Plasma Induced Wiggler Magnetic Field in a Cavity: II-FDTD Method for a Switched Lossy Plasma

The transformation of an elliptically polarized standing source wave in a cavity by a lossy plasma created with arbitrary space and time profiles is numerically computed using the Finite-Difference Time-Domain (FDTD) method. The FDTD equations derived are shown to be very robust and results are presented for several practical scenarios.     

Collisionless Plasma Expansion in the Presence of a Dipole Magnetic Field

The collisionless interaction of an expanding high–energy plasma cloud with a magnetized background plasma in the presence of a dipole magnetic field is examined in the framework of a 2D3V hybrid (kinetic ions and massless fluid electrons) model. The retardation of the plasma cloud and the dynamics of the perturbed electromagnetic fields and the background plasma are studied for high Alfvén–Mach numbers using the particle–in–cellmethod. It is shown that the plasma cloud expands excluding the ambient magnetic field and the background plasma to form a diamagnetic cavity which is accompanied by the generation of a collisionless shock wave. The energy exchange between the plasma cloud and the background plasma is also studied and qualitative agreement with the analytical model suggested previously is obtained (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Longitudinal Susceptibility of S = 1/2 Low-Dimensional Heisenberg Ferromagnet in a Magnetic Field

Longitudinal susceptibility of the spin-1/2 low-dimensional Heisenberg ferromagnet in a magnetic field, is studied by the Green's function method within the random phase approximation. The static and dynamic longitudinal susceptibilities are calculated in the low- and high-field regions. Power laws for the position and height of the static susceptibility maximum are shown not to support the predictions of Landau theory.     

自生磁场对相对论谐波辐射的影响

分析了自生磁场对相对论谐波辐射的影响，得出结论，自生磁场对强激光在欠稠密等离子 产生的相对论相干波辐射有重要作用，自生磁场激发偶次谐波辐射，并对奇次谐波辐射产生影响，对二次，三次谐波作了详细分析，发现，自生磁场激发二次谐波辐射，而对三次谐波辐射有削弱作用，并且它还使谐波的失相时间延长。     

Calculation of Dielectric Function of a Quark-Gluon Plasma

With the hard thermal loop （HTL） resummation technique, we calculate the dielectric function excited by hard gluon in quark-gluon plasma （QCP）. We find that in a section of the space-like region po/p ∈ [0.78, 0.95], there are two extremum structures on the dielectric function curve, while the dielectric function in the HTL approximation decreases monotonously without these properties. Through the analyses of the imaginary part of the dielectric function, we conclude that the character of the dielectric function in this region reflects effects of the Landau damping.     

On the Symmetrical Modes in a Cylindrical Nonisothermal Plasma Waveguide in a Finite External Magnetic Field

A MHD, symmetrical, nonpotential waves in nonuniform, cylindrical nonisothermal plasma waveguide placed in a finite external magnetic field H ₀ directed along the axis of the waveguide are considered. The thermal velocity of the electrons ν_Te = (kT_e/m_e)^1/2 (k — Boltzman's constant, T_e — temperature, m_e — mass of the electron) is not neglected. As a consequence we obtain one more solution in the plasma region and respectively an equation of third power on χ² — the transverse wave number. As far as we know only equations of second power on χ² describing non-potential waves are investigated. The dispersion equations are written solving the boundary-value problem. Our results coincide with well known ones when the electron thermal velocity tends to zero.     

Simulation of the External Magnetic Field Effect on Fusion Plasma

Issues of numerical simulation of an experiment on compression and heating of a target in a magnetic field are discussed. It is found that the applied magnetic field predominantly increases the plasma lifetime and plasma jet characteristics (velocity, Mach number, density, etc.). An analysis of the effects of the application of an external magnetic field on the behavior of plasma-driven guns (plasma jets) and laser-driven systems (laser beams) is carried out. Thermodynamic questions in simulation of experiments on magnetic inertial synthesis are touched upon.     

Finite Time Approach to Equilibrium in a Fractional Brownian Velocity Field

We consider the solution of the equation r(t) = W(r(t)), r(0) = r ₀ > 0 where W(⋅) is a fractional Brownian motion (f.B.m.) with the Hurst exponent α∈ (0,1). We show that for almost all realizations of W(⋅) the trajectory reaches in finite time the nearest equilibrium point (i.e. zero of the f.B.m.) either to the right or to the left of r ₀, depending on whether W(r ₀) is positive or not. After reaching the equilibrium the trajectory stays in it forever. The problem is motivated by studying the separation between two particles in a Gaussian velocity field which satisfies a local self-similarity hypothesis. In contrast to the case when the forcing term is a Brownian motion (then an analogous statement is a consequence of the Markov property of the process) we show our result using as the principal tools the properties of time reversibility of the law of the f.B.m., see Lemma 2.4 below, and the small ball estimate of Molchan, Commun. Math. Phys. 205 (1999) 97–111.     

Screening Breakdown in a Plasma by Two Laser Fields and Strong DC Magnetic Field

The effective static dielectric constant of an electron plasma system in the simultaneous presence of two electromagnetic waves and a strong DC magnetic field is calculated. It is found that as the difference Δω of the two electromagnetic wave frequencies matches the plasma frequency ω_ρ a breakdown in screening occurs thereby increasing the plasma heating rate via the external fields due to inverse Bremmstrahlung. An application is made by considering the typical parameters of a hot plasma. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

在自由空间里的运动磁场和时变磁场都没有产生电场

在自由空间里,磁场运动时没有产生电场、时变磁场的辐射运动也没有产生电场.故,“磁生电”的真实原因是：金属电子在广义洛伦兹磁力的作用下的流动而形成Ic,却不是法拉第-麦克斯韦-爱因斯坦在自由空间里虚构的位移电流Id.基于唯物主义自然观,联系电磁感应的物质是洛伦兹的金属电子,却不是法拉第-麦克斯韦-爱因斯坦的真空以太.     

A Note on the Time Development of Quantum Lattice Systems

The time development of quantum lattice systems is studied without any restrictions on the growth condition of the potential . A thermodynamic limit of quantum Gibbs state, a *-algebra and an automorphism group _t for which is a KMS state are constructed.     

Effect of Longitudinal Magnetic Field on the Spread of Erosion Laser Plasma in Vacuum and Generation of Plasma Magnetic Fields

Dynamics of erosion laser plasma in vacuum and generation of magnetic field by moving plasma (in particular, in the presence of external static magnetic field oriented along the direction of plasma motion) are experimentally studied. Radial confinement of the spread of plasma, a decrease in the electrification of target upon plasma formation, and an increase in the induction of the plasma magnetic field by a factor of 10–15 are revealed at an induction of the external magnetic field of about 0.35 T. Dependences of the induction of the plasma magnetic field on the power density of the laser radiation are determined for the above regimes.     

Emission Intensity Enhancement of DC Arc Plasma Induced by External Oscillating Magnetic Field

Direct current (dc) arc plasma with continuous aerosol supply was coupled with an external oscillatingmagnetic field of a few tens of mT and a frequency of up to 1 kHz. Such configuration was used to alter the plasma‐related radiative properties. The magnetic field was oriented perpendicularly to the electric field in the plasma and forced the arc column to oscillate as a whole with respect to the surrounding atmosphere. The magnitude of the appliedmagnetic.eld controls the amplitude of the oscillatory motion. Several parameters that can contribute to the radiative properties of the plasma were investigated (arc current, composition of aerosol introduced into the plasma, amplitude and frequency of the magnetic field applied). Spectral emission from different zones of the plasma column was measured by optical emission spectroscopy (OES). In comparison to steady‐state plasma, the applied magnetic field induces an intensity enhancement of emission of the most analytes considered. The intensity enhancement is strongly affected by the amplitude and frequency of plasma column oscillations, i.e. by plasma column velocity. Also, intensity enhancement depends on the plasma zone observed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Self-Consistent Model of an RF Inductive Plasma Source Located in an External Magnetic Field

A theory for calculating plasma resistance and the RF power absorbed in an inductive plasma source is developed. Conditions are determined under which most of the power is absorbed by the plasma. It is shown that these conditions correspond to excitation of spatial waves (oblique Langmuir wave and helicon). A simple self-consistent model of the plasma source is proposed, which explains the specific features of the plasma sources experimentally observed.     

Plasma Induced Wiggler Magnetic Field in a Cavity

The transformation of an elliptically polarized standing wave in a cavity by a suddenly and uniformly created plasma is discussed. Theoretical expressions for the plasma induced wiggler magnetic field as well as the frequency-upshifted standing wave are derived. By choosing appropriate values of the source wave parameters and plasma parameters, one can get wiggler magnetic field of desired magnitude, direction and wiggler wavelength. A few representative results are discussed.     

有限厚大孔径光电导天线产生的太赫兹辐射远场时域特性分析

采用电流起伏模型,分析了有限厚大孔径光电导天线产生太赫兹脉冲的远场时域特性.模型在包含有限载流子寿命、瞬变载流子迁移率等影响因素的基础上,考虑了激发光脉冲在光电导材料中的时间延迟和吸收衰减,使模型更加趋近于反映真实的物理过程.根据模型分析了光通量、有限载流子寿命和瞬变载流子迁移率,以及光电导材料厚度变化对THz远场时域波形的影响, 并对比分析了考虑光电导材料厚度与不考虑厚度时太赫兹脉冲的时域波形.     

Temperature Field Measurements of the Electric Arc Plasma in a Longitudinal Magnetic Field

Two methods are described to determine local parameters of the unsteady asymmetric plasma. The basis of one method is the parametric approach. This method is used to determine plasma parameters in the case when an assumption can be made on the shape of the intensity isolines. The temperature field was calculated according to the intensity distributions in X direction obtained simultaneously from two lines of sight. The second method was applied for measurements in arbitrary plasma configuration. In this case the temperature fields were calculated according to measurements from lines of sight simultaneously, and the obtained data were used in the Radon transformation inversion.     

Transport Equations of Plasma in a Curvilinear Magnetic Field

The problem of transport equations of a collisional plasma in a curvilinear magnetic field is studied. Two main approaches to this problem are presented: that based on using the Boltzmann kinetic equation and the drift kinetic equation approach. In the frame of the first approach a multimoment transport equation set is found which is more general than the transport equation sets of Braginskii and Grad. The tensor equations of this set are described in an arbitrary curvilinear coordinate system. This allow to use these equations in problems of a plasma confined in toroidal magnetic configurations. Simplification of the multimoment transport equation set in the case of high magnetic field is performed. In the frame of the drift kinetic equation approach, a generalization of the drift transport equations derived earlier by the authors (Zh. Eksp. Teor. Fiz. 83 (1982) 139) is given.     

Effect of an External Magnetic Field on Magnetoplasmons in Finite Thue-Morse Metal-Metal Superlattices

We have investigated the properties of the magnetoplasmon polariton excitation of a finite Thue-Morse superlattice structure which consists of two building blocks with nonzero plasma frequency. We find that there exist some new modes in an external magnetic field.     

Strength of a Magnetically Permeable Surface Layer on Transient Electromagnetic Field by Using Natural-frequency Concept

The complete time-domain fields due to a vertical magnetic dipole on the surface of two-layer earth model are reexamined when the usually neglected magnetic permeability contrast is considered using the natural-frequency concept. It is shown that for two-layered earth model, where the upper one is permeable, the electromagnetic induction response is modified with respect to the nonpermeable case. The step responses of the induced voltage in a horizontal receiving loop is found to have definite diagnostic features for the ground beneath. These features have been demonstrated by numerical results and illustrated by figures.