M. Fitzgerald J. Buchanan S. E. Sharapov V. G. Kiptily M. Sertoli G. Szepesi J. Boom R. Akers D. King JET contributors
Fishbones are ubiquitous in high-performance JET plasmas and are typically considered to be unimportant for scenario design. However, during recent high-performance hybrid experiments, sporadic and explosive fishbones have been observed which correlate with a reduction in performance and main chamber hotspots. Clear evidence has been obtained of fu…
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 PublishedV. G. Kiptily M. Fitzgerald V. Goloborodko S. E. Sharapov C. D. Challis D. Frigione J. Graves M. J. Mantsinen P. Beaumont M. Garcia-Munoz C. Perez von Thun J. F. R. Rodriguez D. Darrow D. Keeling D. King K. G. McClements E. Solano S. Schmuck G. Sips G. Szepesi JET contributors
During development of a high-performance hybrid scenario for future deuterium–tritium experiments on the Joint European Torus, an increased level of fast ion losses in the MeV energy range was observed during the instability of high-frequency n = 1 fishbones. The fishbones are excited during deuterium neutral beam injection combined with…
Preprint PublishedV. Aslanyan S. E. Sharapov D. A. Spong M. Porkolab
A nonlinear bump-on-tail model for the growth and saturation of energetic particle driven plasma waves has been extended to include two populations of fast particles - one dominated by dynamical friction at the resonance and the other by velocity space diffusion. The resulting temporal evolution of the wave amplitude and frequency depends on the re…
Preprint PublishedM. Fitzgerald S.E. Sharapov P. Rodrigues D. Borba
We use the HAGIS code to compute the nonlinear stability of the Q=10 ITER baseline scenario to toroidal Alfveneigenmodes (TAE) and the subsequent effects of these modes on fusion alpha-particle redistribution. Our calculations build upon an earlier linear stability survey [Rodrigues, P. et al. (2015). Nuclear Fusion, 55(8), 083003] which provides a…
Preprint PublishedO.M. Jones M. Cecconello K.G. McClements I. Klimek R.J. Akers W.U. Boeglin D.L. Keeling A.J. Meakins R.V. Perez S.E. Sharapov M. Turnyanskiy The MAST team
The results of a comprehensive investigation into the effects of toroidicity- induced Alfven eigenmodes (TAE) and energetic particle modes on the NBI-generated fast-ion population in MAST plasmas are reported. Fast-ion redistribution due to frequency-chirping TAE in the range 50 kHz to 100 kHz, and frequency-chirping energetic particle modes known …
Preprint PublishedI. Klimek M. Cecconello S. E. Sharapov J. Harrison G. Ericsson
On MAST, compressional Alfven eigenmodes can be destabilized by the presence of a sufficiently large population of energetic particles in the plasma. This dependence was studied in a series of very similar discharges in which increasing amounts of hydrogen were puffed into a deuterium plasma. A simple method to estimate the isotopic ratio nH/nD usi…
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…
PublishedH. Weisen A. C. C. Sips C. D. Challis L.-G. Eriksson S. E. Sharapov P. Batistoni L. D. Horton K.-D. Zastrow EFDA-JET Contributors
After the first high power D-T experiment in JET in 1997 (DTE1), when JET was equipped with Carbon PFC’s, a proposed second high power (up to ~40MW) D-T campaign (DTE2) in the current Be/W vessel will address essential operational, technical, diagnostics and scientific issues in support of ITER. These experiments are proposed to minimize the risk…
PublishedS.E. Sharapov B. Alper H.L. Berk D.N. Borba B.N. Breizman C.D. Challis I.G.J. Classen E.M. Edlund J. Eriksson A. Fasoli E.D. Fredrickson Et Al
Remarkable progress has been made in diagnosing energetic particle instabilities on present-day machines and in establishing a theoretical framework for describing them. This overview describes the much improved diagnostics of Alfven instabilities and modelling tools developed world-wide, and discusses progress in interpreting the observed phenomen…
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