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This paper presents results on the synthesis of germanium nanocrystals in electric arc discharge. During the synthesis, the surface of a germanium anode was heated to the state of surface boiling. Atoms of vaporized germanium were deposited on the surface of a copper substrate. The resulting sample was examined with an electron microscope. The deposited material was shaped as crystalline nanospheres (nanocrystals) with a size ranging from 20 to 200 nm.

A unified self-consistent model is formulated to describe a discharge gap, electrodes, and the formation of the parameters of dc microdischarges in molecular gases at atmospheric pressure. Numerical experiments performed in the current density range from 90 to 2.5 × 106 mA/cm2 have revealed the dependence of the voltage drop on a discharge on the current density, which reproduces the formation of glow, transient from glow to arc, and arc regimes. It has been shown that a transition from the glow discharge to the arc discharge with a free and unfree cathode regime can be implemented depending on boundary conditions on the outer edges of electrodes.

A method for the synthesis of microdiamonds from graphite in an argon arc using germanium as a catalyst is presented. Simple microdiamonds and diamonds of complex configuration are obtained. It has been revealed that forms of synthesized nanomaterials are significantly affected by the buffer gas, the electrical and thermal parameters of the arc discharge, and the presence of germanium at the nucleation stage. Microdiamonds are formed within a few tens of seconds, which is much different from time required for their traditional production.

The paper presents methods for growing silicon nanotubes using an electric discharge with different values of the electric field strength in the interelectrode gap. It is shown that the shapes of the grown nanomaterials are significantly influenced by both the surrounding gaseous medium and the electric field strength in the interelectrode gap. The silicon nanostructures obtained have been a rather complex and, at the same time, definitely regular configuration and can be widely used in electronics, photovoltaics, batteries, and even as structural elements in composite materials.

The effect of the shape of the feeding voltage on the spatiotemporal characteristics of an atmospheric- pressure barrier microdischarge in argon is demonstrated using numerical simulations based on an extended fluid model. Results of simulations performed for sinusoidal and square feeding voltages are analyzed.

A dc gas discharge between copper electrodes in the current range of 5–20 А was studied experimentally. The discharge gap length was varied within 45–70 mm. The cathode was a 10-mm-diameter rod placed in the water flowing out from a dielectric tube. Three discharge configurations differing in the position of the cathode upper end with respect to the water surface were considered: (i) above water; (ii) flush with the water surface, and (iii) under water. The electric and optical characteristics of the discharge in the second configuration were studied in more detail. It is established that the discharge properties are similar to those of an electric arc. Considerable cathode erosion was observed in the third configuration. It is revealed that fine-dispersed copper grains form in the course of erosion.

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.

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.

A method has been proposed for decomposition of heavy hydrocarbons into light fractions in arc plasma with rotating electrodes immersed in the hydrocarbon feedstock. Chromatographic analysis of the product gases has been performed, and the carbonaceous deposits formed on the electrodes during the experiment have been studied using electron microscopy and infrared spectroscopy.

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.