R. B. Morales S. Heuraux R. Sabot S. Hacquin
All density profile reconstruction techniques for both O-mode and X-mode are based on the assumption that the cut-off frequency profile is monotonic. However, there are many sources of perturbations to the plasma that generate hollow areas in the cut-off frequency profile, breaking the aforementioned assumption. This causes a significant immediate …
Preprint PublishedLee Aucott Rob Bamber Artem Lunev Tim Darby Philippe Maquet Nathalie Gimbert Sunil Pak Mike Walsh Victor Udintsev Glenn Eaton Brendan Conway
The United Kingdom Atomic Energy Authority are involved in the design and manufacture of the diagnostic windows for ITER. ITER is an international project, with 35 nations collaborating to design, construct and operate a prototype controlled nuclear fusion reactor in southern France. As well as providing line of sight for diagnostics, the window…
Preprint PublishedV.H. Hall-Chen F.I. Parra J.C. Hillesheim
The use of Doppler Backscattering (DBS) in spherical tokamaks is challenging since the magnetic pitch angle can be large (up to 35, compared to 15 in standard tokamaks like JET). Moreover the pitch angle varies both spatially and temporally. Hence, the probe beam is generally not perpendicular to the magnetic field. This misalignment, which affec…
Preprint PublishedS.F. Smith S.J.P. Pamela A. Fil M. Hoelzl G.T.A. Huijsmans A. Kirk D. Moulton O. Myatra A.J. Thornton H.R. Wilson
ELM simulations for the MAST-U Super-X tokamak have been obtained, using the JOREK code. The JOREK visco-resistive MHD model has been used to obtain comparisons of divertor configurations. The simulations show a factor 10 decrease in the peak heat flux to the outer target of the Super-X in comparison to a conventional divertor configuration. A roll…
Preprint PublishedC.D. Challis S. Brezinsek I. Coffey M. Fontana N. Hawkes D. Keeling D. King G. Pucella E. Viezzer JET Contributors
The initial current ramp phase of JET hybrid plasmas is used to optimise the target q-profile for main heating to allow access to high beta and avoid MHD instabilities. Mixed protium-deuterium experiments, carried out at JET since the installation of the beryllium-tungsten wall, have shown that the q-profile evolution during this Ohmic phase varies…
Preprint PublishedJ. Morris N. Asakura Y. Homma
Protecting the divertor in a nuclear fusion power plant is a key criteria for operation. Detailed divertor and scrape-off-layer (SOL) modelling is computationally intensive and unsuitable for a systems code. For the use of such models in systems codes they need to be simplified and made computationally fast, while still capturing the most important…
Preprint PublishedT. Tremethick S. Kirk K. Keogh A. O’Hare E. Harford B. Quirk
As part of the European Research Roadmap to the Realisation of Fusion Energy, the DEMO reactor aims to show the feasibility of a fusion power plant. Due to the loss of revenue created by downtime and the potential for a breakdown to render a reactor inoperable, maintenance is “mission critical” for a power plant. The harsh environment of a fusi…
Preprint Published