  In this work, an implicit scheme for particle-in-cell/Fourier electromagnetic
simulations is developed and applied to studies of Alfv\'en waves in one
dimension and three-dimensional tokamak plasmas. An analytical treatment is
introduced to achieve efficient convergence of the iterative solution of the
implicit field-particle system. First, its application to the one-dimensional
uniform plasma demonstrates its applicability in a broad range of $\beta/m_e$
values. Second, toroidicity induced Alfv\'en eigenmodes (TAE) are simulated in
a three-dimensional axisymmetric tokamak plasma, using the widely studied case
defined by the International Tokamak Physics Activity (ITPA) Energetic Particle
(EP) Topical Group. The real frequency and the growth (or damping) rate of the
TAE with (or without) EPs agree with previous results reasonably well. The full
f electromagnetic particle scheme established in this work provides a possible
natural choice for EP transport studies where large profile variation and
arbitrary particle distribution functions need to be treated in kinetic
simulations.
