Photodetachment microscopy of H– ion in time-dependent electric and magnetic fields

2018 ◽  
Vol 96 (9) ◽  
pp. 961-968
Author(s):  
De-hua Wang
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Interference Pattern ◽  
Current Distribution ◽  
Time Dependent ◽  
Electron Current ◽  
Detector Plane ◽  
Electron Trajectories ◽  
Electric And Magnetic Fields

We examine the dynamics of electrons photodetached from the H– ion in time-dependent electric and magnetic fields for the first time. The photodetachment microscopy patterns caused by a time-dependent gradient electric field and magnetic field have been analyzed in great detail based on the semiclassical theory. The interplay of the gradient electric field and magnetic field forces causes an intricate shape of the electron wave and multiple electron trajectories generated by a fixed energy point source can arrive at a given point on the microchannel-plate detector. The interference effects between these electron trajectories cause the oscillatory structures of the electron probability density and electron current distribution, and a set of concentric interference fringes are found at the detector. Our calculation results suggest that the photodetachment microscopy interference pattern on the detector can be adjusted by the electron energy, magnetic field strength, and position of the detector plane. Under certain conditions, the interference pattern in the electron current distribution might be seen on the detector plane localized at a macroscopic distance from the photodetachment source, which can be observed in an actual photodetachment microscopy experiment. Therefore, we make predictions that our work should serve as a guide for future photodetachment microscopy experiments in time-dependent electric and magnetic fields.

Quasi-static electric and magnetic fields in vacuum

2018 ◽  
Author(s):  
J. Pierrus
Keyword(s):  
Magnetic Field ◽  
Nineteenth Century ◽  
Magnetic Fields ◽  
Electric Field ◽  
Electromagnetic Induction ◽  
Point Of View ◽  
Time Dependent ◽  
Important Phenomenon ◽  
Electric And Magnetic Fields ◽  
Practical Standpoint

In this chapter, the transition from time-independent to time-dependent source densities and fields is made. It is here that Faraday’s famous nineteenth-century experiments on electromagnetic induction are first encountered. This important phenomenon—whereby a changing magnetic field produces an induced electric field (whose curl is now no longer zero)—forms the basis of most of the questions and solutions which follow. Some new and interesting examples—not usually found in other textbooks—are introduced. These are treated both from an analytical and numerical point of view. Also considered here is the standard yet important topic (at least from a practical standpoint) of mutual and self-inductance. Several questions deal with this concept.

Modified Morris-Lecar neuron model: Effects of very low frequency electric fields and of magnetic fields on the local and network dynamics of an excitable media

2021 ◽  
Author(s):  
Karthikeyan Rajagopal ◽  
Irene Moroz ◽  
Balamurali Ramakrishnan ◽  
Anitha Karthikeyan ◽  
Prakash Duraisamy
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Neuron Model ◽  
Low Noise ◽  
Spiral Waves ◽  
Excitable Media ◽  
Field Frequency ◽  
Electric And Magnetic Fields ◽  
Electric Field Frequency

Abstract A Morris-Lecar neuron model is considered with Electric and Magnetic field effects where the electric field is a time varying sinusoid and magnetic field is simulated using an exponential flux memristor. We have shown that the exposure to electric and magnetic fields have significant effects on the neurons and have exhibited complex oscillations. The neurons exhibit a frequency-locked state for the periodic electric field and different ratios of frequency locked states with respect to the electric field frequency is also presented. To show the impact of the electric and magnetic fields on network of neurons, we have constructed different types of network and have shown the network wave propagation phenomenon. Interestingly the nodes exposed to both electric and magnetic fields exhibit more stable spiral waves compared to the nodes exhibited only to the magnetic fields. Also, when the number of layers are increased the range of electric field frequency for which the layers exhibit spiral waves also increase. Finally the noise effects on the field affected neuron network are discussed and multilayer networks supress spiral waves for a very low noise variance compared against the single layer network.

Suppression of runaway of electrons in a Lorentz plasma. II. crossed electric and magnetic fields

1970 ◽  
Vol 4 (3) ◽  
pp. 441-450 ◽  
Author(s):  
Barbara Abraham-Shrauner
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Electric Fields ◽  
Cyclotron Frequency ◽  
Collision Frequency ◽  
Uniform Electric Field ◽  
Drift Motion ◽  
Electric And Magnetic Fields ◽  
The Magnetic Field

Suppression of runaway of electrons in a weak, uniform electric field in a fully ionized Lorentz plasma by crossed magnetic and electric fields is analysed. A uniform, constant magnetic field parallel to a constant or harmonically time varying electric field does not alter runaway from that in the absence of the magnetic field. For crossed, constant fields the passage to runaway or to free motion as described by constant drift motion and spiral motion about the magnetic field is lengthened in time for strong magnetic fields. The new ‘runaway’ time scale is roughly the ratio of the cyclotron frequency to the collision frequency squared for cyclotron frequencies much greater than the collision frequency. All ‘runaway’ time scales may be given approximately by t2E Teff where tE is the characteristic time of the electric field and Teff is the ffective collision time as estimated from the appropriate component of the electrical conductivity.

NONLINEAR CURRENT DENSITY IN QUANTUM WELLS WITH PARABOLIC POTENTIAL UNDER CROSSED ELECTRIC AND MAGNETIC FIELDS

2012 ◽  
Vol 01 (02) ◽  
pp. 1250021
Author(s):  
BUI DINH HOI ◽  
TRAN CONG PHONG
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Quantum Wells ◽  
Effective Mass ◽  
Current Density ◽  
Electrical Transport ◽  
Physical Parameters ◽  
Electric And Magnetic Fields ◽  
Dc Electric Field

The DC electrical transport in a quantum well (QW) with parabolic confinement potential [Formula: see text] (where m and ωz are the effective mass of electron and the confinement frequency in z direction, respectively) subjected to a crossed DC electric field and magnetic field, is studied theoretically. The scattering by optical phonons is taken into account at high temperatures and strong magnetic fields. We obtained the expression for nonlinear current density (NCD) involving external (electric and magnetic) fields and characteristic parameters of QW. The dependence of NCD on the DC electric field is complicated. The analytical result is computationally evaluated and graphically plotted for a specific parabolic QW of GaAs / AlGaAs . The numerical results show the appearance of maximum peaks satisfying the condition of intersubband magnetophonon resonance (MPR) effect in the presence of a DC electric field. Especially, we show that the effect can be applied in experiment to determine some physical parameters by using magnetic field, such as the numbers of Landau levels for which electrons transfer, the effective mass, the charge of electrons or the confinement frequency characterized for PQW.

Molecular Rovibronic Symmetries in Electric and Magnetic Fields

1975 ◽  
Vol 53 (19) ◽  
pp. 2210-2220 ◽  
Author(s):  
James K. G. Watson
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Symmetry Groups ◽  
Nuclear Spins ◽  
Symmetry Classification ◽  
Electric And Magnetic Fields ◽  
Field Symmetry ◽  
Point Groups

The structures of the symmetry groups for the rovibronic levels of a molecule in a homogeneous electric or magnetic field are derived, and the symmetry classification of the levels in terms of the representations and corepresentations of these groups is discussed. Specific results are given for molecules of the point groups C3, C2v, C3v, D2d, and Td in an electric field. Symmetry in combined electric and magnetic fields and the inclusion of nuclear spins are considered briefly.

scholarly journals Decoding of the Skin Sensations to the Low Intensive Electric and Magnetic Fields

2021 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Human Skin ◽  
Electric And Magnetic Fields ◽  
The Brain

The article represents the ability of the human skin sensitive receptors and receptors of the proprioception to detect and code the very low intensive electric and magnetic fields. Was made the classification of the skin sensations to the electric field (EF) and magnetic field (MF) – 34 kind sensations. Was made the electrophysiology pattern of every one sensation to the electric field (EF) and magnetic field (MF) – how the skin sensitive receptors and receptors of proprioception code the electric and magnetic fields to be translate from the sensitive nerve to the brain.

scholarly journals Phase transitions in nanostructured water confined in carbon nanotubes by external electric and magnetic fields: a molecular dynamics investigation

RSC Advances ◽  
2021 ◽  
Vol 11 (18) ◽  
pp. 10532-10539
Author(s):  
Mohsen Abbaspour ◽  
Hamed Akbarzadeh ◽  
Sirous Salemi ◽  
Leila Bahmanipour
Keyword(s):  
Magnetic Field ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Phase Transitions ◽  
Magnetic Fields ◽  
Electric Field ◽  
Electric And Magnetic Fields

Phase transitions from pentagonal to twisted pentagonal, spiral and circle-like shapes by electric field from 104 to 107 (V m−1). Magnetic fields have small effects but the highest magnetic field (300 T) makes the pentagonal shape more ordered.

scholarly journals Effect of combined electric and magnetic fields on the helium spectrum

1929 ◽  
Vol 122 (790) ◽  
pp. 599-603 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Classical Theory ◽  
Stark Effect ◽  
Classical View ◽  
Electric And Magnetic Fields ◽  
Perpendicular Component ◽  
The Individual ◽  
The Magnetic Field

This paper deals with the observed effect of simultaneous electric and magnetic fields on certain of the more intense helium lines, and is further limited to the case where the fields are uniform and parallel. The effect of parallel fields was first considered by Garbasso, who adopted the classical view of the “rough” Stark-effect on H β as given by Voigt, and concluded that the effects due to the two fields should be simply superimposed. Shortly after this he was able to make visual observations which were restricted to H α owing to intensity requirements. A source of the Lo Surdo type was placed along the axis of the hollow poles of a Weiss magnet, and the analysis made with a Michelson echelon. In the electric field alone Garbasso observed two parallel components and one undisplaced perpendicular component. This corresponds to a so-called “rough” analysis of the Stark-effect in which the individual components are not observed. In the magnetic field he found a normal Zeeman pattern. With combined parallel fields there appeared two parallel components in the position of the Stark components of like polarisation, and two symmetrically placed perpendicular components with the normal Zeeman separation. This simple result could not be given a satisfactory interpretation on classical theory.

ASONIKA-EMC: modeling of electromagnetic processes in electronics designs

2020 ◽  
pp. 3-13
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Electromagnetic Waves ◽  
Electronic Devices ◽  
Functional Capabilities ◽  
Electromagnetic Processes ◽  
Electric And Magnetic Fields ◽  
Calculation Results ◽  
Intensity Magnetic Field

The information about the ASONIKA-EMC program, intended for calculating the distribution of electric and magnetic fields intensity inside and outside of the electronic devices housings, as well as for determining the ef¬fectiveness of shielding electric and magnetic fields at effect of the electromagnetic waves in the frequency range 10...30 000 MHz, is adduced. Functional capabilities are described, an example of calculation and analysis of calculation results is adduced. Keywords: radio engineering device; modeling; electric field; magnetic field; electric field intensity; magnetic field strength; shielding.

Horizontal Magnetic Dipole Embedded in a Two-Layer Conducting Medium

1972 ◽  
Vol 50 (6) ◽  
pp. 607-616 ◽  
Author(s):  
V. Ramaswamy ◽  
H. W. Dosso ◽  
J. T. Weaver
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Magnetic Dipole ◽  
Low Frequency ◽  
Bottom Layer ◽  
Conducting Medium ◽  
Dimensionless Form ◽  
Electric And Magnetic Fields ◽  
The Magnetic Field

The solutions for low-frequency fields of a horizontal magnetic dipole embedded within a two-layer conductor are derived. For convenience, the solutions are expressed in dimensionless form. The amplitudes and phases of the electric and magnetic fields along the surface of the bottom layer are calculated numerically and their dependence on the ratio of the conductivities of the two layers is investigated. Results indicate that, in general, the electric field induced by a subsurface horizontal magnetic dipole is more sensitive to the bottom-layer conductivity than is the magnetic field. Some of the results discussed in this paper are of interest in studying the seabed conductivity.

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