Basic processes of coherent whistler mode wave-particle interactions in the magnetosphere are studied by self-consistent computer simulations. The wave equations used in the simulation to determine the wave amplitude and frequency are discussed and physical interpretations of them are given. Nonlinear processes of the wave growth in a uniform magnetic field are examined in detail. Difference between uniform (periodic) and nonuniform (encounter) interactions is studied. Taking into account, the inhomogeneity of the dipole geomagnetic filled, we found that untrapped resonant electrons as well as trapped electrons play significant roles in the wave evolution. The roles of trapped and untrapped electrons are different and exchange their roles depending on the sign of the geomagnetic gradient. In the hemisphere where the whistler wave propagates toward the equator, trapped electrons cause wave growth, while untrapped resonant electrons cause wave damping. In the opposite hemisphere, these roles are exchange. Four simulations are carried out to demonstrate these differences separately.