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Application of methods of computational physics for the study of plasma-solid interaction
Hromádka, Jakub ; Hrach, Rudolf (advisor) ; Novák, Stanislav (referee)
Low-temperature plasma and its interaction with immersed solids is studied in this work. The research of the physical processes on this interface is performed by two-dimensional particle computer model. The model uses molecular dynamic method. Mutual forces between particles are computed by Particle- in-Cell method. The main application of the model is in the area of the probe diagnostic of plasma. Simple problems are compared with theory and two dimensional effects are discused. Contribution of particle modeling to plasma research is showed on the problem of interaction of sheaths around cylidrical probes. We deal with question whether we are able to get some information about unevennesses at the surface of solid immersed in plasma by measuring probe characteristics in its surroundings. We also studied the influence of plasma electronegativity on the parameters of sheaths around cylidrical probes. Powered by TCPDF (www.tcpdf.org)
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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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Modelling of plasma-solid interaction
Nožka, Jan ; Hrach, Rudolf (advisor) ; Hron, Jaroslav (referee)
Title: Modelling of plasma-solid interaction Author: Jan Nožka Department: Institute of Theoretical Physics Supervisor: prof. RNDr. Rudolf Hrach, DrSc., Department of Surface and Plasma Science Abstract: This work is devoted to computer modeling of the low-temperature argon plasma discharge. We created one basic particle model and one basic fluid model. Furthermore, we created a model of electron-electron interaction in three dimensions. This model is able to stabilize nonequilibrium electron gas in the expected equilibrium. This model was developed to investigate the influence of electron-electron scattering on the acceleration of electrons above the speed that is sufficient for excitation or ionization of neutral argon atom. At the end of this work there are results that shed a light on the importance of this interaction in comparison with the amount of fast electrons that are present in the plasma due to electric filed field.
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Study of plasma-solid interaction by methods of computational physics
Palacký, Jakub ; Hrach, Rudolf (advisor) ; Novák, Stanislav (referee)
The diploma thesis is focused on the study of low-temperature plasma by methods of computational physics, namely particle modelling. The solution focuses on the time- effective execution of simulations, which is concerned, among the other things, with the use of parallelization techniques aimed at maximize shortening of the calculation time. The Langmuir probe was chosen as the most common representative of the probe diagnostics. The main goal of this work was to observe plasma interaction with the embedded solid. Current research on plasma modelling intensively explores dynamic phenomena such as wave propagation or turbulence and instability. For this reason, much of the work is devoted to the dynamics in electropositive and electronegative plasma.
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Plasma diagnostics by probes with complex geometries
Palacký, Jakub ; Hrach, Rudolf (advisor) ; Roučka, Štěpán (referee)
In investigating the behaviour of the plasma, it is important to know its parameters. For this purpose, there are many diagnostic methods, one of which is a probe diagnostic. It is a local method in which there is contact of the plasma with embedded material. This work deals with this diagnostic method. It gives a comprehensive overview of the currently used probes in low-temperature and especially in high-temperature plasmas. It focuses on the development and use of the latest advances in the field of computational physics for creating two-dimensional model of low-temperature plasma with immersed solid. The task is prepare particle model of low-temperature plasma with immersed metal electrode, then run simulation of measurement and to interpret measured data.
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Application of methods of computational physics for the study of plasma-solid interaction
Hromádka, Jakub ; Hrach, Rudolf (advisor) ; Novák, Stanislav (referee)
Low-temperature plasma and its interaction with immersed solids is studied in this work. The research of the physical processes on this interface is performed by two-dimensional particle computer model. The model uses molecular dynamic method. Mutual forces between particles are computed by Particle- in-Cell method. The main application of the model is in the area of the probe diagnostic of plasma. Simple problems are compared with theory and two dimensional effects are discused. Contribution of particle modeling to plasma research is showed on the problem of interaction of sheaths around cylidrical probes. We deal with question whether we are able to get some information about unevennesses at the surface of solid immersed in plasma by measuring probe characteristics in its surroundings. We also studied the influence of plasma electronegativity on the parameters of sheaths around cylidrical probes. Powered by TCPDF (www.tcpdf.org)
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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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Advanced techniques of computer modelling in low- and high-temperature plasma physics
Pekárek, Zdeněk ; Hrach, Rudolf (advisor) ; Kudrna, Pavel (referee) ; Hron, Jaroslav (referee)
This thesis identifies the obstacles in efficient modelling of interaction of plasma and solid surfaces. It presents an enhanced method of solving the Poisson equation optimized to meet the requirements of the Particle-in-Cell modelling approach. A number of applications are discussed, including models of the plasma-facing wall of the nuclear fusion device, tokamak, and its interaction with particle fluxes driven by the intrinsic magnetic field. Another area of applications covers the modelling of plasma probes deployed to diagnose properties of plasma in various experiments. The thesis also includes the computer library code and instructions enabling a rapid use of the Poisson solver method in a third party computer code which implements the PIC approach in a compatible manner.
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Modelling of plasma-solid interaction
Nožka, Jan ; Hrach, Rudolf (advisor) ; Hron, Jaroslav (referee)
Title: Modelling of plasma-solid interaction Author: Jan Nožka Department: Institute of Theoretical Physics Supervisor: prof. RNDr. Rudolf Hrach, DrSc., Department of Surface and Plasma Science Abstract: This work is devoted to computer modeling of the low-temperature argon plasma discharge. We created one basic particle model and one basic fluid model. Furthermore, we created a model of electron-electron interaction in three dimensions. This model is able to stabilize nonequilibrium electron gas in the expected equilibrium. This model was developed to investigate the influence of electron-electron scattering on the acceleration of electrons above the speed that is sufficient for excitation or ionization of neutral argon atom. At the end of this work there are results that shed a light on the importance of this interaction in comparison with the amount of fast electrons that are present in the plasma due to electric filed field.
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