Theory of waves in Tokamaks

This work intends to present a theorical treatment of Alfven and geodesic wave behavior in tokamak plasma, showing their function on the viability study for the construction of a fusion reactor for energy production. The Tokamak is a toroidal chamber where the plasma stays confined under effects of a strong magnetic field where its can reach high temperature in necessary conditions for nuclear fusion. It is presented the behavior of Alfvén waves and deeper Geodesic Acoustic Modes. For Alfvén waves, it is described it\'s nature, a comum wave in any plasma under magnetic field, when properly perturbed, Alfvén waves can propagate on the magnetic field line, also it is presented possible applications. It\'s presented a theorical treatment where Alfvén modes in cilindrical coordinates, approximation for Tokamak with high aspect ratio. In Geodesic Acoustic Mode, GAM, driven by the todoidal curvature and symmetry of Tokamak, it is showed possible applications and a interaction with Alfvén waves. A perturbation that propagate in poloidal direction, symmetrical in toroidal direction, with toroidal number $N=0$ and poloidal number $M = 0, \\pm 1, \\pm 2 , ...$, a theorical treatment on rotation effects of electrons and ions in form of flux along the magnetic field line, on dispersion relation and instability of GAM is presented. In the end, it is presented a data analysis on COMPASS shoots, where is showed a possible qualitative correspondence between GAM dispersion and instabilities with the theory and experiment. (AU)