  We investigate the effect of bulk velocity of the solar wind on the
propagation characteristics of ion-cyclotron waves (ICWs). Our model is based
on the kinetic theory. We solve the Vlasov equation for O VI ions and obtain
the dispersion relation of ICWs. Refractive index of the medium for a streaming
bi-Maxwellian velocity distribution proved to be higher than that of the
bi-Maxwellian velocity distribution. The bulk velocity of the solar polar
coronal holes' plasma increases the value of the refractive index by a factor
of 1.5 (3) when the residual contribution is included (neglected). The ratio of
the refractive index of interplume lanes to the plume lanes at the coronal base
is also higher than we found for the bi-Maxwellian velocity distribution, i.e.
$k_{interplume}/k_{plume}=2.5$.
