共查询到20条相似文献,搜索用时 15 毫秒
1.
A. Yu. Romanov V. P. Silin S. A. Uryupin 《Journal of Experimental and Theoretical Physics》1997,84(4):687-693
We investigate the Weibel instability in a plasma with a nonstationary three-temperature electron distribution generated by
inverse bremsstrahlung of an intense elliptically polarized electromagnetic wave. We show that electron-ion collisions in
this strong high frequency field are simultaneously the cause of the development of the instability and the reason it is suppressed.
We find plasma and radiation parameters for which spontaneous quasistationary solenoidal electromagnetic fields can increase
by many times.
Zh. éksp. Teor. Fiz. 111, 1245–1257 (April 1997) 相似文献
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V. P. Krainov 《Journal of Experimental and Theoretical Physics》2003,96(3):430-435
The Weibel instability increment is analytically derived for plasma produced at the barrier-suppression ionization of atoms and atomic ions by a superintense femtosecond laser pulse. The cases of linear and circular polarization are considered. Relativistic effects are discussed. It is found that the instability increment is larger for the circular polarization than for the linear polarization. This increment can attain the plasma frequency. Barrier-suppression ionization decreases the increment compared with the case of tunneling ionization. Relativistic effects also decrease the value of the increment. Estimates of the produced maximum quasistatic magnetic field are given. 相似文献
4.
The general pattern of Weibel instability attributed to thermal anisotropic distribution in the electron component is obtained
using the technique of discrete simulation of self-consistent radiationless plasma. The dependences of the initial medium
anisotropy of the key instability parameters (the characteristic period and the maximum magnetic field energy) are investigated. 相似文献
5.
Romanov DV Bychenkov VY Rozmus W Capjack CE Fedosejevs R 《Physical review letters》2004,93(21):215004
The nonlinear evolution of the thermal Weibel instability is studied by using three-dimensional particle-in-cell simulations. After a fast saturation due to a reduction in the temperature anisotropy, the instability evolves to a quasistationary state which includes a single mode long wavelength helical magnetic field and a finite degree of temperature anisotropy. The nonlinear stability of this state is explained by periodic variations of the temperature anisotropy axis. At long time scales the magnetic field, wave number, and temperature anisotropy slowly evolve to the decreasing magnitudes. 相似文献
6.
An analytical solution is found to the vortex electron anisotropic hydrodynamic equations that describe the nonlinear evolution of the long-wavelength Weibel instability. The presented analytical approach shows that the long-wavelength Weibel instability saturates without a decrease in the temperature anisotropy in the single-mode regime due to the rotation of the anisotropy axes. The generated magnetic field is circular-polarized, and its amplitude varies periodically in time. 相似文献
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《等离子体物理论文集》2017,57(8):351-356
The Weibel instability plays an important role in stopping hot electrons and energy deposition mechanism in fast ignition of inertial fusion process. In this paper, the ion Weibel instability in counter propagating electron‐ion plasmas is investigate. The obtained results show that the growth rate of Weibel instability will be decreased about 40% with the anisotropy velocity as vxe = 2vze = 20; the ion density ratio, b = n 0i 1/n 0i 2, and density gradient, are increasing 50 and 90% respectively. The ion streaming in density gradient of dense plasma leads to increasing the Weibel instability growth rate and its amplification through ion streaming in the large wavenumber. The maximum unstable wavenumber has been decreased with decreasing the ion beam density ratio. For fixed ion density ratio, increasing 90% of the density gradient in the near of fuel plasma corona leads to reducing growth rate and unstable wavenumber about 43 and 42% respectively. 相似文献
10.
N. G. Zaki 《Pramana》2010,75(4):719-726
The Weibel instability (WI) of relativistic electron beam (REB) penetrating an infinite collisional plasma was studied in
the following models: (i) REB model, where the total equilibrium distribution function f
0($
\vec p
$
\vec p
) is approximated by nonrelativistic background electron and REB distribution functions and (ii) relativistic monoenergetic
beam (RMB) model, where f
0($
\vec p
$
\vec p
) is approximated by nonrelativistic background electrons and RMB distribution functions. 相似文献
11.
A study is made of the electromagnetic instability of a homogeneous plasma with a highly anisotropic one-or two-dimensional velocity distribution in the absence of a magnetic field. It is shown that, if the velocity distribution has a center of symmetry, then the plasma is always unstable against sufficiently long electromagnetic waves. This instability plays an important role in both laboratory plasma devices and cosmic rays. 相似文献
12.
We present three-dimensional, fully relativistic, fluid simulations of the dynamics of inhomogeneous counter streaming beams with the aim of understanding the magnetic structures that can be expected to form as a consequence of the development of the so-called Weibel instability. Ringlike structures in the transverse direction are generated as a consequence of the development of a spatially resonant mode. We describe the structures generated by beams of equal initial density and velocity and by a fast, less dense beam compensated by a slower, denser beam. We consider these two cases as schematic models of a laser produced beam propagating in a plasma with nearly equal density and in a plasma much denser than the injected beam. 相似文献
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Based on our work hep-ph/0510121, we discuss further the numerical study of classical SU(2) 3+1-D Yang-Mills equations for matter produced in a high-energy heavy-ion collision. The growth of the amplitude of fluctuations
as exp(Γ
) (where g
2μ is a scale arising from the saturation of gluons in the nuclear wave function) is shown to be robust over a wide range of
initial amplitudes that violate boost invariance. We argue that this growth is due to a non-Abelian Weibel instability, the
scale of which is set by a dynamically generated plasmon mass. We discuss the relation of Γ to the prediction from kinetic
theory. 相似文献
15.
S. V. Bulanov T. Zh. Esirkepov M. Kando H. Kiriyama K. Kondo 《Journal of Experimental and Theoretical Physics》2016,122(3):426-433
Physical processes in a plasma under the action of relativistically strong electromagnetic waves generated by high-power lasers have been briefly reviewed. These processes are of interest in view of the development of new methods for acceleration of charged particles, creation of sources of bright hard electromagnetic radiation, and investigation of macroscopic quantum-electrodynamical processes. Attention is focused on nonlinear waves in a laser plasma for the creation of compact electron accelerators. The acceleration of plasma bunches by the radiation pressure of light is the most efficient regime of ion acceleration. Coherent hard electromagnetic radiation in the relativistic plasma is generated in the form of higher harmonics and/or electromagnetic pulses, which are compressed and intensified after reflection from relativistic mirrors created by nonlinear waves. In the limit of extremely strong electromagnetic waves, radiation friction, which accompanies the conversion of radiation from the optical range to the gamma range, fundamentally changes the behavior of the plasma. This process is accompanied by the production of electron–positron pairs, which is described within quantum electrodynamics theory. 相似文献
16.
V. G. Novikov V. S. Vorob’ev L. G. D’yachkov A. F. Nikiforov 《Journal of Experimental and Theoretical Physics》2001,92(3):441-453
Radiative transfer in a nonequilibrium plasma in an external electric field is considered. The system of kinetic equations determining the populations of atomic levels is written taking into account the combination of collision and radiative processes and is solved together with the kinetic equation for photon of various frequencies, which are emitted and absorbed in the radiative transitions from the states of the continuous and discrete spectra. The shape of spectral lines is determined from the solution of the quantum-mechanical problem on the emission of an atom in the electric field of the plasma and an external magnetic field, taking the Doppler effect into consideration. The developed approach is used in the model calculation of radiative transfer under the conditions corresponding to the edge plasma in a tokamak, which is simulated by a homogeneous plane layer of a deuterium plasma. It is shown that the joint action of the external magnetic field and the electric plasma fields considerably affects the spectral and integrated characteristics of the radiation. 相似文献
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V. Yu. Mart’yanov V. V. Kocharovsky Vl. V. Kocharovsky 《Journal of Experimental and Theoretical Physics》2008,107(6):1049-1060
We have studied the features of formation and the possible stationary structures of a self-consistent magnetic field in a relativistic collisionless plasma, which are characteristic of a simple geometry of the Weibel instability that is well known in the nonrelativistic case. The universal condition is established, the growth rate is determined, and the criteria of saturation of the Weibel instability are analyzed for a broad class of anisotropic particle distribution functions (for definiteness, in application to an electron-positron plasma). A nonlinear equation of the Grad-Shafranov type describing the potential current structures is derived and its solutions are analytically studied. Special attention is paid to spatially harmonic, nonlinear current configurations with parameters determined by the properties of the initial homogeneous plasma subject to the Weibel instability. It is demonstrated that the magnetic field energy density in the obtained solutions (both harmonic and nonharmonic) can be comparable with the kinetic energy density of plasma particles. 相似文献
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A. S. Baranov 《Journal of Experimental and Theoretical Physics》2006,102(3):509-514
Electromagnetic instability of an unmagnetized homogeneous relativistic plasma with an anisotropic velocity distribution having a center of symmetry is analyzed. A stability criterion is derived for slowly varying long-wavelength perturbations. The criterion is formulated as a set of equalities that are not valid for ellipsoidal velocity distributions, but can be satisfied for other anisotropic distributions. The relativistic case is special only in that the rest mass is replaced with the relativistic one. 相似文献