A discrete-timeWigner distribution is used to yield a time-frequency representation of nonstationary magnetic activity at the edge of a tokamak plasma, thereby contributing to the magnetohydrodynamic analysis of the underlying phenomena, more precisely, to the identification of toroidal Alfvén eigenmodes. Index Terms- Fusion plasmas, magnetohydrodynamics, time-frequency analysis, toroidal Alfvén eigenmodes, Wigner distributions.