2008

Rep'ev, A.G., Repin, P.B., Danchenko, E.G.   Structure of the glow of a nanosecond diffuse discharge in a strongly nonuniform electric field   // Technical Physics, 2008, Volume 53, Issue 7, Pages 858 - 865

RFNC - VNIIEF, Sarov, Russian Federation

The structure of the glow of a diffuse discharge in air under atmospheric pressure is studied in detail in the " rod ( cathode ) - plane " geometry for an electrode gap of  10 cm  and a cathode tip radius from  3 cm to 2,4 µm. The amplitude of voltage across the gap was ~ 220 kV  for voltage growth rate of  ~ 10 ¹³ V / s  and a pulse duration of 180 ns.  It is found that the shape of the discharge glow strongly depends on the radius of the cathode tip. For large values of the radius, the multichannel form of the glow prevails, which is statistically transformed into a volume glow as the radius decreases from  5 mm to 60 µm.  This transition is accompanied by a decrease in the amplitude of the discharge current from  440 to 140 A  on the average. For ultrasmall radii of the cathode ( 2,4 - 7,7 µm  ),  the multichannel form of the glow prevails again and the amplitude of the discharge current increases up to  ~300 A.

Boyko, B.A., Dubinov, A.E., Selemir, V.D.   Waveformation during high - speed collision between a plate and a cone  // Technical Physics, 2008, Volume 53, Issue 3, Pages 376 - 379

RFNC - VNIIEF, Sarov, Russian Federation

The results of experimental studies of waveformation in a contact molten layer during an axial collision of metallic plates with metallic bodies in the form of truncated right circular cones are reported. A closed regular structure of the contact layer in the form of a series ( train ) of long waves is formed on the external surfaces of copper and aluminum cones. The results of measurements of the wavelength as a function of the group velocity fit into the ascending branch of the dispersion curve for the wave.

Karelin, V.I., Tren'kin, A.A.   Self - similar spatial structure of a streamer - free nanosecond discharge  // Technical Physics, 2008, Volume 53, Issue 3, Pages 314 - 320

RFNC - VNIIEF, Sarov, Russian Federation

The microstructure of a current channel is experimentally found under the conditions when homogeneous air gaps are subjected to nanosecond voltage pulses in an electric field insufficient for streamer generation. As a possible mechanism of microstructure formation, instability of the ionization process at the avalanche stage leading to the formation of a self - similar spatial structure is considered. The fractal dimension of this structure is determined. In inhomogeneous gaps, the avalanche is shown to be unstable as well. The energy benefit of structuring is considered. It is demonstrated that the microstructure of streamer discharges in homogeneous gaps can also be treated in terms of the model suggested.

Kholin, S.A., Anisina, I.M., Madyanov, A.Yu.   Green's functions for the non - stationary kinetic equation with constant speed  // Transport Theory and Statistical Physics, 2008, Volume 37, Issue 2 - 4, Pages 361 - 376

RFNC - VNIIEF, Sarov, Russian Federation

Green's functions for the one - speed non - stationary and stationary transport equation in a homogeneous medium are considered. For an anisotropically scattering medium, in which we represent the scattering phase function by a truncated series of Legendre polynomials, Green functions are determined for isotropic and monodirectional plane source emissions. These solutions are represented by contour integrals in the complex plane with a cut on [ - 1, 1 ]. Numerical results are given.