Studium plazmatu v zařízeních typu tokamak spektroskopickými metodami

V Ústavu fyziky plazmatu Akademie věd, v oddělení Tokamak, se spektroskopickými metodami zkoumá záření vysokoteplotního plazmatu ve viditelné, ultrafialové a infračervené oblasti. Toto záření přináší informace týkající se parametrů tokamakového plazmatu a jejich změn, co je důležité z hlediska budoucí realizace fúzního reaktoru. V rámci této disertační práce byl proveden vývoj spektroskopické diagnostiky pro pozorování záření plazmatu a jeho změn v čase v tokamaku COMPASS. Byla udělána absolutní kalibrace vyvinutých systémů za účelem propočtu měřeného signálu na jednotky záření. V první části disertační práce jsou podrobně popsány zdroje nepřesností absolutního měření v podmínkách tokamaku. Měřené záření plazmatu v rozsahu vlnových délek 257-1083 nm bylo interpretováno s použitím databáze NIST a programu FLYCHK. Byla odhadnuta hustota iontů pro nejvýznamnější nečistoty. V jazyku IDL byl vyvinutý program pro odhad efektivního iontového náboje z poměru brzdného záření skutečného a vodíkového plazmatu v okolí vlnové délky 523 nm. Pro výpočet brzdného záření vodíkového plazmatu byly použity profily elektronové hustoty a teploty měřené Thomsonovým rozptylem. V poslední části práce je uveden příklad použití spektroskopických dat pro studium zahřívání plazmatu použitím svazku neutrálních částic.In Tokamak department of Institute of Plasma Physics, radiation of high-temperature plasma is investigated using spectroscopic methods in visible, ultraviolet and infrared regions. The radiation gives information regarding tokamak plasma parameters and their changes, which is necessary for future realization of fusion reactor. In the frame of this doctoral thesis the development of spectroscopic diagnostics for observing of plasma radiation and its temporal evolution in COMPASS tokamak was performed. The absolute calibration of developed systems in order to recalculate measured signal to units of radiation was done. The sources of imprecisions of absolute measurements in tokamak conditions are properly discussed in the first part of the dissertation. Plasma radiation in the range 257-1083 nm was measured and interpreted using NIST database and FLYCHK code. Ion density for the most significant impurities was estimated. IDL code for effective ion charge estimation as a ratio of real and hydrogen plasma Bremsstrahlung radiation near 523 nm was developed. Profiles of electron density and temperature measured by Thomson scattering system were used for hydrogen plasma Bremsstrahlung radiation calculations. The example of applying of spectroscopic data for studying of COMPASS plasma heating using neutral beam...Faculty of Mathematics and PhysicsMatematicko-fyzikální fakult

Measurements of Ion Temperature in the Edge Plasma of the COMPASS Tokamak

The two-grating spectrometer, which has been developed for the ISTTOK tokamak, allows an estimation of the temporal evolution of both ion temperature and poloidal velocity of the edge plasma by analysis of Doppler-shifted and broadened CIII spectral lines at ~465nm. At the current phase of the COMPASS tokamak operation, the first measurements of ion temperature using the optical system based on the spectrometer were performed and first results are presented

Study of plasma in tokamak-type devices with spectroscopic methods

In Tokamak department of Institute of Plasma Physics, radiation of high-temperature plasma is investigated using spectroscopic methods in visible, ultraviolet and infrared regions. The radiation gives information regarding tokamak plasma parameters and their changes, which is necessary for future realization of fusion reactor. In the frame of this doctoral thesis the development of spectroscopic diagnostics for observing of plasma radiation and its temporal evolution in COMPASS tokamak was performed. The absolute calibration of developed systems in order to recalculate measured signal to units of radiation was done. The sources of imprecisions of absolute measurements in tokamak conditions are properly discussed in the first part of the dissertation. Plasma radiation in the range 257-1083 nm was measured and interpreted using NIST database and FLYCHK code. Ion density for the most significant impurities was estimated. IDL code for effective ion charge estimation as a ratio of real and hydrogen plasma Bremsstrahlung radiation near 523 nm was developed. Profiles of electron density and temperature measured by Thomson scattering system were used for hydrogen plasma Bremsstrahlung radiation calculations. The example of applying of spectroscopic data for studying of COMPASS plasma heating using neutral beam..

Aplikace magneticke diagnostiku pro tokamak COMPASS

The paper outlines the main parameters and characteristics of typical plasma shapes. The reasons, basic physical principles and mechanisms for controlling of a plasma position in vertical and horizontal directions by means of magnetic sensors in the COMPASS tokamak are described below. All main parameters for the position control equate here. The sketchy description of diagnostic sensors and poloidal coils are used for control in COMPASS is done by the authors too. The progress report of current work is present as a summary

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 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 investigate

Progress in Multichannel Optical System for Visible Plasma Radiation Measurements at COMPASS Tokamak

The paper outlines main parameters and characteristics of the multichannel optical system for visible plasma radiation measurements, which is currently under construction on the COMPASS tokamak. Alignment of the fiber endpiece and the detector is described in the contribution. Measured spectra in wavelength ranges 250-475 nm and 457–663nm are shown for typical short-lasting discharges of the COMPASS tokamak, which is not yet equipped with a plasma position stabilization system

Study of plasma in tokamak-type devices with spectroscopic methods

In Tokamak department of Institute of Plasma Physics, radiation of high-temperature plasma is investigated using spectroscopic methods in visible, ultraviolet and infrared regions. The radiation gives information regarding tokamak plasma parameters and their changes, which is necessary for future realization of fusion reactor. In the frame of this doctoral thesis the development of spectroscopic diagnostics for observing of plasma radiation and its temporal evolution in COMPASS tokamak was performed. The absolute calibration of developed systems in order to recalculate measured signal to units of radiation was done. The sources of imprecisions of absolute measurements in tokamak conditions are properly discussed in the first part of the dissertation. Plasma radiation in the range 257-1083 nm was measured and interpreted using NIST database and FLYCHK code. Ion density for the most significant impurities was estimated. IDL code for effective ion charge estimation as a ratio of real and hydrogen plasma Bremsstrahlung radiation near 523 nm was developed. Profiles of electron density and temperature measured by Thomson scattering system were used for hydrogen plasma Bremsstrahlung radiation calculations. The example of applying of spectroscopic data for studying of COMPASS plasma heating using neutral beam..

Návrh nového optického systému pro měření viditelného záření plazmatu na tokamaku COMPASS

The paper outlines main parameters and characteristics of the currently designed multichannel optical system for visible plasma radiation measurements on the COMPASS tokamak. It based on registration of visible light in large observation angle (~70-80º) for 35 lines of sights by means of detectors (photodiode or photomultiplier array) and spectrometer. System has resolution about 1cm in vertical direction. The aim of the introduced system is to get information about parameters of tokamak plasma (impurity content and their distribution) and fast processes, which take place in it

První spektroskopicky měření na tokamaku COMPASS

Spectroscopic measurements were performed on the re-installed COMPASS tokamak during the first experiments. The impurity survey spectrometer HR 2000+ was used for registration of the most intensive spectral lines in the visible range 457-663nm temporally integrated over the discharge duration. An attempt to estimate the ion temperature from Doppler broadening of selected spectral lines is described

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 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