SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Eriksson Henrik) ;pers:(Weckmann Armin)"

Sökning: WFRF:(Eriksson Henrik) > Weckmann Armin

  • Resultat 1-10 av 284
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Eriksson, Frida, 1986, et al. (författare)
  • Interpretative and predictive modelling of Joint European Torus collisionality scans
  • 2019
  • Ingår i: Plasma Physics and Controlled Fusion. - : Institute of Physics Publishing (IOPP). - 0741-3335 .- 1361-6587. ; 61:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Transport modelling of Joint European Torus (JET) dimensionless collisionality scaling experiments in various operational scenarios is presented. Interpretative simulations at a fixed radial position are combined with predictive JETTO simulations of temperatures and densities, using the TGLF transport model. The model includes electromagnetic effects and collisions as well as (E)over-right-arrow x (b)over-right-arrow shear in Miller geometry. Focus is on particle transport and the role of the neutral beam injection (NBI) particle source for the density peaking. The experimental 3-point collisionality scans include L-mode, and H-mode (D and H and higher beta D plasma) plasmas in a total of 12 discharges. Experimental results presented in (Tala et al 2017 44th EPS Conf.) indicate that for the H-mode scans, the NBI particle source plays an important role for the density peaking, whereas for the L-mode scan, the influence of the particle source is small. In general, both the interpretative and predictive transport simulations support the experimental conclusions on the role of the NBI particle source for the 12 JET discharges.
  •  
2.
  • Joffrin, E., et al. (författare)
  • Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
  • 2019
  • Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
  • 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.
  •  
3.
  • Maggi, C. F., et al. (författare)
  • Isotope identity experiments in JET-ILW with H and D L-mode plasmas
  • 2019
  • Ingår i: Nuclear Fusion. - : Institute of Physics Publishing (IOPP). - 0029-5515 .- 1741-4326. ; 59:7
  • Tidskriftsartikel (refereegranskat)abstract
    • NBI-heated L-mode plasmas have been obtained in JET with the Be/W ITER-like wall (JET-ILW) in H and D, with matched profiles of the dimensionless plasma parameters, rho*, nu*, beta and q in the plasma core confinement region and same T-i/T-e and Z(eff). The achieved isotope identity indicates that the confinement scale invariance principle is satisfied in the core confinement region of these plasmas, where the dominant instabilities are Ion Temperature Gradient (ITG) modes. The dimensionless thermal energy confinement time, Omega(i) tau(E,th), and the scaled core plasma heat diffusivity, A chi(eff)/B-T, are identical in H and D within error bars, indicating lack of isotope mass dependence of the dimensionless L-mode thermal energy confinement time in JET-ILW. Predictive flux driven simulations with JETTO-TGLF of the H and D identity pair is in very good agreement with experiment for both isotopes: the stiff core heat transport, typical of JET-ILW NBI heated L-modes, overcomes the local gyro-Bohm scaling of gradient-driven TGLF, explaining the lack of isotope mass dependence in the confinement region of these plasmas. The effect of E x B shearing on the predicted heat and particle transport channels is found to be negligible for these low beta and low momentum input plasmas.
  •  
4.
  •  
5.
  •  
6.
  • Andersson Sundén, Erik, et al. (författare)
  • An assessment of nitrogen concentrations from spectroscopic measurements in the JET and ASDEX upgrade divertor
  • 2019
  • Ingår i: Nuclear Materials and Energy. - : Elsevier. - 2352-1791. ; 18, s. 147-152
  • Tidskriftsartikel (refereegranskat)abstract
    • The impurity concentration in the tokamak divertor plasma is a necessary input for predictive scaling of divertor detachment, however direct measurements from existing tokamaks in different divertor plasma conditions are limited. To address this, we have applied a recently developed spectroscopic N II line ratio technique for measuring the N concentration in the divertor to a range of H-mode and L-mode plasma from the ASDEX Upgrade and JET tokamaks, respectively. The results from both devices show that as the power crossing the separatrix, P-sep, is increased under otherwise similar core conditions (e.g. density), a higher N concentration is required to achieve the same detachment state. For example, the N concentrations at the start of detachment increase from approximate to 2% to approximate to 9% as P-sep, is increased from approximate to 2.5 MW to approximate to 7 MW. These results tentatively agree with scaling law predictions (e.g. Goldston et al.) motivating a further study examining the parameters which affect the N concentration required to reach detachment. Finally, the N concentrations from spectroscopy and the ratio of D and N gas valve fluxes agree within experimental uncertainty only when the vessel surfaces are fully-loaded with N.
  •  
7.
  • Angioni, C., et al. (författare)
  • Dependence of the turbulent particle flux on hydrogen isotopes induced by collisionality
  • 2018
  • Ingår i: Physics of Plasmas. - : American Institute of Physics (AIP). - 1070-664X .- 1089-7674 .- 1070-6631 .- 1089-7666. ; 25:8
  • Tidskriftsartikel (refereegranskat)abstract
    • The impact of the change of the mass of hydrogen isotopes on the turbulent particle flux is studied. The trapped electron component of the turbulent particle convection induced by collisionality, which is outward in ion temperature gradient turbulence, increases with decreasing thermal velocity of the isotope. Thereby, the lighter is the isotope, the stronger is the turbulent pinch, and the larger is the predicted density gradient at the null of the particle flux. The passing particle component of the flux increases with decreasing mass of the isotope and can also affect the predicted density gradient. This effect is however subdominant for usual core plasma parameters. The analytical results are confirmed by means of both quasi-linear and nonlinear gyrokinetic simulations, and an estimate of the difference in local density gradient produced by this effect as a function of collisionality has been obtained for typical plasma parameters at mid-radius. Analysis of currently available experimental data from the JET and the ASDEX Upgrade tokamaks does not show any clear and general evidence of inconsistency with this theoretically predicted effect outside the errorbars and also allows the identification of cases providing weak evidence of qualitative consistency.
  •  
8.
  • Bobkov, V, et al. (författare)
  • Impact of ICRF on the scrape-off layer and on plasma wall interactions : From present experiments to fusion reactor
  • 2019
  • Ingår i: Nuclear Materials and Energy. - : Elsevier. - 2352-1791. ; 18, s. 131-140
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent achievements in studies of the effects of ICRF (Ion Cyclotron Range of Frequencies) power on the SOL (Scrape-Off Layer) and PWI (Plasma Wall Interactions) in ASDEX Upgrade (AUG), Alcator C-Mod, and JET-ILW are reviewed. Capabilities to diagnose and model the effect of DC biasing and associated impurity production at active antennas and on magnetic field connections to antennas are described. The experiments show that ICRF near-fields can lead not only to E x B convection, but also to modifications of the SOL density, which for Alcator C-Mod are limited to a narrow region near antenna. On the other hand, the SOL density distribution along with impurity sources can be tailored using local gas injection in AUG and JET-ILW with a positive effect on reduction of impurity sources. The technique of RF image current cancellation at antenna limiters was successfully applied in AUG using the 3-strap AUG antenna and extended to the 4-strap Alcator C-Mod field-aligned antenna. Multiple observations confirmed the reduction of the impact of ICRF on the SOL and on total impurity production when the ratio of the power of the central straps to the total antenna power is in the range 0.6 < P-cen / P-total < 0.8. Near-field calculations indicate that this fairly robust technique can be applied to the ITER ICRF antenna, enabling the mode of operation with reduced PWI. On the contrary, for the A2 antenna in JET-ILW the technique is hindered by RF sheaths excited at the antenna septum. Thus, in order to reduce the effect of ICRF power on PWI in a future fusion reactor, the antenna design has to be optimized along with design of plasmafacing components.
  •  
9.
  • Bombarda, F., et al. (författare)
  • Runaway electron beam control
  • 2019
  • Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
  • Tidskriftsartikel (refereegranskat)
  •  
10.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 284
Typ av publikation
tidskriftsartikel (276)
forskningsöversikt (7)
konferensbidrag (1)
Typ av innehåll
refereegranskat (284)
Författare/redaktör
Andersson Sundén, Er ... (283)
Conroy, Sean (283)
Eriksson, Jacob, Dr, ... (283)
Sjöstrand, Henrik, 1 ... (283)
Zychor, I (282)
visa fler...
Ström, Petter (282)
Cecconello, Marco (282)
Rubel, Marek (281)
Possnert, Göran, 195 ... (281)
Weiszflog, Matthias (281)
Frassinetti, Lorenzo (280)
Hellsten, Torbjörn (280)
Bykov, Igor (280)
Ericsson, Göran (280)
Hjalmarsson, Anders (280)
Menmuir, Sheena (271)
Petersson, Per (266)
Bergsåker, Henric (249)
Rachlew, Elisabeth, ... (248)
Hellesen, Carl, 1980 ... (242)
Skiba, Mateusz, 1985 ... (241)
Binda, Federico, 198 ... (239)
Dzysiuk, Nataliia (212)
Johnson, Thomas (189)
Tholerus, Emmi (180)
Stefanikova, Estera (144)
Garcia-Carrasco, Alv ... (143)
Garcia Carrasco, Alv ... (138)
Elevant, Thomas (136)
Ivanova, Darya (136)
Ratynskaia, Svetlana (123)
Olivares, Pablo Vall ... (123)
Tolias, Panagiotis (120)
Asp, E (109)
Tholerus, Simon, 198 ... (94)
Zhou, Yushun (89)
Jonsson, Thomas, 197 ... (77)
Zhou, Yushan (55)
Dzysiuk, N. (51)
Binda, F. (40)
Skiba, M. (40)
Hellesen, C (39)
Rachlew, Elisabeth (34)
Bergsåker, Henrik (30)
Zoletnik, S (26)
Huber, A (23)
Nordman, Hans, 1957 (22)
Strand, Pär, 1968 (22)
Bonanomi, N. (22)
visa färre...
Lärosäte
Kungliga Tekniska Högskolan (283)
Uppsala universitet (259)
Chalmers tekniska högskola (26)
Språk
Engelska (284)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (284)
Teknik (13)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy