  Aims: To model broad H-alpha wings observed in symbiotic binaries by an
optically thin, bipolar stellar wind from their hot components as an
alternative to that considering the Raman scattering of Ly-beta photons on
atomic hydrogen. Methods: Profile-fitting analysis. Comparison of the observed
broad H-alpha wings and their luminosity with those predicted by the model.
Results: Synthetic H-alpha profiles fit excellently the observed wings for |RV|
> 200 km/s in our sample of 10 symbiotic stars during the quiescent as well as
active phases. The wing profile formed in the stellar wind can be approximated
by a function f(RV) proportional to RVexp-2, which is of the same type as that
arising from the Raman scattering. Therefore it is not possible to distinguish
between these two processes only by modeling the line profile. Some
observational characteristics of the H-alpha emission suggest the ionized
stellar wind from the hot component to be the dominant source contributing to
the H-alpha wings during active phases. The model corresponding mass-loss rates
from the hot components are of a few x 10exp(-8) M(Sun)/yr and of a few x
(10exp(-7) - 10exp(-6)) M(Sun)/yr during quiescent and active phases,
respectively.
