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Session 80 - Solar Corona and Transition Region.
Oral session, Thursday, June 13
Wisconsin Center,

[80.04] The Solar Coronal Temperature Structure and the Heliospheric Current Sheet

R. C. Altrock (Phillips Lab. and NSO/Sac Peak), P. Hick, B. V. Jackson (UCSD/CASS), G. Slater (Lockheed Solar and Astrophysics Lab.), T. W. Henry (NSO/Sac Peak)

We explore the large-scale temperature structure of the low corona using synoptic temperature maps, derived from the intensity ratio of the green (Fe XIV) and red (Fe X) coronal lines as observed at the National Solar Observatory/Sacramento Peak, and temperature maps derived from the Al0.1 and AlMgMn filter intensity ratio measured by the Yohkoh/SXT instrument. The red/green intensity ratio is sensitive to coronal plasma with temperatures in the range of 1--2 MK and is therefore useful for studying the `quiet' corona. The Yohkoh/SXT filter ratio covers a much wider range of coronal temperature (\ge 1 MK) and, in particular, is sensitive to the high temperatures (\ge 3 MK) commonly observed above active regions. We use the temperature maps to study the evolution of the large-scale coronal temperature distribution, in particular in relation to the large-scale magnetic field, as given by the `source surface' maps derived from the Stanford potential field model. We find that the large-scale high-temperature features follow the heliospheric current sheet remarkably well, especially when the current sheet is stable over several rotations.

Program listing for Thursday