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Studium turbulence plazmatu tokamaku pomocí reciprokých sond
Ondáč, Peter ; Horáček, Jan (advisor) ; Komm, Michael (referee)
This thesis deals with the study of turbulence in tokamak plasma and im- provement of an computer model ESEL. The first chapter deals with the theory related to the study of turbulence in the plasma. For the study of these tur- bulences the results of the probe measurements on the ASDEX Upgrade and COMPASS tokamak and model results from a computer model of the turbulent ESEL are used. The second chapter describes the used probes and the third chapter describes the model ESEL. Contribution of the work is mainly in the fourth and fifth chapter, which summarize the results of the comparisons be- tween the experimental data and model ESEL. The sixth chapter summarizes the most important conclusions from these comparisons. Some agreements and discrepancies were shown. One of the main results of the thesis is the impor- tance of one extra term in one governing equation of the ESEL, which means its improvement. However at present the ESEL is still not able to fully describe the tokamak plasma boundary. 1
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Selected issues of thermonuclear fusion in tokamak-like magnetic containers
Ondáč, Peter ; Tichý, Milan (advisor) ; Kudrna, Pavel (referee)
In this thesis there are summarized in the form of basic knowledge the basic problems of fusion research. It serves as an introduction to this field of physics for beginners, but also intermediate candidates. The first two chapters set out the basic terms and ideas associated with controlled thermonuclear fusion. Further described is the magnetic confinement in tokamaks. Physically most important is the third chapter, which includes more advanced parts of physics. It discusses the main focus of this work, i.e. some of the major problems hindering fusion research. Final fourth chapter is relaxed. It discusses the ideas and visions for the near and distant future.
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Experimental Investigation of the Anode Area in the Hybrid Water-Gas DC Arc Plasma Torch
Ondáč, Peter ; Hrabovský, Milan (advisor)
This thesis focuses on an experimental study of the anode area of the hybrid water- gas DC arc plasma torch that is used in many industrial applications, including plasma spraying, hydrocarbon reforming, pyrolysis, and organic waste gasification. The effects of ambient pressure and plasma generation conditions on the torch's plasma jet were studied, with particular focus on the torch's anode area. Movement of the anode arc attachment is described in detail, including its speed, range of its motion on the anode surface, restrike periods, and the frequency of its many sudden decelerations and re-accelerations. It was found that the anode erosion can be compared relatively simply by quick processing of high-speed camera videos. The anode erosion was also measured directly. Many electric probe measurements were made in the anode area of this plasma torch for the first time. By using these electric probes, shock waves, turbulent vortices, and plasma potential fluctuations were studied directly. It was found that a mean plasma electric field and a mean plasma electrical conductivity in the anode area can be satisfactorily estimated also non-intrusively by quick processing of high-speed camera videos. Moreover, schlieren videos of the plasma jet in the anode area were created. 1
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Experimental Investigation of the Anode Area in the Hybrid Water-Gas DC Arc Plasma Torch
Ondáč, Peter ; Hrabovský, Milan (advisor)
This thesis focuses on an experimental study of the anode area of the hybrid water- gas DC arc plasma torch that is used in many industrial applications, including plasma spraying, hydrocarbon reforming, pyrolysis, and organic waste gasification. The effects of ambient pressure and plasma generation conditions on the torch's plasma jet were studied, with particular focus on the torch's anode area. Movement of the anode arc attachment is described in detail, including its speed, range of its motion on the anode surface, restrike periods, and the frequency of its many sudden decelerations and re-accelerations. It was found that the anode erosion can be compared relatively simply by quick processing of high-speed camera videos. The anode erosion was also measured directly. Many electric probe measurements were made in the anode area of this plasma torch for the first time. By using these electric probes, shock waves, turbulent vortices, and plasma potential fluctuations were studied directly. It was found that a mean plasma electric field and a mean plasma electrical conductivity in the anode area can be satisfactorily estimated also non-intrusively by quick processing of high-speed camera videos. Moreover, schlieren videos of the plasma jet in the anode area were created. 1
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Experimental Investigation of the Anode Area in the Hybrid Water-Gas DC Arc Plasma Torch
Ondáč, Peter ; Hrabovský, Milan (advisor) ; Pekárek, Stanislav (referee) ; Bartlová, Milada (referee)
This thesis focuses on an experimental study of the anode area of the hybrid water- gas DC arc plasma torch that is used in many industrial applications, including plasma spraying, hydrocarbon reforming, pyrolysis, and organic waste gasification. The effects of ambient pressure and plasma generation conditions on the torch's plasma jet were studied, with particular focus on the torch's anode area. Movement of the anode arc attachment is described in detail, including its speed, range of its motion on the anode surface, restrike periods, and the frequency of its many sudden decelerations and re-accelerations. It was found that the anode erosion can be compared relatively simply by quick processing of high-speed camera videos. The anode erosion was also measured directly. Many electric probe measurements were made in the anode area of this plasma torch for the first time. By using these electric probes, shock waves, turbulent vortices, and plasma potential fluctuations were studied directly. It was found that a mean plasma electric field and a mean plasma electrical conductivity in the anode area can be satisfactorily estimated also non-intrusively by quick processing of high-speed camera videos. Moreover, schlieren videos of the plasma jet in the anode area were created. 1
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Measuring of Mean Plasma Electrical Conductivity in Anode Area of Plasma Torches with an External Anode
Ondáč, Peter ; Mašláni, Alan ; Hrabovský, Milan
We developed a non-intrusive direct procedure of measuring an average electrical conductivity of a plasma volume in hot anode areas of those plasma torches. For our measurements, we used a high-speed camera, a high-voltage probe, and a hybrid water–argon plasma torch. The measurements were made for various values of ambient pressure, arc electric current, and argon flow rate. The measured plasma conductivity is in agreement with a model, camera observations and indirectly also with spectroscopy measurements. The procedure provides missing experimental data on the average plasma electrical conductivity and estimates average plasma temperature in the anode areas. The procedure can be theoretically used in every plasma torch where the anode arc attachment movement can be observed during a restrike process\n
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Studium turbulence plazmatu tokamaku pomocí reciprokých sond
Ondáč, Peter ; Horáček, Jan (advisor) ; Komm, Michael (referee)
This thesis deals with the study of turbulence in tokamak plasma and im- provement of an computer model ESEL. The first chapter deals with the theory related to the study of turbulence in the plasma. For the study of these tur- bulences the results of the probe measurements on the ASDEX Upgrade and COMPASS tokamak and model results from a computer model of the turbulent ESEL are used. The second chapter describes the used probes and the third chapter describes the model ESEL. Contribution of the work is mainly in the fourth and fifth chapter, which summarize the results of the comparisons be- tween the experimental data and model ESEL. The sixth chapter summarizes the most important conclusions from these comparisons. Some agreements and discrepancies were shown. One of the main results of the thesis is the impor- tance of one extra term in one governing equation of the ESEL, which means its improvement. However at present the ESEL is still not able to fully describe the tokamak plasma boundary. 1
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Selected issues of thermonuclear fusion in tokamak-like magnetic containers
Ondáč, Peter ; Tichý, Milan (advisor) ; Kudrna, Pavel (referee)
In this thesis there are summarized in the form of basic knowledge the basic problems of fusion research. It serves as an introduction to this field of physics for beginners, but also intermediate candidates. The first two chapters set out the basic terms and ideas associated with controlled thermonuclear fusion. Further described is the magnetic confinement in tokamaks. Physically most important is the third chapter, which includes more advanced parts of physics. It discusses the main focus of this work, i.e. some of the major problems hindering fusion research. Final fourth chapter is relaxed. It discusses the ideas and visions for the near and distant future.
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Arc–Anode Attachment Area in DC Arc Plasma Torch at Low Pressure
Ondáč, Peter ; Mašláni, Alan ; Hrabovský, Milan
Studying the processes in the anode attachment area of a DC arc plasma torch helps to extend the lifetime of the anode, stabilize the plasma flow for plasma spraying and better understand the movement of the anode attachment. In this work, such processes were studied at low pressure, by a non-disturbing method, using a high-speed camera and a high voltage probe. We also found pressure ranges, in which the following transitions were observed: the constricted/diffuse anode attachment, and subsonic/supersonic plasma jet\n
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