S. C. Chapman P. T. Lang R. O. Dendy L. Giannone N. W. Watkins ASDEX 4 Upgrade Team
The ITER tokamak needs to sustain a plasma in a regime of high energy confinement (H-mode) to exceed fusion breakeven where power output exceeds input. H-mode plasmas are typically unstable to edge localised modes (ELMs), in which plasma escapes and strikes the plasma facing components. Scaled up to ITER, the energy released by ELMs can cause criti…
PreprintR. S. Hemsworth D. Boilson P. Blatchford M. Dalla Palma G. Chitarin H. P. L. de Esch F. Geli M. Dremel J. Graceffa D. Marcuzzi G. Serianni D. Shah M. Singh M. Urbani P. Zaccaria
The heating neutral beam injectors (HNBs) of ITER are designed to deliver 16.7MWof 1 MeVD0 or 0.87 MeVH0 to the ITER plasma for up to 3600 s. They will be the most powerful neutral beam (NB) injectors ever, delivering higher energy NBs to the plasma in a tokamak for longer than any previous systems have done. The design of the HNBs is based on the …
PublishedJ.S.Wróbel D. Nguyen-Manh S.L. Dudarev K.J. Kurzyd?owski
The properties of point defects in Fe-Cr-Ni alloys are investigated, using density functional theory (DFT), for two alloy compositions, Fe50Cr25Ni25 and Fe55Cr15Ni30, assuming various degrees of short-range order. DFT-based Monte Carlo simulations are applied to explore short-range order parameters and generate representative structures of alloys. …
Preprint PurchaseS. Wiesen M. Groth S. Brezinsek M. Wischmeier JET contributors
An overview is given on the recent progress on edge modelling activities for the JET ITER like wall using the computational tools like the SOLPS or EDGE2D-EIRENE code. The validation process of these codes on JET with its metallic plasma-facing components is an important step towards predictive studies for ITER and DEMO in relevant divertor operati…
Preprint PublishedS. Zheng D. B. King L. Garzotti E. Surrey T. N. Todd
It has long been recognised that the shortage of external tritium sources for fusion reactors using D-T, the most promising fusion fuel, requires all such fusion power plants (FPP) to breed their own tritium. It is also recognised that the initial start-up of a fusion reactor will require several kilograms of tritium within a scenario in which radi…
Preprint PublishedM. Romanelli V. Parail P. da Silva Aresta Belo G. Corrigan L. Garzotti D. Harting F. Koechl E. Militello-Asp R. Ambrosino M. Cavinato A. Kukushkin A. Loarte M. Mattei R. Sartori
ITER operations require effective fuelling of the core plasma for conditions in which neutral dynamics through the scrape-off layer (SOL) is expected to affect significantly the efficiency of gas penetration. On the basis of previous analysis for stationary conditions, pellets are foreseen to provide core fuelling of high-Q DT scenarios. In this pa…
Preprint PublishedE. Havlickova M. Wischmeier B. Lipschultz G. Fishpool
An impurity seeding scan has been simulated in three different divertor configurations of MAST-U, showing the effect of the divertor geometry on the transition to detachment. The three configurations include a conventional short divertor, a Super-X divertorwith large poloidal flux expansion and a Super-X divertor with small poloidal flux expansion.…
Preprint PublishedR. McAdams
A high pumping speed is required in neutral beam injectors to minimise re-ionisation of the neutral beams. The neutral beam injectors on MAST use titanium sublimation pumps. These pumps do not have a constant pumping speed; their pumping speed depends on the gettering surface history and on both the integrated and applied gas load. In this paper we…
Preprint PublishedG. G. Plunk P. Helander P. Xanthopoulos J. W. Connor
We investigate the linear theory of the ion-temperature-gradient (ITG) mode, with the goal of developing a general understanding that may be applied to stellarators. We highlight the Wendelstein 7X (W7-X) device. Simple fluid and kinetic models that follow closely from existing literature are reviewed and two new first-principle models are presente…
PublishedL.W.G. Morgan L.W. Packer
The generation of tritium in sufficient quantities is an absolute requirement for a next step fusion device such as DEMO due to the scarcity of tritium sources. A number of methods have been proposed in order to meet this requirement, however a lithium-based tritium breeding blanket that surrounds the fusion plasma is widely considered to be the mo…
Published