Observations of reconnected flux tubes within the midaltitude cusp

The paper presents three events interpreted as reconnected flux tubes that correspond to the extensions of FTEs which have penetrated deep into the magnetosphere down to the midaltitudes of the polar cusp. Low-energy plasma, high-energy plasma, magnetic fields, and electric fields are used to identify the signatures of reconnected flux tubes. Characteristics of spatial scale, time duration, and frequency of occurrence between flux transfer events and midaltitude cusp reconnected flux tubes are shown to be consistent, although they differ in the direction of motion. However, the merging cell topology and the interplanetary magnetic field effect can explain this difference. Larger-scale events can be explained by motion of the cusp resulting from a quasi-steady reconnection process. The field-aligned currents associated with reconnected flux tubes at midaltitudes within the cusp are shown to be consistent with twisting of magnetic field lines and with closure by Pedersen currents. It is considered possible that what appears to be field-aligned currents closing by Pedersen ionospheric currents may also be interpreted as currents carried by Alfven waves.