THE AURORA DURING THE PASSAGE OF THE MAY 27, 1996 MAGNETIC CLOUD

On May 27, 1996 two all-sky cameras in Antarctica observed the aurora during the passage of a magnetic cloud. Compression of the magnetosphe re by the solar wind dynamic pressure pulse in front of the magnetic c loud caused a short, strong, and localized blue auroral emission which moved towards noon in the late morning sector. The emission was cause d by electrons of 8 keV energy. The high dynamic pressure caused a dif fuse large-scale (at least 3 h MLT and 50 latitude) blue emission on c losed field lines. The high energy electron precipitation disappeared after the enhanced solar wind dynamic pressure region had passed the s ub-solar magnetopause.