Simultaneous High- and Low-latitude Reconnection: ESR and DMSP Observations

We present EISCAT Svalbard Radar and DMSP observations of a double cusp during an interval of predominantly northward IMF on November 26, 2001. In the cusp region, the ESR dish pointing northward, recorded sunward ionospheric flow at high latitudes (above 81GLAT) indicating that reconnection takes place in the magnetospheric lobe. Meanwhile, the same dish also recorded bursts of poleward flow, indicative of bursty reconnection at the subsolar magnetopause. Within this time interval, the DMSP F13 satellite passed in the close vicinity of the Svalbard archipelago. The particle measurement on board reveals a double cusp structure in which two oppositely oriented ion dispersions are recorded. We interpret this set of data in terms of simultaneous merging at low- and high-latitude magnetopause. We shall discuss the conditions that fulfill the anti-parallelism criterion between the Interplanetary Magnetic Field and the Earth's magnetic field lines at both reconnection sites. We also shall discuss the consequences of the presence of two X-lines in the dayside polar ionosphere.