Effects of Electric Field on Primary Electron Trajectories in Miniature Gridded Ion Thrusters

2020 ◽  
Author(s):  
Juan-Pablo Almanza-Soto
1990 ◽  
Vol 45 (6) ◽  
pp. 763-770 ◽  
Author(s):  
U. Eberl

AbstractTwo-step sequential and unistep, superexchange primary electron transfer form primary radical pair states which differ in the direction and magnitude of their dipole moments as revealed in the X-ray structure analysis. The direction can be measured by the excitation anisotropy of electric field induced changes of the fluorescence yield. This method determines angles between the dipole of the primary radical pair and photoselected transition moments (in absorption and emission) of cofactors in the reaction centers. Transitions particularly favourable for discrimination between the two models of primary electron transfer are discussed.


1974 ◽  
Vol 52 (17) ◽  
pp. 1716-1722
Author(s):  
C. Berger ◽  
A. Adnot ◽  
J.-D. Carette

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.


2017 ◽  
Vol 95 (5) ◽  
pp. 507-513 ◽  
Author(s):  
De-hua Wang

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.


2018 ◽  
Vol 96 (9) ◽  
pp. 961-968
Author(s):  
De-hua Wang

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.


2002 ◽  
Vol 80 (6) ◽  
pp. 661-674
Author(s):  
K Raouadi ◽  
R Renoud ◽  
B Askri ◽  
B Yangui ◽  
Z Fakhfakh

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]


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