  New axisymmetric (2D) models for dust-driven winds of C-stars are presented
which include hydrodynamics with radiation pressure on dust, equilibrium
chemistry and time-dependent dust formation with coupled grey Monte Carlo
radiative transfer. Considering the most simple case without stellar pulsation
(hydrostatic inner boundary condition) these models reveal a more complex
picture of the dust formation and wind acceleration as compared to earlier
published spherically symmetric (1D) models. The so-called exterior
$\kappa$-mechanism causes radial oscillations with short phases of active dust
formation between longer phases without appreciable dust formation, just like
in the 1D models. However, in 2D geometry, the oscillations can be out-of-phase
at different places above the stellar atmosphere which result in the formation
of dust arcs or smaller caps that only occupy a certain fraction of the total
solid angle. These dust structures are accelerated outward by radiation
pressure, expanding radially and tangentially like mushroom clouds, while
dust-poor matter is falling back towards the star at other places. A highly
dynamical and turbulent dust formation zone is created in this way, which again
leads to inhomogeneous dust production. Further away from the star, flow
instabilities (e.g. Rayleigh-Taylor) have time to fragment the outward moving
arcs and shells to produce numerous small-scale cloud-like sub-structures.
