Plasma discontinuities in galaxy clusters
Sharp transitions in the plasma properties - shocks and tangential discontinuities - provide useful diagnostics of the underlying dynamics and energetics. I will discuss the search for
strong virial shocks around galaxy clusters, and the thermal and nonthermal signatures of weak merger shocks discovered in a handful of clusters. Most of the sharp edges in the intracluster medium were unexpectedly found to be tangential discontinuities. I will discuss
the constraints they impose on the flow and on the magnetic field.