scholarly journals Stability and instability of relativistic electrons in classical electromagnetic fields

1997 ◽  
Vol 89 (1-2) ◽  
pp. 37-59 ◽  
Author(s):  
Elliott H. Lieb ◽  
Heinz Siedentop ◽  
Jan Philip Solovej
Keyword(s):  
Electromagnetic Fields ◽  
Relativistic Electrons ◽  
Stability And Instability

scholarly journals Positronia’ Clouds in Universe

Universe ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 42
Author(s):  
Igor M. Dremin
Keyword(s):  
Electromagnetic Fields ◽  
Cross Sections ◽  
Galactic Center ◽  
Heavy Ion ◽  
Strong Interactions ◽  
Relativistic Electrons ◽  
Heavy Nuclei ◽  
Nuclear Collisions ◽  
Electron Positron ◽  
Low Mass

The intense emission of 511 keV photons from the Galactic center and within terrestrial thunderstorms is attributed to the formation of parapositronia clouds. Unbound electron–positron pairs and positronia can be created by strong electromagnetic fields produced in interactions of electrically charged objects, in particular, in collisions of heavy nuclei. Kinematics of this process favors abundant creation of the unbound electron–positron pairs with very small masses and the confined parapositronia states which decay directly to two 511 keV quanta. Therefore, we propose to consider interactions of electromagnetic fields of colliding heavy ions as a source of low-mass pairs which can transform to 511 keV quanta. Intensity of their creation is enlarged by the factor Z4 (Z is the electric charge of a heavy ion) compared to protons with Z = 1. These processes are especially important at very high energies of nuclear collisions because their cross sections increase proportionally to cube of the logarithm of energy and can even exceed the cross sections of strong interactions which may not increase faster than the squared logarithm of energy. Moreover, production of extremely low-mass e+e−-pairs in ultraperipheral nuclear collisions is strongly enhanced due to the Sommerfeld-Gamow-Sakharov (SGS) factor which accounts for mutual Coulomb attraction of non-relativistic electrons to positrons in case of low pair-masses. This attraction may lead to their annihilation and, therefore, to the increased intensity of 511 keV photons. It is proposed to confront the obtained results to forthcoming experimental data at NICA collider.

Instrumentation for detecting channelling radiation in the high-voltage electron microscope

1983 ◽  
Vol 41 ◽  
pp. 318-319
Author(s):  
J. H. Butler ◽  
C. J. Humphreys
Keyword(s):  
Monochromatic Light ◽  
Incident Beam ◽  
Laboratory Frame ◽  
Relativistic Electrons ◽  
Voltage Electron ◽  
Dipole Emission ◽  
Sinusoidal Oscillations ◽  
Pass Through ◽  
Incident Beam Energy ◽  
Increasing Function

Electromagnetic radiation is emitted when fast (relativistic) electrons pass through crystal targets which are oriented in a preferential (channelling) direction with respect to the incident beam. In the classical sense, the electrons perform sinusoidal oscillations as they propagate through the crystal (as illustrated in Fig. 1 for the case of planar channelling). When viewed in the electron rest frame, this motion, a result of successive Bragg reflections, gives rise to familiar dipole emission. In the laboratory frame, the radiation is seen to be of a higher energy (because of the Doppler shift) and is also compressed into a narrower cone of emission (due to the relativistic “searchlight” effect). The energy and yield of this monochromatic light is a continuously increasing function of the incident beam energy and, for beam energies of 1 MeV and higher, it occurs in the x-ray and γ-ray regions of the spectrum. Consequently, much interest has been expressed in regard to the use of this phenomenon as the basis for fabricating a coherent, tunable radiation source.

Effect of pulsed electromagnetic fields on maturation of regenerate bone in a rabbit limb lengthening model

2005 ◽  
Vol 24 (1) ◽  
pp. 2-10 ◽  
Author(s):  
Kenneth F. Taylor ◽  
Nozumu Inoue ◽  
Bahman Rafiee ◽  
John E. Tis ◽  
Kathleen A. McHale ◽  
...  
Keyword(s):  
Electromagnetic Fields ◽  
Limb Lengthening ◽  
Pulsed Electromagnetic Fields ◽  
Pulsed Electromagnetic
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