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Information × Registration Number 0213U007231, 0112U001311 , R & D reports Title Investigation of the structure and properties of the low-pressure gas discharges with a flat and hollow electrodes popup.stage_title Head Lisovskiy Valeriy, Registration Date 22-04-2013 Organization Kharkov National University named after V.N. Karazin popup.description2 The object of the work: Gas breakdown and discharge properties in the radiofrequency and constant electric fields between flat and hollow electrodes. The purpose of the work: Investigation of the conditions of the dc discharge ignition in long tubes (with a length greater than the radius of the tube), and the burning modes between flat and hollow electrodes in a constant and radio-frequency electric fields. Research method: Measuring the breakdown curves in a constant and radiofrequency electric fields in tubes of different geometry, probe measurements of the plasma parameters, as well as theoretical analysis of the processes involved in the breakdown of low-pressure gas and discharge. In this work we investigated the ambipolar diffusion in electronegative plasmas. It was shown that in a plasma with a density of negative ions, more than 10 times the density of electrons, it is necessary to take into account the mobility of the negative and positive ions. It was found that in highly electronegative plasma diffusion ceases to be ambipolar, the coefficients of ambipolar diffusion of charged particles are approximately equal to the free diffusion coefficients. Was studied experimentally the ignition DC glow discharge in nitrogen at different distances between the electrodes in long discharge tubes. It was shown that the usual Paschen's law is valid only for short discharge tubes for which L/R 1 (L and R - the length and radius of the tube, respectively). When L/R > 1 increase in the gap L shifts the breakdown curves Udc(p) to the higher breakdown voltage and a lower gas pressures. When L/R > 20 increase in L shifts the breakdown curve to higher breakdown voltages, but their minimum are at nearly constant gas pressure. This paper studies in experiment the diffuse and contracted modes of dc glow discharge in CF4. The existence region for the contracted mode with pressure unchanged is found to be limited from the small inter-electrode gap side, this boundary being multi-valued. A contracted column establishes in a stratified positive column with current increasing and inter-electrode gap or gas pressure fixed. However with subsequent current increase the length of the positive column decreases (with simultaneous considerable expansion of the negative glow), and contraction vanishes. At longer inter-electrode gap the current increase does not lead to contraction vanishing. It is shown that with low gas pressure p < 0.1 Torr discharge is in the high-voltage (electron beam) form with ascending current-voltage characteristic, when secondary electrons are accelerated along electric field lines and form an electron beam. In the gas pressure range p ? 0.1 Torr the discharge at low current burns in the glow mode, in which the discharge glow is practically absent in the cavity between the plates of the cathode, and the current-voltage characteristic of the discharge is ascending. At higher current the discharge goes into the hollow cathode mode, filling the space between the plates, and it has an almost vertical current-voltage characteristic. The transition from a glow discharge mode into a hollow one possesses a hysteresis. At gas pressures p ~ 1 Torr the hollow cathode effect disappears. Product Description popup.authors Артюшенко К.П. Богодельний І.А. Дахов О.М. Дерев'янко В.О. Лісовський В.О. popup.nrat_date 2020-04-02 Close