In the second magnetohydrodynamic (MHD) ballooning stable domain of a high-beta tokamak plasma, the Schrödinger equation for ideal MHD shear Alfvén waves has discrete solutions corresponding to standing waves trapped between pressure-gradient-induced potential wells. Our goal is to understand how these so-called α-induced toroidal Alfvén eigenmodes (αTAE) are modified by the effects of finite Larmor radii (FLR) and kinetic compression of thermal ions in the limit of massless electrons. In this paper, we neglect kinetic compression in order to isolate and examine in detail the effect of FLR terms. After a review of the physics of ideal MHD αTAE, the effect of FLR on the Schrödinger potential, eigenfunctions and eigenvalues is described with the use of parameter scans. The results are used in a companion paper to identify instabilities driven by wave–particle resonances in the second stable domain.
Theory and observations of high frequency Alfvén eigenmodes in low aspect ratio plasmas