Stability of a liquid-dielectric jet in a longitudinal electrostatic field

Conclusions A longitudinal electrostatic field tends to stabilize a jet of liquid dielectric.     

Ionization wave in a longitudinal RF field

We investigate a stationary one-dimensional ionization wave produced in a cold gas by an alternating electric field of frequency (the field is parallel to the direction of propagation of the wave). Primary attention is given to specific features associated with the existence of a plasma resonance transition region at the front of the wave, where the electric-field amplitude and, therefore, the collisional ionization rate of the gas have a pronounced maximum at low electron-collision frequencies . We investigate analytically and calculate numerically the parameters of the wave, which is described by a nonlinear diffusion equation. It is shown that a made of ultrafast discharge propagation with ionization wave velocity V for /0 can be established in the gas due to resonance effects even if the external electric field has amplitude far below breakdown.Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 10, pp. 991–1000, October, 1995.     

Gravitational-to-electromagnetic wave conversion in electrostatic field of earth-ionosphere resonator

The conversion of a plane gravitational wave into electromagnetic radiation in the presence of the fair-weather static electric field of the earth-ionosphere resonator is examined. The spatial and frequency characteristics of the induced electromagnetic field of the earth-ionosphere cavity are studied in the range of Schumann resonance frequencies (f=10–100 Hz). Numerical estimates are obtained for the amplitudes of the electromagnetic fields, and the possibilities of a natural gravitational-wave detector are considered.Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, No. 6/7, pp. 488–497, June–July, 1992.     

静电波对磁化等离子体的共振加热的理论及数值模拟研究

利用多标度展开得到了更一般的静电波与磁化等离子体回旋运动间的共振条件；通过数值模拟证实了理论分析，发现分数频率同样可以产生共振加热；发现加热效果即使对于相同频率的波，也不是随驱动波的振幅单调增强，而是存在一些优势振幅，即在特定频率特定振幅下有特别好的加热效果. 关键词： 等离子体 共振加热 非线性动力学     

A slow wave free-electron laser in a longitudinal wiggler field

Linearized Vlasov-Maxwell equations are solved to obtain the growth rate of free electron laser instability from a tenuous relativistic electron beam propagating in a partially dielectric loaded waveguide immersed in combined axial and longitudinal wiggler magnetic fields. The instability appears via cyclotron resonance interactions for wave perturbations very close to w-kV_z-w_c=nk ₀V_Z where n is the general harmonic number. For n=0, the gain is similar to a slow wave cyclotron amplifier. For n⩾1, the growth rate is substantially larger than the standard slow wave free electron laser scheme utilizing a transverse wiggler field     

On the capillary stability of a cylindrical dielectric liquid jet in a longitudinal electrostatic field

A dispersion relation is derived for capillary waves with arbitrary symmetry (with arbitrary azimuthal numbers) on the surface of a cylindrical jet of an ideal incompressible dielectric liquid subjected to an electrostatic field aligned with the symmetry axis of the jet. It is shown that only long axisymmetric waves can experience capillary instability in such a system. The wavenumber range into which unstable waves fall begins with a zero value, and its width depends on the permittivities of the liquid and ambient and on the electrostatic field strength squared. As the field strength grows, the wavenumber range for unstable waves rapidly narrows and the capillary instability growth rate, as well as the wavenumber of the wave with the greatest growth rate, decreases.     

Electron in a quantized plane-wave field and in the classical field of a longitudinal electric wave

The Dirac equation is solved for an electron moving in a quantized plane-wave field in the classical field of a longitudinal traveling electric wave propagating in one direction. Through a canonical transformation of the photon creation and annihilation operators the problem is reduced to a quasiparticle problem; the quasiparticle energy depends on the time and the coordinates.     

Electromagnetic wave generation in a cylindrical resonator by electrons orbiting in a radial electrostatic field

The mechanisms leading to the generation of microwaves by electrons orbiting in a radial electrostatic field produced by a positively charged filament on the axis of a cylindrical resonator are investigated theoretically. The dispersion relations describing the interaction of the waves with the electrons are obtained. It is shown that the generation of electromagnetic fields is possible on account of both Cherenkov and plasma resonances. The frequencies and growth rates of waves under Cherenkov resonance conditions and also plasma resonance conditions in uniform and nonuniform electron layers are found. The advantages and disadvantages of different generation mechanisms are determined. Zh. Tekh. Fiz. 68, 91–94 (August 1998)     

Asymptotic analysis of nonlinear nonaxisymmetric waves on the surface of a neutral dielectric jet in a longitudinal electrostatic field

The problem of calculation of finite-amplitude waves on the cylindrical surface of an ideal incompressible dielectric liquid jet in a uniform electrostatic field collinear to the unperturbed jet axis is solved using a second-order asymptotic analytic procedure in ratio of the wave amplitude to the jet radius. Nonlinear corrections to the jet profile, velocity field potential, and electrostatic potentials inside and outside the jet are of resonant nature. The degenerate resonant interaction between the wave determining the initial strain and the waves excited due to nonlinearity of the hydrodynamic equations can take place for waves with different symmetries (different azimuth numbers).     

Amplification in photorefractive materials via a higher order wave

It is shown that power exchange is possible in photorefractive materials even though the grating produced by the two incident waves is in phase with their interference pattern. The reason is that the interaction of the principal waves will produced higher order waves and their presence will form further gratings which assist power transfer between the principle beams. Under favourable conditions significant amounts of power may be transferred.     

Saturation of a one-sided multipactor in a decelerating electrostatic field

We analyze the saturation mechanism of a vacuum resonance microwave discharge (multipactor) where the decelerating electrostatic field returns electrons to the secondary-emission multiplying surface. It is found that the Coulomb defocusing of electron bunches prevails over their microwave focusing (toward the resonance phase of the field) in the stationary state, making it possible to extract superfluous secondary electrons when the electron bunches are reproduced on the discharge surface. Using this model, we determine the main characteristics of this multipactor, such as the magnitude and phase disposition of the resonant electron bunch. An explanation of the increase in the discharge power with increase in the secondary-emission coefficient is given. Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 11, pp. 1097–1104, November, 1999.     

Amplification of longitudinal plasma oscillations upon a decrease in plasma concentration

Amplification of plasma oscillations in a homogeneous plasma by reducing its concentration is considered. The frequency of plasma oscillations decreases upon a decrease in the plasma concentration, and the resonant velocity of the plasma electrons, which is equal to the wave phase velocity, also decreases. Due to this, the number of resonant electrons exponentially increases in the equilibrium plasma. Since the energy of plasma oscillations is mainly determined by the contribution of the resonant electrons, this energy also increases exponentially.     

Orientation of KRb molecules in a switched electrostatic field

We theoretically investigate the orientation of the cold KRb molecules induced in a switched electrostatic field by numerically solving the full time-dependent Schrdinger equation. The results show that the periodic field-free molecular orientation can be realized for the KRb molecules by rapidly switching off the electrostatic field. Meanwhile, by varying the switching times of the electrostatic field, the adiabatic and nonadiabatic interactions of the molecules with the applied field can be realized. Moreover, the influences of the electrostatic field strength and the rotational temperature to the degree of the molecular orientation are studied. The investigations show that increasing the electrostatic field will increase the degree of the molecular orientation, both in the constant-field regime and in the field-free regime, while the increasing of the rotational temperature of the cold molecules will greatly decrease the degree of the molecular orientation.     

Dispersing of a charged drop in an electrostatic field

The characteristics of the breakup of a charged drop in a uniform electrostatic field are calculated on the basis of Onsager’s principle of minimum dissipation of energy in nonequilibrium processes. The ranges of the physical parameters where daughter droplets are emitted from two tips and from one tip of an unstable parent drop and when emission is completely absent are found. The dimensionless radii, charges, and specific charges of the daughter droplets are determined. Zh. Tekh. Fiz. 69, 26–30 (December 1999)     

Disintegration of a drop in an external electrostatic field

Regular features of the disintegration of both a drop of a perfectly conducting liquid and a drop of a dielectric liquid into two or three parts in an external uniform electric field are studied using the principle of minimizing the potential energy of the final state of a closed system with spontaneous processes.     

Electron spectrograph with a hyperbolic electrostatic field

The electron-optical properties of an energy analyzer representing a parallel-plate capacitor with a linear distribution of the potential on the upper plate are studied. It is shown that first-order focusing conditions in this analyzer do not depend on the particle energy and the linear dispersion is proportional to the square root of the energy. Such an analyzer can simultaneously record an electron spectrum in a wide energy range, that is, operate as a spectrograph. Double focusing conditions in a box-type analyzer are found, which allows the relative aperture of the spectrograph to be raised several-fold.