Numerical simulation of high-current pulsed arc discharge in air

Computational model of high-current pulsed arcdischarge in air is proposed. This is, in general, two-dimensional model with taking into account gas dynamics of the discharge channel, real air thermodynamics in a wide range of pressure and temperature, electrodynamics of the discharge including pinch effect, and radiation. One-dimensional version of the model is tested and verified on several numerical and experimental works reported recently. It is concluded that low and moderate current discharges are satisfactorily described with the developed model. Then, developed model was applied to simulate the electric discharge in air for the currents of 1 - 250 kA and characteristic rise times in 13 - 25 µs, and results of calculations were compared with experimental ones. It was concluded that most of characteristics of the discharge are predicted well. Namely, arc column radius and shock wave position agree well with experimental data for all current amplitudes and rise times considered. Radial distributions of temperature and electron density also satisfactorily agree with experimental data. It was found that pinch effect should be considered for currents higher than 100 kA.

High-current arc discharge in air

Computational model of high-current pulsed arc discharge in air is proposed. This is, in general, two-dimensional model with taking into account gas dynamics of the discharge channel, real air thermodynamics in a wide range of pressure and temperature, electrodynamics of the discharge including pinch effect, and radiation. The developed model was applied to simulate the electric discharge in air for the currents of 1 - 250 kA and characteristic rise times in 13 - 25 µs, and results of calculations were compared with experimental ones. It was concluded that most of characteristics of the discharge are predicted well. Namely, arc column radius and shock wave position agree well with experimental data for all current amplitudes and rise times considered. Radial distributions of temperature and electron density also satisfactorily agree with experimental data. It was found that pinch effect should be considered for currents higher than 100 kA.

Jet Shape Analysis and Removal Function Optimization of Atmospheric Plasma Processing Applied in Optical Fabrication

When using Inductively Coupled Plasma (ICP) as a machining tool, its processing method based on the principle of chemical etching leads to no contact stress between the tool and the material, thereby generating no mechanical damage. In recent years, this issue has been widely concerned in the field of optical fabrication. However, there are many differences between low power ICP jet and conventional ICP jet, one of which is that the former does not easily form a rotation-symmetric removal function due to its obvious pinch effect. In this research, the electromagnetism principle of the plasma pinch effect was analyzed firstly, and the jet shape under the pinch effect was classified. Then, experimental study was carried out on the plasma jet shape under the pure Ar and mixed gas of CF4-Ar, and the influence law of the reaction gas on the jet propagation shape was analyzed. Finally, the rotational symmetry of the removal function of plasma jet processing was optimized, and the nozzle design criteria based on pinch effect were proposed.

On the magnetic skeleton of solar and stellar coronae or about possibility of coronal loop formation by the mechanical pinch effect

It is shown that the mechanical pinch can be responsible for the loop structure of solar and stellar coronae.

On the Magnetic Skeleton of Solar and Stellar Coronae or About Possibility of Coronal Loop Formation by the Mechanical Pinch Effect

It is shown that the mechanical pinch can be responsible for the loop structure of solar and stellar coronae.

Electroplastic Deformation by Twinningmetals

The article deals with theoretical and experimental approaches to electroplastic deformation caused by twinning of metals. The author specifies physical fundamentals of Kinetics regarding the development of twinning caused by the excitation of electronic subsystem of metals. Physical models of new channels for the realization of twinning aroused under conditions of electroplasticity have been discussed. Mechanisms of plasticized influence of a surface electric charge have been defined as well as the contribution of a dynamic pinch-effect in the elastic plastic deformation of metals with the participation of the intrinsic magnetic field of the current. The dynamic pinch effect creates ultrasonic vibration of the lattice system while Kinetics changes and plastic deformation are stimulated increasing the amplitude of the oscillations of rectilinear dislocations and the periodic change in the position of the dislocation loops with an increase in the probability of detachment of dislocations from the stoppers. When deformed above the yield point and due to the pinch effect the intrinsic magnetic field of the current diffuses into the crystal where the diffusion rate depends both on the conductivity of the metal and on the frequency of the current. It is necessary to take into account the physical conditions for the creation of ponderomotive effects in relation to specific technically important materials for the practical use of electroplastic deformation technology, especially when processing metals with pressure.