engleski

RECIPROCAL INFLUENCE OF MULTIPLE HARMONIC AC-DRIVEN PLASMA NEEDLE JET AND SAMPLE SURFACE

Atmospheric pressure plasma jets are often used to treat samples of various sizes, made out of various materials. Here we report on reciprocal influence between the sample surface and atmospheric plasma jet. This correlation is important since it changes plasma parameters and plasma itself, depending on the sample-material surface, presence of liquid or treatment distance. However, in experiments and treatments of surfaces with atmospheric plasma jets, this relationship is usually disregarded. The designed multiple harmonics source was applied to a single electrode plasma jet and a comparison between the most commonly used single harmonic (sine voltage waveform) and the original multiple harmonics AC- driven atmospheric pressure plasma jet was performed. Some advantages compared to single harmonics driven jets were discovered. In order to investigate reciprocal influence, we implemented electromagnetic and optical emission spectroscopy characterization of atmospheric multiple harmonic AC-driven plasma needle jet (25 kHz, 2.5 kV, 3 mA). Characterization was performed during treatment of various samples. We have shown that sample material and its distance from the tip of the electrode have a pronounced influence on atmospheric pressure plasma jet electromagnetic and optical characteristics, such as jet length, shape, colour, voltage, current, power, electromagnetic field and concentrations of plasma species. It was shown that for a given flow there is a critical distance (≈ 15 mm) between the tip of the wire and the sample surface for which jet emission intensity, especially ionic, is at maximum. Here we presented the evidence that during thin film deposition, or any other treatment of samples with atmospheric plasma jets, one must take into account the reciprocal influence of sample surface and plasma jet, while the sample material, its size and distance from the beginning of the jet changes both discharge and plasma parameters.

atmospheric plasma jet; sample influence

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