Stability of a charged drop of a viscous electrically conducting liquid in a viscous electrically conducting medium

A dispersion relation is derived for capillary oscillations of a charged electrically conducting viscous drop in an electrically conducting viscous medium. It is shown that aperiodic instability of the charged interface between the two media can arise in this system, with a growth rate that depends qualitatively differently on the ratio of their conductivities in different ranges of values of this ratio. In a certain range of conductivity ratios the drop undergoes oscillatory instability. Zh. Tekh. Fiz. 69, 34–42 (October 1999)     

The stability of a shearing viscous star with an electromagnetic field

We analyze the role of the electromagnetic field for the stability of a shearing viscous star with spherical symmetry. Matching conditions are given for the interior and the exterior metrics. We use a perturbation scheme to construct the collapse equation. The range of instability is explored in Newtonian and post Newtonian (pN) limits. We conclude that the electromagnetic field diminishes the effects of the shearing viscosity in the instability range and makes the system more unstable in both Newtonian and post Newtonian approximations.     

Sphere in the field of a coil in an infinite conducting and magnetic medium

The secondary field of a sphere magnetized by the field of a coil carrying an alternating current is calculated and analyzed. The sphere and coil are assumed to be situated in a conducting and magnetic medium.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 12, No. 7, pp. 31–36, July, 1969.     

Accretion of a conducting medium onto a spherically symmetric black hole imbedded in a magnetic field

The relativistic motion of a conducting continuous medium in the vicinity of a black hole imbedded in a magnetic field is discussed. Expressions are obtained which characterize the variation of the magnetic field as a result of the accretion of matter.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 69–71, November, 1981.     

Propagation of electromagnetic waves in a conducting magnetic medium

We study helicon-spin waves (hybrid polaritons) in a ferromagnetic conducting medium in a strong static magnetic field and determine their existence domains. It is shown that the spatial dispersion of the conductivity tensor gives rise to collisionless damping of these waves when they propagate obliquely to the magnetic field. In the absence of collisionless damping (for wave propagation along the magnetic field), the conditions of amplification of hybrid polaritons in a static electric field are determined. Institute of Radiophysics and Electronics, National Academy of Sciences of Ukraine, Kharkov, Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol.43, No. 1, pp. 38–44, January 2000.     

Current density and field fluctuations in a conducting medium

We study thermal fluctuations in a conducting medium which may be spatially non-uniform and anisotropic. The fluctuation spectra for charge and current density, and for the electromagnetic fields, are expressed in terms of the basic propagators of the macroscopic equations. The theory is based on an application of the generalized Nyquist theorem.     

Estimation of energy dissipated during superconducting wire motion in a magnetic field

An experiment was carried out to study the motion of superconducting wire under the influence of electromagnetic force. Experiments were conducted at 4.2 K by varying the experimental conditions such as tension to the superconducting wire, current ramp rate, and the use of different insulating materials at the interface of the superconducting wire. We were able to examine in detail the structure of the voltage spikes caused by sudden wire motion. The velocity of the wire motion, distance moved by the wire, and energy dissipated during wire motion are estimated.     

Nonuniform quasistatic electric field in a weakly conducting anisotropic medium

The intensity distribution of a nonuniform electric field in a quadrupole electrooptic deflector, the properties of the medium in which are described simultaneously by permittivity and conductivity tensors which are not proportional to each other, is calculated as a function of the phase of the ac control voltage. It is shown that the space charge arising in this case is phase-shifted relative to the control voltage. The computational results are compared with experimental data. Zh. Tekh. Fiz. 67, 51–54 (October 1997)     

Brownian motion in a quantizing magnetic field

A model previously discussed by the author to study Brownian motion of charged carriers in a quantizing magnetic field is extended to include a Landau level-dependent friction parameter. A phase-space Fokker-Planck equation is used to derive a generalized diffusion equation describing spatial diffusion of the carriers, coupled with random jumps between adjacent Landau levels. This partial differential-difference equation is solved analytically. The longitudinal “global” diffusion coefficient is calculated and shown to be enhanced over the value in the extreme quantum limit.     

Effect of a magnetic field on weakly conducting aqueous systems

It is shown that rearrangment and orientation of impurity molecular formations can alter the structure of weakly conducting aqueous systems moving in a magnetic field.Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 4, pp. 89–94, April, 1985.     

Large-scale magnetic field generation by randomly forced shearing waves

A rigorous theory for the generation of a large-scale magnetic field by random nonhelically forced motions of a conducting fluid combined with a linear shear is presented in the analytically tractable limit of low magnetic Reynolds number (Rm) and weak shear. The dynamo is kinematic and due to fluctuations in the net (volume-averaged) electromotive force. This is a minimal proof-of-concept quasilinear calculation aiming to put the shear dynamo, a new effect recently found in numerical experiments, on a firm theoretical footing. Numerically observed scalings of the wave number and growth rate of the fastest-growing mode, previously not understood, are derived analytically. The simplicity of the model suggests that shear dynamo action may be a generic property of sheared magnetohydrodynamic turbulence.     

Neutrino propagation in a medium with a magnetic field

Data on the mean multiplicity of strange hadrons produced in minimum bias proton-proton and central nucleus-nucleus collisions at momenta between 2.8 and 400 GeV/c per nucleon have been compiled. The multiplicities for nucleon-nucleon interactions were constructed. The ratios of strange particle multiplicity to participant nucleon as well as to pion multiplicity are larger for central nucleus-nucleus collisions than for nucleon-nucleon interactions at all studied energies. The data at AGS energies suggest that the latter ratio saturates with increasing masses of the colliding nuclei. The strangeness to pion multiplicity ratio observed in nucleon-nucleon interactions increases with collision energy in the whole energy range studied. A qualitatively different behaviour is observed for central nucleus-nucleus collisions: the ratio rapidly increases when going from Dubna to AGS energies and changes little between AGS and SPS energies. This change in the behaviour can be related to the increase in the entropy production observed in central nucleus-nucleus collisions at the same energy range. The results are interpreted within a statistical approach. They are consistent with the hypothesis that the Quark Gluon Plasma is created at SPS energies, the critical collision energy being between AGS and SPS energies.     

模拟静电场实验中导电介质的选择

通过比较3种静电场描绘仪器的实验结果,分析误差产生的原因,指出选择导电介质应注意的问题。     

Dynamics of cylindrical conducting shells in a pulsed longitudinal magnetic field

A theoretical model is constructed for describing the motion of a cylindrical conducting shell in a pulsed longitudinal magnetic field generated by an external solenoid. The model takes into account the dynamics of the electric circuit (with the solenoid as its part), inertial and strength properties of the shell, magnetic field diffusion, and heating of the solenoid and shell materials. Difference schemes are constructed for the numerical solution of the system of the defining differential equations, and the criteria of their stability are analyzed. The model is used for studying magnetic-p ulse compression of hollow shells, as well as magnetic field compression in their inner cavity, and the effect of controlling parameters such as the starting charge voltage of the energy storage system and the size of the shell being compressed on the process dynamics is analyzed. Various approximations for calculating the shell heating (adiabatic approximation and uniform heating approximation) are analyzed in comparison with rigorous calculations. The possibility of conducting shell expansion due to magnetic field diffusion into the inner cavity is investigated.     

Brownian motion of a charged particle in a magnetic field

We develop and numerically illustrate an exact solution of the multivariate, stochastic, differential equations that govern the velocity and position of a charged particle in a plane normal to a uniform, stationary, magnetic field. The equations self-consistently incorporate the Lorentz force into an Ornstein-Uhlenbeck collision model. Properties of the solution in the infinite dissipation limit are explored and the spectral energy density function is found     

Capillary disintegration of a suspended filamentary drop of a viscous magnetic fluid in a longitudinal magnetic field

A differential equation that describes the axisymmetric motion of two immiscible magnetic fluids of the same density and viscosity is derived. It includes in explicit form the contribution of capillary forces localized at the interface between the fluids, which has the form of a weakly distorted cylindrical surface. With this equation, a dispersion relation for the problem of capillary instability of an extended axisymmetric drop placed in a uniform longitudinal magnetic field is obtained. The effect of magnetic forces on the capillary disintegration of the drop for the extreme cases (large and small Ohnesorge numbers) is analyzed.