Stable ellipticity-induced Alfven eigenmodes in the Joint European Torus
An external antenna excites stable eigenmodes in elongated Ohmically heated plasmas in the Joint European Torus (JET) [P.-H. Rebut, R. J. Bickerton, and B. E. Keen, Nucl. Fusion 25, 1011 (1985)]. The frequency of the modes (240-290 kHz) falls in the gap in the magnetohydrodynamic (MHD) continuum that is produced by ellipticity. Some modes are very weakly damped (gamma/omega < 10(-3)). (C) 1997 American Institute of Physics.