Direct Measurement of the Damping of Toroidicity-Induced Alfvén Eigenmodes

Abstract

This Letter presents the first direct experimental measurements of the damping of toroidicity-induced Alfv\'en eigenmodes (TAE), carried out in the JET tokamak. These measurements were obtained during the first experiments to drive these modes with antennas external to a tokamak plasma. Different regimes corresponding to different dominant TAE absorption mechanisms with a wide range of damping rates, ${10}^{\ensuremath{-}3}\ensuremath{\le}\ensuremath{\gamma}/\ensuremath{\omega}\ensuremath{\le}{10}^{\ensuremath{-}1}$, have been identified in Ohmically heated plasma discharges.