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Diagnostics of plasmas for technological applications
Turek, Zdeněk ; Kudrna, Pavel (advisor) ; Kousal, Jaroslav (referee)
The subject of the master thesis is the extension of the measurement of plasma para- meters by the Langmuir probe in a system with a planar magnetron and a hollow cathode operating in pulse mode. The main tasks are to modify the measuring circuit to increase the maximum probe current and to put the USB oscilloscope into operation for data collection with higher resolution and higher sampling rate. Furthermore, the function of the entire device will be verified using test circuits and also by measuring the probe characteristics in discharges in a system with a magnetron and a hollow cathode in both continuous and pulse mode. 1
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Recombination of molecular ions with electrons at low temperatures
Kálosi, Ábel ; Plašil, Radek (advisor) ; Kudrna, Pavel (referee)
The aim of this work is the experimental study of recombination of molecular ions with electrons at low temperatures (< 300 K). The work gives an overview of the diagnostic methods, modelling of chemical kinetics, and experimental ap- paratuses Cryo-FALP II and SA-CRDS used in the undertaken measurements. Two processes were studied in the course of this work: state-selective binary disso- ciative recombination of H+ 3 ions in para-H+ 3 and ortho-H+ 3 states, and H2-assisted ternary recombination of H+ 3 . The main result of the state-selective dissociative recombination study is that the rate of recombination in the para-H+ 3 state is at least three times higher than in the ortho-H+ 3 state at 60 K. The study of H2- assisted recombination gave a better understanding of ternary processes of H+ 3 ions and removed further discrepancies between results of afterglow experiments.
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The investigation of low pressure HCPJ system for Ti02 film deposition
Perekrestov, Roman ; Kudrna, Pavel (advisor) ; Klusoň, Jan (referee) ; Straňák, Vítězslav (referee)
Title: The investigation of low pressure HCPJ system for TiO2 film deposition Author: Mgr. Roman Perekrestov Department / Institute: Department of Surface and Plasma Science Supervisor of the doctoral thesis: doc. Mgr. Pavel Kudrna, Dr. Abstract: Plasma sources are widely used for deposition of thin films for both commercial solutions as well as for research purposes. In particular, information about plasma parameters in such systems is of a great importance not only to ensure reproducibility, but also for the targeted influence on properties of deposited thin films. The aim of the dissertation was the study of plasma parameters with respect to the growth and properties of thin films deposited by means of HCPJ sputtering system. The investigated plasma system was plasma jet powered in DC mode. The diagnostics of the discharge was carried out by means of a cylindrical Langmuir probe, quadrupole mass and optical spectrometer. Neutral gas temperature in discharge was measured by an optic-fibre thermometer. The growth of nanoparticles in a gas phase was studied using scattering of laser beam light. For the diagnostics of Ti/TiO2 thin films were used XPS, SEM, AFM, TEM, XRD and EDX methods. The photovoltaic performance of TiO2 thin films was tasted in dye-sensitized solar cells. Keywords: plasma jet, Langmuir...
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Design and implementation of the plasma control system for the COMPASS tokamak
Janky, Filip ; Horáček, Jan (advisor) ; Kudrna, Pavel (referee) ; Svoboda, Vojtěch (referee)
Design and implementation of the plasma control system Mgr. Filip Janky The COMPASS tokamak was recommissioned in 2007 and it needed new digital controllers for its experimental research. This thesis presents the design and imple- mentation of control of main plasma parameters such as plasma current, plasma position, plasma shape and electron density. Improved plasma current control with resetting set points suppresses overshooting and thus increases the length of the flat top phase. A method for estimating the plasma position, gain tuning for the controller and decreasing latencies and delays to obtain robust position control are presented. Lower delays improve plasma stability and decrease the frequency of disruptions. The plasma shape controller is a feedforward controller with a method to suppress oscillations which are coming from mutual inductance between power supplies controlling plasma horizontal position, plasma shape and plasma current, which all use the same coil. Averaged electron density is corrected in real-time according to the interferometer line of sight and a non-linearity of measurement. Controllers and their improvements described here, played a major role in achiev- ing H-mode scenario and fulfilling the experimental program. Keywords: tokamak, plasma current control, plasma position...
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Pirate parties as liberal parties?
Kudrna, Pavel ; Brunclík, Miloš (advisor) ; Perottino, Michel (referee)
The diploma thesis aims to confirm whether Pirate parties are liberal and left-libertarian parties and that they are similar to green parties in this way. After 2006 Pirate parties emerged gradually as a new alternative to manage the politics and democracy in Western democracies. Pirates came up with themes such as the fight against copyright or the protection of individuals within the internet. In the first theoretical part of this thesis both liberalism and left-libertarianism as well as Green parties are discussed. The second empirical part deals with Pirate parties. First, their origin and development are described and, with an emphasis on Swedish, German, Icelandic and the Czech Pirate Party - because of their relevance associated with electoral successes -, basic elements of their programmes are introduced. Based on those findings the analysis confronting the elements of liberalism and left-libertarianism with programmes of Pirate parties is performed in the final section of the thesis. The hypothesis that Pirate parties are predominantly left-libertarian parties is proved. Powered by TCPDF (www.tcpdf.org)
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The Process of the Transition to Democracy in Czechoslovakia in the Period of November - December 1989
Kudrna, Pavel ; Štefek, Martin (advisor) ; Koubek, Jiří (referee)
This bachelor thesis analyses the transition of Czechoslovakia towards democracy with emphasis on the first period of the transition: November and December 1989. The paper introduces different transitological approaches and applies them to the Czechoslovakia case. Traditional approaches, for instance Rustow, Mainwaring, Karlová and Schmitter, Przeworski, and others, are used to reflect upon the transition phases and typology. The thesis furthermore takes into consideration major historiographical works on the final phase or fall of non-democratic regimes and establishing a new system. The analysis also emphasises the actors of the transition. Powered by TCPDF (www.tcpdf.org)
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Pulsed plasma systems
Klusoň, Jan ; Kudrna, Pavel (advisor) ; Krčma, František (referee) ; Čada, Martin (referee)
The doctoral thesis deals with the experimental study of the low-temperature plasma designated for the preparation of thin films using the method of physical sputtering. It describes measurements which were realized on two types of devices - on the low-pressure plasma jet sputtering system and on the planar magnetron. The plasma diagnostics in the discharge excited in the pulse regime represent the main theme of the thesis. The discharge in the low-pressure plasma jet was studied by means of an electrostatic Langmuir probe, in the case of the planar magnetron, mass spectroscopy with energetic as well as time resolution was used. To understand the results achieved in the pulse generated plasma good knowledge of the basic continuous DC regime of the discharge excitation is essential. Therefore a considerable part of the thesis deals purely with the continuous DC discharge. In the case of the low- pressure plasma jet, the attention was focused also on the characteristic property of this plasma source, which is the flow from the jet.
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Computer study of probe diagnostics in high-temperature plasma
Lachnitt, Jan ; Hrach, Rudolf (advisor) ; Kudrna, Pavel (referee)
Title: Computational study of probe diagnostics in high-temperature plasma Author: Jan Lachnitt Department: Department of Surface and Plasma Science Supervisor: prof. RNDr. Rudolf Hrach, DrSc., Department of Surface and Plasma Science Abstract: This work is concerned to the particle computer modelling of the interaction of plasma, especially edge plasma, with immersed solids, especially probes. First, the speed and accuracy of several algorithms of the electrostatic force calculation were compared. One of the algorithms has been newly proposed. Then, a two-dimensional model of the interaction of collision-less plasma with a probe was created. This model has been applied to experimental data from CASTOR tokamak. The crucial point of this work is the creation of a fully three-dimensional particle model. This model has been tested for accuracy and speed and has been parallelized for higher efficiency. Keywords: plasma, probe diagnostics, computational physics, particle modelling
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Studies of tokamak edge plasma and its interaction with the first wall
Komm, Michael ; Kudrna, Pavel (advisor) ; Hrach, Rudolf (referee) ; Svoboda, Vojtěch (referee)
Title: Studies of tokamak edge plasma and its interaction with the first wall Author: Michael Komm Department: Department of Surface and Plasma Science Thesis director: doc. Mgr. Pavel Kudrna, Dr. KFPP Thesis supervisor: Dr. Renaud Dejarnac, IPP CAS CR Abstract: This work presents results of simulations of nuclear fusion related problems, using both 2D PIC code (SPICE2) and full 3D code (SPICE3). The simulations allowed us to predict particle and heat loads coming from plasma onto the divertor tiles, which is a key problem for the next-step de- vices. The results of simulations contributed to the research of fuel retention in the gaps between divertor tiles. We we also able to explain the behaviour of the Katsumata probe and verify the validity of its measurements. Keywords: Tokamak, PIC, divertor, tritium, Katsumata
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