Pouvoir de transmission d'un système fente–fente en optique corpusculaire

1974 ◽  
Vol 52 (17) ◽  
pp. 1716-1722
Author(s):  
C. Berger ◽  
A. Adnot ◽  
J.-D. Carette
Keyword(s):  
Electric Field ◽  
Initial Conditions ◽  
Transmission Efficiency ◽  
Electron Trajectories ◽  
Transmission Properties ◽  
Slit System ◽  
Geometrical Dimensions

A method to calculate the transmission properties of a slit–slit system in electronic optics is described. It includes the following steps: calculation of the electric field between the electrodes, calculation of the electron trajectories point by point as a function of the initial conditions, and finally counting of the electrons which reach the second slit. Calculated and measured values of the transmission efficiency for usual geometrical dimensions of this system are presented.

Time-dependent electric field effect on the photodetachment dynamics of negative ions

2017 ◽  
Vol 95 (5) ◽  
pp. 507-513 ◽  
Author(s):  
De-hua Wang
Keyword(s):  
Electric Field ◽  
Probability Density ◽  
External Electric Field ◽  
Negative Ions ◽  
Time Dependent ◽  
Negative Ion ◽  
Electric Field Effect ◽  
Electron Trajectories ◽  
Oscillatory Pattern ◽  
Electron Probability Density

This paper addresses the photodetachment dynamics of a negative ion in a time-dependent electric field based on the semiclassical open-orbit theory. The photodetached electron probability density in a real time domain is studied in a gradient electric field for the first time. It is found that because of the influence of the gradient electric field, two or more electron trajectories can arrive at a given point on the detector, and the interference effect between these electron trajectories causes oscillatory structures in the electron probability density. Our calculation results suggest that when the external electric field changes very slowly with time, only two electron trajectories can arrive at a given point on the detector and the electron probability density exhibits a regular two-term oscillatory pattern. However, when the electric field changes quickly with time, four electron trajectories can reach the detector, which makes the oscillatory structures in the electron probability density become much more complicated. In addition, the electric field strength, photon energy, and the position of the detector can affect the electron probability density of this system sensitively. Our study provides a clear and intuitive picture for the photodetachment dynamics of the negative ion in the external electric field from a time-dependent viewpoint and may guide the future experimental researches on the photodetachment microscopy of negative ions in the time-dependent electric field.

scholarly journals Optical Transmission Properties and Electric Field Distribution of Interacting 2D Silver Nanorod Arrays

2008 ◽  
Vol 18 (7) ◽  
pp. 1075-1079 ◽  
Author(s):  
Paul R. Evans ◽  
René Kullock ◽  
William R. Hendren ◽  
Ron Atkinson ◽  
Robert J. Pollard ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Optical Transmission ◽  
Electric Field Distribution ◽  
Nanorod Arrays ◽  
Transmission Properties

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.

Contribution à l'étude des effets de charge sur l'émission X des matériaux isolants non métallisés

2002 ◽  
Vol 80 (6) ◽  
pp. 661-674
Author(s):  
K Raouadi ◽  
R Renoud ◽  
B Askri ◽  
B Yangui ◽  
Z Fakhfakh
Keyword(s):  
Electron Beam ◽  
Electric Field ◽  
Generating Function ◽  
Exposure Time ◽  
Primary Beam ◽  
X Rays ◽  
Electron Trajectories ◽  
Characteristic Lines

The presence of charges perturbs the X-microanalysis on insulator samples. Attempts to suppress these effects have been fruitless and a better understanding of the charge phenomenon is the only way to a clear interpretation of the results of a X-microanalysis. From a simulation of the charges implanted by an electron beam on an insulator target, we compute, as a fuction of the integrated dose, the characteristics of the emitted X-rays, such as the generating function ϕ (ρ z) or the intensity of the characteristic lines. We underline the role of the electric field on the primary beam and on the electron trajectories in the target. These results allow the analysis of experimentally measured X-rays. Our studies on the effects of the diameter of the probe and on the exposure time led us to establish the best conditions for the successful X-microanalysis of an insulator. [Journal translation]

scholarly journals Reduction in Human Interaction with Magnetic Resonant Coupling WPT Systems with Grounded Loop

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7253
Author(s):  
Xianyi Duan ◽  
Junqing Lan ◽  
Yinliang Diao ◽  
Jose Gomez-Tames ◽  
Hiroshi Hirayama ◽  
...  
Keyword(s):  
Electric Field ◽  
Human Body ◽  
High Efficiency ◽  
Transmission Efficiency ◽  
Human Interaction ◽  
Whole Body ◽  
Maximum Efficiency ◽  
Spatial Average ◽  
Power Transfer ◽  
Resonant Coupling

Wireless power transfer (WPT) systems have attracted considerable attention in relation to providing a reliable and convenient power supply. Among the challenges in this area are maintaining the performance of the WPT system with the presence of a human body and minimizing the induced physical quantities in the human body. This study proposes a magnetic resonant coupling WPT (MRC-WPT) system that utilizes a resonator with a grounded loop to mitigate its interaction with a human body and achieve a high-efficiency power transfer at a short range. Our proposed system is based on a grounded loop to reduce the leakage of the electric field, resulting in less interaction with the human body. As a result, a transmission efficiency higher than 70% is achieved at a transmission distance of approximately 25 cm. Under the maximum-efficiency conditions of the WPT system, the use of a resonator with a grounded loop reduces the induced electric field, the peak spatial-average specific absorption rate (psSAR), and the whole-body averaged SAR by 43.6%, 69.7%, and 65.6%, respectively. The maximum permissible input power values for the proposed WPT systems are 40 and 33.5 kW, as prescribed in the International Commission of Non-Ionizing Radiation Protection (ICNIRP) guidelines to comply with the limits for local and whole-body average SAR.

Time asymptotic statistics of the Vlasov equation

1977 ◽  
Vol 17 (3) ◽  
pp. 553-569 ◽  
Author(s):  
Georg Knorr
Keyword(s):  
Phase Space ◽  
Electric Field ◽  
Vlasov Equation ◽  
Reasonable Agreement ◽  
Initial Conditions ◽  
Velocity Space ◽  
Expectation Values ◽  
Asymptotic Statistics ◽  
Field Spectrum

A statistical description of the Vlasov equation is made possible by truncation of phase space in the velocity co-ordinates and writing the equation in terms of Fourier components in configuration and velocity space. Invariants of the resulting nonlinear turbulence equations are discussed. Expectation values and in particular an electric field spectrum of the form (β+ ακ2)-1 are derived. α and β are constants; α is always positive; β may be negative, depending on the initial conditions of the plasma. The spectrum is in reasonable agreement with available experiments and simulations.

Longitudinal sound waves in a collisionless, quasineutral plasma

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
J. J. Ramos
Keyword(s):  
Electric Field ◽  
Time Evolution ◽  
Initial Conditions ◽  
Normal Modes ◽  
Adjoint Problem ◽  
Plasma Phys ◽  
Landau Damping ◽  
Linear Perturbation ◽  
Sound Waves ◽  
Quasineutral Plasma

The time evolution of slow sound waves in a homogeneous, collisionless and quasineutral plasma, in particular their Landau damping, is investigated using the kinetic-magnetohydrodynamics formulation of Ramos (J. Plasma Phys. vol. 81, 2015 p. 905810325; vol. 82, 2016 p. 905820607). In this approach, the electric field is eliminated from a closed, hybrid fluid-kinetic system that ensures automatically the fulfilment of the charge neutrality condition. Considering the time dependence of a spatial-Fourier-mode linear perturbation with wavevector parallel to the equilibrium magnetic field, this can be cast as a second-order self-adjoint problem with a continuum spectrum of real and positive squared frequencies. Therefore, a conventional resolution of the identity with a continuum basis of singular normal modes is guaranteed, which simplifies significantly a Van Kampen-like treatment of the Landau damping. The explicit form of such singular normal modes is obtained, along with their orthogonality relations. These are used to derive the damped time evolution of the fluid moments of solutions of initial-value problems, for the most general kinds of initial conditions. The non-zero parallel electric field is not used explicitly in this analysis, but it is calculated from any given solution after the later has been obtained.

VIBRATIONS OF PIEZOELECTRIC LAYER of CLASS 6mm WITH RIGIDLY CLAMPED AND FREE EDGES UNDER INITIAL CONDITIONСS

2020 ◽  
Vol 54 (3 (253)) ◽  
pp. 146-152
Author(s):  
Mels V. Belubekyan ◽  
Ararat A. Papyan
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Piezoelectric Layer ◽  
Initial Conditions ◽  
The Other ◽  
Internal Electric Field ◽  
Free Edges

The paper considers the problem of vibration of a piezoelectric layer of the class $6~mm$ with initial conditions in the form of impact of an external electric field or displacement, when one edge is rigidly grounded and the other is free. The layer displacement and internal electric field are determined.

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