Toroidal Alfvén eigenmode stability in JET internal transport barrier afterglow experiments

Nuclear Fushion

article

F. Napoli¹  Ž. Štancar²  R. Dumont³  D. Keeling⁴  M. Fitzgerald⁴  S.E. Sharapov⁴  P. Siren⁵  E. Tholerus⁴  M. Dreval⁶  G. Szepesi⁴  P. Vallejos⁷  T. Johnson⁷  N. Fil⁴  J. Ferreira⁸  P. Rodrigues⁸  A. Figueiredo⁸  D. Borba⁸  R. Coelho⁸  F. Nabais⁸  J. Mailloux⁴  H.J.C. Oliver⁴  C. Di Troia¹ 

[1] ENEA, Fusion and Nuclear Safety Department;Jožef Stefan Institute;CEA;CCFE, Culham Science Centre;Department of Physics, University of Helsinki;National Science Centre ‘Kharkiv Institute of Physics and Technology’, Institute of Plasma Physics;Fusion Plasma Physics;Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa

关键词: JET;    D–T;    TAE;    alpha;    ITB;    afterglow;    stability;   

DOI  :  10.1088/1741-4326/ac84ee

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

In this work, we use reduced and perturbative models to examine the stability of toroidal Alfvén eigenmodes (TAEs) during the internal transport barrier (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 such as frequency and position. When ion cyclotron resonant heating (ICRH) is used to destabilize TAEs, the core-localised modes that are predicted to be most strongly driven by minority ICRH fast ions correspond to the modes observed in the DD experiments, and conversely, modes that are predicted to not be driven are not observed. Linear damping rates due to a variety of mechanisms acting during the afterglow are calculated, with important contributions coming from the neutral beam and radiative damping. For DT equivalent extrapolations of discharges without ICRH heating, we find that for the majority of modes, alpha drive is not sufficient to overcome radiative damping.

【 授权许可】

Unknown