scholarly journals Electron acceleration by high current-density relativistic electron bunch in plasmas

2007 ◽  
Vol 25 (2) ◽  
pp. 313-319 ◽  
Author(s):  
C.T. ZHOU ◽  
M.Y. YU ◽  
X.T. HE
Keyword(s):  
Relativistic Electron ◽  
Electron Bunch ◽  
High Current Density ◽  
Electron Acceleration ◽  
High Energy ◽  
Energy Gain ◽  
Small Scale ◽  
High Current ◽  
Particle In Cell ◽  
Very High Energy

Electron acceleration by a short high-current relativistic electron bunch (EB) in plasmas at three characteristic densities is studied by particle-in-cell simulation. It is found that if the EB is appropriately matched to the background plasma, the blowout space-charge field of the EB can accelerate the trailing bunch electrons at very high energy gain rate. This high energy gain, as well as the large-amplitude wakefield, the turbulent small-scale electron plasma waves, and the formation of large current peaks, are studied. The evolution of the EB, its blowout field, and other related parameters are shown to be self-similar.

scholarly journals Small-Scale Dissipative Processes in Stellar Atmospheres

1980 ◽  
Vol 5 ◽  
pp. 581-590
Author(s):  
J. W. Leibacher ◽  
R. F. Stein
Keyword(s):  
Velocity Field ◽  
Energy Flux ◽  
Thermal Energy ◽  
Solar Flares ◽  
Acoustic Waves ◽  
High Current Density ◽  
Stellar Atmospheres ◽  
Small Scale ◽  
High Current ◽  
Strong Magnetic Fields

AbstractThe outer atmospheres of stars must be heated by some non-thermal energy flux to produce chromospheres and coronae. We discuss processes which convert the non-thermal energy flux of organized, macroscopic motions into random, microscopic (thermal) motions. Recent advances in our description of the chromosphere velocity field suggest that the acoustic waves observed there transmit very little energy, and hence are probably incapable of heating the upper chromosphere and corona. The apparent failure of this long held mechanism and the growing appreciation of the importance of strong magnetic fields in the chromosphere and corona have led to hypotheses of heating by the dissipation of currents (both oscillatory and quasi-steady). This follows discoveries in laboratory and ionospheric plasmas and work on solar flares, that instabilities can concentrate currents into thin high current density filaments where they dissipate rapidly.

scholarly journals Self-magnetic field effects on laser-driven wakefield electron acceleration in axially magnetized ion channel

2020 ◽  
Vol 38 (4) ◽  
pp. 222-228
Author(s):  
A. Kargarian ◽  
K. Hajisharifi
Keyword(s):  
Magnetic Field ◽  
Ion Channel ◽  
Relativistic Electron ◽  
Electron Energy ◽  
Plasma Wave ◽  
Electron Acceleration ◽  
Energy Gain ◽  
The Self ◽  
Magnetic Field Effects ◽  
Field Effects

AbstractIn this paper, we have investigated the relativistic electron acceleration by plasma wave in an axially magnetized plasma by considering the self-magnetic field effects. We show that the optimum value of an external axial magnetic field could increase the electron energy gain more than 40% than that obtained in the absence of the magnetic field. Moreover, results demonstrate that the self-magnetic field produced by the electric current of the energetic electrons plays a significant role in the plasma wakefield acceleration of electron. In this regard, it will be shown that taking into account the self-magnetic field can increase the electron energy gain up to 36% for the case with self-magnetic field amplitude Ωs = 0.3 and even up to higher energies for the systems containing stronger self-magnetic field. The effects of plasma wave amplitude and phase, the ion channel field magnitude, and the electron initial kinetic energy on the acceleration of relativistic electron have also been investigated. A scaling law for the optimization of the electron energy is eventually proposed.

Formation of nanophases in a Cu–Zn alloy under high current density electropulsing

2000 ◽  
Vol 15 (10) ◽  
pp. 2065-2068 ◽  
Author(s):  
W. Zhang ◽  
M. L. Sui ◽  
K. Y. Hu ◽  
D. X. Li ◽  
X. N. Guo ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
High Energy ◽  
Coarse Grained ◽  
High Current ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Before And After ◽  
Electropulsing Treatment ◽  
Zn Alloy

The microstructure of samples before and after a high current density electropulsing treatment was characterized by using high-resolution transmission electron microscopy. It has been found that in the coarse-grained Cu–Zn alloy subjected to the electropulsing treatment, two nanophases were formed, α–Cu(Zn) and β′–(CuZn), the average grain size of which is about 11 nm. A possible mechanism for the formation of nanophases was proposed. The experimental results indicated that electropulsing, as an instantaneous high-energy input, plays an important role in the nonequilibrium microstructural changes in materials and serves as a potential processing approach to synthesize nanostructured materials.

scholarly journals Lithium Metal Anode for High-Power and High-Capacity Rechargeable Batteries

2021 ◽  
Vol 03 (02) ◽  
pp. 1-1
Author(s):  
Nobuyuki Imanishi ◽  
◽  
Daisuke Mori ◽  
Sou Taminato ◽  
Yasuo Takeda ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Specific Capacity ◽  
High Capacity ◽  
High Energy ◽  
Rechargeable Batteries ◽  
High Energy Density ◽  
Current Status ◽  
High Current ◽  
Lithium Metal

Because lithium metal exhibits high specific capacity and low potential, it is the best candidate for fabricating anodes for batteries. Rechargeable batteries fabricated using lithium anode exhibit high capacity and high potential cathode; these can be potentially used to fabricate high energy density batteries (>500 Wh kg–1) that can be used for the development of next-generation electric vehicles. However, the formation and growth of lithium dendrites and the low coulombic efficiency recorded during lithium plating and stripping under conditions of high current density hinder the use of lithium metal as the anodic material for the development of practical rechargeable batteries. In this short review, we outline the current status and prospects of lithium anodes for fabricating batteries in the presence of non-aqueous liquid, polymer, and solid electrolytes operated under conditions of high current density.

scholarly journals Stochastic Electron Acceleration by Temperature Anisotropy Instabilities under Solar Flare Plasma Conditions

2022 ◽  
Vol 924 (2) ◽  
pp. 52
Author(s):  
Mario Riquelme ◽  
Alvaro Osorio ◽  
Daniel Verscharen ◽  
Lorenzo Sironi
Keyword(s):  
Critical Role ◽  
Electron Acceleration ◽  
High Energy ◽  
Temperature Anisotropy ◽  
Particle In Cell ◽  
Long Term Effect ◽  
Spectral Break ◽  
Cell Plasma ◽  
Electron Magnetic Moment

Abstract Using 2D particle-in-cell plasma simulations, we study electron acceleration by temperature anisotropy instabilities, assuming conditions typical of above-the-loop-top sources in solar flares. We focus on the long-term effect of T e,⊥ > T e,∥ instabilities by driving the anisotropy growth during the entire simulation time through imposing a shearing or a compressing plasma velocity (T e,⊥ and T e,∥ are the temperatures perpendicular and parallel to the magnetic field). This magnetic growth makes T e,⊥/T e,∥ grow due to electron magnetic moment conservation, and amplifies the ratio ω ce/ω pe from ∼0.53 to ∼2 (ω ce and ω pe are the electron cyclotron and plasma frequencies, respectively). In the regime ω ce/ω pe ≲ 1.2–1.7, the instability is dominated by oblique, quasi-electrostatic modes, and the acceleration is inefficient. When ω ce/ω pe has grown to ω ce/ω pe ≳ 1.2–1.7, electrons are efficiently accelerated by the inelastic scattering provided by unstable parallel, electromagnetic z modes. After ω ce/ω pe reaches ∼2, the electron energy spectra show nonthermal tails that differ between the shearing and compressing cases. In the shearing case, the tail resembles a power law of index α s ∼ 2.9 plus a high-energy bump reaching ∼300 keV. In the compressing runs, α s ∼ 3.7 with a spectral break above ∼500 keV. This difference can be explained by the different temperature evolutions in these two types of simulations, suggesting that a critical role is played by the type of anisotropy driving, ω ce/ω pe, and the electron temperature in the efficiency of the acceleration.

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