Search results for "current"
showing 10 items of 2224 documents
Design of a System to Compose 50 Hz Alternating and Static Magnetic Field From Induction Coil and Permanent Magnets
2020
We demonstrate a technical solution to achieve an intense 50 Hz alternating magnetic field and a static magnetic field made by a permanent magnet at the same place. A compact coil built using the Bitter coil concept is customized to support alternating current, thus creating an alternating magnetic field. A complementary permanent magnet assembly is built around it to achieve the superposition of both fields along the axis of symmetry. Results from the experimental model are compared to both numerical and analytical models.
Neutral-current supernova-neutrino cross sections for Pb204,206,208 calculated by Skyrme quasiparticle random-phase approximation
2019
The present work constitutes a detailed study of neutral-current (NC) supernova-neutrino scattering off the stable even-even lead isotopes Pb204,206,208. This is a continuation of our previous work [Almosly et al., Phys. Rev. C. 94, 044614 (2016)10.1103/PhysRevC.94.044614] where we investigated charged-current processes on the same nuclei. As in the previous work, we have adopted the quasiparticle random-phase approximation (QRPA) as the theory framework and use three different Skyrme interactions to build the involved nuclear wave functions. We test the Skyrme forces by computing the location of the lowest-order isovector spin-multipole giant resonances and comparing with earlier calculati…
Arrays of Josephson junctions in an environment with vanishing impedance
1999
The Hamiltonian operator for an unbiased array of Josephson junctions with gate voltages is constructed when only Cooper pair tunnelling and charging effects are taken into account. The supercurrent through the system and the pumped current induced by changing the gate voltages periodically are discussed with an emphasis on the inaccuracies in the Cooper pair pumping. Renormalisation of the Hamiltonian operator is used in order to reliably parametrise the effects due to inhomogeneity in the array and non-ideal gating sequences. The relatively simple model yields an explicit, testable prediction based on three experimentally motivated and determinable parameters.
Design of a double-gap Hughes-type coupled-cavity for a Ka-band Extended Interaction Klystron
2020
In this paper, the design of a Ka-band Extended-Interaction Klystron (EIK) working at 2$\pi$ mode. The interaction structure is a three-gap Hughes-type coupled-cavity. Based on the results obtained with the 3D model developed by using CST, “cold electrical parameters” have been calculated, necessary to measure the interaction with the electron beam. The structure stability and the synchronization with the electron beam are analyzed The large-signal analysis is performed by 1D software AJDISK. Under the beam voltage and current of 19.55 kV and 0.95 A, respectively, an RF output power value of 3.86 kW and a bandwidth gain value of 37. 06 dB have been obtained
Magnetic field analysis and leakage inductance calculation in current transformers by means of 3-D integral methods
1996
This paper presents 3D integral approach to power current transformer magnetic field and inductance calculations. A minimization of the kernel norm has been carried out for the integral equation governing the field. The software package TRACAL3, based on the integral methods for field and inductance calculations, has been developed and implemented for personal computers. The application of the 3D mathematical models has been made for the leakage field in a current transformer. The results of calculations were compared with measurement data. The comparison yields good agreement.
Supersymmetry currents and WZ-like terms in (supersymmetry)2 models
1990
Abstract Using the superfield formulation of the N = 1 spinning superparticle model as an example, the superfield currents associated with the target space supersymmetry are given, and the component expression of the corresponding superalgebra is found to describe a graded “doubling” of the Poincare superalgebra. Further, it is shown how the torsion-like term in the spinning super-particle model can be obtained from the form associated with the Green-Schwarz WZ term for the superstring, and a possible way of introducing extended spinning supersymmetric objects is discussed.
Dynamical and current-induced Dzyaloshinskii-Moriya interaction: Role for damping, gyromagnetism, and current-induced torques in noncollinear magnets
2020
Both applied electric currents and magnetization dynamics modify the Dzyaloshinskii-Moriya interaction (DMI), which we call current-induced DMI (CIDMI) and dynamical DMI (DDMI), respectively. We report a theory of CIDMI and DDMI. The inverse of CIDMI consists in charge pumping by a time-dependent gradient of magnetization ${\ensuremath{\partial}}^{2}\mathbit{M}(\mathbit{r},t)/\ensuremath{\partial}\mathbit{r}\ensuremath{\partial}t$, while the inverse of DDMI describes the torque generated by ${\ensuremath{\partial}}^{2}\mathbit{M}(\mathbit{r},t)/\ensuremath{\partial}\mathbit{r}\ensuremath{\partial}t$. In noncollinear magnets, CIDMI and DDMI depend on the local magnetization direction. The re…
Spinmotive force due to motion of magnetic bubble arrays driven by magnetic field gradient
2014
Interaction between local magnetization and conduction electrons is responsible for a variety of phenomena in magnetic materials. It has been recently shown that spin current and associated electric voltage can be induced by magnetization that depends on both time and space. This effect, called spinmotive force, provides for a powerful tool for exploring the dynamics and the nature of magnetic textures, as well as a new source for electromotive force. Here we theoretically demonstrate the generation of electric voltages in magnetic bubble array systems subjected to a magnetic field gradient. It is shown by deriving expressions for the electric voltages that the present system offers a direc…
MHD modeling of coronal loops: the transition region throat
2014
The expansion of coronal loops in the transition region may considerably influence the diagnostics of the plasma emission measure. The cross sectional area of the loops is expected to depend on the temperature and pressure, and might be sensitive to the heating rate. The approach here is to study the area response to slow changes in the coronal heating rate, and check the current interpretation in terms of steady heating models. We study the area response with a time-dependent 2D MHD loop model, including the description of the expanding magnetic field, coronal heating and losses by thermal conduction and radiation from optically thin plasma. We run a simulation for a loop 50 Mm long and qu…
Leptonic CP violation with massless neutrinos
1989
Abstract Leptonic CP violation may arise in the SU(2) ⊗ U(1) theory even if the neutrinos are strictly massless and, as a result, it is potentially large. Theoretical scenarios include isosinglet neutral heavy leptons which are present in many extensions of the standard electroweak theory such as superstring inspired models. We discuss in detail the nature of this CP violation and show that it can occur in a two-generation model. Possible effects are briefly discussed.