共查询到20条相似文献,搜索用时 15 毫秒
1.
A regime in which a uniformly magnetized plasma does not maximize the entropy and possibly becomes unstable to a spatial perturbation in the magnetic field is explored. The physical implication is considered in the context of current generation, magnetic field reconnection, and the dynamo effect. 相似文献
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The Rayleigh ‐ Taylor (RT) instability is investigated analytically in an inhomogeneous plasma in an external magnetic field. For the case of two distinct fluid layers separated by a sharp boundary and for a fluid of a continuously varying density, RT dispersion relations have been obtained and analyzed. Stability criteria of the excited modes are disscussed with respect to the mode propagation relative to the applied magnetic field. The magnetic field is found to act as a stabilizer up to a threshold value that can be determined from the dispersion relation. 相似文献
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In consideration of adiabatic dust charge variation, the
combined effect of the external magnetized field and the dust
temperature on head-on collision of the three-dimensional dust
acoustic solitary waves is investigated. By using the extended
Poincar\'e--Lighthill--Kuo method, the phase shifts and the
trajectories of two solitons after the collision are obtained. The
effects of the magnitude and the obliqueness of the external
magnetic field and the dust temperature on the
solitary wave collisions are discussed in detail. 相似文献
5.
Propagation properties of dust-electron-acoustic waves in weakly magnetized dusty nonthermal plasmas
The linear and nonlinear properties of dust-electron acoustic waves (DEAWs) propagating in magnetized, collisionless, dusty plasma system containing inertial cold electrons, Maxwellian hot electrons, nonthermal ions, and arbitrarily (positively or negatively) charged stationary dust are investigated. The reductive perturbation technique is employed to reduce the basic set of fluid equations to the modified Korteweg-de Vries equation or Ostrovsky's equation, which governs the dynamics of small amplitude DEAWs in a weakly magnetized dusty nonthermal plasma. The approximate analytical as well as numerical solutions reveal that the basic characteristics of DEA nonlinear structures are found to be significantly modified by the key plasma configuration parameters. It is found that the leading compressive or rarefactive solitary wave structure separates from a trailing wave packet during a considerable time under the influence of magnetic field-induced Lorentz force. 相似文献
6.
H. Himura H. Wakabayashi Y. Yamamoto A. Sanpei S. Masamune M. Isobe S. Okamura K. Matsuoka 《Hyperfine Interactions》2007,174(1-3):83-88
Experimental studies on nonneutral (pure electron) plasmas of finite temperature, trapped in helical closed magnetic surfaces
have been conducted. The helical electron plasmas are produced with thermal electrons launched from the outside of the last
closed flux surface (LCFS). About 150 μs after the electron injection, the plasmas reach equilibrium state. Around the LCFS, a steep gradient of plasma space potential
φ
s
is formed. The corresponding radial electric field is about 2.5 kV/m. On the other hand, around the magnetic axis of helical
magnetic surfaces, φ
s
is almost constant, indicating that there are little electrons there. The volume-averaged electron density is on the order
of 1013 m–3, smaller than the Brillouin density limit. The confinement time seems to be limited by a disruptive instability, and is so
far about 1.5 ms.
相似文献
7.
A two-dimensional electromagnetic Particle-in-Cell (PIC) simulation model is proposed to study the propagation of intense, ion beams with beaIn width wb small compared to the electron skin depth c/wpe through background plaslnas in tile presence of external applied magnetic fields. The effcctive eleetron gyrora,dius wge is found to be an important parameter for ion beam transport in the presence of magnetic fields,In the bealn regions, the background plasmas respond differently to the ion beanl of width wb〈wge and wb 〉 wge for the given magnetic field and beaan encrgy, For the case of beam width wb 〈 wge with relative weak external magnetic fiehts, the rotalion effects of plasma electrons a,re found to be signifieant and contributes to the signitica,nt enilaneeinent of the self electric and seif-magnetic fields. While for the ease of beam width wb 〉 wge with relative strong external magnetic fields, the rotation effects of plasma cleetrons are strongly inhibited and a, well neutraliza, tion of ion beam current can be found. Finally, the influences of diftiuent beam widths. beam energies and magnetic fields on the neutralization of ion bc, anl eurrellt are summarized for the eases of wb 〈 wge〈 c/wpe,wge 〈wb〈c/wbp and wb〈c/wpe〈wge. 相似文献
8.
V. A. Harutyunyan K. S. Aramyan H. Sh. Petrosyan G. H. Demirjian 《Physica E: Low-dimensional Systems and Nanostructures》2004,24(3-4):173-177
Single electronic states and direct optical transitions in the quantized spherical layer under the presence of static radial electric field are considered. In dipole approximation, the electrooptical absorption coefficient for interband and inband–intersubband direct transitions are calculated. The selection rules and explicit dependence of absorption coefficient from the field factor and geometrical sizes of the model are revealed. 相似文献
9.
The quantized states in a quantum-well semiconductor laser are simulated analytically by a magnetic field perpendicular to the well (infinite quasi-one-dimensional potential well) by deriving a close relationship for the magnetic-field strength which becomes a discrete quantity. 相似文献
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The collective behaviour of two‐dimensional (2D) liquid dusty plasmas under perpendicular magnetic fields is studied using Langevin dynamic simulations. Based on the positions and velocities of the simulated dust particles, the dynamic parameters of intermediate scattering functions and probability distribution functions are calculated. It is found that, under different 2D liquid dusty plasma conditions, the motion of individual dust particles tends to be more super‐diffusive under stronger perpendicular magnetic fields, well consistent with the previous finding using a different diagnostic technique. 相似文献
13.
M. S. Bawa'aneh 《等离子体物理论文集》2003,43(7):447-455
Stimulated Brillouin backscattering (SBBS) from a magnetized homogeneous plasma is investigated. Effect of a dc–magnetic field on SBBS growth rate is obtained and compared with that for non–magnetized plasmas. Numerical calculations show an increase in the instability growth rate for small magnetic fields, then a decrease in the growth rate as the magnetic field increases till a cut–off field is reached, beyond which SBBS is brought to stability. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
Zhi-Min Liao 《Physics letters. A》2010,374(33):3332-3334
Quantized two-terminal conductance plateaus in graphene were observed and were explained through the mechanism of different Landau level filling factors in inhomogeneous sample. Furthermore, the quantized conductance plateaus are different due to the difference of the carrier exchange through the graphene-substrate interface during the increasing and decreasing gate voltage-sweeps. 相似文献
15.
Magnetic field dependence of critical current for collapse of quantized Hall resistance Icr(collapse) and critical current for breakdown of dissipationless state Icr(breakdown) have been measured near the filling factor ν=4 of Landau levels in a GaAs/AlGaAs heterostructure Hall bar. The difference Icr(breakdown)−Icr(collapse) decreases against the increase and the decrease in ν from 4 and the critical behavior disappears outside of the region 3.85<ν<4.15. 相似文献
16.
On the basis of a quantum‐statistical approach to the electrical conductivity of nonideal plasmas we derive analytical results in the classical low‐density regime, in the degenerate Born limit, and for the contribution of the Debye‐Onsager relaxation effect. These explicit results are used to construct an improved interpolation formula of the electrical conductivity valid in a wide range of temperature and density which allows to compare with available experimental data of nonideal plasmas. 相似文献
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Giorgio Sonnino Alessandro Cardinali Gyorgy Steinbrecher Philippe Peeters Alberto Sonnino Pasquale Nardone 《Physics letters. A》2013
We derive the expression of the reference distribution function for magnetically confined plasmas far from the thermodynamic equilibrium. The local equilibrium state is fixed by imposing the minimum entropy production theorem and the maximum entropy (MaxEnt) principle, subject to scale invariance restrictions. After a short time, the plasma reaches a state close to the local equilibrium. This state is referred to as the reference state. The aim of this Letter is to determine the reference distribution function (RDF) when the local equilibrium state is defined by the above mentioned principles. We prove that the RDF is the stationary solution of a generic family of stochastic processes corresponding to an universal Landau-type equation with white parametric noise. As an example of application, we consider a simple, fully ionized, magnetically confined plasmas, with auxiliary Ohmic heating. The free parameters are linked to the transport coefficients of the magnetically confined plasmas, by the kinetic theory. 相似文献
20.
The consensus problem of second-order multi-agent systems with quantized link is investigated in this Letter. Some conditions are derived for the quantized consensus of the second-order multi-agent systems by the stability theory. Moreover, a result characterizing the relationship between the eigenvalues of the Laplacians matrix and the quantized consensus is obtained. Examples are given to illustrate the theoretical analysis. 相似文献