  Using the one-to-one correspondence between the Poynting vector in a
microwave billiard and the probability current density in the corresponding
quantum system probability densities and currents were studied in a microwave
billiard with a ferrite insert as well as in an open billiard. Distribution
functions were obtained for probability densities, currents and vorticities. In
addition the vortex pair correlation function could be extracted. For all
studied quantities a complete agreement with the predictions from the
random-superposition-of-plane-waves approach was obtained.
