Shock-induced conductivity waves in a conductor placed in an external magnetic field

Electromagnetic processes in a shock-compressed conductor placed in an external magnetic field are analyzed. The motion of the shock wave results in the appearance of two countercurrents that flow ahead of the shock front in the uncompressed-material region and near the back boundary of the conductor, respectively. The observed electromagnetic pattern is due to current diffusion and convective transfer in the conductor. When the shock wave arrives at the conductor, the absolute value of the currents grows tending (in the case of a considerable sample thickness) to a constant determined by the condition of magnetic-field trapping by the material. In this case, the electromagnetic pattern is characterized by two space-separated current waves: a stationary steady wave moving along the uncompressed material with phase velocity and a nonstationary diffusion wave which originates at the back boundary of the conductor. Voltage recordings at one of the sample surfaces can be used to determine the material parameters in a compressed state.Translated from Fizika Goreniya i Vzryva, Vol. 32, No. 6, pp. 116–122, November–December, 1996.     

Effect of Temperature on the Formation of Stable and Metastable Aluminide Phases in Al‒Zr‒Nb Alloys

Russian Journal of Non-Ferrous Metals - The conditions of the formation of stable and metastable aluminides Aln(Zr1 – xNbx) formed during the crystallization of superheated...     

Properties of porous silicon-nitride materials

Conclusions Newly developed porous silicon-nitride materials from elements have a thin walled porous structure, which in comparison with known materials for the same kind and similar porosity have a lower thermal conductivity, high strength, deformability, and thermal-shock resistance as well as satisfactory resistance to oxidation at temperatures of about 800°C.Translated from Ogneupory, No. 7, pp. 20–23, July, 1988.     

Electromagnetic effects in a measurement cell for investigating the electrical properties of shock-compressed substances

A qualitative analysis was performed of the electromagnetic effects on a measurement cell for investigating the electrical properties of substances in a transition to the metallic state. The signal shape is significantly affected by the geometries of the measurement and power circuits, as well as by the loading system. A measurement cell design is developed which provides reliable recording of the electrical conductivity of the substance in shock waves.Institute of Hydrology and Hydrotechnology, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk. Translated from Fizika Goreniya i Vzryva, No. 2, pp. 71–76, March–April, 1994.     

Preparation and Heat Resistance of Porous Titanium Carbosilicide

Refractories and Industrial Ceramics - The results of studies on the preparation of titanium carbosilicide with porosities of 20, 40, and 60% are presented. Experimental samples were obtained using...     

A capacitive storage for a tabletop X-ray laser for dense-plasma diagnostics

The results of investigation of a pulsed capacitive energy storage for a tabletop-type X-ray laser for dense-plasma (up to 3 × 10²² cm^?3) diagnostics are presented. It is assumed that plasma of Ne-like argon is the active medium of the X-ray laser and an electric discharge occurs inside a 150-mm-long ceramic capillary 3–4 mm in diameter. In previous experiments on the SIGNAL accelerator, the main initial conditions for generation of laser X rays were determined and X rays at a wavelength of 46.9 nm were obtained. The pulsed capacitive-energy storage unit is built in the form of a flat capacitor filled with deionized water. It has been revealed that deionized water as the dielectric filling the flat capacitor is not broken down in a 10-mm-wide gap at a pulsed voltage <130 kV and a charging-pulse duration of ～300 ns. In this case, the parameters of the pulsed capacitive-energy storage correspond to those required for generation of laser X rays: a current amplitude in the load of 50 ± 1 kA and a period of the current in the load of 196 ± 2 ns. The small jitter of the duration of the charging pulse (288 ± 6 ns) of the flat capacitor offers a hope for satisfactory synchronization of a laser X-ray pulse with a diagnosed plasma object.