| 1. |
- Moiseenko, V. E., et al.
(författare)
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Stellator research at IPP KIPT : Status and prospects
- 2019
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Ingår i: PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. - : KHARKOV INST PHYSICS & TECHNOLOGY. - 1562-6016. ; :1, s. 3-8
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Tidskriftsartikel (refereegranskat)abstract
- Features of the recent Uragan-2M campaign are reviewed together with some theoretical advances. They include experiments with B4C limiter, studies of various 1. . . 20 kHz oscillations, development of a new in-situ diagnostics for wall conditions, i.e. the thermal desorption probe, the improved numerical model of RF plasma production in stellarators in the ion cyclotron and electron-cyclotron frequency ranges, a new positive-definite form of time-harmonic Maxwell's equations and plasma start-up studies.
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| 2. |
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| 3. |
- Lozin, A.V., et al.
(författare)
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Two-strap rf antenna in uragan-2m stellarator
- 2020
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Ingår i: Problems of Atomic Science and Technology. - : Problems of Atomic Science and Technology. ; 130:6, s. 10-14
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Kovtun, Yu.V., et al.
(författare)
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ICRF plasma production in gas mixtures in the Uragan-2M stellarator
- 2023
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Ingår i: Fusion engineering and design. - : Elsevier BV. - 0920-3796 .- 1873-7196. ; 194
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Tidskriftsartikel (refereegranskat)abstract
- This paper summarizes previous results and presents new studies on the ICRF plasma creation both in pure gases and gas mixtures. In all the experiments, the two-strap antenna was operated in monopole phasing with applied RF power of ∼100 kW. The research for plasma creation was carried out at RF frequencies near the fundamental hydrogen cyclotron harmonic.
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| 5. |
- Vergniory, M. G., et al.
(författare)
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Exchange interaction and its tuning in magnetic binary chalcogenides
- 2014
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 89:16
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Tidskriftsartikel (refereegranskat)abstract
- Using a first-principles Green's function approach we study magnetic properties of the magnetic binary tetradymite chalcogenides Bi2Se3, Bi2Te3, and Sb2Te3. The magnetic coupling between transition-metal impurities is long range, extends beyond a quintuple layer, and decreases with increasing number of d electrons per 3d atom. We find two main mechanisms for the magnetic interaction in these materials: the indirect exchange interaction mediated by free carriers and the indirect interaction between magnetic moments via chalcogen atoms. The calculated Curie temperatures of these systems are in good agreement with available experimental data. Our results provide deep insight into exchange interactions in magnetic binary tetradymite chalcogenides and open a way to design new materials for promising applications.
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| 6. |
- Kovtun, Yu.V., et al.
(författare)
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Design and application of glow discharge cleaning at Uragan-2M stellarator
- 2021
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Ingår i: Problems of Atomic Science and Technology. - : Charkov Institute of Physics and Technology. ; 27:1, s. 19-24
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Tidskriftsartikel (refereegranskat)abstract
- For the Uragan-2M stellarator, a glow discharge cleaning (GDC) system is developed. An overview of the GDC system design is presented. The first experimental studies of GDC in an argon atmosphere have been carried out. The dependence of the breakdown voltage on the argon pressure is determined. The current-voltage characteristics of the gas discharge were measured as a function of the working gas pressure also in presence of a magnetic field.
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| 7. |
- Lozin, A.V., et al.
(författare)
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Uragan-2m gas mixing system
- 2021
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Ingår i: Problems of Atomic Science and Technology. - : Problems of Atomic Science and Technology. ; 134:4, s. 195-199
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Tidskriftsartikel (refereegranskat)abstract
- Gas mixture system (GMS) was developed, created and installed at Uragan-2M (U-2M) device. GMS is based on already known gas mixing method successive puffing. It is implemented through successive puffing of several gases from separate high pressure cylinders into working volume. A number of experiments were carried out to create a He+H2 gas mixture with different percentages. The results of measurements of the He+H2 percentage in the GMS and the U-2M vacuum chamber are in good agreement each to other. This system allows you to change the pressure of the mixture in the U-2M chamber at a constant percentage of gases in the mixture.
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| 8. |
- Moiseyenko, Volodymyr, et al.
(författare)
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First experiments on ICRF discharge generation by a W7-X-like antenna in the Uragan-2M stellarator
- 2020
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Ingår i: Journal of Plasma Physics. - : Cambridge University Press (CUP). - 0022-3778 .- 1469-7807. ; 86:5
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Tidskriftsartikel (refereegranskat)abstract
- In support of the ICRF experiments planned on the Wendelstein 7-X (W7-X) stellarator, i.e. fast ion generation, wall conditioning, target plasma production and heating, a first experimental study on plasma production has been made in the Uragan-2M (U-2M) stellarator using W7-X-like two-strap antenna. In all the experiments, antenna monopole phasing was used. The W7-X-like antenna operation with launched radiofrequency power of ~100 kW have been performed in helium (p = (4–14) × 10−2 Pa) with the vacuum vessel walls pre-loaded with hydrogen. Production of plasma with a density higher than 1012 cm−3 was observed near the first harmonic of the hydrogen cyclotron frequency. Operation at first hydrogen harmonic is feasible in W7-X future ICRF experiments.
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| 9. |
- Moiseyenko, Volodymyr, et al.
(författare)
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Plasma Production in ICRF in the Uragan-2M Stellarator in Hydrogen–Helium Gas Mixture
- 2022
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Ingår i: Journal of fusion energy. - : Springer. - 0164-0313 .- 1572-9591. ; 41:2
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Tidskriftsartikel (refereegranskat)abstract
- Plasma production experiments in helium at Uragan-2M have been performed to investigate the role of the hydrogen minority in helium. The experiments presented here were carried on with a controlled minority hydrogen concentration. The hydrogen minority allowed one to increase plasma density more than three times as compared with pure helium. The obtained plasma density is highest for whole time of Uragan-2M operation. The developed scenario allowed to decrease the neutral gas pressure at which the plasma production is possible. This is a requirement for achieving regimes of plasma production with full ionization. Although the initial gas mixture 14%H2 + 86%He can be treated as optimum, there is no sensitive dependence on hydrogen minority concentration, which makes the scenario robust. This study, together with initial LHD experiments, confirm the prospects of target plasma production by ICRF waves for stellarator type machines.
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| 10. |
- Park, D. S., et al.
(författare)
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The emergence of magnetic ordering at complex oxide interfaces tuned by defects
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Complex oxides show extreme sensitivity to structural distortions and defects, and the intricate balance of competing interactions which emerge at atomically defined interfaces may give rise to unexpected physics. In the interfaces of non-magnetic complex oxides, one of the most intriguing properties is the emergence of magnetism which is sensitive to chemical defects. Particularly, it is unclear which defects are responsible for the emergent magnetic interfaces. Here, we show direct and clear experimental evidence, supported by theoretical explanation, that the B-site cation stoichiometry is crucial for the creation and control of magnetism at the interface between non-magnetic ABO3-perovskite oxides, LaAlO3 and SrTiO3. We find that consecutive defect formation, driven by atomic charge compensation, establishes the formation of robust perpendicular magnetic moments at the interface. Our observations propose a route to tune these emerging magnetoelectric structures, which are strongly coupled at the polar-nonpolar complex oxide interfaces.
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