Effect of parameters of the discharge circuit on the mode of energy input into the gas in a self-sustained discharge

A model is proposed for calculating the characteristics of volumetric gas discharges used in the pumping of electric-discharge lasers. The dependence of the mode of energy input into the plasma of the gas discharge on the parameters of the discharge circuit is discussed.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 2, pp. 42–46, March–April, 1976.In conclusion, the authors thank Yu. D. Korolev for useful discussions.     

Gas dynamics modeling of a plasmoid created by the Gatchina discharge

Whether plasmoids produced by the Gatchina discharge has a gas-dynamic nature is examined. The analysis is performed using two models for the formation of hot gas flows in the discharge region. The heating of the gas by a bulk heat source near the central electrode and by hot jet formed over the surface of the discharge region and having a maximum velocity in an area above the central electrode are considered. Predictions of the second model are demonstrated to be in closer agreement with experimental data.     

Hydrodynamic analogies between the equations of classical hydrodynamics and electrodynamics in electrochemistry

It is shown that the use of equations of hydrodynamics of an incompressible and compressible fluid gives similar results for a number of experimental data from the field of classical electrodynamics used in electrochemistry. The analogue of electric current in wires is a stream that creates around itself a flow of a fluid. The analogue of electric field is the acceleration of a flow, whereas the analogue of magnetic induction is the frequency of a rotational motion of the fluid. Ampere’s law in hydrodynamics describes the interaction of flows with real bodies in terms of the Zhukovsky equation. The power laws in the fluid are similar, with some distinctions, to Maxwell equations. The expansion of the equations of conservation of momentum and mass in a series in perturbations leads to wave equations also similar to the Maxwell equations for the propagation of electromagnetic waves.     

Sorption of cadmium ions from aqueous solutions onto nanoporous modified carbon sorbents

Physicochemical properties of nanoporous modified carbon sorbents and sorption of cadmium ions (0.1–20 mg L^?1) onto them from nitrate solutions at pH 5–7 were studied. The acid-base nature of functional oxygen-containing groups on the carbon surface of the sorbents was determined. The ability to sorb cadmium ions depends on the kind of chemical modification of the sorbent surface.     

Synchronization of local oscillators in oxidation reactions of C1–C4 hydrocarbons over metal catalysts

The synchronization of reaction rate oscillations in the oxidation of C₁–C₄ hydrocarbons over polycrystalline nickel, cobalt, and palladium foils has been investigated. The synchronization of foil temperature oscillations during the reaction takes place via the diffusion of the reactants in the gas phase. For the nickel catalysts, the synchronization of the oscillators occurs in the same phase, while for the palladium catalysts, both in-phase and antiphase oscillations are observed. This distinction between the dynamic behaviors of the systems of two coupled oscillators is due to the fact that the mechanism of reaction rate oscillations varies from one metal to another.     

Electrohydrodynamic peculiarities of corona discharge interaction with a liquid surface

This study was devoted to experimental investigations of a corona discharge over the surface of the following liquids: tap and distilled water, alcohol, glycerin, and mixtures of alcohol with water and glycerin. One of the electrodes was placed over the liquid surface, while another one was submerged in it. Three modes of discharge over the liquid surface were obtained, namely an ordinary corona, an intermediate mode, and an arc discharge mode. In these modes, a funnel-shaped deepening, jets, and scattered jets directed toward the upper electrode were observed on the liquid surface under the action of the discharge. A qualitative mode of funnel formation on the liquid surface under the influence of an ionic wind induced by a corona discharge was presented. The formation of jets and scattered jets was related to the development of Tonks-Frenkel and Rayleigh instabilities.     

Breakdown characteristics of air in the lower atmosphere

This study is devoted to an analysis of the ionization and loss of electrons at early stages of discharge development in air at an altitude of 0–12 km. Ionization in an external electric field and background ionization, electron attachment and detachment from atomic and molecular oxygen, charge exchange, and negative ion conversion are considered. The dependence of the process rate constants on pressure is taken into account. It is demonstrated that the electric field at which effective air ionization begins decreases with increasing altitude.     

Ultrafast spin avalanches in crystals of nanomagnets in terms of magnetic detonation

Recent experiments [W. Decelle et al., Phys. Rev. Lett. 102, 027203 (2009)] have discovered ultrafast propagation of spin avalanches in crystals of nanomagnets, which is 3 orders of magnitude faster than the traditionally studied magnetic deflagration. The new regime has been hypothetically identified as magnetic detonation. Here we demonstrate unequivocally the possibility of magnetic detonation in the crystals, as a front consisting of a leading shock and a zone of Zeeman energy release. We study the key features of the process and find that the magnetic detonation speed only slightly exceeds the sound speed in agreement with the experimental observations. For combustion science, our results provide a unique physical example of extremely weak detonation.     

129I-Mössbauer study of diffusion effects in the superionic conductor Ag3SI

The superionic conductor Ag₃SI was studied by¹²⁹I-Mössbauer spectroscopy in the rhombohedral γ-phase and in the cubic β-phase at temperatures between 4.2 K and 180 K. In the low-temperature γ-phase, one observes well below the γ-β phase transition at 157 K a motional-narrowing-like decrease of the electric-quadrupole interaction, roughly linear with temperature, which points to a diffusional motion of the Ag⁺ ions already in the γ-phase. Diffusional effects are also reflected by anomalous decrease of thef-factor in the same temperature region, which originates from a restricted short-range diffusional displacement of the iodide ions induced by the hopping Ag⁺ ions.