Bursts of Pc 1-2 related to flux transfer events

Instances of sporadic reconnection of geomagnetic and interplanetary magnetic field lines have been measured by spacecraft passing through the dayside magnetopause region. The ionospheric signature of the reconnection events (flux transfer events) is a topic of current interest in that, if one is evident, then ground magnetic field data can be used to monitor the rate of dayside reconnection and conditions under which it occurs in a manner not possible with rapidly moving spacecraft. The proposed ground magnetic signature of a flux transfer event (FTE) is a large-amplitude one-cycle Pc 5 (150-600-sec period) pulse produced by a large vortex of ionospheric Hall current generated by the field-aligned current in the helix tube that has reconnected. This article provides additional data on the possible ground signatures of FTEs.