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- Joffrin, E., et al.
(författare)
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Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Forskningsöversikt (refereegranskat)abstract
- For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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| 3. |
- Moon, Sunwoo, 1984-
(författare)
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Impact of erosion and deposition processes on wall materials in tokamaks
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Understanding of material migration and control of fuel retention are essential for the safe operation of a reactor-class fusion machine. Work presented in the thesis focuses on erosion-deposition processes which are decisive for the formation and properties of co-deposited fuel-containing layers on plasma-facing and diagnostic components, and for the dust formation. The thesis is based on experiments carried out in plasma devices such as JET-ILW, KSTAR, EXTRAP-T2R, TOMAS and, in materials research laboratories where comprehensive analyses of the plasma-exposed materials were performed by a large number of complementary ion, electron and optical methods. The major objectives were to determine: (a) plasma impact on test mirrors; (b) properties of metal dust generated under operation with metal walls in JET with the ITER-Like Wall; (c) material transport to areas shadowed from the direct plasma line-of-sight; (d) neutral particle fluxes in wall conditioning discharges. All these topics are inter-related and, they are in line with the ITER needs in areas of diagnostic development, mitigation of fuel inventory and detailed knowledge of dust particles generated in the tokamak with metal walls. The novelty in research is demonstrated by several elements. Plasma impact on diagnostic mirrors was determined by exposure of test mirrors in JET two types of holders including the ITER-like assembly resembling a diagnostic duct in a reactor. Dust studies allowed for the determination of particles’ properties (size, weight) and, for the classification of various detected objects. The impact of tile shaping and intentional misalignment on fuel retention was revealed in a dedicated experiment in KSTAR. A neutral particle analyser was first tested at EXTRAP-T2R and then installed at the TOMAS facility. Particle fluxes were characterized in wall conditioning discharges heated by electron- and ion cyclotron systems.
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