scholarly journals Electrostatic and electromagnetic waves driven by current free electron beam instability: Effects of positron, background composition, and ion-to-electron mass ratio

AIP Advances ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 075112
Author(s):  
C.-S. Jao ◽  
L.-N. Hau
Keyword(s):  
Electron Beam ◽  
Free Electron ◽  
Electromagnetic Waves ◽  
Electron Mass ◽  
Beam Instability ◽  
Mass Ratio

scholarly journals The Effect of Ion-to-Electron Mass Ratio on the Electron Beam-Plasma Interaction

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Maryamsadat Rafiei ◽  
Mostafa Sahrai ◽  
Mahboub Hosseinpour ◽  
Abdolrasoul Esfandyari-Kalejahi
Keyword(s):  
Electron Beam ◽  
Acoustic Waves ◽  
Electromagnetic Waves ◽  
Second Harmonic ◽  
Coupling Mechanism ◽  
Electron Mass ◽  
Mass Ratio ◽  
Electron Stream ◽  
Beam Plasma ◽  
Electron Beam Plasma

Two-dimensional electromagnetic particle-in-cell simulations are carried out to investigate the effect of ion-to-electron mass ratio on the evolution of warm electron beam-plasma instability. Four cases are considered: A: mi/me = 0 (two-electron stream instability); B: mi/me = 1 (pair plasma); C: mi/me = 100; and D: mi/me = 1000. It is shown that the generation of Langmuir waves in the fundamental mode of electron plasma frequency and the subsequent dynamics of large-amplitude solitons are not affected by the ion species. However, it determines the decay process of solitons and the excitation of electromagnetic waves in the second harmonic. In the first two cases, mi/me = 0 and 1, there is no sign of emission in the second harmonic, while the strongest emission in the second harmonic is found for the case of largest mass ratio, mi/me = 1000. This confirms the two-step wave-wave coupling mechanism for the generation of second harmonic electromagnetic waves, which requires the excitation of ion-acoustic waves in the first step. Moreover, the dispersion diagrams of all excited waves are presented.

scholarly journals The Uehling correction to the energy levels in a pionic atom

2006 ◽  
Vol 84 (2) ◽  
pp. 107-113 ◽  
Author(s):  
S G Karshenboim ◽  
E Yu. Korzinin ◽  
V G Ivanov
Keyword(s):  
Free Electron ◽  
Vacuum Polarization ◽  
Energy Levels ◽  
Analytic Form ◽  
Electron Mass ◽  
Mass Ratio ◽  
Pionic Atom ◽  
Closed Analytic Form

We consider a correction to energy levels in a pionic atom induced by the Uehling potential, i.e., by a free electron vacuum-polarization loop. The calculation is performed for circular states (l = n–1). The result is obtained in a closed analytic form as a function of Zα and the pion-to-electron mass ratio. Certain asymptotics of the result are also presented.PACS Nos.: 12.20.Ds, 36.10.Gv

Emission of Electromagnetic Waves from Langmuir Waves Generated by Electron Beam Instability in Pair Plasmas

1999 ◽  
Vol 68 (2) ◽  
pp. 471-477 ◽  
Author(s):  
Daisuke Gyobu ◽  
Jun-ichi Sakai ◽  
Masanori Eda ◽  
Torsten Neubert ◽  
Mitsuhiro Nambu
Keyword(s):  
Electron Beam ◽  
Electromagnetic Waves ◽  
Beam Instability ◽  
Langmuir Waves

scholarly journals New Limit on Space-Time Variations in the Proton-to-Electron Mass Ratio from Analysis of Quasar J110325-264515 Spectra

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 344
Author(s):  
T. D. Le
Keyword(s):  
Fine Structure ◽  
Structure Constant ◽  
Space Time ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Mass Ratio ◽  
Quasar Spectra ◽  
Time Variations ◽  
Using Data ◽  
The Universe

Astrophysical tests of current values for dimensionless constants known on Earth, such as the fine-structure constant, α , and proton-to-electron mass ratio, μ = m p / m e , are communicated using data from high-resolution quasar spectra in different regions or epochs of the universe. The symmetry wavelengths of [Fe II] lines from redshifted quasar spectra of J110325-264515 and their corresponding values in the laboratory were combined to find a new limit on space-time variations in the proton-to-electron mass ratio, ∆ μ / μ = ( 0.096 ± 0.182 ) × 10 − 7 . The results show how the indicated astrophysical observations can further improve the accuracy and space-time variations of physics constants.

scholarly journals Delay-detune scan for longitudinal electron beam characterization at free-electron lasers

2020 ◽  
Vol 23 (12) ◽  
Author(s):  
Svitozar Serkez ◽  
Gianluca Geloni ◽  
Marc Guetg ◽  
Vitali Kocharyan ◽  
Shan Liu ◽  
...  
Keyword(s):  
Electron Beam ◽  
Free Electron ◽  
Free Electron Lasers ◽  
Beam Characterization
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