S B L Chislett-McDonald E Surrey J Naish A Turner D P Hampshire
All high field superconductors producing magnetic fields above 12 T are brittle. Nevertheless, they will probably be the materials of choice in commercial tokamaks because the fusion power density in a tokamak scales as the fourth power of magnetic field. Here we propose using robust, ductile superconductors during the reactor commissioning phase i…
PreprintDavid Schworer Nick Walkden Ben Dudson Fulvio Militello Huw Leggate Miles Turner
The here presented work studies the dynamics of filaments using 3D full-f fluid simulations in the presence of detached background profiles. It was found that evolving the neutrals on the time-scale of the filament did not have a significant impact on the dynamics of the filament. In general a decreasing filament velocity with increasing plasma den…
Preprint PublishedI. Turner A J T. Holmes
A model for a beam-driven plasma neutraliser for a 1MeV, 40A beam of D- ions is presented and is based on the dimensions of the ITER gas neutraliser. For the beam-driven plasma neutraliser there is no need for an external power source for producing and sustaining the plasma. Instead the use of high magnetic fields is employed for plasma confinement…
Preprint PublishedI. Turner R. McAdams W. Arter A. Ash M. Barnard D. Ciric I. Day D. Keeling D. King C. Lane M. Nicassio T. Robinson A. Shepherd J. Zacks
Increased neutralisation and hence injected neutral beam power can be achieved by increasing the neutraliser target. This has the potential to increase the loading on the ion source backplate due to backstreaming electrons. Measurements of the backplate power loading due to backstreaming electrons are presented for the JET EP2 neutral beam injector…
Preprint PublishedI Turner A J T Holmes J Zacks R McAdams
A 1D model of an RF driven ion source is presented and is based on the ionisation of thermal electrons. The RF source differs from traditional filament and arc ion sources because there are no primary electrons present, and is simply composed of an antenna region (driver) and a main plasma discharge region. However the model does still make use …
Preprint PublishedA. Turner A. Burns B. Colling J. Leppänen
Nuclear analysis supporting the design and licensing of ITER is traditionally performed using MCNP and the reference model ‘C-Model’, however the complexity of C-Model has resulted in the geometry creation and integration process becoming increasingly time-consuming. Serpent 2 is still a beta code, however recent enhancements mean that it could…
Preprint PublishedD. Schwörer N. R. Walkden H. Leggate B. D. Dudson F. Militello T. Downes M. M. Turner
This paper presents the effect of self-consistent plasma backgrounds including plasma-neutral interactions, on the dynamics of filament propagation. The principle focus is on the influence of the neutrals on the filament through both direct interactions and through their influence on the plasma background. Both direct and indirect interactions infl…
Preprint PublishedA. Turner
As radiation transport models for ITER become increasingly complex, the use of traditional constructive solid geometry (CSG) modelling approaches such as MCNP presents significant disadvantages during model creation and integration. Studies were performed to assess the capabilities of alternative mesh-based neutronics workflows offered by the MCNP …
PreprintR. McAdams A. J. T. Holmes D. B. King E. Surrey I. Turner J. Zacks
A summary of negative ion development work being presently undertaken at the Culham Centre for Fusion Energy (CCFE) is given. The Small Negative Ion Facility (SNIF) has an RF driven volume ion source with beam extraction at energies up to 30keV. The extracted beam of Hions has an associated co-extracted electron beam with an electron to ion ratio o…
Preprint PublishedR. McAdams A. Sparkes A. Ash I. Day D. King M. Kovari A. Shepherd I. Turner J. Zacks D. Ciric JET EFDA Contributors
In normal operation the JET neutral beam injectors have the operating gas supplied to the ion source and the neutraliser. For tritium operation the gas is supplied to both the ion source and neutraliser at a point close to the earth grid (grid gas) due to the difficulty in producing a gas line with a secondary containment and a ceramic break fo…
Preprint Published