Simultaneous measurements of polar cap electron distributions in opposite hemispheres

On January 16, 1983, the NOAA 6 and NOAA 7 satellites traversed polar cap auroral arcs in the northern hemisphere while the DMSP‐F6 satellite traversed similar polar cap arcs in the southern hemisphere. All of these encounters were in the morning local time sector and were made within 5 min in universal time of one another. The interplanetary magnetic field at this time had a strong northward B z . The satellite observations of auroral electrons indicated that the precipitation exhibited a high degree of similarity, indicating a linkage between the two hemispheres. In particular, the source electron distributions, inferred from the satellite observations of precipitating electrons, were identical to within experimental error. For the comparison made when the satellites were closest to the same magnetic local time‐invariant magnetic latitude locations and nearly simultaneous in universal time, the electron spectrums in the northern and southern hemispheres displayed a peak near 1 keV, suggesting a common source and a similar acceleration process for these electrons.