  Solar wind plasma at the Earth's orbit carries transient magnetic field
structures including discontinuities. Their interaction with the Earth's bow
shock can significantly alter discontinuity configuration and stability. We
investigate such an interaction for the most widespread type of solar wind
discontinuities - rotational discontinuities (RDs). We use a set of in situ
multispacecraft observations and perform kinetic hybrid simulations. We focus
on the RD current density amplification that may lead to magnetic reconnection.
We show that the amplification can be as high as two orders of magnitude and is
mainly governed by three processes: the transverse magnetic field compression,
global thinning of RD, and interaction of RD with low-frequency electromagnetic
waves in the magnetosheath, downstream of the bow shock. The first factor is
found to substantially exceed simple hydrodynamic predictions in most observed
cases, the second effect has a rather moderate impact, while the third causes
strong oscillations of the current density. We show that the presence of
accelerated particles in the bow shock precursor highly boosts the current
density amplification, making the postshock magnetic reconnection more
probable. The pool of accelerated particles strongly affects the interaction of
RDs with the Earth's bow shock, as it is demonstrated by observational data
analysis and hybrid code simulations. Thus, shocks should be distinguished not
by the inclination angle, but rather by the presence of foreshocks populated
with shock reflected particles. Plasma processes in the RD-shock interaction
affect magnetic structures and turbulence in the Earth's magnetosphere and may
have implications for the processes in astrophysics.
