Solar Physics Division Meeting 2000, June 19-22
Session 2. Corona, Solar Wind, Flares, CMEs, Solar-stellar, Instrumentation, Other
Display, Chair: J. Krall, Monday-Thursday, June 19, 2000, 8:00am-6:00pm, Forum Ballroom

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[2.32] UVCS/SOHO Observations of Equatorial and Polar Coronal Holes

J. L. Kohl, M. P. Miralles, S. R. Cranmer, R. M. Suleiman (Harvard-Smithsonian CfA)

A large equatorial coronal hole was observed above the west limb with the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO from November 1999 to March 2000. Observations in H I Ly\alpha and O VI 103.2, 103.7 nm provided spectroscopic diagnostics of proton and O5+ velocity distributions and outflow velocities. These properties will be compared to those of the large polar coronal holes observed near solar minimum. The equatorial coronal hole corresponded to a high-speed solar wind stream at 1 AU, but there were significant differences between the interplanetary properties of this stream and the steady high-speed wind seen over the poles at solar minimum. The several obvious differences between the two structures in the extended corona may be associated with the different densities and magnetic field configurations and flux tube expansion factors. Preliminary results from a detailed empirical model of the equatorial coronal hole will be presented.

This work is supported by NASA under Grant NAG5-7822 to the Smithsonian Astrophysical Observatory, by the Italian Space Agency and by PRODEX (Swiss contribution).

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