N.R. Walkden J. Adamek S. Allan B. D. Dudson S. Elmore G. Fishpool J. Harrison A. Kirk M. Komm
The ball pen probe (BPP) technique is used successfully to make profile measurements of plasma potential, electron temperature, and radial electric field on the Mega Amp Spherical Tokamak. The potential profile measured by the BPP is shown to significantly differ from the floating potential both in polarity and profile shape. By combining the BPP p…
Preprint PublishedD. Hancock T. Barrett J. Foster M. Fursdon G. Keech S. McIntosh W. Timmis M. Rieth J. Reiser
The design of a divertor target for DEMO remains one of the most challenging engineering tasks to be overcome on the path to fusion power. Under the European DEMO programme, a promising concept known as Thermal Break has been developed at CCFE. This concept is a variation of the ITER tungsten divertor in which the pure Copper interlayer between Cop…
Preprint PublishedT. Eade S. Lilley Z. Ghani E. Delmas
The requirement for maintenance in areas with relatively high shutdown dose rate fields is a key issue to address in the design and engineering of ITER, next generation devices and future commercial fusion reactors. In order to estimate the shutdown dose rate during maintenance and intervention scenarios CCFEs Mesh Coupled implementation of the R…
Preprint PublishedL. W. G. Morgan J. Shimwell M. R. Gilbert
A large number of materials exist which have been labeled as low activation structural materials (LAM). Most often, these materials have been designed in order to substitute-out or completely remove elements that become activated and contribute signi cantly to shut-down activity after being irradiated by neutrons in a reactor environment. To date, …
Preprint PublishedW. A. Hornsby P. Migliano R. Buchholz S. Grosshauser A. Weikl D. Zarzoso F. J. Casson E. Poli A. G. Peeters
The non-linear evolution of a magnetic island is studied using the Vlasov gyro-kinetic code GKW. The interaction of electromagnetic turbulence with a self-consistently growing magnetic island, generated by a tearing unstable >0 current profile, is considered. The turbulence is able to seed the magnetic island and bypass the linear growth phase b…
Preprint PublishedN. R. Walkden B. D. Dudson L. Easy G. Fishpool J. T. Omotani
This paper presents a numerical investigation of isolated filament dynamics in a simulation geometry representative of the scrape-off layer (SOL) of the Mega Amp Spherical Tokamak (MAST) previously studied in [N.R.Walkden et.al, Plasma Phys. Control. Fusion, 55 (2013) 105005]. This paper focuses on the evolution of filament cross-sections at the ou…
Preprint PublishedL. Carbajal S. C. Chapman R. O. Dendy N. W. Watkins J. W. S. Cook
Preferential ion heating in the solar wind, observed as the occurrence of an ion beam which drifts along the background magnetic field with a velocity close to the local Alfven speed, is still an open problem. Several mechanisms have been identified that might work together in the solar wind to drive the observed ion heating. These mechanisms resul…
PreprintD. A. Thomas K. J. Brunner S. J. Freethy B. K. Huang V. F. Shevchenko R. G. L. Vann
The Synthetic Aperture Microwave Imaging (SAMI) diagnostic has conducted proof-of-principle 2D Doppler backscattering (DBS) experiments on MAST. SAMI actively probes the plasma edge using a wide ( 40° vertical and horizontal) and tuneable (10-35.5 GHz) beam. The Doppler backscattered signal is digitised in vector form using an array of eight Vival…
Preprint PublishedJ. S. K. L. Gibson S. G. Roberts D. E. J. Armstrong
Nanoindentation has been performed on tungsten, unimplanted and helium-implanted to $ 600 appm, at temperatures up to 750 1 C. The hardening effect of the damage was 0.90 GPa at 50 1 C, but is negligible above 450 1 C. The hardness value at a given temperature did not change on re-testing after heating to 750 1 C. This suggests that the helium is t…
PublishedH. Zhu R.O. Dendy S.C. Chapman S. Inagaki
It is known that rapid edge cooling of magnetically confined plasmas can trigger heat pulses that propagate rapidly inward. These can result in large excursion, either positive or negative, in the electron temperature at the core. A set of particularly detailed measurements was obtained in Large Helical Device(LHD) plasmas [S. Inagaki et al, Plasma…
Preprint Published