Division of Environmental Physics - Students
Faculty of Mathematics, Physics and Informatics, Comenius University Bratislava

Students

Lukáš DVONČ
alumni student

PhD. study
2011 - 2016

Supervisor: Mário Janda
Title:
Modeling of plasma chemical processes in transient spark in N2-O2 mixture
Abstract:
The primary aim of this work is to create a computational model capable to describe chemical processes induced by a relatively new type of discharge named transient spark (TS). TS is a DC driven pulsed atmospheric pressure discharge with high repetition frequency (~ kHz) of short (~100 ns) high current pulses (~A). It was already applied for various environmental and biological applications. One part of this work will be related to the development of computational package for the calculation the evolution of concentration of plasma species, taking into account the pulse character of TS. Developed package is based on available open source ZDPlaskin libraries. Another part of this work will be associated with development of a physical model describing time evolution of reduced electric field strength (E/N) in TS. For this purpose we will use Open Foam, a open source multi physical modeling platform. It will be used for simulation of hydrodynamic effects involved in TS, namely during the streamer-to-spark transition phase. The results of the whole model will be compared with experimental data, obtained mainly by time resolved optical emission spectroscopy. Thus we can evaluate the model.

MSc. study
2009 - 2011

Supervisor: Mário Janda
Title:
Kinetic model of plasma generated by transient spark.
Abstract:
The primary aim of this work was to create a computational model capable to describe chemical processes induced by a relatively new type of discharge named transient spark (TS). TS is a DC driven pulsed atmospheric pressure discharge with high repetition frequency (~ kHz) of short (~100 ns) high current pulses (~A). It was already applied for various environmental and biological applications. The main part of this work was related to the development of computational package, which can calculate the evolution of concentration of plasma species, taking into account the pulse character of TS. Developed package is based on available open source ZDPlaskin libraries. Created package is able to characterize both short high current pulse phase of the discharge with fast changes of plasma, and the long relaxation phase (~ ms) with slow changes of plasma parameters. Time evolution of reduced electric field strength (E/N) characterizing TS is loaded from an external file. The concentration of electrons (ne) can be loaded from an external file too, but it can be also calculated by the program itself. The time evolution of E/N and ne for these external files was estimated from measured electrical parameters of TS. Next, developed model was used to calculate the evolution of various species in air plasma generated by TS. The evolution of excited N2 and O species, as well as there interactions is described in this work. Calculated data were finally qualitatively compared with experimentally obtained emission intensities of N2 (C) and O* species. Good agreement was observed if both E/N and ne were loaded from external files. On the other hand, significant differences were observed if ne was calculated by the model itself. It can be most probably explained by inaccurate approximation of E/N profile.

Bc. study
2007 - 2008

Supervisor: Zdenko Machala
Title:

Abstract: