Search results for "electric [charge]"
showing 10 items of 729 documents
Narrow-band tunable terahertz detector in antiferromagnets via staggered-field and antidamping torques
2018
We study dynamics of antiferromagnets induced by simultaneous application of dc spin current and ac charge current, motivated by the requirement of all-electrically controlled devices in the terahertz (THz) gap (0.1--30 THz). We show that ac electric current, via N\'eel spin-orbit torques, can lock the phase of a steady rotating N\'eel vector whose precession is controlled by a dc spin current. In the phase-locking regime the frequency of the incoming ac signal coincides with the frequency of auto-oscillations, which for typical antiferromagnets falls into the THz range. The frequency of auto-oscillations is proportional to the precession-induced tilting of the magnetic sublattices related …
Linear Dichroism in Photoemission from Oriented Molecules
1993
It is shown that oriented molecules reveal both Linear Dichroism (LD) and Linear Dichroism in the Angular Distribution (LDAD) of photoelectrons, which means a difference between photoelectron currents ejected at a definite angle by linearly polarized light of two mutually perpendicular polarizations. Measurements of LD and LDAD enable one to investigate the orientation of molecules and to make an essential step towards the complete quantummechanical experiment. As an example, LDAD in a model case of oriented heteronuclear diatomic molecules is presented.
Effects of electric charges on hydrophobic forces. II.
2000
We study by molecular-dynamics simulations the effect of electric charges of either sign on hydrophobic interactions and on the dynamics of hydration water, using explicit water and very simplified solutes. Results show that the presence of a charged solute can disrupt the "hydrophobic contact bond" between two apolar solutes nearby, by forcing them towards a different configuration. As a consequence of different structural changes of the solvent caused by charges of opposite sign, the effect is markedly charge-sign-dependent. Analogous weaker effects appear to be induced by the presence of one additional apolar element. The dynamics of hydration water around each solute is also seen to be …
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…
Search for an electric charge of the neutron
2018
The electrical neutrality of the neutron is linked to the electric charge quantization. It is not understood yet if the electric charge is quantized or not. Since the discovery of the neutron, many attempts have been made to measure its electric charge ${q}_{n}$ directly and indirectly. We present a method to search for a possible ${q}_{n}$ by means of an optical setup using ultracold neutrons. In a first run, a statistical sensitivity of $\ensuremath{\delta}{q}_{n}=2.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}\text{ }\text{ }e/\sqrt{\mathrm{day}}$ is achieved. Possible improvements to increase this sensitivity down to $\ensuremath{\delta}{q}_{n}\ensuremath{\approx}1\ifmmode\…
Simulation of forces and 3-D field arising during power autotransformer fault due to electric arc in HV winding
2002
Forces and three-dimensional magnetic fields in high-voltage winding due to an internal short circuit in a power autotransformer are calculated with the computer package OPERA 3D. The considered damage was caused by an electric arc. The materialized deformation of the winding part confirms the simulation results.
Longitudinal dynamics of multiple conserved charges
2021
Abstract It is the goal of the RHIC BES program and the future FAIR and NICA facilities to produce compressed baryonic matter. In experiments such as these, strong gradients in baryon density are expected, and therefore the diffusion of baryon number could play a major role in the description of the fireball. The constituents of the produced matter carry a multitude of conserved charges, namely the baryon number, strangeness and electric charge, so that the diffusion currents of conserved charge couple with each other. Therefore, baryon density gradients in the above-mentioned high-density collision experiments will generate equalizing currents in all conserved charges. In common fluid dyna…
Hidden Dirac Monopoles
2008
Dirac showed that the existence of one magnetic pole in the universe could offer an explanation of the discrete nature of the electric charge. Magnetic poles appear naturally in most grand unified theories. Their discovery would be of greatest importance for particle physics and cosmology. The intense experimental search carried thus far has not met with success. I proposed a universe with magnetic poles which are not observed free because they hide in deeply bound monopole--anti-monopole states named monopolium. I discuss the realization of this proposal and its consistency with known cosmological features. I furthermore analyze its implications and the experimental signatures that confirm…
Hybrid simulation of electron cyclotron resonance heating
2008
Electron Cyclotron Resonance (ECR) heating is a fundamentally important aspect in understanding the physics of Electron Cyclotron Resonance Ion Sources (ECRIS). Absorption of the radio frequency (RF) microwave power by electron heating in the resonance zone depends on many parameters including frequency and electric field strength of the microwave, magnetic field structure and electron and ion density profiles. ECR absorption has been studied in the past by e.g. modelling electric field behaviour in the resonance zone and its near proximity. This paper introduces a new ECR heating code that implements damping of the microwave power in the vicinity of the resonance zone, utilizes electron de…
A hot cavity laser ion source at IGISOL
2008
A development program is underway at the IGISOL (Ion Guide Isotope Separator On-Line) facility, University of Jyvaskyla, to efficiently and selectively produce low-energy radioactive ion beams of silver isotopes and isomers, with a particular interest in N=Z 94Ag. A hot cavity ion source has been installed, based on the FEBIAD (Forced Electron Beam Induced Arc Discharge) technique, combined with a titanium:sapphire laser system for selective laser ionization. The silver recoils produced via the heavy-ion fusion-evaporation reaction, 40Ca(58Ni, p3n)94Ag, are stopped in a graphite catcher, diffused, extracted and subsequently ionized using a three-step laser ionization scheme. The performance…