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Preliminary Measurements of Neutrons From The D-D Reaction in The Compass Tokamak
Dankowski, J. ; Janky, Filip ; Kurowski, A. ; Stöckel, Jan ; Twarog, D.
Recent results of measured fast neutrons created in the D-D reaction on the COMPASS tokamak during ohmic discharges are presented in this paper. Two different type detectors were used during experiment. He-3 detectors and bubble detectors as a support. The measurements are an introduction for neutron diagnostic on tokamak COMPASS and monitoring neutrons during discharges with Neutral Beam Injection (NBI). The He-3 counters and bubble detectors were located in two positions near tokamak vacuum chamber at a distance less than 40 cm to the centre of plasma. The neutrons flux was observed in ohmic discharges. However, analysis of our results does not indicate any clear source of neutrons production during ohmic discharges.
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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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Heat and Particle Deposition on the Plasma-Facing Components
Podolník, Aleš ; Pánek, Radomír ; Komm, Michael ; Dejarnac, Renaud ; Gunn, J. P.
The interaction of plasma with plasma-facing components (PFCs) in tokamaks is of increasing interest because of implications for ITER and next-step devices. The heat and particle fluxes interacting with solid objects can be studied by means of particle-in-cell (PIC) simulations. The aim of this work is to use the existing family of PIC codes SPICE to simulate the heat and particle flux distribution on PFCs. The output of the simulations is then used in new heat equation solver, which calculates the temperature of the PFCs. This solver provides us a testbed for the parallel sparse matrix code development as well as for the complex application aimed at study of the melting of tiles.
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