Combined role of frequency variation and magnetic field on laser electron acceleration

2006 ◽  
Vol 13 (1) ◽  
pp. 013105 ◽  
Author(s):  
D. N. Gupta ◽  
H. Suk
2013 ◽  
Vol 31 (1) ◽  
pp. 91-106 ◽  
Author(s):  
A. V. Artemyev ◽  
M. Hoshino ◽  
V. N. Lutsenko ◽  
A. A. Petrukovich ◽  
S. Imada ◽  
...  

Abstract. In this paper, we consider electron acceleration in the vicinity of X-line and corresponding formation of energy spectra. We develop an analytical model including the effect of the electron trapping by electrostatic fields and surfing acceleration. Speiser, Fermi and betatron mechanisms of acceleration are also taken into account. Analytical estimates are verified by the numerical integration of electron trajectories. The surfing mechanism and adiabatic heating are responsible for the formation of the double power-law spectrum in agreement with the previous studies. The energy of the spectrum knee is about ~150 keV for typical conditions of the Earth magnetotail. We compare theoretical results with the spacecraft observations of electron double power-law spectra in the magnetotail and demonstrate that the theory is able to describe typical energy of the spectra knee. We also estimate the role of relativistic effects and magnetic field fluctuations on the electron acceleration: the acceleration is more stable for relativistic electrons, while fluctuations of the magnetic field cannot significantly decrease the gained energy for typical magnetospheric conditions.


2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).


2020 ◽  
Vol 75 (5) ◽  
pp. 381-391 ◽  
Author(s):  
Heinz-Jürgen Schmidt

AbstractWe investigate the motion of a classical spin processing around a periodic magnetic field using Floquet theory, as well as elementary differential geometry and considering a couple of examples. Under certain conditions, the role of spin and magnetic field can be interchanged, leading to the notion of “duality of loops” on the Bloch sphere.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1720
Author(s):  
Antonios Balassis ◽  
Godfrey Gumbs ◽  
Oleksiy Roslyak

We have investigated the α–T3 model in the presence of a mass term which opens a gap in the energy dispersive spectrum, as well as under a uniform perpendicular quantizing magnetic field. The gap opening mass term plays the role of Zeeman splitting at low magnetic fields for this pseudospin-1 system, and, as a consequence, we are able to compare physical properties of the the α–T3 model at low and high magnetic fields. Specifically, we explore the magnetoplasmon dispersion relation in these two extreme limits. Central to the calculation of these collective modes is the dielectric function which is determined by the polarizability of the system. This latter function is generated by transition energies between subband states, as well as the overlap of their wave functions.


Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1168
Author(s):  
Elena Belenkaya ◽  
Ivan Pensionerov

On 14 January 2008, the MESSENGER spacecraft, during its first flyby around Mercury, recorded the magnetic field structure, which was later called the “double magnetopause”. The role of sodium ions penetrating into the Hermean magnetosphere from the magnetosheath in generation of this structure has been discussed since then. The violation of the symmetry of the plasma parameters at the magnetopause is the cause of the magnetizing current generation. Here, we consider whether the change in the density of sodium ions on both sides of the Hermean magnetopause could be the cause of a wide diamagnetic current in the magnetosphere at its dawn-side boundary observed during the first MESSENGER flyby. In the present paper, we propose an analytical approach that made it possible to determine the magnetosheath Na+ density excess providing the best agreement between the calculation results and the observed magnetic field in the double magnetopause.


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