We have identified four theta auroral events in Polar data that occurred in 1996. In terms of relative luminosities, there was a strong arc on September 6, two moderate arcs on November 1 and November 5, respectively, and a weak arc on May 7. During these events, the Kp index was 1+, 2-, 2, and 2, respectively, corresponding to relatively quiet geomagnetic conditions. In this section, we present detailed measurements for the November 5 and September 6 events whose data coverage are more complete. The other two events lack measurements from some of the instruments, and are summarized in less detail. Only the IMF measurements with time tags, indicating when theta auroral images are available from VIS, examples of auroral images and Hydra plasma data are presented for these two events.
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Shen-Wu Chang
Department of Physics and Astronomy, The University of Iowa, Iowa City, IA 52242
Phone:(319)335-3828; Fax:(319)335-1753;
swc@space-theory.physics.uiowa.edu