scholarly journals Imaging electric field with electrically neutral particles.

2021 ◽  
Author(s):  
Yuan-Yu Jau
Keyword(s):  
Electric Field ◽  
Neutral Particles

HQC with the AC setup associated with topological defects

2011 ◽  
Vol 11 (5&6) ◽  
pp. 444-455
Author(s):  
Knut Bakke ◽  
Cláudio Furtado
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Topological Defect ◽  
Dipole Moments ◽  
Topological Defects ◽  
Quantum Phases ◽  
Neutral Particles ◽  
New Formulation

In this work, we propose a new formulation allowing to realize the holonomic quantum computation with neutral particles with a permanent magnetic dipole moments interacting with an external electric field in the presence of a topological defect. We show that both the interaction of the electric field with the magnetic dipole moment and the presence of topological defect generate independent contributions to the geometric quantum phases which can be used to describe any arbitrary rotation on the magnetic dipole moment without using the adiabatic approximation.

scholarly journals Dielectrophoretic classification of fibres: principles and application to glass fibres suspended in air

2019 ◽  
Vol 213 ◽  
pp. 02053
Author(s):  
Frantisek Lizal ◽  
Milan Maly ◽  
Jakub Elcner ◽  
Arpad Farkas ◽  
Ondrej Pech ◽  
...  
Keyword(s):  
Electric Field ◽  
High Speed ◽  
Deposition Velocity ◽  
Uniform Electric Field ◽  
Electrical Mobility ◽  
Mobility Separation ◽  
Neutral Particles ◽  
Naturally Occurring ◽  
Two Parameters

Particles exposed to an electric field experience forces that influence their movement. This effect can be used for filtration of air, or for size classification of aerosols. The motion of charged particles in a non-uniform electric field is called electrophoresis. Two processes are involved in this phenomenon: 1) charging of particles and 2) electrical mobility separation. If fibres are exposed to electrophoresis, they are separated on the basis of two parameters: diameter and length. Regrettably, as naturally occurring fibres are polydisperse both in diameter and length, the electrophoresis is not very efficient in length classification. In contrast, dielectrophoresis is the motion of electrically neutral particles in a non-uniform electric field due to the induced charge separation within the particles. As deposition velocity of fibres induced by dielectrophoretic force strongly depends on length and only weakly on diameter, it can be used for efficient length classification. Principles of length classification of conducting and non-conducting fibres are presented together with design of a fibre classifier. Lastly, images of motion of fibres recorded by high-speed camera are depicted.

scholarly journals Window with Electrostatic Protection against Dust, Smoke, and Viruses

2021 ◽  
Vol 26 (3) ◽  
Author(s):  
Andrii Andriiovych Pakhomov ◽  
Iryna Olehivna Bevza ◽  
Viacheslav Oleksiiovych Chadyuk
Keyword(s):  
Electric Field ◽  
Indoor Air ◽  
Negative Charge ◽  
Electrostatic Precipitator ◽  
Submicron Particles ◽  
Dust Particles ◽  
Uniform Electric Field ◽  
Plate Electrode ◽  
Neutral Particles ◽  
Large Gradient

The article analyzes the effect of dangerous aerosols on the human body. In order to purify the air from aerosols, the effect of an electric field on them is considered. The electric and dielectrophoretic forces acting on submicron particles in an inhomogeneous electric field of two parallel wires are calculated. It is shown that part of this field is identical to the field between the wire and the grounded plate electrode located in the middle between the wires. This allows using a known formula for the electric field of a two-wire line to calculate the field gradient and the effect of dielectrophoresis on neutral particles. Smoke and dust particles already carry a negative charge, and a more or less uniform electric field is enough to move them. To filter neutral water droplets infected with the virus, you need either a field with a large gradient or a corona discharge. The paper shows that the polarization of particles in an electric field causes the particles to stick together, and larger particles settle faster on the electrodes of the filter. The design of a transparent electrostatic precipitator is proposed, which can be used to protect indoor air from external smoke, dust, or viruses.

scholarly journals <i>Letter to the Editor</i>An analogy to the Reynolds number for the neutral gas component of a weak plasma

2001 ◽  
Vol 19 (1) ◽  
pp. 131-134
Author(s):  
C. M. Hall
Keyword(s):  
Reynolds Number ◽  
Electric Field ◽  
Electric Fields ◽  
Atmospheric Dynamics ◽  
Neutral Particles ◽  
Meteorology And Atmospheric Dynamics ◽  
Neutral Gas ◽  
Electric Fields And Currents ◽  
Induced Velocity ◽  
Gas Component

Abstract. The Reynolds number Re is used as a metric to assess whether or not a flow may contain turbulence. In a weakly ionised gas with an external electric field imposed, ions exert a drag on the neutral particles. Thus, a component of the neutral motion is attributable to the ion-drag. An analogy to Re has been proposed in which the ion-drag-induced velocity contribution to the neutral motion is used. This analogy thus represents the destabilising effect of the electric field on the neutral dynamics. Here quantisation of this proposed metric is investigated.Key words. Meteorology and atmospheric dynamics (turbulence) – Ionosphere (ionosphere-atmosphere interactions; electric fields and currents)

A theory of resonance rectification. The response of a spherical plasma probe to alternating potentials

1966 ◽  
Vol 290 (1421) ◽  
pp. 186-219 ◽  
Keyword(s):  
Boltzmann Equation ◽  
Electric Field ◽  
Linear Boltzmann Equation ◽  
Electron Trajectory ◽  
Neutral Particles ◽  
Alternating Electric Field ◽  
Probe System ◽  
Plasma Probe ◽  
Spherical Plasma ◽  
Steady Potential

It is shown theoretically how a conducting spherical probe behaves when it is immersed in a plasma, and has an alternating potential applied to it. The impedance of the probe and the rectified current which flows to it are derived as functions of the frequency of the applied potential. ‘Resonance’ phenomena are shown to occur at a frequency somewhat less than the plasma frequency. The Boltzmann-Vlasov equation, together with Maxwell's equations, are used to derive an integral equation governing the alternating electric field in the plasma. The steady potential in the sheath used in the time-dependent Boltzmann equation is taken from the work of Bernstein & Rabinowitz (1959). The alternating electric field is calculated on a computer, and from it, the impedance of the probe system is found as a function of frequency. The rectified electron current is obtained by a consideration of electron trajectory perturbations produced by the alternating electric field. This procedure is shown to be equivalent to an approximate solution of the non-linear Boltzmann equation. Collisions between electrons and heavy neutral particles are included through a simple relaxation term in the Boltzmann equation. External magnetic fields and uniform drifting of plasma past the probe are not considered.

The Effect of an External AC or DC Electric Field on Collision and Agglomeration in an Electrostatic Agglomerator

2012 ◽  
Vol 152-154 ◽  
pp. 997-1005
Author(s):  
Xiang Rong Zhang ◽  
Lian Ze Wang
Keyword(s):  
Statistical Analysis ◽  
Electric Field ◽  
A Priori ◽  
Charged Particles ◽  
Particle Charge ◽  
Neutral Particles ◽  
Flow Parameters ◽  
Ac Electric Field ◽  
Initial Charge ◽  
Dc Electric Field

This article simulated the collision and agglomeration between bipolarly charged particles in an electrostatic agglomerator. The EHD turbulent flow was solved and the flow parameters were extracted a priori. The particle initial charge was obtained by tracking particles with a certain diameter in the charging zone. When simulating collision and agglomeration in the agglomerating zone, the initial charge on a particle was sampled from the charge distribution by statistical analysis. The classical stochastic model for calculating collision between neutral particles was extended to calculate collision between charged particles, and the effect of particle charge on collision and agglomeration was embodied in the agglomeration criteria. The effect of an external DC and AC electric field on the collision and agglomeration was investigated.

Theorie der nichtkontrahierten positiven Säule unter dem Einfluß negativer Ionen

1962 ◽  
Vol 17 (10) ◽  
pp. 848-853 ◽  
Author(s):  
G. Albrecht ◽  
G. Ecker
Keyword(s):  
Differential Equations ◽  
Electric Field ◽  
Nuclear Physics ◽  
Numerical Evaluation ◽  
Positive Column ◽  
Negative Ions ◽  
Negative Ion ◽  
Algebraic Equations ◽  
Neutral Particles ◽  
Positive Ions

We consider a cylindrical positive column of a collision dominated plasma consisting of electrons, positive and negative ions and neutral particles. The qualities of such a column are deduced from an eigenvalue problem which follows from the application of the basic transport equations for such a plasma. The problem presents itself in the form of three simultaneous differential equations with boundary conditions. Applying a procedure which is known from nuclear physics as “Center-Wall-Approximation” we are able to reduce these three differential equations to three simultaneous algebraic equations. The numerical evaluation with the help of a digital computer produces the particle densities in the center of the discharge and the electric field as functions of the total current. The results are particularly interesting in the “subnormal” region of the discharge. With increasing current the subnormal decrease of the electric field is first interrupted due to the build up of the negative ion component which stops the formation of the ambipolar field. The subnormal field-decrease continues only at higher currents when the recombination of negative ions and positive ions remove the influence of the negative ion component. Due to these phenomena the subnormal features appear in two steps. The second one is delayed due to the described influence of the negative ions.

scholarly journals EFFECTIVE ACTION FOR FERMIONS WITH ANOMALOUS MAGNETIC MOMENT FROM FOLDY–WOUTHUYSEN TRANSFORMATION

2013 ◽  
Vol 28 (09) ◽  
pp. 1350029 ◽  
Author(s):  
A. BARDUCCI ◽  
R. GIACHETTI
Keyword(s):  
Partition Function ◽  
Electric Field ◽  
Closed Form ◽  
Magnetic Moment ◽  
Effective Action ◽  
Anomalous Magnetic Moment ◽  
Finite Temperature ◽  
Neutral Particles

In this paper, we calculate the effective action for neutral particles with anomalous magnetic moment in an external magnetic and electric field. We show that we can take advantage from the Foldy–Wouthuysen transformation (FWT) for such systems, determined in our previous works: indeed, by this transformation we have explicitly evaluated the diagonalized Hamiltonian, allowing to present a closed form for the corresponding effective action and for the partition function at finite temperature from which the thermodynamical potentials can be calculated.

First H+ Charge-Exchange Images in the Stim.

1976 ◽  
Vol 34 ◽  
pp. 504-505
Author(s):  
Wm. H. Escovitz ◽  
T. R. Fox ◽  
R. Levi-Setti
Keyword(s):  
Charge Exchange ◽  
Neutral Component ◽  
Channel Electron Multiplier ◽  
Electron Multiplier ◽  
Neutral Particles ◽  
Charged Beam ◽  
Scanning Transmission ◽  
Contrast Mechanism ◽  
Ion Microscopy ◽  
Beam Component

Charge exchange, the neutralization of ions by electron capture as the ions traverse matter, is a well-known phenomenon of atomic physics which is relevant to ion microscopy. In conventional transmission ion microscopes, the neutral component of the beam after it emerges from the specimen cannot be focused. The scanning transmission ion microscope (STIM) enables the detection of this signal to make images. Experiments with a low-resolution 55 kV STIM indicate that the charge-exchange signal provides a new contrast mechanism to detect extremely small amounts of matter. In an early version of charge-exchange detection (fig. 1), a permanent magnet installed between the specimen and the detector (a channel electron multiplier) sweeps the charged beam component away from the detector and allows only the neutrals to reach it. When the magnet is removed, both charged and neutral particles reach the detector.

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