Comparison of Polar and Equatorial Coronal Holes Observed by UVCS/SOHO: Geometry and Physical Properties
Dobrzycka, D.; Kohl, J.; Strachan, L.; Panasyuk, A.
United States
Abstract
We analyzed UVCS/SOHO data and compared the H I Lyα (121.6 nm) and O VI (103.2 nm, 103.7 nm) emission in the polar and equatorial coronal holes. We found that the emission lines have similar characteristics in these two types of coronal holes. Both types show evidence for superradially diverging boundaries. The latitudinal distribution of the O VI line ratio may indicate that the equatorial coronal hole has O+5 outflow velocities lower than in the polar coronal holes.