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1. Large-scale collecting mirrors for ITER optical diagnostic

Author

Samsonov, D., primary, Tereschenko, I., additional, Mukhin, E., additional, Gubal, A., additional, Kapustin, Yu., additional, Filimonov, V., additional, Babinov, N., additional, Dmitriev, A., additional, Nikolaev, A., additional, Komarevtsev, I., additional, Koval, A., additional, Litvinov, A., additional, Marchii, G., additional, Razdobarin, A., additional, Snigirev, L., additional, Tolstyakov, S., additional, Marinin, G., additional, Terentev, D., additional, Gorodetsky, A., additional, Zalavutdinov, R., additional, Markin, A., additional, Bukhovets, V., additional, Arkhipushkin, I., additional, Borisov, A., additional, Khripunov, V., additional, Mikhailovskii, V., additional, Modestov, V., additional, Kirienko, I., additional, Buslakov, I., additional, Chernakov, P., additional, Mokeev, A., additional, Kempenaars, M., additional, Shigin, P., additional, and Drapiko, E., additional

Published
2022
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2. Large-scale collecting mirrors for ITER optical diagnostic

Author

D. Samsonov, I. Tereschenko, E. Mukhin, A. Gubal, Yu. Kapustin, V. Filimonov, N. Babinov, A. Dmitriev, A. Nikolaev, I. Komarevtsev, A. Koval, A. Litvinov, G. Marchii, A. Razdobarin, L. Snigirev, S. Tolstyakov, G. Marinin, D. Terentev, A. Gorodetsky, R. Zalavutdinov, A. Markin, V. Bukhovets, I. Arkhipushkin, A. Borisov, V. Khripunov, V. Mikhailovskii, V. Modestov, I. Kirienko, I. Buslakov, P. Chernakov, A. Mokeev, M. Kempenaars, P. Shigin, and E. Drapiko

Subjects
Nuclear and High Energy Physics, Condensed Matter Physics
Abstract

The challenges of large-scale mirror design for in-vessel collection system of ITER Divertor Thomson Scattering (DTS) are under consideration. These are the mirrors located out-of-line vision of fusion plasma (so called “second mirrors” i.e. not First Mirrors) with high-reflective Ag-based coating. The paper outlines: approaches providing optical surface shape and angular position stability; Ag coating applicability in nuclear irradiation, ITER in-vessel application and its resistance to Steam Ingress. Although, this assessment and the proposed solutions are considered in terms of ITER DTS compatibility, they may also appear to be of some use in other ITER diagnostics and in diagnostics of other fusion devices.

Published
2022

3. Three-dimensional simulation of neutral transport in gases and weakly ionized plasmas

Author

Varshavchik, L A, primary, Babinov, N A, additional, Zatylkin, P A, additional, Chironova, A A, additional, Lyullin, Z G, additional, Chernakov, Al P, additional, Dmitriev, A M, additional, Bukreev, I M, additional, Mukhin, E E, additional, Razdobarin, A G, additional, Samsonov, D S, additional, Senitchenkov, V A, additional, Tolstyakov, S Yu, additional, Serenkov, I T, additional, and Sakharov, V I, additional

Published
2020
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4. Integration of Thomson scattering and laser-induced fluorescence in ITER divertor

Author

Mukhin, E.E., primary, Kurskiev, G.S., additional, Gorbunov, A.V., additional, Samsonov, D.S., additional, Tolstyakov, S.Yu., additional, Razdobarin, A.G., additional, Babinov, N.A., additional, Bazhenov, A.N., additional, Bukreev, I.M., additional, Dmitriev, A.M., additional, Elets, D.I., additional, Koval, A.N., additional, Litvinov, A.E., additional, Masyukevich, S.V., additional, Senitchenkov, V.A., additional, Solovei, V.A., additional, Tereschenko, I.B., additional, Varshavchik, L.A., additional, Kukushkin, A.S., additional, Khodunov, I.A., additional, Levashova, M.G., additional, Lisitsa, V.S., additional, Vukolov, K.Yu., additional, Berik, E.B., additional, Chernakov, P.V., additional, Chernakov, Al.P., additional, Chernakov, An.P., additional, Zatilkin, P.A., additional, Zhiltsov, N.S., additional, Krivoruchko, D.D., additional, Skrylev, A.V., additional, Mokeev, A.N., additional, Andrew, P., additional, Kempenaars, M., additional, Vayakis, G., additional, and Walsh, M.J., additional

Published
2019
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5. Integration of Thomson scattering and laser-induced fluorescence in ITER divertor

Author

N.A. Babinov, P.V. Chernakov, A.G. Razdobarin, D.I. Elets, E.E. Mukhin, A.V. Gorbunov, Valery S. Lisitsa, An.P. Chernakov, I.B. Tereschenko, D.D. Krivoruchko, N.S. Zhiltsov, I.M. Bukreev, A.E. Litvinov, L.A. Varshavchik, A.N. Bazhenov, S.V. Masyukevich, A. M. Dmitriev, S. Yu. Tolstyakov, G. S. Kurskiev, P. A. Zatilkin, K.Yu. Vukolov, Philip Andrew, M. Kempenaars, Michael Walsh, V.A. Solovei, George Vayakis, Al.P. Chernakov, A.V. Skrylev, A.S. Kukushkin, M. G. Levashova, E.B. Berik, I.A. Khodunov, A.N. Mokeev, D.S. Samsonov, V.A. Senitchenkov, and A.N. Koval

Subjects
Nuclear and High Energy Physics, Materials science, Optics, Thomson scattering, business.industry, Divertor, Condensed Matter Physics, Laser-induced fluorescence, business
Published
2019

6. Digital filter polychromator for Thomson scattering applications

Author

Solokha, V, primary, Kurskiev, G, additional, Mukhin, E, additional, Tolstyakov, S, additional, Babinov, N, additional, Bazhenov, A, additional, Bukreev, I, additional, Dmitriev, A, additional, Kochergin, M, additional, Koval, A, additional, Litvinov, A, additional, Masyukevich, S, additional, Razdobarin, A, additional, Samsonov, D, additional, Semenov, V, additional, Solovey, V, additional, Chernakov, P, additional, Chernakov, Al, additional, and Chernakov, An, additional

Published
2018
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7. In situplasma cleaning of ITER diagnostic mirrors in noble-gas RF discharge

Author

Dmitriev, A M, primary, Babinov, N A, additional, Bazhenov, A N, additional, Bukreev, I M, additional, Kochergin, M M, additional, Koval, A N, additional, Kurskiev, G S, additional, Litvinov, A E, additional, Masyukevich, S V, additional, Mukhin, E E, additional, Razdobarin, A G, additional, Samsonov, D S, additional, Solokha, V V, additional, Tolstyakov, S Yu, additional, Andrew, P, additional, Leipold, F, additional, Shigin, P A, additional, Reichle, R, additional, Bukhovets, V L, additional, Gorodetsky, A E, additional, Markin, A V, additional, Zakharov, A P, additional, Zalavutdinov, R Kh, additional, Chernakov, An P, additional, Chernakov, Al P, additional, Chernakov, P V, additional, Chernoizumskaya, T V, additional, Kobelev, A A, additional, Smirnov, A S, additional, and Marzinovsky, I A, additional

Published
2017
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8. Tokamak research at the Ioffe Institute

Author

Bakharev, N.N., primary, Abdullina, G.I., additional, Afanasyev, V.I., additional, Altukhov, A.B., additional, Askinazi, L.G., additional, Babinov, N.A., additional, Bazhenov, A.N., additional, Belokurov, A.A., additional, Blekhshtein, M.D., additional, Bondarchuk, E.N., additional, Bukreev, I.M., additional, Bulanin, V.V., additional, Chernakov, An.P., additional, Chernyshev, F.V., additional, Chugunov, I.N., additional, Dmitriev, A.M., additional, Doinikov, D.N., additional, Dyachenko, V.V., additional, Esipov, L.A., additional, Gin, D.B., additional, Gorbunov, A.V., additional, Gurchenko, A.D., additional, Gusakov, E.Z., additional, Gusev, V.K., additional, Heuraux, S., additional, Iliasova, M.V., additional, Irzak, M.A., additional, Kamenshikov, S.N., additional, Kavin, A.A., additional, Khilkevitch, E.M., additional, Khromov, N.A., additional, Kiselev, E.O., additional, Kiviniemi, T.P., additional, Kobelev, A.A., additional, Kornev, V.A., additional, Koval, A.N., additional, Kouprienko, D.V., additional, Krikunov, S.V., additional, Krutkin, O.L., additional, Kurskiev, G.S., additional, Lashkul, S.I., additional, Lebedev, S.V., additional, Lechte, C., additional, Leerink, S., additional, Litvinov, A.E., additional, Lobanov, K.M., additional, Masyukevich, S.V., additional, Martynov, A.A., additional, Medvedev, S.Yu., additional, Melnik, A.D., additional, Minaev, V.B., additional, Mineev, A.B., additional, Mironov, M.I., additional, Miroshnikov, I.V., additional, Mukhin, E.E., additional, Naidenov, V.O., additional, Navolotsky, A.S., additional, Nesenevich, V.G., additional, Niskala, P., additional, Novokhatskii, A.N., additional, Oshuev, K.Yu., additional, Patrov, M.I., additional, Petrov, A.V., additional, Petrov, M.P., additional, Petrov, S.Ya., additional, Petrov, Yu.V., additional, Polunovsky, I.A., additional, Popov, A.Yu., additional, Razdobarin, A.G., additional, Razumenko, D.V., additional, Rozhdestvensky, V.V., additional, Sakharov, N.V., additional, Samsonov, D.S., additional, Saveliev, A.N., additional, Senichenkov, V.A., additional, Shchegolev, P.B., additional, Shevelev, A.E., additional, Sladkomedova, A.D., additional, Smirnov, A.I., additional, Smirnov, A.S., additional, Solokha, V.V., additional, Solovei, V.A., additional, Stepanov, A.Yu., additional, Telnova, A.Yu., additional, Tokarev, V.A., additional, Tolstyakov, S.Yu., additional, Tretinnikov, P.V., additional, Tereschenko, I.B., additional, Tukachinsky, A.S., additional, Tukhmeneva, E.A., additional, Varfolomeev, V.I., additional, Varshavchick, L.A., additional, Yashin, A.Yu., additional, Zhilin, E.G., additional, and Zhubr, N.A., additional

Published
2019
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10. Three-dimensional simulation of neutral transport in gases and weakly ionized plasmas.

Author

Varshavchik, L A, Babinov, N A, Zatylkin, P A, Chironova, A A, Lyullin, Z G, Chernakov, Al P, Dmitriev, A M, Bukreev, I M, Mukhin, E E, Razdobarin, A G, Samsonov, D S, Senitchenkov, V A, Tolstyakov, S Yu, Serenkov, I T, and Sakharov, V I

Subjects
PLASMA sheaths, PLASMA gases, PLASMA flow, COLLISIONS (Nuclear physics), KITES
Abstract

Transport and redeposition of plasma-facing materials in future fusion devices may have a critical influence on performance of in-vessel components. Evaluation of the impurity migration in diagnostic ports is important to predict degradation of in-vessel optics during the main plasma discharges as well as for development of in-situ cleaning maintenance. The Monte-Carlo code KITe was developed for modeling transport of neutral particles in weakly ionized plasma. The code employs advanced neutral particle collision model. The first KITe simulation and experimental validation of sputtered atom transport demonstrate performance of the proposed approach. [ABSTRACT FROM AUTHOR]

Published
2021
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11. Digital filter polychromator for Thomson scattering applications

Author

S.V. Masyukevich, N Babinov, A.N. Bazhenov, A.G. Razdobarin, V.A. Solovey, D.S. Samsonov, V Solokha, M.M. Kochergin, G. S. Kurskiev, Al.P. Chernakov, An.P. Chernakov, A.E. Litvinov, P.V. Chernakov, Sergey Tolstyakov, A. M. Dmitriev, A.N. Koval, I.M. Bukreev, V.V. Semenov, and E.E. Mukhin

Subjects
010302 applied physics, Physics, History, business.industry, Thomson scattering, 01 natural sciences, 010305 fluids & plasmas, Computer Science Applications, Education, Polychromator, Optics, 0103 physical sciences, business, Digital filter
Published
2018

12. In situplasma cleaning of ITER diagnostic mirrors in noble-gas RF discharge

Author

A. A. Kobelev, Philip Andrew, V. L. Bukhovets, A.V. Markin, R. Kh. Zalavutdinov, S.V. Masyukevich, I.M. Bukreev, M.M. Kochergin, A.G. Razdobarin, Roger Reichle, S. Yu. Tolstyakov, Al.P. Chernakov, A.P. Zakharov, P.V. Chernakov, A.E. Gorodetsky, D.S. Samsonov, A.N. Bazhenov, A.E. Litvinov, E. E. Mukhin, A. M. Dmitriev, T. V. Chernoizumskaya, N.A. Babinov, V.V. Solokha, A. S. Smirnov, P. Shigin, A.N. Koval, Frank Leipold, An.P. Chernakov, I. A. Marzinovsky, and G. S. Kurskiev

Subjects
In situ, Materials science, Plasma cleaning, business.industry, Noble gas (data page), Condensed Matter Physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, 0103 physical sciences, Optoelectronics, 010306 general physics, business, Rf discharge, Mathematical Physics
Published
2017

14. In situmonitoring hydrogen isotope retention in ITER first wall

Author

Mukhin, E.E., primary, Andrew, P., additional, Anthoine, A.D., additional, Bazhenov, A.N., additional, Barnsley, R., additional, Bukreev, I.M., additional, Bukhovets, V.L., additional, Chernakov, A.P., additional, Gorodetsky, A.E., additional, Kochergin, M.M., additional, Koval, A.N., additional, Kukushkin, A.B., additional, Kukushkin, A.S., additional, Kurskiev, G.S., additional, Levashova, M.G., additional, Litvinov, A.E., additional, Litunovsky, V.N., additional, Markin, A.V., additional, Mazul, I.V., additional, Masyukevich, S.V., additional, Miroshnikov, I.V., additional, Nemov, A.S., additional, Novokhatsky, A.N., additional, Razdobarin, A.G., additional, Sherstnev, E.V., additional, Samsonov, D.S., additional, Semenov, V.V., additional, Smirnov, A.S., additional, De Temmerman, G., additional, Tolstyakov, S.Yu., additional, Zalavutdinov, R.Kh., additional, and Walsh, M.J., additional

Published
2016
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15. In situ monitoring hydrogen isotope retention in ITER first wall

Author

M.G. Levashova, A.E. Gorodetsky, A. B. Kukushkin, A.N. Bazhenov, D.S. Samsonov, M.M. Kochergin, A.N. Koval, Robin Barnsley, S.V. Masyukevich, G. De Temmerman, V.N. Litunovsky, Philip Andrew, V. L. Bukhovets, I. V. Miroshnikov, A. S. Smirnov, A.S. Kukushkin, A. N. Novokhatsky, A.D. Anthoine, A.V. Markin, I.M. Bukreev, Alexander Nemov, V.V. Semenov, Michael Walsh, G. S. Kurskiev, E.V. Sherstnev, S. Yu. Tolstyakov, I.V. Mazul, E. E. Mukhin, R. Kh. Zalavutdinov, Anton Chernakov, A.G. Razdobarin, and A.E. Litvinov

Subjects
Nuclear and High Energy Physics, Materials science, Hydrogen, chemistry.chemical_element, Plasma, Radiation, Condensed Matter Physics, Laser, 01 natural sciences, 010305 fluids & plasmas, law.invention, Ion, chemistry, law, 0103 physical sciences, Thermal, Irradiation, Atomic physics, 010306 general physics, Spectroscopy
Abstract

Tritium retention inside the vacuum vessel is a potentially serious constraint in the operation of large-scale fusion machines like ITER. An in situ diagnostics for first wall H/D/T retention by laser induced desorption spectroscopy (LIDS) is proposed for use between plasma discharges. The technique is based on local baking of the first wall by laser irradiation and subsequent analysis of the in-vessel gas by optical emission spectroscopy of plasma radiation. The local heating implementation, kinetics of H/D/T thermal extraction and the accuracy of optical emission spectroscopy measurements are analysed. To resolve the H/D/T lines spectroscopically, their thermal broadening should be minimized to prevent overlapping of the line shapes. A comparative performance analysis of several types of plasma sources with relatively cold ions is made including the following types of discharges: Penning, RF multipactor, laser torch and ECR. All these radiation sources require rather low power and could be used for remote in situ measurements of relative densities of the thermally extracted hydrogen isotopes.

Published
2016

16. RF discharge forin situmirror surface recovery in ITER

Author

Razdobarin, A.G., primary, Dmitriev, A.M., additional, Bazhenov, A.N., additional, Bukreev, I.M., additional, Kochergin, M.M., additional, Koval, A.N., additional, Kurskiev, G.S., additional, Litvinov, A.E., additional, Masyukevich, S.V., additional, Mukhin, E.E., additional, Samsonov, D.S., additional, Semenov, V.V., additional, Tolstyakov, S.Yu., additional, Andrew, P., additional, Bukhovets, V.L., additional, Gorodetsky, A.E., additional, Markin, A.V., additional, Zakharov, A.P., additional, Zalavutdinov, R.Kh., additional, Chernakov, P.V., additional, Chernoizumskaya, T.V., additional, Kobelev, A.A., additional, Miroshnikov, I.V., additional, and Smirnov, A.S., additional

Published
2015
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17. A study of core Thomson scattering measurements in ITER using a multi-laser approach

Author

Kurskiev, G.S., primary, Sdvizhenskii, P.A., additional, Bassan, M., additional, Andrew, P., additional, Bazhenov, A.N., additional, Bukreev, I.M., additional, Chernakov, P.V., additional, Kochergin, M.M., additional, Kukushkin, A.B., additional, Kukushkin, A.S., additional, Mukhin, E.E., additional, Razdobarin, A.G., additional, Samsonov, D.S., additional, Semenov, V.V., additional, Tolstyakov, S.Yu., additional, Kajita, S., additional, and Masyukevich, S.V., additional

Published
2015
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18. RF discharge forin situmirror surface recovery in ITER

Author

T. V. Chernoizumskaya, S.V. Masyukevich, Philip Andrew, A.V. Markin, V. L. Bukhovets, E.E. Mukhin, A.P. Zakharov, A. S. Smirnov, M.M. Kochergin, P.V. Chernakov, I.M. Bukreev, A.N. Koval, A. A. Kobelev, I. V. Miroshnikov, S. Yu. Tolstyakov, A.N. Bazhenov, R. Kh. Zalavutdinov, D.S. Samsonov, A.G. Razdobarin, A.E. Litvinov, V.V. Semenov, A.E. Gorodetsky, A. M. Dmitriev, and G. S. Kurskiev

Subjects
Nuclear and High Energy Physics, Glow discharge, Materials science, Plasma cleaning, business.industry, Dielectric barrier discharge, Plasma, engineering.material, Condensed Matter Physics, Ion, Coating, Sputtering, Electrode, engineering, Optoelectronics, business
Abstract

Almost all optical diagnostic systems in ITER will require the implementation of mirror recovery and protection systems. Plasma cleaning is considered to be the most promising technique for the removal of metal deposits from optical surfaces. The engineering and physical aspects of RF discharge application for continuous or periodic plasma treatment are discussed with a focus on implementation under ITER conditions. The ion flux parameters obtained in capacitively coupled (CC) RF discharge were measured in the mock-up of a plasma cleaning system. The uniformity of sputtering in CC RF discharge with and without a magnetic field was studied experimentally for the cylindrical discharge reactor geometry and compared with numerical simulations. The sharp increase in the sputtering rate resulting from the non-uniform radial distribution of the ion flux was observed near the electrode edges. The longitudinal magnetic field improves sputtering uniformity. It was demonstrated that Al/Al2O3 deposits can be removed in the Ne and D2 plasma of CC RF discharge but long-term exposition results in the degradation of the polycrystalline molybdenum mirror surface. The efficiency of Al sputtering in the atmosphere containing O2 and N2 fractions was studied in the D2/O2 and D2/N2 plasma of glow discharge. The addition of 2% of oxygen or nitrogen increases the sputtering yield by 3–4 times as compared with that in a nominally pure D2 discharge. The impact of metal deposits on the performance of diagnostic mirrors is discussed. It was shown that an ultrathin metallic film with a thickness as low as a few nm may cause a significant degradation of diagnostic mirrors with a transparent coating.

Published
2015

19. A study of core Thomson scattering measurements in ITER using a multi-laser approach

Author

M. Bassan, A.S. Kukushkin, E.E. Mukhin, I.M. Bukreev, G. S. Kurskiev, P. A. Sdvizhenskii, Vladimir V. Semenov, S. Yu. Tolstyakov, A.G. Razdobarin, S.V. Masyukevich, Philip Andrew, Shin Kajita, D.S. Samsonov, A.N. Bazhenov, A. B. Kukushkin, P.V. Chernakov, and M.M. Kochergin

Subjects
Physics, Nuclear and High Energy Physics, Tokamak, Thomson scattering, business.industry, Electron, Condensed Matter Physics, Temperature measurement, law.invention, Wavelength, Optics, law, Temporal resolution, Calibration, Electron temperature, business
Abstract

The electron component is the main channel for anomalous power loss and the main indicator of transient processes in the tokamak plasma. The electron temperature and density profiles mainly determine the operational mode of the machine. This imposes demanding requirements on the precision and on the spatial and temporal resolution of the Thomson scattering (TS) measurements. Measurements of such high electron temperature with good accuracy in a large fusion device such as ITER using TS encounter a number of physical problems. The 40 keV TS spectrum has a significant blue shift. Due to the transmission functions of the fibres and to their darkening that can occur under a strong neutron irradiation, the operational wavelength range is bounded on the blue side. For example, high temperature measurements become impossible with the 1064 nm probing wavelength since the TS signal within the boundaries of the operational window weakly depends on Te. The second problem is connected with the TS calibration. The TS system for a large fusion machine like ITER will have a set of optical components inaccessible for maintenance, and their spectral characteristics may change with time. Since the present concept of the TS system for ITER relies on the classical approach to measuring the shape of the scattered spectra using wide spectral channels, the diagnostic will be very sensitive to the changes in the optical transmission. The third complication is connected with the deviation of the electron velocity distribution function from a Maxwellian that can happen under a strong ECRH/ECCD, and it may additionally hamper the measurements. This paper analyses the advantages of a 'multi-laser approach' implementation for the current design of the core TS system. Such an approach assumes simultaneous plasma probing with different wavelengths that allows the measurement accuracy to be improved significantly and to perform the spectral calibration of the TS system. Comparative analysis of the conservative and advanced approaches is given.

Published
2015

20. Physical aspects of divertor Thomson scattering implementation on ITER

Author

Mukhin, E.E., primary, Pitts, R.A., additional, Andrew, P., additional, Bukreev, I.M., additional, Chernakov, P.V., additional, Giudicotti, L., additional, Huijsmans, G., additional, Kochergin, M.M., additional, Koval, A.N., additional, Kukushkin, A.S., additional, Kurskiev, G.S., additional, Litvinov, A.E., additional, Masyukevich, S.V., additional, Pasqualotto, R., additional, Razdobarin, A.G., additional, Semenov, V.V., additional, Tolstyakov, S.Yu., additional, and Walsh, M.J., additional

Published
2014
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21. Physical aspects of divertor Thomson scattering implementation on ITER

Author

Leonardo Giudicotti, M.M. Kochergin, A.S. Kukushkin, Philip Andrew, P.V. Chernakov, Michael Walsh, E.E. Mukhin, A.G. Razdobarin, A.E. Litvinov, G. Huijsmans, Roberto Pasqualotto, G. S. Kurskiev, S.V. Masyukevich, A.N. Koval, R.A. Pitts, VA Semenov, I.M. Bukreev, and S. Yu. Tolstyakov

Subjects
Physics, Nuclear and High Energy Physics, Physical aspects, Data interpretation, Thomson scattering, Scattering, Divertor, Nuclear engineering, Iter tokamak, Light scattering, Magnetic confinement fusion, Plasma confinement, Inelastic scattering, Condensed Matter Physics, Plasma diagnostics, Data processing, Nuclear physics, ITER, divertor, diagnostics, Magnetic-confinement devices
Abstract

This paper describes the challenges of Thomson Scattering implementation in the ITER divertor and evaluates the capability to satisfy project requirements related to the range of the measured electron temperature and density. A number of aspects of data interpretation are also discussed. Although this assessment and the proposed solutions are considered in terms of ITER compatibility, they may also be of some use in currently operating magnetic confinement devices.

Published
2014

22. The ITER divertor Thomson scattering system: engineering and advanced hardware solutions

Author

Mukhin, E E, primary, Semenov, V V, additional, Razdobarin, A G, additional, Tolstyakov, S Yu, additional, Kochergin, M M, additional, Kurskiev, G S, additional, Berezutsky, A A, additional, Podushnikova, K A, additional, Masyukevich, S V, additional, Chernakov, P V, additional, Borovkov, A I, additional, Modestov, V S, additional, Nemov, A S, additional, Voinov, A S, additional, Kornev, A F, additional, Stupnikov, V K, additional, Borisov, A A, additional, Baranov, G N, additional, Koval, A N, additional, Makushina, A F, additional, Yelizarov, B A, additional, Kukushkin, A S, additional, Encheva, A, additional, and Andrew, P, additional

Published
2012
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23. First mirrors in ITER: material choice and deposition prevention/cleaning techniques

Author

Mukhin, E.E., primary, Semenov, V.V., additional, Razdobarin, A.G., additional, Tolstyakov, S. Yu., additional, Kochergin, M.M., additional, Kurskiev, G.S., additional, Podushnikova, K.A., additional, Masyukevich, S.V., additional, Kirilenko, D.A., additional, Sitnikova, A.A., additional, Chernakov, P.V., additional, Gorodetsky, A.E., additional, Bukhovets, V.L., additional, Zalavutdinov, R. Kh., additional, Zakharov, A.P., additional, Arkhipov, I.I., additional, Khimich, Yu.P., additional, Nikitin, D.B., additional, Gorshkov, V.N., additional, Smirnov, A.S., additional, Chernoizumskaja, T.V., additional, Khilkevitch, E.M., additional, Bulovich, S.V., additional, Voitsenya, V.S., additional, Bondarenko, V.N., additional, Konovalov, V.G., additional, Ryzhkov, I.V., additional, Nekhaieva, O.M., additional, Skorik, O.A., additional, Vukolov, K. Yu., additional, Khripunov, V.I., additional, and Andrew, P., additional

Published
2011
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24. The ITER divertor Thomson scattering system: engineering and advanced hardware solutions

Author

M.M. Kochergin, A F Kornev, P.V. Chernakov, A.G. Razdobarin, A.S. Kukushkin, A. I. Borovkov, G N Baranov, K. A. Podushnikova, E.E. Mukhin, A S Voinov, V.S. Modestov, Anatoly Borisov, Philip Andrew, A. Encheva, A F Makushina, S.V. Masyukevich, A A Berezutsky, V. K. Stupnikov, Alexander Nemov, G. S. Kurskiev, S Yu Tolstyakov, Vladimir V. Semenov, A.N. Koval, and B A Yelizarov

Subjects
Operability, Materials science, business.industry, Stray light, Thomson scattering, Divertor, Detector, Grating, Laser, law.invention, Polychromator, Optics, law, business, Instrumentation, Mathematical Physics
Abstract

A divertor Thomson scattering (TS) system being developed for ITER has incorporated proven solutions from currently available TS systems. On the other hand any ITER diagnostic has to operate in a hostile environment and very restricted access geometry. Therefore the operation in an environment of intensive stray light, plasma background radiation, the necessity meet the requirement using only a 20 mm gap between divertor cassettes for plasma diagnosis as well as to measure plasma temperatures as low as 1 eV severely constrain the divertor TS diagnostic design. The challenging solutions of this novel diagnostic system which has to ensure its steady performance and also the operability and maintenance are the focus of this report. One of the most demanding parts of the in-vessel diagnostic equipment development is the design assessment using different engineering analyses. The task definition and first results of thermal, e/m and seismic analyses are provided. The process of further improving of the design involves identification of susceptible areas and multiple iterations of the design, as needed. One of the key points for all Thomson scattering diagnostics are the laser capabilities. A high-performance and high-power laser system using a steady-state and high-repetitive mode Nd:YAG laser (2J, 50–100Hz, 3ns) has been developed. The reduced laser pulse duration matched with high-speed low-noise APD detector can be very important under high background light level. For diagnostics such as Thomson scattering and Raman spectroscopy, a high-degree of discrimination against stray light at the laser wavelength is required for successful detection of wavelength-shifted light from the laser-plasma interaction region. For this case of high stray light level, a triple grating polychromator characterized by high rejection and high transmission has been designed and developed. The novel polychromator design minimizes stray light while still maintaining a relatively high transmission.

Published
2012

25. First mirrors in ITER: material choice and deposition prevention/cleaning techniques

Author

D. B. Nikitin, Vladimir V. Semenov, M.M. Kochergin, P.V. Chernakov, V.G. Konovalov, K. A. Podushnikova, Philip Andrew, A.P. Zakharov, E.M. Khilkevitch, A.E. Gorodetsky, S.V. Masyukevich, V. L. Bukhovets, O.M. Nekhaieva, K.Yu. Vukolov, R. Kh. Zalavutdinov, I.I. Arkhipov, O.A. Skorik, S. V. Bulovich, S. Yu. Tolstyakov, A. A. Sitnikova, E.E. Mukhin, A.G. Razdobarin, T.V. Chernoizumskaja, V.N. Bondarenko, A. S. Smirnov, Yu.P. Khimich, G. S. Kurskiev, Demid A. Kirilenko, V.N. Gorshkov, V. S. Voitsenya, V. Khripunov, and I.V. Ryzhkov

Subjects
Nuclear and High Energy Physics, Materials science, Scattering, Plasma parameters, Thomson scattering, business.industry, Divertor, Plasma, Condensed Matter Physics, Optics, Deposition (phase transition), Plasma diagnostics, business, Layer (electronics)
Abstract

We present here our recent results on the development and testing of the first mirrors for the divertor Thomson scattering diagnostics in ITER. The Thomson scattering system is based on several large-scale (tens of centimetres) mirrors that will be located in an area with extremely high (3–10%) concentration of contaminants (mainly hydrocarbons) and our main concern is to prevent deposition-induced loss of mirror reflectivity in the spectral range 1000–1064 nm. The suggested design of the mirrors—a high-reflective metal layer on a Si substrate with an oxide coating—combines highly stable optical characteristics under deposition-dominated conditions with excellent mechanical properties. For the mirror layer materials we consider Ag and Al allowing the possibility of sharing the Thomson scattering mirror collecting system with a laser-induced fluorescence system operating in the visible range. Neutron tests of the mirrors of this design are presented along with numerical simulation of radiation damage and transmutation of mirror materials. To provide active protection of the large-scale mirrors we use a number of deposition-mitigating techniques simultaneously. Two main techniques among them, plasma treatment and blowing-out, are considered in detail. The plasma conditions appropriate for mirror cleaning are determined from experiments using plasma-induced erosion/deposition in a CH4/H2 gas mixture. We also report data on the numerical simulation of plasma parameters of a capacitively-coupled discharge calculated using a commercial CFD-ACE code. A comparison of these data with the results for mirror testing under deuterium ion bombardment illustrates the possibility of using the capacitively-coupled discharge for in situ non-destructive deposition mitigation/cleaning.

Published
2011

26. Tokamak research at the Ioffe Institute.

Author

N.N. Bakharev, G.I. Abdullina, V.I. Afanasyev, A.B. Altukhov, L.G. Askinazi, N.A. Babinov, A.N. Bazhenov, A.A. Belokurov, M.D. Blekhshtein, E.N. Bondarchuk, I.M. Bukreev, V.V. Bulanin, An.P. Chernakov, F.V. Chernyshev, I.N. Chugunov, A.M. Dmitriev, D.N. Doinikov, V.V. Dyachenko, L.A. Esipov, and D.B. Gin

Subjects
CYCLOTRON resonance, RESEARCH institutes, PLASMA Alfven waves, LASER-induced fluorescence, ELECTRON emission, CYCLOTRONS, GAMMA ray spectrometry
Abstract

Recent research at three small tokamaks with different parameters located at the Ioffe Institute—the spherical tokamak Globus-M, the large aspect ratio tokamak FT-2 and the compact tokamak TUMAN-3M—are reviewed. This overview covers energy confinement (Globus-M and FT-2), L–H transition (TUMAN-3M and FT-2), Alfvén waves (Globus-M and TUMAN-3M), ion cyclotron emission (TUMAN-3M), major plasma discharge disruption (Globus-M) and scrape-off layer (Globus-M) studies. A full-f global gyrokinetic modeling benchmark using synthetic diagnostics in FT-2 is described. Anomalous absorption and emission in electron cyclotron resonance heating experiments due to the parametric excitation of localized upper hybrid waves are analyzed theoretically. Progress in the development of the neutral particle analysis, gamma-ray spectrometry and divertor Thomson scattering combined with laser-induced fluorescence diagnostics for ITER is discussed. The status of the new Globus-M2 spherical tokamak is reported. [ABSTRACT FROM AUTHOR]

Published
2019
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28. In situ monitoring hydrogen isotope retention in ITER first wall.

Author

E.E. Mukhin, P. Andrew, A.D. Anthoine, A.N. Bazhenov, R. Barnsley, I.M. Bukreev, V.L. Bukhovets, A.P. Chernakov, A.E. Gorodetsky, M.M. Kochergin, A.N. Koval, A.B. Kukushkin, A.S. Kukushkin, G.S. Kurskiev, M.G. Levashova, A.E. Litvinov, V.N. Litunovsky, A.V. Markin, I.V. Mazul, and S.V. Masyukevich

Subjects
HYDROGEN isotopes, THERMAL stability, IRRADIATION, PLASMA sources
Abstract

Tritium retention inside the vacuum vessel is a potentially serious constraint in the operation of large-scale fusion machines like ITER. An in situ diagnostics for first wall H/D/T retention by laser induced desorption spectroscopy (LIDS) is proposed for use between plasma discharges. The technique is based on local baking of the first wall by laser irradiation and subsequent analysis of the in-vessel gas by optical emission spectroscopy of plasma radiation. The local heating implementation, kinetics of H/D/T thermal extraction and the accuracy of optical emission spectroscopy measurements are analysed. To resolve the H/D/T lines spectroscopically, their thermal broadening should be minimized to prevent overlapping of the line shapes. A comparative performance analysis of several types of plasma sources with relatively cold ions is made including the following types of discharges: Penning, RF multipactor, laser torch and ECR. All these radiation sources require rather low power and could be used for remote in situ measurements of relative densities of the thermally extracted hydrogen isotopes. [ABSTRACT FROM AUTHOR]

Published
2016
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29. RF discharge for in situ mirror surface recovery in ITER.

Author

A.G. Razdobarin, A.M. Dmitriev, A.N. Bazhenov, I.M. Bukreev, M.M. Kochergin, A.N. Koval, G.S. Kurskiev, A.E. Litvinov, S.V. Masyukevich, E.E. Mukhin, D.S. Samsonov, V.V. Semenov, S.Yu. Tolstyakov, P. Andrew, V.L. Bukhovets, A.E. Gorodetsky, A.V. Markin, A.P. Zakharov, R.Kh. Zalavutdinov, and P.V. Chernakov

Subjects
SPUTTERING (Physics), PLASMA flow, CRYSTAL grain boundaries, POLYCRYSTALS, CURRENT density (Electromagnetism)
Abstract

Almost all optical diagnostic systems in ITER will require the implementation of mirror recovery and protection systems. Plasma cleaning is considered to be the most promising technique for the removal of metal deposits from optical surfaces. The engineering and physical aspects of RF discharge application for continuous or periodic plasma treatment are discussed with a focus on implementation under ITER conditions. The ion flux parameters obtained in capacitively coupled (CC) RF discharge were measured in the mock-up of a plasma cleaning system. The uniformity of sputtering in CC RF discharge with and without a magnetic field was studied experimentally for the cylindrical discharge reactor geometry and compared with numerical simulations. The sharp increase in the sputtering rate resulting from the non-uniform radial distribution of the ion flux was observed near the electrode edges. The longitudinal magnetic field improves sputtering uniformity. It was demonstrated that Al/Al2O3 deposits can be removed in the Ne and D2 plasma of CC RF discharge but long-term exposition results in the degradation of the polycrystalline molybdenum mirror surface. The efficiency of Al sputtering in the atmosphere containing O2 and N2 fractions was studied in the D2/O2 and D2/N2 plasma of glow discharge. The addition of 2% of oxygen or nitrogen increases the sputtering yield by 3–4 times as compared with that in a nominally pure D2 discharge. The impact of metal deposits on the performance of diagnostic mirrors is discussed. It was shown that an ultrathin metallic film with a thickness as low as a few nm may cause a significant degradation of diagnostic mirrors with a transparent coating. [ABSTRACT FROM AUTHOR]

Published
2015
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30. A study of core Thomson scattering measurements in ITER using a multi-laser approach.

Author

G.S. Kurskiev, P.A. Sdvizhenskii, M. Bassan, P. Andrew, A.N. Bazhenov, I.M. Bukreev, P.V. Chernakov, M.M. Kochergin, A.B. Kukushkin, A.S. Kukushkin, E.E. Mukhin, A.G. Razdobarin, D.S. Samsonov, V.V. Semenov, S.Yu. Tolstyakov, S. Kajita, and S.V. Masyukevich

Subjects
THOMSON scattering, PLASMA core reactors, TOKAMAKS, ELECTRON temperature, PLASMA boundary layers
Abstract

The electron component is the main channel for anomalous power loss and the main indicator of transient processes in the tokamak plasma. The electron temperature and density profiles mainly determine the operational mode of the machine. This imposes demanding requirements on the precision and on the spatial and temporal resolution of the Thomson scattering (TS) measurements. Measurements of such high electron temperature with good accuracy in a large fusion device such as ITER using TS encounter a number of physical problems. The 40 keV TS spectrum has a significant blue shift. Due to the transmission functions of the fibres and to their darkening that can occur under a strong neutron irradiation, the operational wavelength range is bounded on the blue side. For example, high temperature measurements become impossible with the 1064 nm probing wavelength since the TS signal within the boundaries of the operational window weakly depends on Te. The second problem is connected with the TS calibration. The TS system for a large fusion machine like ITER will have a set of optical components inaccessible for maintenance, and their spectral characteristics may change with time. Since the present concept of the TS system for ITER relies on the classical approach to measuring the shape of the scattered spectra using wide spectral channels, the diagnostic will be very sensitive to the changes in the optical transmission. The third complication is connected with the deviation of the electron velocity distribution function from a Maxwellian that can happen under a strong ECRH/ECCD, and it may additionally hamper the measurements. This paper analyses the advantages of a ‘multi-laser approach’ implementation for the current design of the core TS system. Such an approach assumes simultaneous plasma probing with different wavelengths that allows the measurement accuracy to be improved significantly and to perform the spectral calibration of the TS system. Comparative analysis of the conservative and advanced approaches is given. [ABSTRACT FROM AUTHOR]

Published
2015
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