Visualization of gasdynamic processes at a pulse-periodic discharge initiated by runaway electrons in atmospheric pressure air with a laser monitor
D.V. Beloplotov1, M.V. Trigub2,3, V.F. Tarasenko1, G.S. Evtushenko3, M.I. Lomaev1
1High Current Electronics Institute of the Siberian Branch of the RAS, 634055, Tomsk, 2/3, Academichesky ave. HCEI SB RAS
2V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
3National Research Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk, 634050, Russia
Keywords: наносекундный импульсно-периодический разряд, воздух атмосферного давления, убегающие электроны, теневая методика, лазерный монитор, лазер на парах бромида меди, струи паров металла, цветные мини-струи, nanosecond pulse-periodic discharge, atmospheric pressure air, runaway electrons, schlieren method, laser monitor, copper bromide laser, metal vapor jets, colored mini jets
Abstract
Gasdynamic processes that take place at a pulse-periodic discharge initiated by runaway electrons in atmospheric pressure air were studied with a laser monitor based on a CuBr laser. Voltage pulses (U = 13 kV, FWHM is 10 ns, front duration is 4 ns, negative polarity, f = 60-3200 Hz) applied to a cone copper cathode with diameter of cone base, apex angle, and corner radius of cone apex of 6 mm, 30°, and 0.2 mm, respectively. A flat copper anode was located at a distance of 2 mm from the cathode. It was established that products of discharge plasma with copper vapors are transferred in radial direction along a surface of the flat anode during 2.5 ms to a distance of 24 mm. The temperature of air heated by the discharge in the moment of its expanding was ~ 1 × 103 K. It was shown that use of the laser monitor in transmitted light allows obtaining contrast images of optical inhomogeneities that arise at a gas discharge.
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