相关论文: Eddy currents in accelerator magnets
We consider the scattering of time periodic electro-magnetic fields by metallic obstacles, the eddy current problem. In this interface problem different sets of Maxwell equations must be solved in the obstacle and outside, while the…
The one-loop induced magnetic dipole moments of a neutrino are examined in a background of degenerate electrons in the standard model. For the nonrelativistic neutrino, they are enhanced by a factor \( (8\pF/3\mnu) \), where \pF\ is the…
Magnetic helicity effects are discussed in laboratory and astrophysical settings. First, dynamo action in Taylor-Green flows is discussed for different boundary conditions. However, because of the lack of scale separation with respect to…
All current estimations of the energy released by type I ELMs indicate that, in order to ensure an adequate lifetime of the divertor targets on ITER, a mechanism is required to decrease the amount of energy released by an ELM, or to…
The magnon current holds substantial importance in facilitating the transfer of angular momentum in spin-based electronics. However, the magnon current in three-dimensional magnetic materials remains orders of magnitude too small for…
We quantitatively analyze a familiar classroom demonstration, Van Waltenhofen's eddy current pendulum, to predict the damping effect for a variety of plate geometries from first principles. Results from conformal mapping, finite element…
We study the propagation of surface waves on a current in the presence of an electromagnetic field. A horizontal (vertical) field strengthens (weakens) the counter-current which blocks the waves. We compute the phase space diagrams…
In this note we discuss the numerical solution of the eddy current approximation of the Maxwell equations using the simple Pragmatic Algebraic Model to include hysteresis effects. In addition to the more standard time-stepping approach we…
In the first part of this work an overview of the available data on the paramagnetic effect recently discovered in superconductors was given as well as a possible explanation of the effect. Here the consequences caused by this weakly…
3-D extended-MHD simulations of the magnetized ablative Rayleigh-Taylor instability are presented for the first time. Previous 2-D simulations claiming perturbation suppression by magnetic tension are shown to be misleading, as they do not…
We use a radio-frequency $^{85}$Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We…
The generation of large-scale magnetic field in the kinematic regime in the absence of an alpha-effect is investigated by following two different approaches, namely the test-field method and multiscale stability theory relying on the…
We discuss the theory of electromagnetic fields, with an emphasis on aspects relevant to radiofrequency systems in particle accelerators. We begin by reviewing Maxwell's equations and their physical significance. We show that in free space,…
Theory and recent experiments concerning exchange-driven magnetic excitation (EDME) are reviewed. This phenomenon employs the exchange field produced by a narrowly distributed spin-polarized electron current to excite Larmor precession in a…
We investigate the effects of impurities on the nature of the phase transition in frustrated magnets, in d=4-epsilon dimensions. For sufficiently small values of the number of spin components, we find no physically relevant stable fixed…
The general theory for electric current multipoles appearing at the motion of magnetic dipoles and change in these values or orientation has been suggested. Static multipoles, including an anapole, have been studied in detail.
To give a general description of the influences of electric fields or currents on magnetization dynamics, we developed a semiclassical theory for the magnetization implicitly coupled to electronic degrees of freedom. In the absence of…
We review our current understanding of the critical dynamics of magnets above and below the transition temperature with focus on the effects due to the dipole--dipole interaction present in all real magnets. Significant progress in our…
We revisit in the framework of the classical theory the problem of the accelerated motion of an electron, taking into account the effect of the radiation emission. We present results for the momentum and energy of the electromagnetic field…
Numerical studies of the effect of a dc magnetic field on dynamo action (development of magnetic fields with large spatial scales), due to helically-driven magnetohydrodynamic turbulence, are reported. The apparent effect of the dc magnetic…