Numerical experiments on the effect of acoustic flows on the structure of a constricted glow discharge in argon have been performed in the hybrid approximation. The possibility of controlling the combustion regime of the glow discharge with an extended positive column at a high pressure by means of the formation of acoustic flows at the excitation of a standing acoustic wave has been demonstrated. In this case, the discharge transfers from the constricted combustion regime to the diffuse one and becomes stable.

Effect of acoustic flows on the structure of a constricted glow discharge in argon

A new method of synthesis of multilayer carbon nanotubes from liquid hydrocarbons is proposed. The interaction of an electric arc, fi ring between an anode and a cathode submerged in a thick layer of a heavy-hydrocarbon liquid, with hydrocarbon molecules was investigated for the purpose of obtaining new light fractions of oil and an atomic carbon. The carbonaceous substance deposited on the cathode was analyzed on an electron microscope. Chromatographic investigations of the products of the plasmachemical decomposition of heavy hydrocarbons have been performed. It was established that carbon nanotubes are present in a large amount in the deposit on the cathode and that the volatile oil fractions include gasoline fractions, acetylene, methane, ethane, and other substances.

Growing of Carbon Nanotubes from Hydrocarbons in an Arc Plasma

According to the results of a numerical experiment, we show the possibility of control of the glow discharge parameters and structure by means of creating a supersonic gas flow in the selected section of the interelectrode spacing.

Control of the glow discharge parameters at low pressures by means of a transverse supersonic gas flow

A complex physicomathematical model of heat transfer in packets of cooled microrocket gas-dynamic planar nozzles used for the pumping of gas-dynamic lasers is presented. A small size (~15 mm), due to which they are quickly heated up and require intense heat removal, is a specific feature of such rocket nozzles. The complex physicomathematical model of heat transfer and gas dynamics, as well as heating and cooling, is new, since all the physical processes are coupled at the boundary of a multiply connected domain. The cooling of high-temperature gas-dynamic lasers is one of the main problems in designing them. Numerical results for gas temperatures, the heat transfer coefficient, and cooler temperatures, as well as temperatures in the critical section of the nozzle, are obtained.

The Thermal State of a Packet of Cooled Microrocket Gas-Dynamic Lasers

An innovative plasma-chemical hydrocarbon processing reactor has been developed. It is based on the interaction of nonequilibrium gas-discharge plasma with hydrocarbons in the bulk of a raw material. The results of experiments have shown that nonequilibrium gas-discharge plasma of micro-arc discharge, initiated in the bulk of hydrocarbon raw materials, is a unique tool for their processing. It is shown that this method allows not only decomposing hydrocarbons into light fractions, but also simultaneous obtaining fullerenes and nanotubes.

Plasma-Chemical Decomposition of Hydrocarbons on the Basis of the Micro-Arc Discharge with Disc Electrodes Rotating in the Bulk of Raw Materials

A low-pressure glow discharge in a transverse supersonic gas flow was experimentally studied for the case where the flow only partially fills the interelectrode gap. It is shown that the space region with supersonic gas flow has a higher concentration of gas particles and, therefore, works as a charged particle generator. The near-electrode regions of glow discharge are concentrated specifically in this region. This structure of glow discharge is promising for plasma deposition of coatings under ultralow pressures.

Glow discharge in a transverse supersonic gas flow at low pressures

A drift model of a glow discharge is proposed, which takes account of the nonlocal dependence of the ionization source on the electric field strength. The problem is reduced to solving a nonlinear differential equation of second order for the strength squared using the Newton–Kantorovich quasilinearization method.

Drift model of a glow discharge with account for the nonlocal value of the electric field strength in the ionization source

Thermal characteristics of a direct-current plasma torch have been studied in the framework of numerical simulations of temperature fields in a plasma channel, cathode, and anode. It is established that the temperature of the operating cathode surface exceeds the melting temperature of the cathode material.

B. A. Timerkaev

Papers

Growing of Carbon Nanotubes from Hydrocarbons in an Arc Plasma

Control of the glow discharge parameters at low pressures by means of a transverse supersonic gas flow

Glow discharge in a transverse supersonic gas flow at low pressures

Drift model of a glow discharge with account for the nonlocal value of the electric field strength in the ionization source

Numerical Simulation of Temperature Fields in a Direct-Current Plasma Torch