  We have studied the nonlinear dynamics of whistler waves in magnetized
plasmas. Since plasmas and beam-plasma systems considered here are assumed to
be weakly collisional, the point of reference for the analysis performed in the
present paper is the system of hydrodynamic and field equations. We have
applied the renormalization group method to obtain dynamical equations for the
slowly varying amplitudes of whistler waves. Further, it has been shown that
the amplitudes of eigenmodes satisfy an infinite system of coupled nonlinear
Schr\"{o}dinger equations. In this sense, the whistler eigenmodes form a sort
of a gas of interacting quasiparticles, while the slowly varying amplitudes can
be considered as dynamical variables heralding the relevant information about
the system. An important feature of our description is that whistler waves do
not perturb the initial uniform density of plasma electrons. The plasma
response to the induced whistler waves consists in velocity redistribution
which follows exactly the behaviour of the whistlers. In addition, selection
rules governing the nonlinear mode coupling have been derived, which represent
another interesting peculiarity of our description.
