M. Fitzgerald R. Dumont D. Keeling J. Mailloux S. Sharapov M. Dreval A. Figueiredo R. Coelho J. Ferreira P. Rodrigues F. Nabais D. Borba Ž. Štancar G. Szepesi R.A. Tinguely N Fil P.G. Puglia H.J.C. Oliver V. Kiptily M. Baruzzo M. Lennholm P. Siren J. Garcia C.F. Maggi
A toroidal Alfven eigenmode (TAE) has been observed driven by alpha particles in the Joint European Torus (JET). The observation was made in dedicated deuterium-tritium experiments where radio-frequency (RF) heating was absent, in the so-called “afterglow” period when neutral beam heating was removed. Agreement with reduced and perturbative mod…
PreprintV.G.Kiptily Ye.O.Kazakov M.Nocente J.Ongena M.Dreval T.Craciunescu M.Fitzgerald L.Giacomelli V.Goloborodko D.Rigamonti A.V.Shevelev J.Garcia H.J.C.Oliver S.E.Sharapov Z.Stancar H. Weisen
Alfvén eigenmode (AE) instabilities driven by alpha-particles have been observed in D-3He fusion experiments on the Joint European Torus (JET) with the ITER-like wall (ILW). For the efficient generation of fusion alpha-particles from D-3He fusion reaction, the 3‑ion radio frequency (RF) scenario was used t…
Preprint PublishedN. Fil S.E. Sharapov M. Fitzgerald G.J. Choi Z. Lin R.A. Tinguely H.J.C. Oliver K.G. McClements P.G. Puglia R.J. Dumont M. Porkolab JET Contributors
Recent JET Deuterium experiments with an advanced internal transport barrier (ITB) scenario have been performed to clearly observe destabilised toroidicity-induced Alfvén eigenmodes (TAEs) by fast ions; interestingly, these also exhibit unstable electromagnetic (EM) perturbations in the sub-TAE frequency range. We identify such EM perturbations to…
Preprint PublishedM. Fitzgerald S. E. Sharapov P. Siren E. Tholerus M. Dreval G. Szepesi P. Olivares T. Jonsson N. Fil J. Ferreira P. Rodrigues A. Figueiredo D. Borba R. Coelho F. Nabais J. Mailloux H.J.C. Oliver C. Di Troia F. Napoli Z. Stancar R. Dumont D. Keeling
In this work, we use reduced and perturbative models to examine the stability of TAEs during the ITB afterglow in JET experiments designed for the observation of alpha driven TAEs. We demonstrate that in JET-like conditions, it is sufficient to use an incompressible cold plasma model for the TAE to reproduce the experimental adiabatic features…
PreprintV.G. Kiptily M. Fitzgerald Ye.O. Kazakov M. Nocente J. Ongena S.E. Sharapov M. Dreval Ž. Štancar T. Craciunescu J. Garcia L. Giacomelli V.Goloborodko J. Oliver H. Weisen
Dedicated experiments to generate high-energy D ions and D-3He fusion-born alpha particles have been performed at the Joint European Torus (JET) with the ITER-like wall (ILW). Deuterium ions from neutral beam injection (NBI) with acceleration voltage of 100 keV were accelerated to higher energies in the core of mixed D-3He…
Preprint PublishedIain Farquhar James Davies Oliver Crofts Tony Loving
One of the major challenge in the commercialisation of fusion is maintaining the powerplant reactor in a sufficiently short period of time to achieve commercial levels of plant availability. To inform the development of an appropriate remote maintenance strategy for EU DEMO, a simplified, parametric model, called the Maintenance Duration Estimator …
Preprint PublishedH. J. C. Oliver S. E. Sharapov B. N. Breizman A. K. Fontanilla D. A. Spong D. Terranova JET Contributors
Alfven eigenmodes driven by energetic particles are routinely observed in tokamak plasmas. These modes consist of poloidal harmonics of shear Alfven waves coupled by inhomogeneity in the magnetic field. Further coupling is introduced by 3D inhomogeneities in the ion density during the assimilation of injected pellets. This additional coupling modi…
Preprint PublishedOliver Crofts Antony Loving Richard Gowland Gregory Keech
The development of fusion as a viable power source is moving from the science driven design of experimental devices to the engineering design considerations required to develop a feasible power plant. An effective maintenance plan is essential because the time in maintenance is potentially very large. To be effective a maintenance plan must be o…
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 PublishedH.J.C. Oliver S.E. Sharapov R. Akers I. Klimek M. Cecconello The Mast Team
Compressional Alfven and ion-ion hybrid waves excited by energetic beam ions are studied in plasmas with two ion species. In our experiment, a hydrogendeuterium (H-D) plasma is used to produce instabilities similar to those likely to be present in the burning deuterium-tritium plasmas of future tokamaks. Modes are suppressed in the deuterium cyclot…
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