@article{25a1f5c963e94a34b84b4496c18d07c4,
title = "Modelling of beam-driven Alfv{\'e}n modes in TJ-II plasmas",
abstract = "The properties of hydrogen neutral beam injection driven Alfv{\'e}n eigenmodes (AEs) in the TJ-II flexible heliac are investigated using a reduced magnetohydrodynamic (MHD) model coupled to a realistic MHD equilibrium. The simulation results of AE frequency and radial localization are found to be broadly consistent with experimental observations. The simulation results show that an AE with the same poloidal and toroidal harmonics persists under small variations in on-axis iota values, which is consistent with the experimental observations. The corresponding wave-particle resonance maps suggest, for low bounce harmonics, the possibility of describing nonlinear evolution of the AEs in TJ-II by a sum of two ion populations with different weighting factors, one of which is dominated by drag and the other by diffusion. As the bounce harmonic increases, the resonance region starts to expand and can cover a significant area of the particle phase space until this resonance region vanishes at high bounce harmonics.",
keywords = "Alfv{\'e}n eigenmodes (AEs), drag and diffusion of fast ions, modelling of Alfv{\'e}nic instabilities, steady and chirping modes",
author = "Allah Rakha and Mantsinen, {M. J.} and Melnikov, {A. V.} and Sharapov, {S. E.} and Spong, {D. A.} and A. L{\'o}pez-Fraguas and F. Castej{\'o}n and A. Guti{\'e}rrez-Mill{\'a} and {De Pablos}, {J. L.} and X. S{\'a}ez",
note = "Publisher Copyright: {\textcopyright} EURATOM 2019.",
year = "2019",
month = mar,
day = "14",
doi = "10.1088/1741-4326/ab0030",
language = "English",
volume = "59",
journal = "Nuclear Fusion",
issn = "0029-5515",
publisher = "IOP Publishing",
number = "5",
}
