Excitation of Alfvén waves in magnetized plasmas: the reversed-field pinch configuration case

In this thesis Alfven waves in different geometries are analyzed and characterized, comparing the theoretical models obtained from the ideal MHD model and the results of numerical simulations, performed with a non-linear 3D code, called SpeCyl. In particular, the configurations are analyzed with: uniform axial magnetic field and uniform density first and then a variable one; slightly variable magnetic filed, Tokamak-like, with uniform density; RFP-like magnetic field without the reversal of he field at the edge, with uniform density and various density profiles; finally, a realistic and dinamic RFP field, which evolves in time, with uniform and variable density. Thanks to the results obtained, the experimental spectra of the RFX-mod experiment, in which alfvenic fluctuations were observed in the discharges in the plasmas, were qualitatively compared and interpreted. The physical mechanism from which the experimentally observed Alfven waves originate and a possible identification between the observed and theoretical modes is provided: SAW, CAE, GAE.