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Session 1 - Chromosphere, Corona, Flares.
Display session, Friday, June 27
Ballroom B, Chair: Charles Kankelborg
During the SOHO campaign dedicated to the Global Sun Study, the Ultraviolet Coronagraph Spectrometer (UVCS) has observed the corona at high spectral resolution (0.2 \AA) in several coronal UV lines within 1.5 and 4 solar radii. A complete high resolution observation of the extended corona was obtained in 12 days during August-September 1996. The high spectral resolution observations were aimed to characterize thermal and non-thermal velocity fields along the line--of--sight through the study of the broadening of spectral lines. The major result we obtained is that open field line regions, where we expect the high-speed solar wind flow, are characterized by O VI 1032 and HI Ly $\alpha$ 1216 lines which are broader than in equatorial and mid-latitude streamers. The effect is much more evident in the O VI line. Furthermore, the broadening enhancement in open field line regions is increasing with distance from Sun center.