  Magnetic reconnection is one of the most universal processes in space plasma
that is responsible for charged particle acceleration, mixing and heating of
plasma populations. In this paper we consider a triggering process of
reconnection that is driven by interaction of two discontinuities: solar wind
rotational discontinuity and tangential discontinuity at the Earth's
magnetospheric boundary, magnetopause. Combining the multispacecraft
measurements and global hybrid simulations, we show that solar wind
discontinuities may drive the magnetopause reconnection and cause the mixing of
the solar wind and magnetosphere plasmas around the magnetopause, well
downstream of the solar wind flow. Since large-amplitude discontinuities are
frequently observed in the solar wind and predicted for various stellar winds,
our results of reconnection driven by the discontinuity-discontinuity
interaction may have a broad application beyond the magnetosphere.
