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2011
Neutral beam injection into reversed magnetic shear DIII-D and ASDEX Upgrade plasmas produces a variety of Alfvénic activity including toroidicity-induced Alfvén eigenmodes and reversed shear Alfvén eigenmodes (RSAEs). These modes are studied during the discharge current ramp phase when incomplete current penetration results in a high central sa…
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2011
The constructive interference effect described by Fuchs et al. [1] shows that the mode conversion and thereby the overall heating efficiency can be enhanced significantly when an integer number of fast wave wavelengths can be folded in between the high field side fast wave cutoff and the ion-ion hybrid layer(s) at which the ion Bernstein or ion cyc…
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2011
Intensities and detailed spectral shapes of γ-ray emission peaks were successfully reproduced using a physics model combining the kinetics of the reacting ions with a detailed description of the nuclear reaction differential cross sections for populating the L1-L8 14 N excitation levels yielding the observed γ-ray emission. The results provide a …
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2011
A steady-state tokamak reactor (SSTR) requires a high efficiency current drive system, from plug to driven mega-amps. RF systems working in the ion-cyclotron range of frequencies (ICRF) have high efficiency from plug to antenna but a limited current drive (CD) efficiency and centrally peaked CD profiles. The latter feature is not adequate for a SST…
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2011
The non-active operation phase of ITER will be done in H|4 He plasmas at half the nominal magnetic field, B 0 =2.65T. At this field|for the given frequency range of the ICRF system (f=40-55MHz), three ICRF heating scenarios are available a priori : (i) Fundamental ICRH of majority H plasmas at f?40MHz, (ii) second harmonic (N=2) 3 He ICRH in H plas…
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2009
A set of simulation/interpretation tools based on transmission line theory and on the RF model developed by M. Vrancken [2] has been developed to study the ITER-like Antenna (ILA) at JET. For given tuning element settings, the unique solution of the equations governing the ILA circuit requires solving a system of coupled linear equations relating t…
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2009
ITER and future superconducting fusion machines need efficient wall conditioning techniques for routine operation in between shots in the presence oi permanent high magnetic field for wall cleaning, surface isotope exchange and to control the in-vessel long term tritium retention. Ion Cyclotron Wall Conditioning (ICWC) based on the ICRF discharge i…
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2009
It has been suggested that radial transport in turbulent plasmas may be nonlocal and non-Markovian. In this paper the transport of test particles in the global, electromagnetic, three-dimensional code CUTIE [A. Thyagaraja and et al. , Phys. Plasmas 12 , 090907 (2005)] is characterized. This code includes a nonlinear feedback mechanism between the m…
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2008
The physics studies of the three “heating” systems that are installed on JET are reviewed. Results from the beginning of JET up to now are presented with some emphasis on the more recent ones. The systems were used not only for heating, where JET has laid the groundwork to qualify them for heating the next generation of machines to ignition, bu…
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2008
Small tokamaks may significantly contribute to the better understanding of phenomena in a wide range of fields such as plasma confinement and energy transport; plasma stability in different magnetic configurations; plasma turbulence and its impact on local and global plasma parameters; processes at the plasma edge and plasma-wall interaction; scena…
Showing 61 - 70 of 76 UKAEA Paper Results