Anatomy of a flux transfer event seen by Cluster



[1] Data from Cluster are used to study the structure of a flux transfer event (FTE), seen near the northern cusp. We employ Grad-Shafranov reconstruction, using measured fields from all four spacecraft to produce a map of the FTE cross section. The FTE consists of a flux rope of approximate size 1RE and irregular shape, embedded in the magnetopause. Its axis equation image is tangential to the magnetopause. Since no reconnection signatures are seen, the map provides a fossil record of the prior reconnection process that created the flux rope: the strong core field indicates that it was generated by component merging. An average reconnection electric field ≥0.18 mV/m must have occurred in the burst of reconnection that created the FTE. The total axial (equation image) current and magnetic flux in the FTE were −0.66 MAmp and +2.07 MWeber, respectively.