Cluster Observations of Antiparallel Magnetopause Reconnection
on the Dawnside Northern Flank Compared with MHD Simulations
S. Eriksson, S. R. Elkington, T. D. Phan, S. M. Petrinec, H. Reme, M. W. Dunlop, A. Balogh, R. E. Ergun, and M. Andre

We present detailed Cluster observations of magnetopause reconnection on 30 June 2001 suggesting the downtail passage of active X-lines over the spacecraft on the dawnside northern flank. Evidence consists of accelerated plasma flows both tailward and sunward that satisfies the Walen relation. Plasma density depletions relative to the magnetosheath are also observed during these jets that likely may be interpreted as the boundary layer inside the magnetopause. MHD simulations during this event suggest that Cluster traverses the magnetopause through a region of minimum magnetic field where antiparallel merging is predicted. The observed magnetic field shear in the locally tangential plane ranges between 171 and 177 degrees in good agreement with antiparallel merging.