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Electric Probe Diagnostic of Supersonic Thermal Plasma Jet
Hurba, Oleksiy ; Hrabovský, Milan
This paper describes how electric probes can be used as relatively simple and efficient tool for investigation of structure of flow field in thermal plasma jet at the low pressure. A boundary of plasma jet between nozzle of plasma torch and ambient air was investigated by means of array of moving electric probes. Were defined boundaries of the conducting region and their change with pressure change
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Poisson Equation Solver Parallelisation for Particle-in-Cell Model
Podolník, Aleš ; Komm, Michael ; Dejarnac, Renaud ; Gunn, J. P.
Numerical simulations based on PIC technique like the SPICE2 model developed at IPP ASCR are often used in tokamak plasma physics to investigate the interaction of edge plasma with plasma-facing components. The SPICE2 model has been parallelised with the exception of the Poisson equation solver which considerably slows down the simulations. It is now being upgraded to a parallelised version to be efficient enough to perform more demanding tasks like the ITER tokamak baseline scenario edge plasma whose conditions like high density (up to 1020 m−3) and low temperature (1–2 eV) result in simulations taking several months to compute. Performance and scaling are compared for different cases in order to choose the optimal candidate for aforementioned applications.
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Plasma Boundary Reconstruction using Fast Camera on the COMPASS Tokamak
Háček, Pavel ; Berta, Miklós ; Stöckel, Jan ; Weinzettl, Vladimír ; Budai, C. ; Szabolics, T. ; Bencze, A.
Determination of the plasma boundary is an important task for safe operation of the tokamak and diagnostic systems as well as for correct interpretation of the measured data. Magnetic reconstruction codes routinely used to determine the shape of the plasma have a number of limitations which can make the reconstruction problematic. Recently, it has been demonstrated on several devices that it is possible to provide independent measurement of the plasma boundary by observation of the visiblelight emission using fast framing cameras. In the presented work, a single fast camera on the COMPASS tokamak was used for reconstruction of the optical plasma boundary, assuming a toroidally symmetric visible-light emission profile located in the edge of plasma. As a first result, application of the method on D-shaped COMPASS shot 7145 and its comparison with magnetic reconstruction from the EFIT code is given. Both methods show good agreement with average difference 0.5 cm.
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Study of Alfven Eigenmodes in Tokamak COMPASS
Markovič, Tomáš ; Stöckel, Jan ; Seidl, Jakub ; Melnikov, A. ; Medvedev, S.
Having both MHD and kinetic character plasma Alfven eigenmodes are signicant not only on the eld basic plasma research, but also on the eld of magnetic connement fusion. An introduction to basic physical principles of Alfven eigenmodes under MHD approximation is provided. Presented results of recent experiments on COMPASS suggest occurrence of toroidal Alfven eigenmodes in this tokamak, which is further supported by preliminary linear MHD code simulations, althought more studies will have to be conducted in the future to further investigate presented modes therein.
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Parallel Heat Flux Decay Length Study in the COMPASS Tokamak Using MWIR and LWIR Cameras
Vondráček, Petr ; Horáček, Jan ; Pánek, Radomír ; Gauthier, E.
A comprehensive study of a parallel heat flux in a tokamak scrape-off layer (SOL) has been performed in the COMPASS tokamak recently. Specially shaped high field side (HFS) limiter was used to estimate a heat flux radial decay length for small limiter radial misalignment. Long wavelength IR microbolometer and medium wavelength IR InSb camera were used for this purpose. This paper compares results obtained by the means of both cameras and demonstrates observation of very narrow heat flux decay length close to the last closed flux surface (LCFS) independantly on used camera.
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Global Power Balance in Non-Stationary Discharge Phases in the COMPASS Tokamak
Havlíček, Josef ; Imríšek, Martin ; Kovařík, Karel ; Weinzettl, Vladimír
The global power balance between different input power and sink/loss channels is important for understanding of tokamak physics, particularly for various scaling laws. The power balance is measured easily during stationary discharge phases because the terms for both magnetic field energy and plasma thermal energy build-up can be neglected. However, many important events in tokamak plasmas occur during non-stationary phases of the discharge. This article describes, quantifies and discusses the terms of the global power balance, including time dependent parts, and exemplifies them on the typical ohmic discharge of the COMPASS tokamak.
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