We analytically derive the structures of the low-frequency shear Alfvén continuous spectrum due to resonant wave-particle interactions with magnetically trapped thermal particles in tokamaks. Our theoretical description asymptotically recovers known results in the relevant limits at both high and low frequencies; furthermore, it is relevant for assessing the accurate kinetic structures that are due to shear Alfvén and acoustic wave spectra in toroidal geometry. Since there is a continuous transition between various shear Alfvén wave and MHD fluctuation branches in many situations of experimental interest, the results reported in this work are of practical relevance for their interpretation when used in the theoretical framework of the general 'fishbone-like' dispersion relation. © 2009 IOP Publishing Ltd.
All Science Journal Classification (ASJC) codes
- Nuclear Energy and Engineering
- Condensed Matter Physics