  This thesis discusses the influence of magnetic fields on the instability of
line-driven winds in O-stars and Wolf-Rayet stars. This combination is an
important concept to understand the strong, observed winds from Wolf-Rayet
stars. In the second part of the thesis a model is derived which describes the
wind outside the equatorial plane. This model allows to use the simple approach
of an ordinary differential equation instead of a 2-dim. partial differential
equation.
