Themis-double star-cluster observations of reconnection and dynamics across the dayside magnetopause

Study of the operation and extent across the Earth´s magnetopause of fast magnetic reconnection (MR), the dominant process responsible for energy and plasma transport into the magnetosphere, has recently benefitted from an unprecedented growth in complexity of multi-point, in situ measurements, on the small and meso-scale, from Earth-bound space missions. Recent findings in active sites of MR have increased the theoretical understanding of the detailed structure within the ion diffusion region surrounding the magnetic X-line or null field. Nevertheless, direct measurements of this small region in space are still relatively rare, since clear spatial signatures are difficult, owing to the time variable nature of the near-Earth space environment.