| 1. |
- 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.
|
|
| 2. |
|
|
| 3. |
- Krasilnikov, A., et al.
(författare)
-
Evidence of 9 Be + p nuclear reactions during 2ω CH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas
- 2018
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:2
-
Tidskriftsartikel (refereegranskat)abstract
- The intensity of 9Be + p nuclear fusion reactions was experimentally studied during second harmonic (2ω CH) ion-cyclotron resonance heating (ICRH) and further analyzed during fundamental hydrogen minority ICRH of JET-ILW hydrogen and deuterium plasmas. In relatively low-density plasmas with a high ICRH power, a population of fast H+ ions was created and measured by neutral particle analyzers. Primary and secondary nuclear reaction products, due to 9Be + p interaction, were observed with fast ion loss detectors, γ-ray spectrometers and neutron flux monitors and spectrometers. The possibility of using 9Be(p, d)2α and 9Be(p, α)6Li nuclear reactions to create a population of fast alpha particles and study their behaviour in non-active stage of ITER operation is discussed in the paper.
|
|
| 4. |
|
|
| 5. |
-
- 2018
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
-
Forskningsöversikt (refereegranskat)
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
-
Overview of the JET results
- 2015
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 55:10
-
Tidskriftsartikel (refereegranskat)
|
|
| 20. |
-
- 2018
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:9
-
Tidskriftsartikel (refereegranskat)
|
|
| 21. |
- Abel, I, et al.
(författare)
-
Overview of the JET results with the ITER-like wall
- 2013
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
-
Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
|
|
| 22. |
- Romanelli, F, et al.
(författare)
-
Overview of the JET results
- 2011
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
-
Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- Kalupin, D., et al.
(författare)
-
Numerical analysis of JET discharges with the European Transport Simulator
- 2013
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:12, s. article nr. 123007-
-
Tidskriftsartikel (refereegranskat)abstract
- The 'European Transport Simulator' (ETS) (Coster et al 2010 IEEE Trans. Plasma Sci. 38 2085-92, Kalupin et al 2011 Proc. 38th EPS Conf. on Plasma Physics (Strasbourg, France, 2011) vol 35G (ECA) P. 4.111) is the new modular package for 1D discharge evolution developed within the EFDA Integrated Tokamak Modelling (ITM) Task Force. It consists of precompiled physics modules combined into a workflow through standardized input/output data structures. Ultimately, the ETS will allow for an entire discharge simulation from the start up until the current termination phase, including controllers and sub-systems. The paper presents the current status of the ETS towards this ultimate goal. It discusses the design of the workflow, the validation and verification of its components on the example of impurity solver and demonstrates a proof-of-principles coupling of a local gyrofluid model for turbulent transport to the ETS. It also presents the first results on the application of the ETS to JET tokamak discharges with the ITER like wall. It studies the correlations of the radiation from impurity to the choice of the sources and transport coefficients.
|
|
| 28. |
- Voitsekhovitch, I., et al.
(författare)
-
Integrated modelling for tokamak plasma: Physics and scenario optimisation
- 2012
-
Ingår i: 39th EPS Conference on Plasma Physics 2012, EPS 2012 and the 16th International Congress on Plasma Physics; Stockholm; Sweden; 2 July 2012 through 6 July 2012; Code 96757. - 9781622769810 ; 2, s. 1314-1317
-
Konferensbidrag (refereegranskat)abstract
- Simulations of JET and AUG HS with the GLF23 model show that the observed core confinement improvement can be partly explained by the beneficial s/q effect on the ITG driven transport while the effect of the ExB shear stabilisation is weaker than in H-mode plasmas. Strong stabilising effect of βe on the ITG turbulence has been found, but the transport reduction due to this effect can be limited by the onset of the KBM mode at high βe. The simulations of toroidal rotation in HS with the GLF23 model give an indication of the toroidal momentum pinch (Pr
|
|
| 29. |
- Parail, V., et al.
(författare)
-
Integrated modelling of ITER reference scenarios
- 2009
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 49:7
-
Tidskriftsartikel (refereegranskat)abstract
- The ITER Scenario Modelling Working Group (ISM WG) is organized within the European Task Force on Integrated Tokamak Modelling (ITM-TF). The main responsibility of the WG is to advance a pan-European approach to integrated predictive modelling of ITER plasmas with the emphasis on urgent issues, identified during the ITER Design Review. Three major topics are discussed, which are considered as urgent and where the WG has the best possible expertize. These are modelling of current profile control, modelling of density control and impurity control in ITER (the last two topics involve modelling of both core and SOL plasma). Different methods of heating and current drive are tested as controllers for the current profile tailoring during the current ramp-up in ITER. These include Ohmic, NBI, ECRH and LHCD methods. Simulation results elucidate the available operational margins and rank different methods according to their ability to meet different requirements. A range of ITER-relevant' plasmas from existing tokamaks were modelled. Simulations confirmed that the theory-based transport model, GLF23, reproduces the density profile reasonably well and can be used to assess ITER profiles with both pellet injection and gas puffing. In addition, simulations of the SOL plasma were launched using both H-mode and L-mode models for perpendicular transport within the edge barrier and in the SOL. Finally, an integrated approach was also used for the predictive modelling of impurity accumulation in ITER. This includes helium ash, extrinsic impurities (such as argon) and impurities coming from the wall (including tungsten). The relative importance of anomalous and neo-classical pinch contributions towards impurity penetration through the edge transport barrier and further accumulation in the core was assessed.
|
|
| 30. |
- Romanelli, M., et al.
(författare)
-
JINTRAC: A system of codes for integrated simulation of Tokamak scenarios
- 2014
-
Ingår i: Plasma and Fusion Research. - : Japan Society of Plasma Science and Nuclear Fusion Research. - 1880-6821. ; 9:SPECIALISSUE.2
-
Tidskriftsartikel (refereegranskat)abstract
- Operation and exploitation of present and future Tokamak reactors require advanced scenario modeling in order to optimize engineering parameters in the design phase as well as physics performance during the exploitation phase. The simulation of Tokamak scenarios involves simultaneous modeling of different regions of the reactor, characterized by different physics and symmetries, in order to predict quantities such as particle and energy confinement, fusion yield, power deposited on wall, wall load from fast particles. JINTRAC is a system of 25 interfaced Tokamak-physics codes for the integrated simulation of all phases of a Tokamak scenario. JINTRAC predictions reflect the physics and assumptions implemented in each module and extensive comparison with experimental data is needed to allow validation of the models and improvement of Tokamak-physics understanding. © 2014 The Japan Society of Plasma Science and Nuclear Fusion Research.
|
|
| 31. |
- Simpson, J., et al.
(författare)
-
Investigation of the dependence of p(e,ped) on n(e,sep) in JET H-Mode plasmas using integrated JETTO-MISHKA-FRANTIC simulations
- 2023
-
Ingår i: Nuclear Materials and Energy. - : Elsevier BV. - 2352-1791. ; 34
-
Tidskriftsartikel (refereegranskat)abstract
- Experimentally, it has been observed in high-confinement (H-Mode) plasmas with Edge Localised Modes (ELMs) on JET that the pressure pedestal (p(e,ped)) is degraded by approximately a factor of two when there is a change in electron separatrix density, n(e,sep), from 1 - 4 x 10(19) m(-3). Previous work using the pedestal stability code EUROPED, has been able to predict the degradation of p(e,ped) but only for n(e,sep) = 1.5 x 10(19) m(-3). In this work, we apply a coupled code JETTO-MISHKA-FRANTIC, to self-consistently predict the transport in the pedestal region and neutral source with varying separatrix conditions. The code feeds back on the transport in the pedestal region to achieve profiles that are marginally stable to ideal MHD modes (continuous ELM model in JETTO). When accounting for the change in electron separatrix temperature (T-e,T-sep), ion separatrix temperature (T-e,T-sep) and the poloidally integrated neutral flux crossing the separatrix (Gamma(sep,neui)) as it changes with n(e,sep) (according to a scan in n(e,sep) in the edge code EDGE2D-EIRENE), no degradation in p(e,ped) was observed in JETTO-MISHKA-FRANTIC in contrast to experiment. Instead, an increase in p(e,ped) with n(e,sep) was observed which is driven by an increasing density pedestal (n(e,ped)). Within the presented JETTO-MISHKA-FRANTIC simulations, changing the pedestal width by a factor of two and a half in normalised poloidal flux (psi(n)) resulted in an approximately 40% degradation in p(e,ped) for n(e,sep) = 1 - 3 x 10(19) m(-3). This change in pedestal width was not supported by experimental data. A scan in the ratio of particle and energy transport in the pedestal (D/chi) was found to have a negligible effect on p(e,ped). Qualitative agreement between JETTO-MISHKA-FRANTIC with EUROPED was found when the input density profiles are identical.
|
|
| 32. |
- Garzotti, L., et al.
(författare)
-
Simulations of density profiles in JET hybrid discharges
- 2012
-
Ingår i: 39th EPS Conference on Plasma Physics 2012, EPS 2012 and the 16th International Congress on Plasma Physics; Stockholm; Sweden; 2 July 2012 through 6 July 2012; Code 96757. - 9781622769810 ; 1, s. 157-160
-
Konferensbidrag (refereegranskat)
|
|
