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1

First dedicated observations of runaway electrons in the COMPASS tokamak

100%

Vlainić M., Mlynář J., Weinzettl V., Papřok R., Imríšek M., Ficker O., Vondráček P., Havlíček J.

Nukleonika

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2015

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vol. 60

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issue 2

249-255

EN

Runaway electrons present an important part of the present efforts in nuclear fusion research with respect to the potential damage of the in-vessel components. The COMPASS tokamak a suitable tool for the studies of runaway electrons, due to its relatively low vacuum safety constraints, high experimental flexibility and the possibility of reaching the H-mode D-shaped plasmas. In this work, results from the first experimental COMPASS campaign dedicated to runaway electrons are presented and discussed in preliminary way. In particular, the first observation of synchrotron radiation and rather interesting raw magnetic data are shown.

2

Important problems of future thermonuclear reactors*

88%

Sadowski M. J.

Nukleonika

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2015

|

vol. 60

|

issue 2

331-338

EN

This paper concerns important and difficult problems connected with a design and construction of thermonuclear reactors, which have to use nuclear fusion reactions of heavy isotopes of hydrogen, i.e., deuterium (D) and tritium (T). There are described conditions in which such reactions can occur, and different methods of a high-temperature plasma generation, i.e., high-current electrical discharges, intense microwave pulses, and injection of energetic neutral atoms (NBI). There are also presented experimental facilities which can contain hot plasma for an appropriate period, and particularly so-called tokamaks. The second part presents the technical problems which must be solved in order to build a thermonuclear reactor, that might be used for energetic purposes. There are considered problems connected with a choice of constructional materials for a vacuum chamber, its internal parts, external windings generating a magnetic field, and necessary shields. The next part considers the handling of radioactive tritium; the using of alpha particles (4He) for additional heating of plasma; recuperation of hydrogen isotopes absorbed in the tokamak internal parts, and a removal of a helium excess. There is presented a scheme of a future thermonuclear power plant and critical comments on a road map which should enable the construction of an industrial thermonuclear reactor (DEMO).

3

Selected methods of electron-and ion-diagnostics in tokamak scrape-off-layer

75%

Sadowski M. J.

Nukleonika

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2015

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vol. 60

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issue 2

199-206

EN

This invited paper considers reasons why exact measurements of fast electron and ion losses in tokamaks, and particularly i n a scrape-off-layer and near a divertor region, are necessary in order to master nuclear fusion energy production. Attention is also paid to direct measurements of escaping fusion products from D-D and D-T reactions, and in particular of fast alphas which might be used for plasma heating. The second part describes the generation of so-called runaway and ripple-born electrons which might induce high energy losses and cause severe damages of internal walls in fusion facilities. Advantages and disadvantages of different diagnostic methods applied for studies of such fast electrons are discussed. Particular attention is paid to development of a direct measuring technique based on the Cherenkov effect which might be induced by fast electrons in appropriate radiators. There are presented various versions of Cherenkov-type probes which have been developed by the NCBJ team and applied in different tokamak experiments. The third part is devoted to direct measurements of fast ions (including those produced by the nuclear fusion reactions) which can escape from a high-temperature plasma region. Investigation of fast fusion-produced protons from tokamak discharges is reported. New ion probes, which were developed by the NCBJ team, are also presented. For the first time there is given a detailed description of an ion pinhole camera, which enables irradiation of several nuclear track detectors during a single tokamak discharge, and a miniature Thomson-type mass-spectrometer, which can be used for ion measurements at plasma borders.

4

Soft X-ray Diagnostic System Upgrades and Data Quality Monitoring Features for Tokamak Usage

63%

Wojenski A., Linczuk P., Kolasinski P., Chernyshova M., Mazon D., Kasprowicz G., Pozniak K. T., Gaska M., Czarski T., Krawczyk R., Wojenski A., Linczuk P., Kolasinski P., Chernyshova M., Mazon D., Kasprowicz G., Pozniak K. T., Gaska M., Czarski T., Krawczyk R.

International Journal of Electronics and Telecommunications

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2021

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vol. 67

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issue 1

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First dedicated observations of runaway electrons in the COMPASS tokamak

Important problems of future thermonuclear reactors*

Selected methods of electron-and ion-diagnostics in tokamak scrape-off-layer

Soft X-ray Diagnostic System Upgrades and Data Quality Monitoring Features for Tokamak Usage