  Evolution of the nonequilibrium inhomogeneities and topological defects is
studied in terms of complex kink solutions of the sine-Gordon equation. The
weakly damped oscillation of the sine-Gordon kink, named as the kink quasimode,
is described explicitly. It is shown that the oscillatory kink behavior and the
wave packet generation depend significantly on the initial nonequilibrium kink
profile. In order to specify conditions of the generation of wobbling kinks
with a multibreather structure we reformulate the direct scattering problem
associated with the SG equation as the spectral problem of the Schr\"odinger
operator. We obtain the dependence of the radiation energy, which is emitted
during formation of the multi-frequency wobbling kink, on the effective
dimension of its initial profile.
