P. Svensson O. Embreus S. L. Newton K. Särkimäki O. Vallhagen T. Fülöp
The electron runaway phenomenon in plasmas depends sensitively on the momentum space dynamics. However, efficient simulation of the global evolution of systems involving runaway electrons typically requires a reduced fluid description. This is needed for example in the design of essential runaway mitigation methods for tokamaks. In this paper, we p…
Preprint PublishedM.S. Anastopoulos Tzanis C.J. Ham P.B. Snyder H.R. Wilson
The poloidal harmonics of the toroidal normal modes of an unstable axisymmetric tokamak plasma are employed as basis functions for the minimisation of the 3D energy functional. This approach presents a natural extension of the perturbative method considered in [M.S. Anastopoulos Tzanis et al, Nuclear Fusion 59:126028, 2019]. This variational formul…
Preprint PublishedS. S. Henderson M. Bernert C. Giroud D. Brida M. Cavedon P. David R. Dux J. R. Harrison A. Huber A. Kallenbach J. Karhunen B. Lomanowski G. Matthews A. Meigs R. A. Pitts F. Reimold M. L. Reinke S. Silburn N. Vianello S. Wiesen M. Wischmeier
While current tokamak experiments are beginning to utilise real-time feedback control systems to manage the plasma exhaust, future tokamaks still require validation of theoretical models used to predict the threshold impurity concentration required to facilitate stationary divertor operation. This work exploits new spectroscopic measurements of …
Preprint PublishedF. Militello L. Aho-Mantila R. Ambrosino T. Body H. Bufferand G. Calabro’ G. Ciraolo D. Coster G. Di Gironimo P. Fanelli N. Fedorczak A. Herrmann P. Innocente R. Kembleton J. Lilburne T. Lunt D. Marzullo S. Merriman D. Moulton A. Nielsen J. Omotani G. Ramogida H. Reimerdes M. Reinhart P. Ricci F. Riva A. Stegmeir F. Subba W. Suttrop P. Tamain M. Teschke A. Thrysoe W. Treutterer S. Varoutis M. Wensing A. Wilde M. Wischmeier L.Y. Xiang
A thorough physics and engineering analysis of alternative divertor configurations is carried out by examining benefits and problems by comparing the baseline single null solution with a Snowflake, an X- and a Super-X divertor. It is observed that alternative configurations can provide margin and resilience against large power fluctuations, but the…
Preprint PurchaseA. Sperduti M. Cecconello S. Conroy A. Snicker
A discrepancy between predicted and measured neutron rates on MAST using TRANSP/NUBEAM was observed. Further causes of this discrepancy are here studied by means of TRANSP/NUBEAM and ASCOT/BBNBI simulations. Gyro-Orbit simulations resulted in an approximately 20 % reduction of the fast ion density compare to the Guiding Center with TRANSP/NUBEAM…
Preprint PublishedT. Long J.S. Allcock L. Nie R. M. Sharples M. Xu R. Ke S. Zhang S. A. Silburn J. Howard B. Yuan Y. Yu Z.H. Wang X.M. Song L. Liu
A Doppler coherence imaging spectroscopy diagnostic has been developed on the HL- 2A tokamak for scrape-off-layer impurity plasma flow measurements. Two- dimensional imaging of line-averaged C2+ flow in the high-field-side scrape off layer with time resolution up to 1 ms, has been achieved successfully by this system. The spatial angular resolut…
Preprint PublishedGuoliang Xia Yueqiang Liu L. Li C. J. Ham Z . Wang Shuo Wang
Effects of parallel and poloidal flows, as well as the flow shear, on the resistive wall mode (RWM) instability have been numerically investigated in toroidally rotating plasmas, utilizing a recently updated version of the MARS-F code (Liu Y Q et al 2000 Phys. Plasmas 7 3681). A significant difference between these flow…
Preprint PublishedK.L. van de Plassche J. Citrin C. Bourdelle Y. Camenen F. J. Casson V.I. Dagnelie F. Felici A. Ho JET Contributors
We present an ultrafast neural network (NN) turbulent tokamak transport model, QLKNN, for heat and particle fluxes. QLKNN is a surrogate model based on a database of 3 · 108 flux calculations of the quasilinear gyrokinetic transport model QuaLiKiz. To ensure accurate reproduction of the underlying model, we include known features of the…
Preprint PublishedCF Maggi H Weisen FJ Casson F Auriemma R Lorenzini H Nordman E Delabie F Eriksson J Flanagan D Keeling D King L Horvath S Menmuir A Salmi G Sips T Tala I Voitsekhovich JET Contributors
NBI-heated L-mode plasmas have been obtained in JET with the Be/W ITER-like wall (JET-ILW) in H and D, with matched profiles of the dimensionless plasma parameters in the plasma core confinement region and same Ti/Te and Zeff. The achieved isotope identity indicates that the confinement scale invariance principle is satisfied in the core confine…
Preprint Published