MHD Spectroscopy through Detecting Toroidal Alfvén Eigenmodes and Alfvén Wave Cascades

Abstract Toroidal Alfven eigenmodes and a new class of modes, the Alfven cascades, excited by energetic ions are observed in the JET tokamak. Measurements of these Alfven instabilities are used to solve the inverse problem of identifying the plasma parameters using the dependence of the Alfven spectrum on equilibrium parameters.