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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.
2014 - English
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.
Keywords:
Plasma diagnostics; infrared thermography; infrared camera; tokamak; near SOL
Fulltext is available at external website.
Parallel Heat Flux Decay Length Study in the COMPASS Tokamak Using MWIR and LWIR Cameras
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 ...
Properties of Filamentary Structures in Different Regimes of Plasma Confinement on the COMPASS Tokamak
Kovařík, Karel; Ďuran, Ivan; Stöckel, Jan; Adámek, Jiří; Spolaore, M.; Vianello, N.
2014 - English
A complex electrostatic-magnetic probe diagnostic, called U-probe, has been installed on the tokamak COMPASS recently. Probe composes of two identical towers. Each tower houses radialy separated 3 sets of 3D coils, a triple probe and a rake of six single Langmuir probes. We present measurements of electric and magnetic properties of the filamentary structures in the scrape off layer plasmas during different regimes of plasma confinement on COMPASS tokamak
Keywords:
U-probe; tokamak; COMPASS; plasma; Langmuir probes
Fulltext is available at external website.
Properties of Filamentary Structures in Different Regimes of Plasma Confinement on the COMPASS Tokamak
A complex electrostatic-magnetic probe diagnostic, called U-probe, has been installed on the tokamak COMPASS recently. Probe composes of two identical towers. Each tower houses radialy separated 3 ...
The Absolute Sensitivity Measurements of Spectra in Near IR Range at the COMPASS Tokamak
Naydenkova, Diana; Stöckel, Jan; Weinzettl, Vladimír
2014 - English
The new impurity survey spectrometer HR 2000+ is used for registration of the most intense spectral lines in the 654–1085 nm near IR range with spectral resolution 0.23 nm and temporal resolution from 4 ms to discharge duration at the COMPASS tokamak. The procedure of the absolute calibration of the spectrometer is described and technical issues and experimental limitations connected with its operation are discussed here. The measured spectra are interpreted and results are discussed.
Keywords:
tokamak; COMPASS; spectrometer HR 2000+
Fulltext is available at external website.
The Absolute Sensitivity Measurements of Spectra in Near IR Range at the COMPASS Tokamak
The new impurity survey spectrometer HR 2000+ is used for registration of the most intense spectral lines in the 654–1085 nm near IR range with spectral resolution 0.23 nm and temporal resolution ...
Infrared Thermography on the COMPASS Tokamak
Vondráček, Petr; Horáček, Jan; Cahyna, Pavel; Pánek, Radomír; Uličný, J.
2013 - English
This contribution describes a new slow infrared camera obtained by the COMPASS tokamak at IPP Prague. We focus on the camera limitations affecting the experimental data (temporal and spatial smoothing, time shift). Data time deconvolution used to correct the effect of the long response time of the camera detector is described. The second part of the contribution is devoted to the physic basis for the design of a new fast IR camera system planned for installation in COMPASS during the next year.
Keywords:
Plasma diagnostics; infrared camera; tokamak
Fulltext is available at external website.
Infrared Thermography on the COMPASS Tokamak
This contribution describes a new slow infrared camera obtained by the COMPASS tokamak at IPP Prague. We focus on the camera limitations affecting the experimental data (temporal and spatial ...
New Detection System for Fast Density Measurements Using the Lithium Beam on the COMPASS Tokamak
Háček, Pavel; Berta, M.; Stöckel, Jan; Weinzettl, Vladimír; Anda, G.; Bencze, A.; Zoletnik, S.
2013 - English
The lithium beam diagnostic at COMPASS is designed for measurements of the edge plasma density profile and fluctuations and edge plasma current fluctuations. The principle of the diagnostic is detection of light coming from collisionally excited Li atoms — beam emission spectroscopy (BES) - and a direct detection of the ionized part of the beam (atomic beam probe — ABP). For slow density measurements a charged coupled device (CCD) camera has been installed and is already working. For fast twodimensional density profile and density fluctuation measurements an array of avalanche photodiode detectors (APDs) will be used. The two-dimensional resolution of the measurement will be possible using fast poloidal deflection and chopping of the beam. Apart from routine density profile measurement, the diagnostic will be capable of investigating the turbulent structures in the edge plasma by cross-correlating the signals coming from poloidally deflected virtual beams.
Keywords:
Diagnostic lithium beam; Plasma diagnostics; tokamak
Fulltext is available at external website.
New Detection System for Fast Density Measurements Using the Lithium Beam on the COMPASS Tokamak
The lithium beam diagnostic at COMPASS is designed for measurements of the edge plasma density profile and fluctuations and edge plasma current fluctuations. The principle of the diagnostic is ...
Design and Preliminary Results of the COMPASS Power Supplies Filters
Havlíček, Josef; Zajac, Jaromír
2013 - English
The COMPASS tokamak uses rectifying thyristor converters as Power Supplies for the major slow coils circuits. 24-pulse thyristor converter is used for Toroidal Field circuit and 12-pulse converters are used for Magnetizing, Equilibrium and Shaping Field circuits. A noise generated by the switching of the converters negatively influences diagnostics measuring the plasma. The article describes design phase and some preliminary results of the filters for the Power Supplies
Keywords:
COMPASS tokamak; magnetic field; plasma
Fulltext is available at external website.
Design and Preliminary Results of the COMPASS Power Supplies Filters
The COMPASS tokamak uses rectifying thyristor converters as Power Supplies for the major slow coils circuits. 24-pulse thyristor converter is used for Toroidal Field circuit and 12-pulse converters ...
Absolute Sensitivity Calibration of Visible Spectroscopic Diagnostic and Temporal Evolution of First Window Transmittance at the COMPASS Tokamak
Naydenkova, Diana; Weinzettl, Vladimír; Stöckel, Jan; Háček, Pavel; Imríšek, Martin
2013 - English
An absolute calibration of spectroscopic systems is required to measure many important plasma parameters in tokamak discharges like impurity inflow, recycling and the effective ion charge. The procedure of the absolute calibration is described and technical issues and experimental limitations connected with the tokamak operation are discussed here. Namely, an influence of the first window transmittance and its evolution over experimental campaigns on the validity of the absolute calibration is investigated
Keywords:
COMPASS; tokamak; Visible Spectroscopic Diagnostic; Absolute Sensitivity; Calibration
Fulltext is available at external website.
Absolute Sensitivity Calibration of Visible Spectroscopic Diagnostic and Temporal Evolution of First Window Transmittance at the COMPASS Tokamak
An absolute calibration of spectroscopic systems is required to measure many important plasma parameters in tokamak discharges like impurity inflow, recycling and the effective ion charge. The ...
Observation of Sawtooth Oscillations in the COMPASS Tokamak
Imríšek, Martin; Havlíček, Josef; Weinzettl, Vladimír; Mlynář, Jan
2013 - English
The sawtooth instability in tokamak plasmas results in periodic relaxations of the core plasma density and temperature. The physics of sawtooth is still not fully understood. It is predicted that fusion-born alpha particles will lead to long sawteeth. However, longer sawteeth can seed other instabilities which cause further degradation of plasma confinement. This paper provides brief introduction into sawtooth physics and observations of sawtooth instability in COMPASS. Furthermore, evidence of triggering transition to high confinement regime by sawtooth crash is presented
Keywords:
Sawtooth; tokamak; soft-x ray; COMPASS
Fulltext is available at external website.
Observation of Sawtooth Oscillations in the COMPASS Tokamak
The sawtooth instability in tokamak plasmas results in periodic relaxations of the core plasma density and temperature. The physics of sawtooth is still not fully understood. It is predicted that ...
Observation and Prediction of Runaway Electrons in the COMPASS Tokamak
Papřok, R.; Krlín, Ladislav; Stöckel, Jan
2013 - English
In this paper we present new measurements of HXR radiation from the COMPASS tokamak by the use of scintillation detector, 21-pinhole CdTe semiconductor detector. This radiation is caused by the presence of highly energetic runaway electrons and in the case of Neutral Beam Injection by fusion products. We also present direct runaway electrons measurements by Cherenkov detector. We present a theoretical prediction of runaway production based on theoretical formula and experimental data from Thomson scattering and compare it with a simpler experimental method based on peak counting.
Keywords:
tokamak; COMPASS
Fulltext is available at external website.
Observation and Prediction of Runaway Electrons in the COMPASS Tokamak
In this paper we present new measurements of HXR radiation from the COMPASS tokamak by the use of scintillation detector, 21-pinhole CdTe semiconductor detector. This radiation is caused by the ...
Optické návrhy několika přístrojů sluneční fyziky
Rail, Zdeněk; Jareš, Daniel; Tomka, David; Doleček, Roman
2013 - Czech
Tato práce popisuje optický návrh několika přístrojů, které se používají pro pozorování Slunce. Jedná se o koronograf a chromosférický dalekohled. V obou případech je kladen důraz na jednoduchost vlastního optického systému a dosažení vysoce kvalitních zobrazovacích vlastností. Koronograf je navržen pro 7 optických prvků;, čímž je minimalizováno množství rozptýleného světla. Chromosférický dalekohled je navržen pro dvojlomně polarizační a Fabry-Perotovy filtry. Všechna tato řešení mohou sloužit jako výchozí návrhy pro další složitější přístroje. This paper presents optical designs of several devices which are used in solar astronomy – coronograph and telescope for the observations of chromosphere. We insist on high quality of images and simplicity of the whole optical design. The coronograph is composed of 7 optical parts to minimize dispersed light. The chromospheric telescope is designed both for birefringent and Fabry-Perot filters. All these designs could be used as the initial solutions for much complicated devices
Keywords:
The optical designs of chromospheric telescopes and coronograph; spektrographs with birefringent and Fabry-Perot filters; minimization of number of optical members and scattered light; high quality and contrast images of solar chromosphere and corona
Fulltext is available at external website.
Optické návrhy několika přístrojů sluneční fyziky
Tato práce popisuje optický návrh několika přístrojů, které se používají pro pozorování Slunce. Jedná se o koronograf a chromosférický dalekohled. V obou případech je kladen důraz na jednoduchost ...
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