scholarly journals Influence of electron motion in target atom on stopping power for low-energetic ions

2012 ◽  
Vol 27 (2) ◽  
pp. 113-116
Author(s):  
Nenad Stevanovic ◽  
Vladimir Markovic ◽  
Momir Arsenijevic ◽  
Dragoslav Nikezic

In this paper the stopping power was calculated, representing the electrons of the target atom as an assembly of quantum oscillators. It was considered that the electrons in the atoms have some velocity before interaction with the projectile, which is the main contribution of this paper. The influence of electron velocity on stopping power for different projectiles and targets was investigated. It was found that the velocity of the electron stopping power has the greatest influence at low energies of the projectile.

1992 ◽  
Vol 2 (9) ◽  
pp. 1803-1810 ◽  
Author(s):  
Y. Boudouma ◽  
A. C. Chami ◽  
H. Beaumevieille ◽  
M. Boudjema
Keyword(s):  

2001 ◽  
Vol 285 (3-4) ◽  
pp. 183-190 ◽  
Author(s):  
Yuan-Hong Song ◽  
You-Nian Wang ◽  
Z.L. Mišković

2018 ◽  
Vol 29 (1) ◽  
pp. 155
Author(s):  
Ishraq Ahmed Shakir

The Barkas effect came because of target electrons due to responding to the approaching particle and slightly changing the orbits before occur from interaction of energy loss (denominate target polarization). At high energies (above 20 10   insignificant because the ion moving too fast to cause initial motion the target electrons where at low energies  the Barkas effect is investigated.[1].In present work stopping power, Barkas effects, Bloch and shell corrections have been investigated for the interaction of protons and Helium ions in DNA and liquid water. Braggs rule has been used on each element in DNA and liquid water to determine the parameters correction in Bethe-Bloch formula using Ziegler’s semi-empirical formula [1]. 


Big amount of works deals with solution of differential equations, associated with electron motion in electromagnetic field, using methods of classical electrodynamics. Solution of equation of an electron motion in TEM wave field is interesting task because this equation is mathematical model of big number of wave processes, which are used for researches of different physical processes. The proposed work dedicated to finding the solution for the equation of an electron motion in TEM wave field in laboratory system of coordinates using the theory of almost periodic functions. The work demonstrates that the projections of electron velocity on coordinate axis conform to the wave equation, and, consequently, could be expanded into generalized Fourier series at any value of the wave and electron parameters. In the present work, the formulas received before for electron velocity projection on coordinate axis, are transformed to a well-behaved form, and are broken down into non-perfect generalized Fourier series. Non-perfect Fourier series for projections of electron velocity on coordinate axis are found by means of plotting of complex series, which are called in the theory of almost periodic functions as ”closure of set”. For approximate computation of electron velocity it is possible to restrict oneself to finite number of series harmonics. Application of method of electron velocity components transformation into generalized Fourier series made it possible to find in electron velocity components series terms, which do not depend on time and are equal to average magnitudes of the respective values. Electron velocity components present functions of initial magnitudes of electron velocity components, of generalized phase magnitude and of the wave parameters. Initial magnitudes are not preset at random, but calculated from the equations, the type of which is specified in the work. Electron trajectory in coordinate space is calculated by integrating of the respective expressions for velocity projections on coordinate axis. For demonstration purpose the work deals with the example of electron dynamics in wave polarization plane with consideration of only permanent addends and first harmonics of Fourier series for electron velocity projections on coordinate axis. An approximate solution of the equations of electron dynamics in the plane of polarization of the wave is given. Solution for the equation of electron motion in TEM wave field in the laboratory coordinate system using the theory of almost periodic functions made it possible to solve the problem of dynamics of relativistic electron in the field of progressing TEM wave. It made it possible to demonstrate the availability of time-independent summands in the value of the speed of the electron, which moves in TEM wave. A very important circumstance is also the fact, that the theory makes it possible to investigate electron dynamics depending on the original wave intensity.


Author(s):  
Radoslav Bučík

Impulsive solar energetic particle (ISEP) events show peculiar elemental composition, with enhanced 3He and heavy-ion abundances, markedly different from our Solar System composition. Furthermore, the events are characterized by a wide variety of energy spectral shapes from power laws to rounded spectra toward the low energies. Solar sources of the events have been firmly associated with coronal jets. Surprisingly, new observations have shown that events are often accompanied by so-called extreme-ultraviolet (EUV) coronal waves–a large-scale phenomenon compared to jets. This paper outlines the current understanding of the linkage of EUV waves with jets and energetic ions in ISEP events.


2020 ◽  
Author(s):  
Zhihong Zhong ◽  
Daniel B. Graham ◽  
Yuri V. Khotyaintsev ◽  
Meng Zhou ◽  
Rongxin Tang ◽  
...  

<p>Plasma waves are one of the important products of the magnetic reconnection process.  Plasma waves can produce particle heating, diffusion, and anomalous effects, which can potentially affect magnetic reconnection. We investigate the evolution and properties of plasma waves during a multiple X-line reconnection event at the magnetopause using measurements from the Magnetospheric Multiscale (MMS) mission. Both whistler waves and large-amplitude electrostatic waves were observed around the reconnecting current sheet. In these regions, the electron velocity distribution functions consist of a combination of a cold beam at low energies with an anisotropic population or a loss-cone at high energies. The electrostatic waves corresponded to regions where the cold beams are accelerated, while the whistlers corresponded to regions with significant anisotropies or loss cones. When the cold beams were accelerated to higher energies, the whistlers disappeared since the anisotropy or loss-cone distributions became less apparent. These results present the detailed evolution of the plasma waves reflecting the electron dynamics during magnetic reconnection.</p>


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