◽  
Newtonian Physics ◽  
Inertial Frames

This chapter explores the question of what it means for something to move, and why physics cannot be done without an answer to that question. It does so mostly in the context of Newtonian physics, leaving considerations of the theory of relativity to the next chapter. We cannot simply define motion of one body as relative to another body if we want to do physics—we have to introduce the idea of a ‘rest frame’ that defines which bodies are at rest (Newton called this rest frame ‘absolute space’). But physics also satisfies the relativity principle—it is impossible to distinguish the rest frame from another frame moving at constant speed in that frame. So what physics really requires is not a preferred rest frame, but a family of inertial frames, all moving at uniform speeds relative to one another. The notion of ‘spacetime’ has been introduced as a way of understanding this family of inertial frames, but philosophers of physics disagree as to whether spacetime explains the nature of motion in physics, or merely codifies it. The chapter concludes by explaining how gravity can be thought of as a change in the structure of the inertial frames: though it was Einstein who first saw this clearly, it has nothing to do with relativity and makes sense even in Newtonian physics.

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