Diagnostics of plasma generated in water solutions and its application

This thesis deals with the study of parameters of diaphragm discharge in liquids. NaCl solution of different conductivity was used as a conductive medium. Conductivities were adjusted in the range from 220 to 1000 µS cm-1. Two diagnostic methods were used for the study of plasma parameters. The first one was employed in the laboratory of plasma chemistry at Faculty of Chemistry, Brno University of Technology, namely the optical emission spectroscopy. The second method used for plasma diagnostics was the time resolved ICCD camera at the Laboratoire de Physique des Plasmas at the École Polytechnique in Paris. The reactor for the diagnostics by optical emission spectroscopy had the volume of 4 l, and it was made of polycarbonate. PET diaphragm was placed in the barrier separating the cathode and the anode space. Electrodes were made of titanium coated with platinum. Electric power source supplied a constant DC voltage of maximum 5 kV and electric current up to 300 mA. Spectrometer Jobin Yvon TRIAX 550 with CCD detector was used during the experiments in order to measure overview spectra within the range from 200 to 900 nm as well as OH molecular spectra and Hß line spectra. All spectra were scanned in both discharge polarities, i.e. at the cathode and the anode part of reactor. The basic parameters of the discharge plasma were calculated from the spectra, that means rotational and electron temperature and electron density. Another part of experiment consisted of measurements by the ICCD camera iStar 734. Two types of reactors were used. The first one was the same as the reactor for the measurements by the optical emission spectroscopy. The second one was also made of polycarbonate, but the volume of conductive solution was 110 ml, only. HV electrodes made of stainless steel were placed in this reactor. Ceramic diaphragm (Shapal-MTM) was used in both reactors. Diaphragms had different thickness and diameter of holes. ICCD camera acquired photographs with details of processes of the bubbles generation and discharge operation (propagation of plasma channels), depending on solution conductivity, dimensions of the diaphragm, and with respect to the electrode part of the reactor