K. Arakawa M.-C. Marinica S. Fitzgerald L. Proville D. Nguyen-Manh S. L. Dudarev P.-W. Ma T. D. Swinburne A. M. Goryaeva T. Yamada T. Amino S. Arai Y. Yamamoto K. Higuchi N. Tanaka H. Yasuda T. Yasuda H. Mori
The diffusion of defects in crystalline materials governs macroscopic behaviour in a wide range of processes, including alloying, precipitation, phase transformation, and creep. In real materials, intrinsic defects are unavoidably bound to static trapping centres such as impurity atoms, meaning that their diffusion is controlled by the de-trapping …
PublishedJames Harrison RJ Akers SY Allan JS Allcock JO Allen L Appel M Barnes N Ben Ayed W Boeglin C Bowman J Bradley P Browning P Bryant M Carr M Cecconello CD Challis S Chapman IT Chapman GJ Colyer S Conroy NJ Conway M Cox G Cunningham RO Dendy W Dorland BD Dudson L Easy SD Elmore T Farley X Feng AR Field A Fil GM Fishpool M Fitzgerald
Recent results from MAST address key physics issues for ITER operations and the design of future devices, by advancing our understanding of through analysis of high-resolution data and numerical modelling. Modelling of the interaction between filaments with BOUT++ indicates filaments separated by more than 5x their width move independently, and …
Preprint PublishedM. Fitzgerald J. Buchanan R.J. Akers B.N. Breizman S.E. Sharapov
HALO (HAgis LOcust) solves the initial value Vlasov-Maxwell problem perturbatively for application to certain nonlinear wave-particle problems in tokamak plasmas. It uses the same basic approach as the HAGIS code (Pinches et al., 1998) for wave evolution but is built on the LOCUST-GPU full-orbit code (Akers et al., 2012) for the solution of the Ham…
Preprint PublishedMarco Cecconello A. Sperduti I. Fitzgerald S. Conroy S. J. Holm M. Weiszflog
A Neutron Camera (NC) was used on the Mega Ampere Spherical Tokamak (MAST) to measure the DD neutron emissivity along four collimated lines of sight, two on-axis and two off-axis, all viewing the plasma in tangential direction. The encouraging results obtained suggested that an upgraded NC for MAST-U would provide fundamental information for the st…
Preprint PublishedM. Fitzgerald J. Buchanan S. E. Sharapov V. G. Kiptily M. Sertoli G. Szepesi J. Boom R. Akers D. King JET contributors
Fishbones are ubiquitous in high-performance JET plasmas and are typically considered to be unimportant for scenario design. However, during recent high-performance hybrid experiments, sporadic and explosive fishbones have been observed which correlate with a reduction in performance and main chamber hotspots. Clear evidence has been obtained of fu…
Preprint PublishedS. E. Sharapov H. J. C. Oliver B. N. Breizman M. Fitzgerald L. Garzotti JET contributors
Alfvén Eigenmodes (AEs) are routinely seen in present-day tokamaks and stellarators with energetic particles and they represent an attractive form of MHD spectroscopy that provides valuable information on background plasma and on the energetic particles. Possible use of AEs is assessed for MHD spectroscopy of plasma with high-velocity pellet injec…
Preprint PublishedV. G. Kiptily M. Fitzgerald V. Goloborodko S. E. Sharapov C. D. Challis D. Frigione J. Graves M. J. Mantsinen P. Beaumont M. Garcia-Munoz C. Perez von Thun J. F. R. Rodriguez D. Darrow D. Keeling D. King K. G. McClements E. Solano S. Schmuck G. Sips G. Szepesi JET contributors
During development of a high-performance hybrid scenario for future deuterium–tritium experiments on the Joint European Torus, an increased level of fast ion losses in the MeV energy range was observed during the instability of high-frequency n = 1 fishbones. The fishbones are excited during deuterium neutral beam injection combined with…
Preprint PublishedK. Arakawa M. Marinica S. Fitzgerald L. Proville D. Nguyen-Manh S.L Dudarev P. Wai Ma T.D Swinburne T. Yamada T. Amino S. Arai Y. Yamamoto K. Higuchi N. Tanaka H. Yasuda T. Yasuda H. Mori
Quantum dynamics within solids is usually restricted to low mass particles such as electrons and muons, or single atoms of light elements such as hydrogen. In this letter we report observation of the quantum-assisted motion of self-interstitial atom clusters in tungsten (each of mass 184 Da), travelling distances of several nanometres between trapp…
PreprintZ.S. Qu M.J. Hole M. Fitzgerald
In this paper we have developed a fluid model to study the radial mode structure of the reactive energetic geodesic acoustic modes (reactive EGAMs), a branch of GAM that becomes unstable in the presence of a cold fast ion beam. We have solved the resulting dispersion relationship, a second order ODE, both analytically in restricted cases and numeri…
Preprint PublishedH. Tanabe T. Yamada T. Watanabe K. Gi M. Inomoto R. Imazawa M. Gryaznevich C. Michael B. Crowley N. J. Conway R. Scannell J. Harrison I. Fitzgerald A. Meakins N. Hawkes K. G. McClements T. O'Gorman C. Z. Cheng Y. Ono The MAST team
In the last three years, magnetic reconnection research in the MAST spherical tokamak achieved major progress by use of new 32 chord ion Doppler tomography, 130 channel YAG and 300 channel Ruby Thomson scattering diagnostics. In addition to the previously achieved high power plasma heating during merging, detailed full temperature profile measureme…
Preprint Published