M.A. Van Zeeland W.W. Heidbrink R.K. Fisher M. García Muñoz, G.J. Kramer D.C. Pace R.B. White S. Aekaeslompolo M.E. Austin J.E. Boom I.G.J. Classen S. Da Graça B. Geiger M. Gorelenkova N. N. Gorelenkov A. W. Hyatt N. Luhmann M. Maraschek G. R. McKee R. A. Moyer C. M. Muscatello R. Nazikian H. Park S. Sharapov W. Suttrop G. Tardini B. J. Tobias Y. B. Zhu DIII-D and ASDEX Upgrade Teams
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…
PublishedG. J. Kramer R. Nazikian B. Alper M. De Baar H. L. Berk G.-Y. Fu N. N. Gorelenkov G. Mckee S. D. Pinches T. L. Rhodes S. E. Sharapov W. M. Solomon M. A. Van Zeeland JET EFDA Contributors
Reversed shear Alfvén eigenmodes RSAE that were observed in the Joint European Torus (JET) [P. H. Rebut and B. E. Keen, Fusion Technol. 11 , 13 (1987)] and DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] are studied with the ideal magnetohydrodynamic code NOVA-K C. [Z. Cheng, Phys. Rep. 211 , 1 (1992)]. It was found that the frequency behavior …
PublishedJ. A. Snipes N. Basse C. Boswell E. Edlund A. Fasoli N. N. Gorelenkov R. S. Granetz L. Lin Y. Lin R. Parker M. Porkolab J. Sears S. Sharapov V. Tang S. Wukitch
Alfven eigenmodes (AEs) are studied to assess their stability in high density reactor relevant regimes. Stable AEs are excited with active magnetohydrodynamics antennas in the range of the expected AE frequency. Toroidal Alfven eigenmode (TAE) damping rates have been observed in diverted and limited Ohmic plasmas. Energetic particle modes or TAEs h…
PublishedG. J. Kramer S. E. Sharapov R. Nazikian N. N. Gorelenkov R.V. Budny
Experimental evidence is presented for the existence of the theoretically predicted odd toroidicity induced Alfve?n eigenmode (TAE) from the simultaneous appearance of odd and even TAEs in a normal shear discharge of the joint European torus. The modes are observed in low central magnetic shear plasmas created by injecting lower hybrid current driv…
PublishedR. Nazikian G. J. Kramer C. Z. Cheng N. N. Gorelenkov
The original description of alpha particle driven instabilities in the Tokamak Fusion Test Reactor in terms of toroidal Alfven eigenmodes (TAEs) remained inconsistent with three fundamental characteristics of the observations: (i) the variation of the mode frequency with toroidal mode number, (ii) the chirping of the mode frequency for a given toro…
Published