engleski

Mixing of hot and cold plasma

Cold non-equilibrium atmospheric pressure plasmas are typically generated from noble gases using high voltages with high frequencies, with various electrode configuration. Because of the high concentrations of the reactive species, cold plasmas can be efficiently applied in surface modification, biomedicine, water treatment etc. Atmospheric pressure plasma jets (APPJ) that we are using are not continuous as it seems to our naked eye, but rather consist of fast traveling plasma bullets that can easily be detected with fast ICCD imaging. Since plasma jets are repetitive and reproducible, they can easily be synchronised with the Nd-YAG laser pulses that serve as a different excitation source when focused into the gas medium. So called laser produced plasmas are also rich with reactive species, but opposed to cold plasmas, they have higher ion and electron concentrations, as well as temperatures. Our main goal is to investigate the mutual effect of the applied voltage and laser pulse on the ionisation and excitation dynamics of different molecules and atoms that constitute our produced plasma. Our main diagnostical technique is optical emission spectroscopy with different spectrometers, either with good temporal and spectral resolution but slow acquisition time (monochromator with photomultiplier tube), or fast acquisition time but lower spectral and temporal resolution (CCD spectrometers). Basic introduction to this experiment along with effects of laser and cold plasma combination on emission spectra will be presented here.

laser plasma ; atmospheric pressure plasma jets ; spectroscopy

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