  Kinetic instabilities in weakly collisional, high beta plasmas are
investigated using two-dimensional hybrid expanding box simulations with
Coulomb collisions modeled through the Langevin equation (corresponding to the
Fokker-Planck one). The expansion drives a parallel or perpendicular
temperature anisotropy (depending on the orientation of the ambient magnetic
field). For the chosen parameters the Coulomb collisions are important with
respect to the driver but are not strong enough to keep the system stable with
respect to instabilities driven by the proton temperature anisotropy. In the
case of the parallel temperature anisotropy the dominant oblique fire hose
instability efficiently reduces the anisotropy in a quasilinear manner. In the
case of the perpendicular temperature anisotropy the dominant mirror
instability generates coherent compressive structures which scatter protons and
reduce the temperature anisotropy. For both the cases the instabilities
generate temporarily enough wave energy so that the corresponding (anomalous)
transport coefficients dominate over the collisional ones and their properties
are similar to those in collisionless plasmas.
