Zdenko Machala

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We present nitrogen microwave blown-out plasma at atmospheric pressure and its emission spectra with their spatial distribution. The plasma had a symmetric conical shape until it collapsed to a funnel-like shape at high gas flow rates. We observed the emission of N<sub>2</sub>, N<sub>2</sub> <sup>+</sup>, CN and NO: their Abel-inverted emissivity increased(More)
We present images and basic characteristics and describe transition mechanisms between three dc discharges in atmospheric air point-to-plane or point-to-water gap. With increasing applied voltage, a streamer corona transits to a transient spark: a repetitive spark with very short (~100-ns) current pulses (~1 A) of very limited energy. With an appropriate(More)
Plasma-flow interactions are investigated in transverse direct current glow discharges in atmospheric pressure air. Interestingly, the slower flow "blows out" the discharge farther than the faster flow. We find this counter intuitive result to be mainly due to gas heating in the discharge: the temperature is higher for the slower flow, thus enhancing the(More)
Atmospheric pressure DC-driven self-pulsing transient spark (TS) discharge operated in air and pulse-driven dielectric barrier discharge plasma jet (PJ) operated in helium in contact with water solutions were used for inducing chemical effects in water solutions, and the treatment of bacteria (Escherichia coli), mammalian cells (Vero line normal cells, HeLa(More)
Transient spark, which is a novel type of streamer- to-spark transition discharge, was investigated in N<sub>2</sub>/CO<sub>2</sub>/H<sub>2</sub>O mixtures. It has a pulsed character with short (~100 ns) pulses of high current amplitude (~1 A) with repetitive frequencies of some kilohertz, and it generates nonequilibrium plasma. Emissions of N<sub>2</sub>(More)
The volume scalability of nonequilibrium plasmas produced by electrical discharges in atmospheric pressure air has been investigated. A variety of direct current (DC) and pulsed glow discharges obtained in either slow flow of ambient or fast flow of preheated (~2000 K) air at atmospheric pressure is presented. Single DC and repetitively pulsed discharges(More)
The chemistry induced by atmospheric pressure DC discharges above a water surface in CO2/N2/H2O mixtures was investigated. The gaseous mixtures studied represent a model prebiotic atmosphere of the Earth. The most remarkable changes in the chemical composition of the treated gas were the decomposition of CO2 and the production of CO. The concentration of CO(More)
The effect of electrospraying of water [electrohydrodynamic atomization (EHDA)] was studied in combination with dc streamer corona discharge as a possible method of biodecontamination of water. This effect was investigated under various voltages and water flow rates. The best conditions when the water spray was localized directly in the relatively stable(More)
We have investigated a novel type of streamer-to-spark transition discharge in air at atmospheric pressure, named the transient spark (TS). Despite the DC applied voltage, TS has a pulsed character with very short (&lt;100 ns) high current (&gt;1 A) pulses, with repetitive frequencies of a few kHz. The emission of N<sub>2</sub> 2<sup>nd</sup> and(More)