G P Maddison A E Hubbard J W Hughes J A Snipes B Labombard I M Nunes M N A Beurskens S K Erents M A H Kempenaars B Alper S D Pinches M Valovic R Pasqualotto A Alfier E Giovannozzi JET EFDA Contributors
Experiments on the Alcator C-Mod and JET tokamaks with identical values of nondimensional variables at the pedestal top are expected to have the same local plasma transport for a ratio > 4 in absolute size and thus can help to clarify other effects in pedestal formation. At the high and low fields (7.9 T, 1.4 T respectively) involved, natural-densi…
PublishedH Meyer R J Akers F Alladio L C Appel K B Axon N Ben Ayed P Boerner R J Buttery P G Carolan D Ciric C D Challis I T Chapman Et Al
Several improvements to the MAST plant and diagnostics have facilitated new studies advancing the physics basis for ITER and DEMO, as well as for future spherical tokamaks. Using the increased heating capabilities PNBI ≤ 3.8 MWH-mode at Ip = 1.2 MA was accessed showing that the energy confinement on MAST scales more weakly with Ip and more strong…
PublishedS. Dormido-Canto G. Farias J. Vega R. Dormido J. Sánchez N. Duro H. Vargas A. Murari JET-EFDA Contributors
The last flux surface can be used to identify the plasma configuration of discharges. For automated recognition of JET configurations, a learning system based on support vector machines has been developed. Each configuration is described by 12 geometrical parameters. A multiclass system has been developed by means of the one-versus-the-rest approac…
PublishedL. Cupido A. Cardinali R. Igreja F. Serra M. E. Manso A. Murari JET-EFDA Contributors
The measurement of the fuel mixture remains a very difficult task in thermonuclear plasmas, where the hydrogen isotopes are fully stripped and do not emit line radiation. On the other hand, direct determination of the ion species mix will be essential in the reactor to keep the mixture close to 50/50 and maximize the fusion output. In this paper, t…
PublishedR. J. Buttery R. J. La Haye P. Gohil G. L. Jackson H. Reimerdes E. J. Strait The Diii-D Team
Utilizing a capability to vary neutral beam torque injection in the DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] tokamak, m / n =2/1 neoclassical tearing mode onset thresholds are found to fall by about one unit in βN , from 3 to 2, in ITER-like sawtoothing high-energy confinement modes of plasma operation [R. Aymar, Plasma Phys. Control. Fu…
PublishedAnatoly V. Krasilnikov Mamiko Sasao Yuri A. Kaschuck Vasily G.Kiptily Takeo Nishitani Sergey V.Popovichev Luciano Bertalot
Due to high neutron and gamma-ray yields and large size plasmas many future fusion reactor plasma parameters such as fusion power, fusion power density, ion temperature, fuel mixture, fast ion energy and spatial distributions can be well measured by various fusion product diagnostics. Neutron diagnostics provide information on fusion reaction rate,…
PublishedRJ.E. Jaspers M.G. Von Hellermann E. Delabie J.E. Boom Aj.H. Donne W. Biel N.C. Hawkes O. Neubauer M. Di Maio S. Sadakov F. Klinkhamer B. Snijders A. Hogenbirk
Charge eXchange Recombination Spectroscopy (CXRS) will play a crucial role in the diagnosing of burning plasmas: items like helium ash, transport barriers, impurity content or fuel ratio can all be assessed with CXRS. In fact this is the only direct method to obtain information about the light impurity ions, such as temperature, concentrations and …
PublishedE. Tassi R. J. Hastie F. Porcelli
The linear stability of a class of force-free equilibria in cylindrical geometry is investigated. The class consists of cylindrically symmetric force-free equilibria for which the ratio between the parallel current density and the magnetic field is a step function of the radius. It is suggested that plasmas in reversed field pinches could be roughl…
PublishedP. Sandquist S. E. Sharapov P. Helander M. Lisak
A corrected relativistic collision operator is used to derive a Fokker-Planck equation for the distribution function of relativistic suprathermal electrons in a weakly relativistic plasma, which is then solved by a procedure similar to that employed in Connor and Hastie [Nucl. Fusion 15 , 415 (1975)]. Analytical expressions are derived for the elec…
PublishedPH. Lauber S. Günter M. Brüdgam A. Könies S.D. Pinches Asdex-Upgrade Team
The ability to predict the stability of fast-particle-driven Alfvén eigenmodes in burning fusion plasmas requires a detailed understanding of the dissipative mechanisms that damp these modes. In order to address this question, the linear gyro-kinetic, electromagnetic code L IGKA [1] is employed to investigate their behaviour in realistic tokamak g…
Published