THEORY OF IDEAL AND RESISTIVE M=1 MODES IN TOKAMAKS

A review of the present theoretical understanding of the linear stabil ity of internal m = 1 modes is presented and its connection to phenome na observed in toroidal magnetic confinement experiments, i.e. 'sawtoo th' and 'fishbone' oscillations, is discussed. Particular attention is devoted to the analysis of nonmagnetohydrodynamic (non-MHD) effects, such as those due to finite diamagnetic and electron drift frequencies and to finite ion Larmor radius, and to the special role played by en ergetic particles (whose response is primarily kinetic and which can s tabilize low frequency modes and destabilize new, higher frequency, br anches). Some recent developments in the non-linear theory of these mo des are also discussed. This review complements that of Kuvshinov and Savrukhin (Sov. J. Plasma Phys. 16 (1990) 353).