  The microscopic mechanism of circular currents induced in the vicinity of a
non-magnetic impurity is analyzed for the (time-reversal symmetry breaking)
chiral superconducting state ${\bf d}({\bf k}) = \hat{{\bf z}} (k_x \pm i k_y)$
which is very likely realized in Sr_2RuO_4. From the analytic, not
self-consistent solution of the Bogolyubov-de Gennes equations we find two
types of quasiparticle states, a bound state and the continuum state. Through
impurity scattering the condensate transfers angular momentum to the
quasiparticle states which generate a circular current. At low temperature the
continuum part of the quasiparticle spectrum gives the main contribution. The
non-selfconsistent solution yields a state of finite angular momentum. The
comparison with the corresponding Ginzburg-Landau theory reveals the existence
of a compensating counterflow created by the superconducting condensate. The
currents and magnetic fields appearing around the impurity have possibly been
observed by muon spin relaxation measurements.
