Geodesic acoustic eigenmode for tokamak equilibrium with maximum of local GAM frequency

• The global GAM for tokamak equilibrium with maximum of local GAM frequency is found.
• The eigenfrequency and the spatial structure of global GAM are calculated.
• The analytical results are underpinned by the results of numerical calculations.

The geodesic acoustic eigenmode for tokamak equilibrium with the maximum of local GAM frequency is found analytically in the frame of MHD model. The analysis is based on the asymptotic matching technique.