Mikhail Eduardovich Pinchuk

A numerical model of shock wave propagation in a cylindrical high-pressure gas discharge chamber is validated against experimental data obtained in megaampere discharges in high-pressure hydrogen with a current rise rate dJ/dt≈1011 A/s. The model is based on one-dimensional hydrodynamics of a compressible inviscid gas. A finite-difference scheme with a two-stage energy-release source model is used to solve the system. The model provides a reliable description of the pressure wave dynamics in the discharge chamber. A comparison of simulation results with measured wall-pressure waveforms demonstrates qualitative agreement in shock arrival times, oscillation periods, and pressure extrema over a range of initial conditions.

Numerical simulation of the shock wave propagation in the discharge chamber with the high-current discharge in high density hydrogen at initial pressure of 0.1–32 MPa under non-stationary energy release at current rise of rate of 10 GA/s was carried out by the finite-differences method. The source of the disturbance (shock wave) was a forming discharge channel in the interelectrode gap along the axis of the cylindrical chamber. The power disturbance of the source was given by the experimental power value in near-axis area.

This work compares the presowing treatment of winter wheat seeds with a low-temperature plasma, a constant high-voltage electric field, a plant protection disinfectant, and cold hardening on the resistance of seedlings to freezing and their morphophysiological characteristics at the initial stage of germination. Various treatment combinations were considered, including the effect of the disinfectant jointly with low-temperature plasma treatment. The greatest stimulating effect from the point of view of seedlings’ morphophysiological characteristics was achieved when seeds were cold-hardened. The action of low-temperature plasma is noticeable up to the third day of germination. The treatment with the low-temperature plasma of seeds pretreated and not-pretreated with the disinfectant had a similar effect on the morphophysiological characteristics of seedlings. The plasma treatment and the electric field were combined with each other, i.e., the plasma treatment effects were added to the electric field effects. Resistance to low temperatures was increased with the hardening of seeds treated with the electric field and the disinfectant. Resistance to low temperatures was reduced when treated with the electric field and/or low-temperature plasma after being treated with the disinfectant.

An experimental stand for studying the effect of synchronous gas injection on high-current arc quenching is described, and results obtained with it are presented. An electrodischarge experimental setup for simulating the process of high-pressure cold gas injection into the arcing region at a certain instant in time is part of this stand. A capacitor bank with a capacitance of 38 mF, as well as various measurement and diagnostic systems, are included in the stand. Experiments have been carried out with arcs at a current amplitude of 3–25 kA, a current half-period duration of 10 ms, and a capacitor-bank charging voltage of 0.8–4.5 kV.

A coaxial electrode configuration with surface dielectric barrier discharge is designed to generate a cold plasma jet emerging into the ambient air. A technique to determine the length of plasma extension based on the measurements of average values of current and applied voltage is proposed. The capacity of the discharge cell calculated using current and voltage values agrees with the capacity obtained from the integral length of a plasma layer along a dielectric surface. The average charge deposited on the dielectric surface is determined.

Gas temperature fields in the air corona discharge with a plane comb electrode system have been determined for the negative and positive polarities of the applied voltage. Highly sensitive schlieren technique used in the study allowed detecting a temperature change in tenths of a degree centigrade at room temperature of the gas flow. The obtained results suggest that the gas in the studied electrode system does not undergo heating at the given range of working parameters.

A dependence of total near electrode voltage drops for high-current high-pressure discharges versus current rise rate into discharge in a range of 10⁹–10¹² A/s at initial gas pressure up to 200 MPa is presented. A new technique for the near-electrode voltage drops determination is proposed at conditions of the fast energy input. The technique is based on measuring the characteristics of a shock wave detaching from the discharge channel. Total near electrode voltage drops were increased with the current rise rates from around two hundreds to approximately ten thousand volts.