Gyrocenter shift of low-temperature plasmas and the retrograde motion of cathode spots in arc discharges

The gyrocenter shift phenomenon explained the mechanism of radial electric field formation at the high confinement mode transition in fusion devices. This Letter reports that the theory of gyrocenter shift is also applicable to low temperature high collisional plasmas such as arc discharges by the generalization of the theory resulting from a short mean free path compared with the gyroradius. The retrograde motion of cathode spots in the arc discharge is investigated through a model with the expanded formula of gyrocenter shift. It is found that a reversed electric field is formed in front of the cathode spots when they are under a magnetic field, and this reversed electric field generates a rotation of cathode spots opposite to the Amperian direction. The ion drift velocity profiles calculated from the model are in agreement with the experimental results as functions of magnetic flux density and gas pressure.     

填充等离子体的介质契伦柯夫脉塞

利用自洽线性场理论,普遍讨论了电子在扰动场作用下的三维扰动,进而分别对薄环形相对论电子注和实心相对论电子注在填充等离子体的介质筒慢波波导中激励的契伦柯夫辐射进行了详细的分析,导出了其色散方程和波增长率。分析表明注波互作用是由于慢波系统中的波导模与电子注模耦合所致,填充等离子体后能大大提高注波互作用效率,并详细计算和分析了等离子体密度和电子注半径对波增长率的影响。     

Chaotic behavior of nonlinearly coupled electromagnetic modes in nonuniform magnetoplasmas

It is shown that the nonlinear equations governing the dynamics of weakly interacting electromagnetic disturbances in nonuniform magnetoplasmas can be written as a set of three coupled nonlinear equations, which are a generalization of the Lorentz-Stenflo equations. The chaotic fluid behavior of electromagnetic turbulence is studied on the basis of the newly derived nonlinear equations.     

Approximate Derivative-Dependent Functional Variable Separation for the Generalized Diffusion Equations with Perturbation

As an extension to the derivative-dependent functional variable separation approach, the approximate derivative-dependent functional variable separation approach is proposed, and it is applied to study the generalized diffusion equations with perturbation. Complete classification of these perturbed equations which admit approximate derivative-dependent functional separable solutions is obtained. As a result, the corresponding approximate derivative-dependent functional separable solutions to some resulting perturbed equations are derived by way of examples.     

Approximate Derivative-Dependent Functional Variable Separation for the Generalized Diffusion Equations with Perturbation

As an extension to the derivative-dependent functional variable separation approach, the approximate derivative-dependent functional variable separation approach is proposed, and it is applied to study the generalized diffusion equations with perturbation. Complete classification of these perturbed equations which admit approximate derivative-dependent functional separable solutions is obtained. As a result, the corresponding approximate derivative-dependent functional separable solutions to some resulting perturbed equations are derived by way of examples.     

Gravitation,torsion, and electromagnetism

A term bilinear in the derivative of the torsion is added to the Lagrangian of general relativity to produce torsion that propagates. Using standard variational techniques, field equations are derived with the torsion being interpreted as the electromagnetic potential and the antisymmetric part of the Ricci tensor as the electromagnetic field tensor. The equation of motion is derived from the field equations, and the results are compared to the Einstein-Maxwell formulation.     

Effective dynamics of an electrically charged string with a current

Equations of motion for an electrically charged string with a current in an external electromagnetic field with regard to the first correction due to the self-action are derived. It is shown that the reparameterization invariance of the free action of the string imposes constraints on the possible form of the current. The effective equations of motion are obtained for an absolutely elastic charged string in the form of a ring (circle). Equations for the external electromagnetic fields that admit stationary states of such a ring are derived. Solutions to the effective equations of motion of an absolutely elastic charged ring in the absence of external fields as well as in an external uniform magnetic field are obtained. In the latter case, the frequency at which one can observe radiation emitted by the ring is evaluated. A model of an absolutely nonstretchable charged string with a current is proposed. The effective equations of motion are derived within this model, and a class of solutions to these equations is found.     

Drift-Alfven Vortex in Low β Magnetized Plasma

Nonlineaidrift-Alfven waves in low β magnetized plasma are reconsidered. Sets of nonlinear equations describing drift-Alfven waves are derived and corresponding dipolar vortex solutions are given. The reault shows that the solution belongs to intrinsic magnetized vortex for which the corresponding perturbed magnetic field line and perturbed electric current on the boundary of vortex are continuous.     

Electrodynamics in terms of functions over the groupSU(2): II. Quantization

In a previous article by two of the present authors Carmeli's group-theoretic method for the formulation of wave equations was applied to the case of the electromagnetic field, and the equations for the vector potential were derived. In the present paper a quantization procedure for these equations is carried out in the Lorentz gauge. It involves two independent variables, corresponding to the number of degrees of freedom of the electromagnetic field in a Hilbert space with a positive-definite metric. Conserved quantities are derived.     

狭窄波束型高频引力辐射与电磁场的作用效应

从弱引力场的Einstein-Maxwell方程出发,讨论了晶体空间阵列的狭窄波束型高频引力辐射与电磁场的作用效应,并给出了扰动解。计算表明,在TT(Transvese Traceless)坐标系中,最优辐射方向的引力波束是纯十型极化的,并可使同频的电磁波产生倍频的扰动效应,使静态电磁场产生与时间成线性关系的累积扰动效应。对于任意方向上的引力辐射波束,在垂直于引力波矢的平面内仍然是纯十型极化的。在高频辐射和实验室典型尺度条件下,TT坐标系与Fermi坐标系的差异是可以忽略的。 关键词：     

Asymptotic conditions for the electromagnetic form factors of hadrons represented by the VMD model

A system of linear homogeneous algebraic equations for the coupling constant ratios of vector mesons to hadrons is derived by imposing the assumed asymptotic behavior upon the VMD pole parameterization of an hadron electromagnetic form factor. A similar system of equations with a simpler structure of the coefficients, taken as even powers of the vector-meson masses, is derived by means of integral superconvergent sum rules for the imaginary part of the considered form factor using its appropriate -function approximation. Although both systems have been derived starting from different properties of the electromagnetic form factor and they each have their own appearances, it is shown explicitly that they are fully equivalent. Received: 20 March 2002 / Revised version: 3 December 2002 / Published online: 7 March 2003     

Electromagnetic solitons in bundles of zigzag carbon nanotubes

The possibility of forming solitons in zigzag carbon nanotubes is investigated using the coupled equations for the classical function of the electron distribution and the Maxwell equations for an electromagnetic field. It is demonstrated that the solitons are generated as a result of correlated changes in the classical distribution function and the electric field induced by nonequilibrium electrons of a carbon nanotube. The effective equation describing the dynamics of the electromagnetic field is derived. The existence of solitons is confirmed by the results of numerical calculations. The characteristics of solitons are investigated as a function of the diameter of zigzag carbon nanotubes.     

Electromagnetic field representation in the source region

Representation of electromagnetic fields in the source region in inhomogeneous anisotropic media is developed in terms of Hertz vectors. Differential equations satisfied by these vectors as functions of stream potentials of the sources are obtained. Conditions for representation in terms of uncoupled transverse electric and magnetic modes satisfying second-order differential equations are derived.     

Study of the influence of thin layer loading on the propagation of Lamb waves using perturbation method

I.IntroductionSincethepublicationoftheclassicalpaper"Onthewavesinanelasticplate"byH.Lambin1917l1l,theterm"LaInbwave"hasbeenusedtorefertoanelasticdisturbancepropagatinginasolidplatewithfreeboundaries.Lambwavesarewidelyusedintheapplicationsofthedefectinspectionofthinwa.lledmaterial[2'8].InrecelltyearsLambwaveshavebeenwide1yusedinthefabricationofsensors.LamInwavesensorsdetectthechangesofenvironmentbymeasuringthechangeofphasevelocityofLambwaves.IncomparisonwithbuIkwavesandSAW's,Lambwavsprovi…     

The Electromagnetic Analogue of Some Gravitational Perturbations in Cosmology

Recently attention has been drawn to the fact that perfect fluid tensor perturbations (with perturbed vorticity and acceleration vanishing) of isotropic cosmological models have a perturbed Weyl tensor with electric part satisfying a linear, homogeneous, third-order wave equation while the magnetic part satisfies a linear, homogeneous, second-order wave equation. We construct an analogous class of electromagnetic test fields in the isotropic cosmological models for which the electric vector satisfies a third-order, linear and homogeneous wave equation while the magnetic vector satisfies a second-order, linear and homogeneous wave equation. If the perfect fluid has an equation of state we give a simplified derivation of the authors' previous perturbation analysis describing gravitational waves carrying arbitrary information. We also present the analogous solutions of Maxwell's equations which contain electromagnetic waves conveying arbitrary information.     

Calculation of the stark effect in hydrogen atoms by using the hypervirial relations

By applying the hypervirial relations to the separation equations in parabolic coordinates for the Stark effect, the separation constants and the perturbed energy are derived to the fifth order of the electric field.     

完全填充手征等离子体波导的电磁波传输特性

应用纵向分量法推导出了柱坐标系下均匀手征等离子体媒质中电磁场的横向分量与纵向分量的关系, 并导出了纵向分量满足的波动方程, 在柱坐标系下求解该波动方程并应用圆柱状导体边界条件导出了完全填充手征等离子体金属圆波导的色散方程。数值求解色散方程给出了模式色散图, 得到了新的有意义的结果。     

Microscopic derivation of kinetic equations for interacting optical two-level systems

Kinetic equations are derived for optical two-level atoms interacting with a molecular subsystem treated as a thermostat. It is assumed that the kinetics is determined by the electric dipole interaction perturbed by the thermal motion. Dynamic parts of the kinetic equations coincide with the corresponding terms of optical Bloch equations, whereas nonlinear relaxation and shift terms have the specific form and are absent in the phenomenological generalized Bloch equations. It is shown that the relaxation kinetics can be substantially different from the exponential one and depends on the initial state of the system. In particular, the inversion relaxation is frozen at small deviations from the equilibrium. The possibility of observation of the optical bistability is discussed.     

完全填充手征等离子体波导的电磁波传输特性

 应用纵向分量法推导出了柱坐标系下均匀手征等离子体媒质中电磁场的横向分量与纵向分量的关系, 并导出了纵向分量满足的波动方程, 在柱坐标系下求解该波动方程并应用圆柱状导体边界条件导出了完全填充手征等离子体金属圆波导的色散方程。数值求解色散方程给出了模式色散图, 得到了新的有意义的结果。     

微扰法研究薄膜负载对Lamb波传播的影响

许多Lamb波传感应用中,板周围环境的微小变化即待检测的外部微小变化,可看作是对于薄板中Lamb波的自由边界条件的微扰。本文选择合适的微扰边界条件,推导了适用于多种薄膜负载的各向同性板中弹性波传播的一般特征方程,应用此一般特征方程讨论了传感应用中常见的液体薄膜负载、各向同性固体薄膜负载对薄板Lamb波传播的影响,并与精确理论进行了比较,同时本文还用此方法分析了传感中常见而且精确理论计算较为复杂的粘滞液层负载和固体复合层负载的情况。最后我们对负载液层薄膜时的情况进行了初步实验研究,验证了我们的微扰近似理论。