A. J. Webster J. Morris T. N. Todd S. Brezinsek P. Coad J. Likonen M. Rubel JET EFDA Contributors
A unique sequence of 120 almost identical plasmas in the Joint European Torus (JET) recently provided two orders of magnitude more statistically equivalent data than ever previously available. The purpose was to study movement of eroded plasma-facing material from JET’s new Beryllium wall, but it has allowed the statistical detection of otherwise…
PublishedS. C. Chapman R. O. Dendy T. N. Todd N. W. Watkins A. J. Webster F. Calderon J. Morris JET EFDA Contributors
A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in …
PublishedA.J. Webster R.O. Dendy F.A. Calderon S. C. Chapman E. Delabie D. Dodt R. Felton T. N. Todd F. Maviglia J. Morris V. Riccardo B. Alper S. Brezinsek P. Coad J. Likonen M. Rubel JET EFDA Contributors
For a two week period during the Joint European Torus (JET) 2012 experimental campaign, the same high confinement plasma was repeated 151 times. The dataset was analysed to produce a probability density function (pdf) for the waiting times between edge-localised plasma instabilities (“ELMs”). The result was entirely unexpected. Instead of a smo…
PublishedE. Havlícková W. Fundamenski M. Wischmeier G. Fishpool A.W. Morris
One of the first studies of MAST Upgrade divertor configurations with SOLPS5.0 are presented. We focus on understanding main prospects associated with the novel geometry of the Super-X divertor (SXD). This includes a discussion of the effect of magnetic flux expansion and volumetric power losses on the reduction of target power loads, the effect of…
PublishedS.N. Gerasimov T.C. Hender J. Morris V. Riccardo L.E. Zakharov JET EFDA Contributors
A key feature of disruptions during Vertical Displacement Events (VDEs), discovered in JET in 1996, is the toroidal variation in the measured plasma current Ip, i.e. the plasma current asymmetries, lasting for almost the entire current quench. The unique magnetic diagnostics at JET (full set of poloidal coils and saddle loops recorded either from t…
PublishedM. Kovari R. Kemp H. Lux P. Knight J. Morris D.J. Ward
PROCESS is a reactor systems code – it assesses the engineering and economic viability of a hypothetical fusion power station using simple models of all parts of a reactor system, from the basic plasma physics to the generation of electricity. It has has been used for many years, but details of its operation have not been previously published. Th…
PublishedC. D. Warrick R. J. Buttery G. Cunningham S. J. Fielding T. C. Hender B. Lloyd A.W. Morris M. R. O’Brien T. Pinfold K. Stammers M. Valovic M. Walsh,* H. R. Wilson Compass-D Rf Teams
Lower hybrid current drive (LHCD) with modest powers ( 10% of the total power input) has been used for the first time to completely stabilize performance limiting neoclassical tearing modes in many COMPASS-D tokamak discharges. The stabilizing effect in these experiments is consistent with a reduction in the free energy available in the current pro…
PublishedParag Vyas Denis Mustafa A. William Morris
Theoretical and experimental work on the vertical position control system on the COMPASS-D tokamak is described. An analog proportional 1 derivative (P 1 D) system is currently used, and two important sources of disturbance are observed in the system. One source is 600-Hz noise from thyristor power supplies, and the other is impulselike disturbance…
PublishedA. W. Morris P. G. Carolan Fl Fitzpatrick T. C. Hender T. N. Todd
The question of the influence of nonaxisymmetric field perturbations on tokamaks is investigated. Recent experiments in the COMPASS-C tokamak [in Proceedings of the 15th Symposium on Fusion Technology, Utrecht (North-Holland, Amsterdam, 1989), Vol. 1, p. 3611 with externally applied helical fields reveal that magnetic islands do not appear until th…
Published