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MHD nestability plazmatu pozorované ve výbojích tokamaku COMPASS
Kripner, Lukáš ; Němeček, Zdeněk (advisor) ; Havlíček, Josef (referee)
Compass tokamak (R = 0.56 m, a = (0.23 × 0.38) m, Ip = 200 − 400 kA, BT = 1.2 − 2.1 T and pulse length up to 1 s) is the smallest device with ITER-relevant plasma geometry with scale 1:10 to the ITER size. A tokamak plasma confinement is strongly limited by an occurrence of magnetohydrodynamic (MHD) instabilities occurring during the discharge. In the thesis, theoretical considerations and a typical behaviour of the tokamak plasma MHD instabilites are summarized based on the lite- rature overview. This discussion is complemented with an overview of the Compass diagnostics and different data analysis techniques. Finally, the examples of the Compass plasma behaviour influenced by sawtooth instability and tearing modes are shown and discussed. 1
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Rozložení tepelných toků na stěnu tokamaku způsobených okrajovými nestabilitami
Kripner, Lukáš ; Cahyna, Pavel (advisor) ; Urban, Jakub (referee)
Edge localized modes (ELMs) are a concern for future magnetic fusion devices, such as ITER, due to the large transient heat loads they generate on the plasma facing components. A very promising method of ELM suppression is an application of resonant magnetic perturbations (RMP); however, such application leads to localized places of higher heat fluxes called footprints. Both ELMs and RMP could limit the operational lifetime of the device. In this thesis, we analyze the temporal and spatial distribution of footprints using the tangle distance method in the aim to prevent a transient overheating. We also analyze quasi-double-null configuration of the ITER plasma which can be expected to be the most susceptible to overheating of the upper wall. Based on the modelling, the potentially dangerous configurations of the RMP have been shown. Using the ELM filament model included in the LOCUST GPU code, we study temporal and spatial distribution of the heat fluxes caused by ELMs in the axially symmetric and the asymmetric magnetic field. The results are compared with published experimental observations. Powered by TCPDF (www.tcpdf.org)
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Rozložení tepelných toků na stěnu tokamaku způsobených okrajovými nestabilitami
Kripner, Lukáš ; Cahyna, Pavel (advisor) ; Urban, Jakub (referee)
Edge localized modes (ELMs) are a concern for future magnetic fusion devices, such as ITER, due to the large transient heat loads they generate on the plasma facing components. A very promising method of ELM suppression is an application of resonant magnetic perturbations (RMP); however, such application leads to localized places of higher heat fluxes called footprints. Both ELMs and RMP could limit the operational lifetime of the device. In this thesis, we analyze the temporal and spatial distribution of footprints using the tangle distance method in the aim to prevent a transient overheating. We also analyze quasi-double-null configuration of the ITER plasma which can be expected to be the most susceptible to overheating of the upper wall. Based on the modelling, the potentially dangerous configurations of the RMP have been shown. Using the ELM filament model included in the LOCUST GPU code, we study temporal and spatial distribution of the heat fluxes caused by ELMs in the axially symmetric and the asymmetric magnetic field. The results are compared with published experimental observations. Powered by TCPDF (www.tcpdf.org)
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MHD nestability plazmatu pozorované ve výbojích tokamaku COMPASS
Kripner, Lukáš ; Němeček, Zdeněk (advisor) ; Havlíček, Josef (referee)
Compass tokamak (R = 0.56 m, a = (0.23 × 0.38) m, Ip = 200 − 400 kA, BT = 1.2 − 2.1 T and pulse length up to 1 s) is the smallest device with ITER-relevant plasma geometry with scale 1:10 to the ITER size. A tokamak plasma confinement is strongly limited by an occurrence of magnetohydrodynamic (MHD) instabilities occurring during the discharge. In the thesis, theoretical considerations and a typical behaviour of the tokamak plasma MHD instabilites are summarized based on the lite- rature overview. This discussion is complemented with an overview of the Compass diagnostics and different data analysis techniques. Finally, the examples of the Compass plasma behaviour influenced by sawtooth instability and tearing modes are shown and discussed. 1
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